CN101872964B

CN101872964B - Wide area measurement system based back-up protection method of multi-terminal high-voltage power transmission area

Info

Publication number: CN101872964B
Application number: CN201010217048XA
Authority: CN
Inventors: 马静; 王增平; 林富洪; 曾惠敏; 叶东华
Original assignee: North China Electric Power University
Current assignee: North China Electric Power University
Priority date: 2010-07-02
Filing date: 2010-07-02
Publication date: 2013-01-09
Anticipated expiration: 2030-07-02
Also published as: CN101872964A

Abstract

The invention discloses a backup protection method for a multi-terminal high-voltage transmission area based on a wide-area measurement system, which belongs to the technical field of electric power system relay protection. Utilize the wide-area measurement system in the multi-terminal high-voltage transmission area, and realize the backup protection of the multi-terminal high-voltage transmission area based on wide-area information by adding a centralized decision-making server and a remote control execution system, and synchronize the voltage and current phasors of the nodes equipped with phasor measurement units Real-time measurement, through the calculation and analysis of the main station and wide-area backup protection server, accurately determine the specific fault phase and fault line, and issue control commands to the execution sub-stations of each line in the area. In the present invention, by adding a centralized decision-making server and a remote control execution system, a decision can be made within 200 milliseconds at most and delivered to each execution sub-station, so as to realize the backup protection of the multi-terminal high-voltage transmission area based on wide-area information, and avoid protection errors due to faults. Actions that cause large-scale power outages.

Description

Multi-terminal high-voltage transmission area backup protection method based on wide-area measurement system

技术领域 technical field

本发明属于电力系统继电保护技术领域，具体地说是涉及一种基于广域测量系统的多端高压输电区域的后备保护方法。The invention belongs to the technical field of electric power system relay protection, and in particular relates to a backup protection method for a multi-terminal high-voltage transmission area based on a wide-area measurement system.

背景技术 Background technique

电网发生故障后，电力系统中的线路保护用于实现对故障线路的自动和快速切除并隔离故障，以保证人身和设备安全以及无故障部分的正常运行。线路的主保护根据线路的就地信息，在故障时即刻跳开就地断路器，切除就地线路，隔离故障。线路的后备保护用于在线路主保护失灵或线路断路器失灵的情况下，跳开本地或其他线路的断路器实现线路故障的隔离。然而，随着电网结构日趋复杂，运行方式日益灵活，基于本地信息来进行决策和判断的传统后备保护存在着诸多缺陷：①后备保护配合关系复杂，动作时间长，严重时有可能不满足系统稳定性所要求的极限切除时间，进而成为大电网的安全隐患；②后备保护配置与整定的难度大，且不能跟踪系统运行方式的变化，甚至有可能出现保护失配或灵敏度不足的情况；③当运行方式变化时，为保证远后备保护的选择性，定值计算工作量巨大，在超高压电网中甚至有可能无法配合；每一元件上往往配置多种后备保护，使得保护构成复杂，成本增加。因此，在复杂电网环境下，审视后备保护存在的问题，研究新的后备保护原理与配置方案是保障电网安全的重要内容。After a fault occurs in the power grid, the line protection in the power system is used to automatically and quickly remove the faulty line and isolate the fault, so as to ensure the safety of people and equipment and the normal operation of the non-faulty part. According to the local information of the line, the main protection of the line immediately trips the local circuit breaker in case of a fault, cuts off the local line, and isolates the fault. The back-up protection of the line is used to trip the circuit breaker of the local or other lines to isolate the line fault when the main protection of the line fails or the circuit breaker fails. However, as the power grid structure becomes more complex and the operation mode becomes more flexible, the traditional backup protection based on local information for decision-making and judgment has many defects: ①The backup protection coordination relationship is complex and the action time is long, which may not meet the requirements of system stability in severe cases ②The configuration and setting of backup protection is very difficult, and it cannot track the change of system operation mode, and there may even be protection mismatch or insufficient sensitivity; ③When When the operation mode changes, in order to ensure the selectivity of the remote backup protection, the calculation workload of the fixed value is huge, and it may not even cooperate in the ultra-high voltage power grid; each component is often equipped with multiple backup protections, which makes the protection structure complicated and the cost increases . Therefore, in the complex power grid environment, examining the existing problems of backup protection and researching new backup protection principles and configuration schemes are important contents to ensure the security of the power grid.

高压输电线路是电网正常运行的大动脉，既担负着传送巨大功率的任务，又是各大电网联网运行的纽带，其运行可靠性影响着整个电网的供电可靠性，同时又是电力系统中发生故障最多的地方。若后备保护误切除正常高压线路，将导致该线路上大量功率发生转移，进而容易引起其他线路上后备保护因被保护线路过负荷而误动，从而加速系统崩溃，导致大面积长时间停电事故的发生。2003年8月14日的美加大停电事故就是由于美国俄亥俄州北部Akron到Cleveland之间的4条联络线因过负荷被后备保护切除而快速扩展。2006年7月1日，500kV嵩山至郑州两回输电线路因故障后保护误动相继切除，直接造成豫西、豫中多条220kV线路因过载而被后备保护切除，导致豫西大停电。因此，研究主干高压输电区域广域后备保护原理具有重要的实践意义。The high-voltage transmission line is the main artery of the normal operation of the power grid. It is not only responsible for the task of transmitting huge power, but also the link for the network operation of the major power grids. Its operation reliability affects the reliability of the power supply of the entire power grid. most places. If the backup protection accidentally cuts off the normal high-voltage line, it will cause a large amount of power to be transferred on this line, which will easily cause the backup protection on other lines to malfunction due to the overload of the protected line, thereby accelerating the system collapse and causing large-scale long-term power outages. occur. The blackout in the United States and Canada on August 14, 2003 was due to the rapid expansion of the four connection lines between Akron and Cleveland in northern Ohio, USA, due to overload being cut off by backup protection. On July 1, 2006, two 500kV Songshan-Zhengzhou transmission lines were disconnected one after another due to faulty protection malfunctions, which directly caused multiple 220kV lines in western Henan and central Henan to be disconnected by backup protection due to overload, resulting in a major power outage in western Henan. Therefore, it is of great practical significance to study the principle of wide-area backup protection in trunk high-voltage transmission areas.

随着广域同步相量测量技术的出现以及计算机处理能力的提高，使得集中获得区域电网多点的同步电气量，并进行集中分析决策成为可能。本发明将利用多端高压输电区域的广域测量系统，通过增加集中决策服务器以及远方控制执行系统实现基于广域信息的多端高压输电区域的后备保护。避免因为故障后保护误动作而造成大面积停电的故障。With the emergence of wide-area synchronized phasor measurement technology and the improvement of computer processing capabilities, it is possible to centrally obtain the synchronized electrical quantities of multiple points in the regional power grid and conduct centralized analysis and decision-making. The present invention utilizes the wide-area measurement system of the multi-terminal high-voltage power transmission region, and realizes the backup protection of the multi-terminal high-voltage power transmission region based on wide-area information by adding a centralized decision-making server and a remote control execution system. Avoid faults caused by large-area power outages due to faulty post-fault protection malfunctions.

发明内容 Contents of the invention

本发明的目的在于提供一种基于广域测量系统的多端高压输电区域后备保护方法，利用多端高压输电区域的广域测量系统，通过增加集中决策服务器以及远方控制执行系统实现基于广域信息的多端高压输电区域后备保护。The purpose of the present invention is to provide a backup protection method for a multi-terminal high-voltage transmission area based on a wide-area measurement system. Using the wide-area measurement system for a multi-terminal high-voltage transmission area, the multi-terminal information based on wide-area information is realized by adding a centralized decision-making server and a remote control execution system. Backup protection for high-voltage transmission areas.

本发明的目的是通过以下技术方案实现：The purpose of the present invention is to realize through the following technical solutions:

首先利用多端高压输电区域现有的广域测量系统实现对该区域所有安装有相量测量单元节点的电压、电流相量的同步实时量测，经WAMS主站及广域后备保护服务器的计算分析，准确确定具体的故障相和故障线路，并下发控制命令到该区域内各线路的执行子站。具体步骤如下：First, use the existing wide-area measurement system in the multi-terminal high-voltage transmission area to realize the synchronous real-time measurement of the voltage and current phasors of all nodes installed with phasor measurement units in the area, and calculate and analyze through the WAMS master station and the wide-area backup protection server , accurately determine the specific fault phase and fault line, and issue control commands to the execution substations of each line in the area. Specific steps are as follows:

(1)制定相量测量单元配置方案，各相量测量单元实时量测安装点处的电压、电流相量，根据实时量测的电压、电流相量计算得到电压、电流的幅值和相位，并把幅值、相位计算结果以及断路器位置、刀闸位置等状态量及相应时刻的时标通过通信网络上送到主站的相量数据集中器；(1) Formulate the configuration plan of the phasor measurement unit, each phasor measurement unit measures the voltage and current phasor at the installation point in real time, and calculates the amplitude and phase of the voltage and current according to the real-time measured voltage and current phasor, And send the amplitude, phase calculation results, circuit breaker position, knife switch position and other state quantities and the time scale of the corresponding time to the phasor data concentrator of the master station through the communication network;

(2)广域后备保护服务器获取上述(1)上送到主站相量数据集中器的数据进行计算分析，采用广域电流差动保护检测保护区内是否发生故障，若发现保护区域内发生故障，则确定具体的故障相别和过渡电阻情况，并根据故障线路选择方法准确确定故障线路；当确定故障线路和故障相别后，主站立刻向故障线路上的执行子站发出跳闸命令；(2) The wide-area backup protection server obtains the data sent to the main station phasor data concentrator in the above (1) for calculation and analysis, and uses wide-area current differential protection to detect whether a fault occurs in the protection area. If there is a fault, determine the specific fault phase difference and transition resistance, and accurately determine the fault line according to the fault line selection method; when the fault line and fault phase difference are determined, the master station immediately sends a trip command to the execution sub-station on the fault line;

(3)利用通讯系统和主站判断决策系统的固有延迟，实现线路传统主保护、线路传统后备保护与基于广域测量系统的多端高压输电区域后备保护的时间配合。(3) Utilize the inherent delay of the communication system and the judgment and decision-making system of the main station to realize the time coordination of the traditional main protection of the line, the traditional backup protection of the line and the backup protection of the multi-terminal high-voltage transmission area based on the wide-area measurement system.

本发明提出的广域线路后备保护系统的主要特征如下：The main features of the wide-area line backup protection system proposed by the present invention are as follows:

(1)所述多端高压输电区域是一条由外端口配置相量测量单元、内部不配置相量测量单元且含多个支路的输电线路即类似T形输电线路，或者是由配置相量测量单元节点所围成的包含多条输电线路的电网区域，该区内母线节点未配置相量测量单元。(1) The multi-terminal high-voltage transmission area is a transmission line with a phasor measurement unit configured on the outer port, no phasor measurement unit inside and multiple branches, that is, a T-shaped transmission line, or a phasor measurement unit configured The grid area surrounded by unit nodes contains multiple transmission lines, and the bus nodes in this area are not equipped with phasor measurement units.

(2)多端高压输电区域的相量测量单元配置方案指在多端高压输电区域最外围各变电站配置相量测量单元，多端高压输电区域内部各变电站不配置相量测量单元。(2) The phasor measurement unit configuration scheme in the multi-terminal high-voltage transmission area refers to the configuration of phasor measurement units in the outermost substations of the multi-terminal high-voltage transmission area, and the configuration of phasor measurement units in each substation inside the multi-terminal high-voltage transmission area.

(3)数据通信系统：通信网络采用电力数据以太网也可采用专线，实时采集的同步相量数据采用TCP协议传输，而主站广域后备保护服务器下发的控制命令采用UDP协议传输。测量数据到主站的延迟不超过150ms，控制命令发出到执行子站，延迟不超过50ms。(3) Data communication system: the communication network adopts power data Ethernet or dedicated line, the synchrophasor data collected in real time is transmitted by TCP protocol, and the control commands issued by the wide-area backup protection server of the master station are transmitted by UDP protocol. The delay from the measurement data to the master station is no more than 150ms, and the delay from the control command to the execution sub-station is no more than 50ms.

(4)广域后备保护功能：包括保护区内故障检测和故障支路选择，实现方法如下：(4) Wide-area backup protection function: including fault detection and fault branch selection in the protection area, the realization method is as follows:

a)广域后备保护决策服务器实时根据主站采集到的各相量测量单元安装点处的电压、电流相量，采用广域电流差动保护检测保护区内是否发生故障，当发现保护区域内发生故障则确定具体的故障相别和过渡电阻情况。a) The wide-area backup protection decision-making server uses the wide-area current differential protection to detect whether a fault occurs in the protection area according to the voltage and current phasors at the installation points of each phasor measurement unit collected by the main station in real time. If a fault occurs, determine the specific fault phase and transition resistance.

b)上述步骤(a)中的广域电流差动保护包括广域全电流差动保护和广域故障分量差动保护，二者相互补充用于承担多端高压输电区域的内部故障检测任务，其中，广域全电流差动保护指广域后备保护服务器对各相量测量单元上送的实时量测数据直接进行相序变换，选取多端高压输电区域的中心位置为参考点，基于分布参数模型，由多端高压输电区域的首末端各序分量分别向参考点推算得到参考点处的各序差动电流和各序制动电流，然后合成得到各相对应的差动电流和制动电流，最后利用比率制动特性构成全电流差动保护；广域故障分量电流差动保护指广域后备保护服务器计算各相量测量单元安装点处的正、负、零序电压故障分量和正、负、零序电流故障分量，选取多端高压输电区域的中心位置为参考点，基于分布参数模型，由多端高压输电区域的首末端各序故障分量分别向参考点推算得到参考点处的各序故障分量差动电流和各序故障分量制动电流，然后合成得到各相对应的故障分量差动电流和故障分量制动电流，最后利用比率制动特性构成故障分量电流差动保护。b) The wide-area current differential protection in the above step (a) includes wide-area full-current differential protection and wide-area fault component differential protection. The two complement each other to undertake the internal fault detection task of the multi-terminal high-voltage transmission area, where , Wide-area full-current differential protection means that the wide-area backup protection server directly performs phase sequence transformation on the real-time measurement data sent by each phasor measurement unit, and selects the center position of the multi-terminal high-voltage transmission area as the reference point. Based on the distributed parameter model, The differential currents and braking currents of each sequence at the reference point are calculated from the sequence components at the beginning and end of the multi-terminal high-voltage transmission area to the reference point, and then synthesized to obtain the corresponding differential currents and braking currents. Finally, use Ratio braking characteristics constitute full current differential protection; wide-area fault component current differential protection refers to the calculation of positive, negative and zero-sequence voltage fault components and positive, negative and zero-sequence voltage fault components at the installation points of each phasor measurement unit by the wide-area backup protection server For the current fault component, the center of the multi-terminal high-voltage transmission area is selected as the reference point. Based on the distributed parameter model, the differential current of each sequence fault component at the reference point is calculated from the first and last sequence fault components of the multi-terminal high-voltage transmission area to the reference point respectively. and the braking current of each sequence fault component, and then synthesize the corresponding fault component differential current and fault component braking current, and finally use the ratio braking characteristic to form the fault component current differential protection.

c)当检测到保护区域内发生故障，则根据故障线路选择方法准确确定故障线路，然后主站向故障线路的执行子站发送动作命令，向保护区内其他正常线路的执行子站发送闭锁命令，其中，故障线路选择方法指基于分布参数模型，由各端正序分量分别向参考端推算求出故障线路选择方程的解χ_IR(I＝1，…，N)，若χ_IR(I＝1，…，N)之间满足χ_1R＜χ_2R＜...＜χ_KR＜χ_K+1R＝...＝χ_NR，则_PK+1_PK线路故障；若χ_IR(I＝1，…，N)之间满足χ_1R＜χ_2R＜...χ_K-1R＜χ_K+1R＝...＝χ_NR＜χ_KR，则K_PK线路故障；其中R为参考端，N为多端高压区域最外围的节点总数。c) When a fault occurs in the protection area, the fault line is accurately determined according to the fault line selection method, and then the master station sends an action command to the execution sub-station of the fault line, and sends a blocking command to the execution sub-station of other normal lines in the protection area , wherein, the fault line selection method refers to based on the distribution parameter model, the positive sequence components of each end are respectively calculated to the reference end to obtain the solution χ _IR (I=1,...,N) of the fault line selection equation, if χ _IR (I=1 , ..., N) satisfy χ _1R <χ _2R <...<χ _KR <χ _K+1R =...=χ _NR , then _{the PK} +1 _PK line is faulty; if χ _IR (I=1,... , N) between χ _1R <χ _2R <...χ _K-1R <χ _K+1R =...=χ _NR <χ _KR , then the K _PK line is faulty; where R is the reference terminal and N is the multi-terminal The total number of nodes in the outermost periphery of the high pressure area.

d)上述步骤(c)中的故障线路选择方程指基于分布参数模型的双端线路同步故障测距方法，其表达式为

其中

χ_IR为由I端正序分量向参考端R推算得到的故障线路选择方程的解，

为参考端R的正序电压、电流；

为P₁节点到参考端R的距离；

为由I端正序分量向P₁节点推算得到的P₁节点电压、P₁节点出口电流；Z_c1、γ₁为输电线路正序波阻抗和传播常数。d) The fault line selection equation in the above step (c) refers to the double-ended line synchronous fault location method based on the distributed parameter model, and its expression is

in

χ _IR is the solution of the fault line selection equation calculated from the positive sequence component of terminal I to the reference terminal R,

is the positive sequence voltage and current of the reference terminal R;

is the distance from _P1 node to the reference terminal R;

_P1 node voltage and _P1 node outlet current calculated from the positive sequence component of terminal I to P1 node; Z _c1 and _γ1 are transmission line positive sequence wave _impedance and propagation constant.

上述在主站后备保护决策服务器中实现后备保护的计算分析时间不超高200ms。The calculation and analysis time for implementing the backup protection in the backup protection decision server of the main station is not more than 200ms.

(5)执行子站：执行子站的核心由与逻辑跳闸控制器构成，其输入是断路器的开合状态(开为0，合为1)和来自于广域后备保护主站的跳闸信号(正常为0，跳闸为1)，只有当断路器的开合状态和来自于广域后备保护主站的跳闸信号输入全为1时，与逻辑跳闸控制器输出为1，才跳开相应的线路断路器。(5) Execution sub-station: The core of the execution sub-station is composed of a logic trip controller, and its input is the opening and closing state of the circuit breaker (open is 0, closed is 1) and the trip signal from the wide-area backup protection master station (normal is 0, trip is 1), only when the open and close state of the circuit breaker and the trip signal input from the wide-area backup protection master station are all 1, and the output of the logic trip controller is 1, the corresponding circuit breaker will be tripped. circuit breaker.

本发明基于广域测量系统实现多端高压输电区域后备保护，最多可在200毫秒内做出决策并送达各执行子站。传统线路后备保护为了实现选择性而采取分段阶梯时延的方法，通常一级阶梯时延就需要500毫秒，多级时延可能高达数秒。因此，本发明动作速度慢于线路主保护，快于基于本地量决策的传统线路后备保护。从而，可在保留传统主干高压输电区域线路主保护和传统线路后备前提下，在二者之间增加一道新防线，即本发明所提出的基于广域测量系统的多端高压输电区域后备保护方法。The invention realizes the backup protection of the multi-terminal high-voltage transmission area based on the wide-area measurement system, and can make a decision within 200 milliseconds at most and send it to each execution sub-station. In order to achieve selectivity, traditional line backup protection adopts the step-by-step delay method. Usually, the delay of one step is 500 milliseconds, and the delay of multiple steps may be as high as several seconds. Therefore, the action speed of the present invention is slower than the line main protection, and faster than the traditional line backup protection based on local quantity decision-making. Therefore, under the premise of retaining the main protection of the traditional backbone high-voltage transmission area and the backup of the traditional line, a new line of defense can be added between the two, that is, the multi-terminal high-voltage transmission area backup protection method based on the wide-area measurement system proposed by the present invention.

附图说明 Description of drawings

图1为本发明中基于广域测量系统多端高压输电区域的后备保护总体方案示意图；Fig. 1 is a schematic diagram of the backup protection overall scheme based on the multi-terminal high-voltage transmission area of the wide-area measurement system in the present invention;

图2为本发明中主站和执行子站结构示意图；Fig. 2 is a schematic structural diagram of the master station and the execution sub-station in the present invention;

图3为本发明中基于广域测量系统多端高压输电区域后备保护功能计算分析示意图；Fig. 3 is a schematic diagram of the calculation and analysis of the backup protection function in the multi-terminal high-voltage transmission area based on the wide-area measurement system in the present invention;

图4a为本发明中P_K+1P_K线路故障时多端高压输电区域示意图；Figure 4a is a schematic diagram of a multi-terminal high-voltage power transmission area when the P _K+1 P _K line fails in the present invention;

图4b为本发明中KP_K线路故障时多端高压输电区域示意图；Figure 4b is a schematic diagram of the multi-terminal high-voltage transmission area when the KP _K line fails in the present invention;

图4c为本发明中P_HP_H-1线路故障时多端高压输电区域示意图；Figure 4c is a schematic diagram of the multi-terminal high-voltage transmission area when the P _H P _H-1 line fails in the present invention;

图4d为本发明中HP_H线路故障时多端高压输电区域示意图；Figure 4d is a schematic diagram of the multi-terminal high-voltage transmission area when the HP _H line fails in the present invention;

图5为本发明中P_K+1P_K线路故障时P_K+1P_K线路的正序序网图；Fig. 5 is the positive sequence sequence net figure of P _K+1 P _K circuit when P _K+1 P _K circuit fault among the present invention;

图6为P_K+1P_K支路、KP_K支路故障时χ_IR(I＝1，2，3，......，N)之间满足的关系；Fig. 6 satisfies the relation between χ _IR (I=1,2,3,...,N) when P _K+1 P _K branch, KP _K branch fault;

图7为5端高压输电单相模型示意图。Figure 7 is a schematic diagram of a 5-terminal high-voltage transmission single-phase model.

具体实施方式 Detailed ways

下面结合附图和实例对本发明作进一步详细的说明。Below in conjunction with accompanying drawing and example the present invention is described in further detail.

本发明的总体设计方案见图1所示。图1所示的多端高压输电区域可以是一条由外端口配置相量测量单元、内部不配置相量测量单元且含多个支路的输电线路即类似T形输电线路，或者是由配置相量测量单元节点所围成的包含多条输电线路的电网区域，该区内母线节点未配置相量测量单元。The overall design scheme of the present invention is shown in Figure 1. The multi-terminal high-voltage transmission area shown in Figure 1 can be a transmission line with a phasor measurement unit configured on the outer port, no phasor measurement unit inside and multiple branches, that is, a T-shaped transmission line, or a phasor configuration The grid area enclosed by the measurement unit nodes contains multiple transmission lines, and the bus nodes in this area are not equipped with phasor measurement units.

本发明的主站和执行子站的详细结构见图2所示。在多端高压输电区域设置广域后备保护主站，通常可利用现有的广域测量系统的通信网络和主站的数据集中处理单元。在被保护区域的最外围各变电站设置相量测量单元，被保护区域内各变电站不设置相量测量单元，并在被保护区域内各条线路设置执行子站。主站和子站之间通过电力系统的电力数据网或带宽的专用数据通道进行通信。建议对量测数据采用TCP协议传输，对控制命令采用UDP协议传输，以保证命令执行的快速性。The detailed structures of the master station and the execution sub-station of the present invention are shown in FIG. 2 . To set up a wide-area backup protection master station in a multi-terminal high-voltage transmission area, the existing communication network of the wide-area measurement system and the data centralized processing unit of the master station can usually be used. Set up phasor measurement units in the outermost substations of the protected area, and set up no phasor measurement units in each substation in the protected area, and set execution sub-stations in each line in the protected area. Communication between the master station and the sub-station is carried out through the power data network of the power system or a dedicated data channel with high bandwidth. It is recommended to use TCP protocol for transmission of measurement data and UDP protocol for control commands to ensure the rapidity of command execution.

多端高压输电广域后备保护的具体实现过程如下：The specific implementation process of multi-terminal high-voltage transmission wide-area backup protection is as follows:

(1)各相量测量单元每隔10ms进行一次相量计算，根据电压、电流的录波值计算得到电压、电流的幅值和相位，并把幅值和相位计算结果以及断路器位置、刀闸位置等状态量及相应时刻的时标通过网络上送到主站的相量数据集中器。(1) Each phasor measurement unit performs a phasor calculation every 10ms, and calculates the amplitude and phase of the voltage and current according to the recorded wave values of the voltage and current, and calculates the results of the amplitude and phase as well as the position of the circuit breaker, the knife State quantities such as the gate position and the time scale of the corresponding time are sent to the phasor data concentrator of the master station through the network.

(2)主站的相量数据集中器实现相量数据的接收，并通过实时数据库和历史数据库实现数据的存储、查询、调用和维护。广域测量系统主站的广域后备保护服务器以10ms为周期从实时数据库获取被保护区域的断面数据，采用广域电流差动保护检测保护区域内是否发生故障。若广域电流差动保护动作，说明被保护区域内存在故障，并准确确定具体的故障相别和过渡电阻大小情况。当发现并确定被保护区内发生故障后，采用故障选择方法准确确定具体的故障线路。然后，主站立刻向故障线路的执行子站的控制装置发出跳闸命令。本发明中主站后备保护决策服务器的计算分析见图3所示，具体实现过程如下：(2) The phasor data concentrator of the master station realizes the reception of phasor data, and realizes the storage, query, call and maintenance of data through real-time database and historical database. The wide-area backup protection server of the main station of the wide-area measurement system obtains the section data of the protected area from the real-time database at a period of 10ms, and uses the wide-area current differential protection to detect whether there is a fault in the protected area. If the wide-area current differential protection operates, it means that there is a fault in the protected area, and accurately determine the specific fault phase difference and the size of the transition resistance. When a fault is found and determined in the protected area, the fault selection method is used to accurately determine the specific fault line. Then, the master station immediately sends a trip command to the control device of the execution sub-station of the faulty line. The computing analysis of master station backup protection decision-making server among the present invention is shown in Fig. 3, and concrete realization process is as follows:

一、内部故障检测1. Internal fault detection

保护区域外围端节点编号时满足

且各节点编号为1，...，N。由N端电压

N端电流

推算P_N-1节点电压

和出口电流

根据式(1)算得。

\{\begin{matrix} {\overset{\cdot}{U}}_{P_{N - 1}} = {\overset{\cdot}{U}}_{N, P_{N - 1}} = {\overset{\cdot}{U}}_{N} \cosh γ_{1} l_{{N, P}_{N - 1}} - {\overset{\cdot}{I}}_{N} Z_{c 1} \sinh γ_{1} l_{{N, P}_{N - 1}} \\ {\overset{\cdot}{I}}_{{N, P}_{N - 1}} = {\overset{\cdot}{I}}_{N} \cosh γ_{1} l_{N, P_{N - 1}} - {\overset{\cdot}{U}}_{N} \sinh γ_{1} l_{N, P_{N - 1}} / Z_{c 1} \\ {\overset{\cdot}{I}}_{N - 1, P_{N - 1}} = {\overset{\cdot}{I}}_{N - 1} \cosh γ_{1} l_{N - 1, P_{N - 1}} - {\overset{\cdot}{U}}_{N - 1} \sinh γ_{1} l_{N - 1, P_{N - 1}} / Z_{c 1} \\ {\overset{\cdot}{I}}_{P_{N - 1}}^{'} = {\overset{\cdot}{I}}_{N, P_{N - 1}} + {\overset{\cdot}{I}}_{N - 1, P_{N - 1}} = {\overset{\cdot}{I}}_{P_{N - 1}} \end{matrix} - - - (1)

When the number of end nodes on the periphery of the protection area satisfies

And each node is numbered 1,...,N. By the N terminal voltage

N terminal current

Estimate the P _N-1 node voltage

and export current

Calculated according to formula (1).

\{\begin{matrix} {\overset{\cdot}{u}}_{P_{N - 1}} = {\overset{&Center Dot;}{u}}_{N, P_{N - 1}} = {\overset{\cdot}{u}}_{N} \cosh γ_{1} l_{{N, P}_{N - 1}} - {\overset{&Center Dot;}{I}}_{N} Z_{c} 1 \sinh γ_{1} l_{{N, P}_{N - 1}} \\ {\overset{&Center Dot;}{I}}_{{N, P}_{N - 1}} = {\overset{\cdot}{I}}_{N} \cosh γ_{1} l_{N, P_{N - 1}} - {\overset{\cdot}{u}}_{N} \sinh γ_{1} l_{N, P_{N - 1}} / Z_{c 1} \\ {\overset{&Center Dot;}{I}}_{N - 1, P_{N - 1}} = {\overset{\cdot}{I}}_{N - 1} \cosh γ_{1} l_{N - 1, P_{N - 1}} - {\overset{&Center Dot;}{u}}_{N - 1} \sinh γ_{1} l_{N - 1, P_{N - 1}} / Z_{c 1} \\ {\overset{\cdot}{I}}_{P_{N - 1}}^{'} = {\overset{&Center Dot;}{I}}_{N, P_{N - 1}} + {\overset{\cdot}{I}}_{N - 1, P_{N - 1}} = {\overset{&Center Dot;}{I}}_{P_{N - 1}} \end{matrix} - - - (1)

由P_N-1节点电压

P_N-1节点出口电流

推算P_N-2节点电压

和P_N-2节点出口电流

根据式(2)算得。by the P _N-1 node voltage

P _N-1 node outlet current

Estimate the P _N-2 node voltage

and P _N-2 node outlet current

Calculated according to formula (2).

$\{\begin{matrix} {\overset{\cdot \cdot}{U u}}_{{P P}_{N N - - 22}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{N N - - 11}} cosh cosh {γ γ}_{11} {l l}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} - - \\ {\overset{\cdot \cdot}{I I}}_{{P P}_{N N - - 11}}^{' '} {Z Z}_{c c 11} sin sin {γ γ}_{11} {l l}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} \\ {\overset{\cdot \cdot}{I I}}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} = = {\overset{\cdot \cdot}{I I}}_{{P P}_{N N - - 11}}^{' '} cosh cosh {γ γ}_{11} {l l}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} - - \frac{{\overset{\cdot &Center Dot;}{U u}}_{{P P}_{N N - - 11}}}{{Z Z}_{c c 11}} sinh sinh {γ γ}_{11} {l l}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} \\ {\overset{\cdot &Center Dot;}{I I}}_{N N - - 22,, {P P}_{N N - - 22}} = = {\overset{\cdot &Center Dot;}{I I}}_{N N - - 22} cosh cosh {γ γ}_{11} {l l}_{{N N - - 22,, P P}_{N N - - 22}} - - \frac{{\overset{\cdot &Center Dot;}{U u}}_{N N - - 22}}{{Z Z}_{c c 11}} sinh sinh {γ γ}_{11} {l l}_{N N - - 22,, {P P}_{N N - - 22}} \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{N N - - 22}}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{N N - - 11},, {P P}_{N N - - 22}} + + {\overset{\cdot &Center Dot;}{I I}}_{N N - - 22 {P P}_{N N - - 22}} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{N N - - 22}} \end{matrix} - - - - - - ((22))$

依次类推，推算出P_K+1节点电压P_K+1节点出口电流且满足 ${\overset{\cdot}{U}}_{P_{K + 1}} = {\overset{\cdot}{U}}_{P_{K + 2}, P_{K + 1}},$ ${\overset{\cdot}{I}}_{P_{K + 1}}^{'} = {\overset{\cdot}{I}}_{P_{K + 1}} .$ By analogy, the P _K+1 node voltage is calculated P _K+1 node outlet current and satisfied ${\overset{&Center Dot;}{u}}_{P_{K + 1}} = {\overset{&Center Dot;}{u}}_{P_{K + 2}, P_{K + 1}},$ ${\overset{&Center Dot;}{I}}_{P_{K + 1}}^{'} = {\overset{\cdot}{I}}_{P_{K + 1}} .$

其中，l_PK+1，PK表示线路P_K+1P_K之间的距离；r点为参考点；l_K，PK表示线路KP_K之间的距离。Among them, l _{PK+1, PK} represents the distance between lines P _K+1 P _K ; point r is a reference point; l _{K, PK} represents the distance between lines KP _K.

1)P_K+1P_K支路故障1) P _K+1 P _K branch fault

图4a为本发明中P_K+1P_K线路故障时多端高压输电区域示意图。图5为P_K+1P_K线路故障时P_K+1P_K线路的正序序网图。由P_K+1节点电压

出口电流

推算P_K节点电压

和出口电流

根据式(3)算得。Fig. 4a is a schematic diagram of the multi-terminal high-voltage transmission area when the P _K+1 P _K line is faulty in the present invention. Fig. 5 is a positive sequence sequence network diagram of the P _K+1 P _K line when the P _K+1 P _K line fails. By P _K+1 node voltage

export current

Estimated P _K node voltage

and export current

Calculated according to formula (3).

$\{\begin{matrix} {\overset{\cdot \cdot}{U u}}_{{P P}_{K K + + 11},, {P P}_{K K}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{K K}} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh {γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}})) \\ {\overset{\cdot \cdot}{I I}}_{{P P}_{K K}}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{K K + + 11},, {P P}_{K K}} + + {\overset{\cdot &Center Dot;}{I I}}_{K K,, {P P}_{K K}} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{K K}} + + {\overset{\cdot \cdot}{I I}}_{f f} cosh cosh {γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}})) \end{matrix} - - - - - - ((33))$

其中，

l_f表示故障点f距P_K+1节点的距离。in,

l _f represents the distance between the fault point f and the P _K+1 node.

依此类推，在参考点r处满足：And so on, at the reference point r satisfies:

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{τ τ},, r r}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{τ τ + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{τ τ},, r r}))]] \\ {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{τ τ},, r r} = = {\overset{\cdot &Center Dot;}{U u}}_{r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{T T},, r r}))]] \end{matrix} - - - - - - ((44))$

其中，

为P_T节点流向r点的实际电流，

为r点的实际电压。in,

is the actual current flowing from P _T node to point r,

is the actual voltage at point r.

同理，由R端电量向参考点r处推算可得

In the same way, it can be calculated from the power at the R terminal to the reference point r

又由于在参考点r处满足

所以此时在参考点r处(物理意义上r点为一高斯点)基于基尔霍夫电流定律构成广域电流差动保护，其制动量和差动量分别为And since at the reference point r satisfies

Therefore, at this time, at the reference point r (point r is a Gauss point in the physical sense), a wide-area current differential protection is formed based on Kirchhoff’s current law, and the braking amount and differential amount are respectively

${I I}_{Dr Dr.} = = | | {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r}^{' '} + + {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot \cdot}{I I}}_{f f 11} + + {\overset{\cdot &Center Dot;}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . .$

$- - {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{T T},, r r}))]] + + {\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{T T},, r r}))]] | |$

${I I}_{Br Br} = = | | {\overset{\cdot \cdot}{I I}}_{{P P}_{T T},, r r}^{' '} - - {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot \cdot}{I I}}_{f f 11} + + {\overset{\cdot \cdot}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . .$

$- - {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{T T},, r r}))]] + + {\overset{\cdot \cdot}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} - - {l l}_{{P P}_{T T},, r r}))]] - - 22 {\overset{\cdot &Center Dot;}{I I}}_{r r,, load load} | |$

若保护区内正常，此时

其中

为流经r点的负荷电流分量。If the protected area is normal, at this time

in

is the load current component flowing through point r.

2)KP_K支路故障2) KP _K branch fault

图4b为KP_K线路故障时多端高压输电区域示意图。由上述式(1)中推导可知，在P_K节点处满足

其中

为P_K+1P_K支路上由P_K+1点流至P_K点的实际电流。Figure 4b is a schematic diagram of the multi-terminal high-voltage transmission area when the KP _K line is faulty. It can be seen from the derivation in the above formula (1) that at the node P _K satisfies

in

is the actual current flowing from point P _K+1 to point P _K on P _K+1 P _K branch.

于是算得 ${\overset{\cdot}{I}}_{P_{K}}^{'} = {\overset{\cdot}{I}}_{K, P_{K}} + {\overset{\cdot}{I}}_{P_{K + 1}, P_{K}} = {\overset{\cdot}{I}}_{P_{K}} + {\overset{\cdot}{I}}_{f} \cosh γ_{1} (l_{f} - l_{K, P_{K}})$ So it counts ${\overset{\cdot}{I}}_{P_{K}}^{'} = {\overset{&Center Dot;}{I}}_{K, P_{K}} + {\overset{&Center Dot;}{I}}_{P_{K + 1}, P_{K}} = {\overset{\cdot}{I}}_{P_{K}} + {\overset{\cdot}{I}}_{f} \cosh γ_{1} (l_{f} - l_{K, P_{K}})$

由P_K节点处电压

节点出口电流

继续向参考点r处推算，可得The voltage at _{the K} node by P

Node outlet current

Continue to calculate to the reference point r, we can get

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{τ τ},, r r}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{τ τ + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{τ τ},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] \\ {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{τ τ},, r r} = = {\overset{\cdot &Center Dot;}{U u}}_{r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{T T},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] \end{matrix} - - - - - - ((55))$

同理，由R端电量向参考点r处推算可得

于是，在参考点r处基于基尔霍夫电流定律构成广域电流差动保护，其制动量和差动量分别为Therefore, at the reference point r, a wide-area current differential protection is formed based on Kirchhoff's current law, and the braking and differential values are respectively

${I I}_{Dr Dr.} = = | | {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r}^{' '} + + {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot &Center Dot;}{I I}}_{f f 11} + + {\overset{\cdot \cdot}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{T T},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] + +$

${\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{T T},, r r}))]] cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] | |$

${I I}_{Br Br} = = | | {\overset{\cdot \cdot}{I I}}_{{P P}_{T T},, r r}^{' '} - - {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot \cdot}{I I}}_{f f 11} + + {\overset{\cdot \cdot}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{T T},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] + + {\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}}$

$+ + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T + + 11},, {P P}_{T T}} + + {l l}_{{P P}_{T T},, r r}))]] cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] - - 22 {\overset{\cdot &Center Dot;}{I I}}_{r r,, load load} | |$

其中，l_f表示故障点f距K端节点的距离。Among them, l _f represents the distance between the fault point f and the K-terminal node.

3)P_HP_H-1支路故障3) P _H P _H-1 branch failure

图4c为P_HP_H-1线路故障时多端高压输电区域示意图。由上述式(4)可得，P_HP_H-1支路故障时，由R端电量向参考点r处推算，存在式(6)关系。Figure 4c is a schematic diagram of the multi-terminal high-voltage transmission area when the P _H P _H-1 line is faulty. From the above formula (4), it can be obtained that when the P _H P _H-1 branch fails, the power at the terminal R is calculated from the power at the reference point r, and the relationship of formula (6) exists.

$\{\begin{matrix} {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} = = {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r} + + {\overset{\cdot \cdot}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - - {l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] \\ {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11},, r r} = = {\overset{\cdot &Center Dot;}{U u}}_{r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - - {l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] \end{matrix} - - - - - - ((66))$

其中，l_f表示故障点f距P_H-1节点的距离。Among them, l _f represents the distance between the fault point f and the P _H-1 node.

同理，由N端电量向参考点r处推算可得

In the same way, it can be calculated from the power at the N terminal to the reference point r

于是，在参考点r处基于基尔霍夫电流定律构成广域电流差动保护，其制动量和差动量分别为：Therefore, at the reference point r, a wide-area current differential protection is formed based on Kirchhoff’s current law, and its braking and differential values are:

${I I}_{Dr Dr.} = = | | {\overset{\cdot \cdot}{I I}}_{{P P}_{T T},, r r}^{' '} + + {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot &Center Dot;}{I I}}_{f f 11} + + {\overset{\cdot &Center Dot;}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - - {l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - -$

${l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] | |$

${I I}_{Br Br} = = | | {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r}^{' '} - - {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot &Center Dot;}{I I}}_{f f 11} + + {\overset{\cdot &Center Dot;}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - - {l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] + + {\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{{P P}_{H h},, {P P}_{H h - - 11}} - -$

${l l}_{{P P}_{H h + + 11},, {P P}_{H h}} - - . . . . . . - - {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} - - {l l}_{{P P}_{T T - - 11},, r r}))]] - - 22 {\overset{\cdot &Center Dot;}{I I}}_{r r,, load load} | |$

4)HP_H支路故障4) HP _H branch failure

图4d为HP_H线路故障时多端高压输电区域示意图。由上述式(5)可得，HP_H支路故障时，由R端电量向参考点r处推算，存在式(7)关系。Figure 4d is a schematic diagram of the multi-terminal high-voltage transmission area when the HP _H line is faulty. From the above formula (5), it can be obtained that when the HP _H branch fails, the power at the R terminal is calculated from the power at the reference point r, and the relationship of formula (7) exists.

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r} + + {\overset{\cdot \cdot}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}} + + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . . + + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] \\ {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11},, r r} = = {\overset{\cdot &Center Dot;}{U u}}_{r r} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}} + + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . . + + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] \end{matrix} - - - - - - ((77))$

同理，由N端电量向参考点r处推算可得

${I I}_{Dr Dr.} = = | | {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r}^{' '} + + {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot &Center Dot;}{I I}}_{f f 11} + + {\overset{\cdot &Center Dot;}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}} + + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . .$

$+ + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] + + {\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}} + + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . .$

$+ + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] | |$

${I I}_{Br Br} = = | | {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T},, r r}^{' '} - - {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11},, r r}^{' '} | | = = | | (({\overset{\cdot \cdot}{I I}}_{f f 11} + + {\overset{\cdot &Center Dot;}{I I}}_{f f 22})) cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}} + + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . .$

$+ + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] + + {\overset{\cdot &Center Dot;}{I I}}_{f f 00} cosh cosh [[{γ γ}_{00} (({l l}_{{P P}_{H h + + 11},, {P P}_{H h}}$

$+ + {l l}_{{P P}_{H h + + 22},, {P P}_{H h + + 11}} + + . . . . . . + + {l l}_{{P P}_{T T - - 11},, {P P}_{T T - - 22}} + + {l l}_{{P P}_{T T - - 11},, r r}))]] cosh cosh [[{γ γ}_{00} (({l l}_{f f} - - {l l}_{H h,, {P P}_{H h}}))]] - - 22 {\overset{\cdot \cdot}{I I}}_{r r,, load load} | |$

其中，l_f表示故障点f距H端节点的距离。Among them, l _f represents the distance between the fault point f and the H terminal node.

上述分析中的N、T、T-1、I、I-1、K+1、K、K-1、H、H-1表示多端高压输电区域外端口节点的编号；P_K+1、P_K、P_K-1、P_I、P_I-1、P_T、P_T-1、P_H、P_H-1表示多端高压输电区域内部节点的编号。N, T, T-1, I, I-1, K+1, K, K-1, H, H-1 in the above analysis represent the numbers of port nodes outside the multi-terminal high-voltage transmission area; P _K+1 , P _K , P _K-1 , _PI , PI _-1 , _PT , PT _-1 , _PH , PH _-1 represent the numbers of internal nodes in the multi-terminal high-voltage transmission area.

上述分析了不同线路故障时，由N端和R端向r点推算所得的差动量和制动量情况。于是，在r点采用比例制动特性判断故障相别。当发生高阻接地故障时，可采用零序电流分量构成零序电流差动保护。The above analyzes the differential and braking conditions calculated from the N terminal and the R terminal to the r point when different lines are faulty. Therefore, at point r, the proportional braking characteristic is used to judge the fault phase difference. When a high-impedance ground fault occurs, the zero-sequence current component can be used to form a zero-sequence current differential protection.

高阻接地故障时，因负荷电流影响，上述广域全电流差动保护可能无法正确动作，由零序分量差动保护动作跳开三相。这样虽能切除故障，但跳开了正常相，造成了不必要的保护动作行为发生。在非全相运行时零序电流差动保护必须退出，此时若再发生高阻接地故障，保护将出现拒动而无法及时地切除故障。由上述推导过程可知，当利用各序故障分量替代前文相应的各序全电流分量时，上述推导过程依然成立。因此，本发明考虑引入故障分量并在上述推导基础上，提出一种广域故障分量电流差动保护，即利用故障分量替代上述相应的全电流分量，即利用故障分量正序分量代替正序分量、故障分量负序分量代替负序分量、故障分量零序分量代替零序分量。广域故障分量电流差动保护判据与广域全电流差动保护判据相同，都采用比例制动特性判别故障相别。When a high-impedance ground fault occurs, due to the influence of the load current, the above-mentioned wide-area full-current differential protection may not operate correctly, and the three-phase is tripped by the zero-sequence component differential protection action. Although the fault can be removed in this way, the normal phase is skipped, causing unnecessary protection actions to occur. The zero-sequence current differential protection must exit during non-full-phase operation, and if a high-resistance ground fault occurs again at this time, the protection will refuse to operate and the fault cannot be removed in time. It can be seen from the above derivation process that when the fault components of each sequence are used to replace the corresponding full current components of each sequence above, the above derivation process still holds true. Therefore, the present invention considers the introduction of fault components and on the basis of the above derivation, proposes a wide-area fault component current differential protection, that is, the fault component is used to replace the corresponding full current component, that is, the fault component positive sequence component is used to replace the positive sequence component , The negative sequence component of the fault component replaces the negative sequence component, and the zero sequence component of the fault component replaces the zero sequence component. The criterion of wide-area fault component current differential protection is the same as that of wide-area full-current differential protection, both of which use proportional braking characteristics to distinguish faults.

因故障分量本身的特点该广域故障分量电流差动保护适用于故障后两周内，故障40ms后将退出运行，由广域全电流差动保护承担保护任务，因此，本发明所提出的广域故障分量电流差动保护与广域全电流差动保护相互补充用于承担多端高压输电区域的内部故障检测。Due to the characteristics of the fault component itself, the wide-area fault component current differential protection is suitable for two weeks after the fault, and will stop running after 40ms of fault, and the wide-area full-current differential protection undertakes the protection task. Therefore, the wide-area fault component current differential protection proposed by the present invention Domain fault component current differential protection and wide-area full current differential protection complement each other to undertake internal fault detection in multi-terminal high-voltage transmission areas.

二、故障线路选择方法Second, the fault line selection method

1)P_K+1P_K支路故障1) P _K+1 P _K branch fault

当由I(I≥K+1)端向参考端R推算求故障点距参考端R的距离χ_IR时，参考点r选在P_T节点处时，由式(4)即可得式(8)。When the distance χ _IR between the fault point and the reference terminal R is calculated from the I (I≥K+1) terminal to the reference terminal R, and when the reference point r is selected at the P _T node, the formula (4) can be obtained ( 8).

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T},, {P P}_{T T - - 11}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11}} + + {\overset{\cdot \cdot}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K + + 11}} - - . . . . . . - - {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}} + + {\overset{\cdot \cdot}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] \end{matrix} - - - - - - ((88))$

其中，T＝K+1，K，…，2；l_f表示故障点f距P_K+1节点的距离。于是，构造故障线路选择方程如式(9)。Among them, T=K+1, K, ..., 2; l _f represents the distance between fault point f and P _K+1 node. Therefore, construct the fault line selection equation as formula (9).

${\overset{\cdot &Center Dot;}{U u}}_{R R} cosh cosh (({γ γ}_{11} {χ χ}_{IR IR})) - - {\overset{\cdot \cdot}{I I}}_{R R} {Z Z}_{} c c 11 sinh sinh (({γ γ}_{11} {χ χ}_{IR IR})) = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{22},, {P P}_{11}} cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{11},, R R} - - {χ χ}_{IR IR}))]] - - {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{11}}^{' '} sinh sinh [[{γ γ}_{11} (({l l}_{{P P}_{11},, R R} - - {χ χ}_{IR IR}))]] - - - - - - ((99))$

由式(8)和式(9)可得 $χ_{IR} = l_{P_{K + 1}, P_{K}} + l_{P_{K}, P_{K - 1}} + . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R} - l_{f}, I &GreaterEqual; K + 1 - - - (10)$ From formula (8) and formula (9) can get $χ_{IR} = l_{P_{K + 1}, P_{K}} + l_{P_{K}, P_{K - 1}} + . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R} - l_{f}, I &Greater Equal; K + 1 - - - (10)$

实际应用中由

求得χ_IR。其中

B = \frac{1}{2} \exp (- γ_{1} l_{P_{1}, R}) [{\overset{\cdot}{U}}_{P_{2}, P_{1}} + Z_{c 1} {\overset{\cdot}{I}}_{P_{1}}^{'}] - \frac{1}{2} [{\overset{\cdot}{U}}_{R} - Z_{c 1} {\overset{\cdot}{I}}_{R}] .

In practical application by

Find χ _IR . in

B = \frac{1}{2} \exp (- γ_{1} l_{P_{1}, R}) [{\overset{\cdot}{u}}_{P_{2}, P_{1}} + Z_{c 1} {\overset{&Center Dot;}{I}}_{P_{1}}^{'}] - \frac{1}{2} [{\overset{\cdot}{u}}_{R} - Z_{c 1} {\overset{&Center Dot;}{I}}_{R}] .

当由I(I≤K)端向R端推算求故障点f距参考端R的距离χ_IR时，由P₁节点电压

出口电流

推算P_I-1节点电压和出口电流

如式(11)所示。When the distance χ _IR between the fault point f and the reference terminal R is calculated from the I (I≤K) terminal to the R terminal, the node voltage of _P1

export current

Estimate the P _I-1 node voltage and export current

As shown in formula (11).

$\{\begin{matrix} {\overset{\cdot \cdot}{U u}}_{{P P}_{11},, {P P}_{I I - - 11}} = = {\overset{\cdot \cdot}{U u}}_{{P P}_{I I}} cosh cosh {γ γ}_{11} {l l}_{{P P}_{I I},, {P P}_{I I - - 11}} - - {\overset{\cdot \cdot}{I I}}_{{P P}_{I I}}^{' '} {Z Z}_{c c 11} sinh sinh {γ γ}_{11} {l l}_{{P P}_{I I},, {P P}_{I I - - 11}} \\ = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{I I - - 11}} - - {\overset{\cdot \cdot}{I I}}_{f f} {Z Z}_{c c 11} sinh sinh {γ γ}_{11} {l l}_{{P P}_{I I},, {P P}_{I I - - 11}} cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} \\ - - . . . . . . - - {l l}_{{P P}_{I I + + 11},, {P P}_{I I}))]]} \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{I I},, {P P}_{I I - - 11}} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{I I}}^{' '} cosh cosh {γ γ}_{11} {l l}_{{P P}_{I I},, {P P}_{I I - - 11}} - - \frac{{\overset{\cdot &Center Dot;}{U u}}_{{P P}_{I I}}}{{Z Z}_{c c 11}} sinh sinh {γ γ}_{11} {l l}_{{P P}_{I I},, {P P}_{I I - - 11}} \\ {\overset{\cdot \cdot}{I I}}_{I I - - 11,, {P P}_{I I - - 11}} = = {\overset{\cdot &Center Dot;}{I I}}_{I I - - 11} cosh cosh {γ γ}_{11} {l l}_{I I - - 11,, {P P}_{I I - - 11}} - - \frac{{\overset{\cdot \cdot}{U u}}_{I I - - 11}}{{Z Z}_{c c 11}} sinh sinh {γ γ}_{11} {l l}_{I I - - 11},, {P P}_{I I - - 11} \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{I I - - 11}}^{' '} = = {\overset{\cdot \cdot}{I I}}_{{P P}_{I I},, {P P}_{I I - - 11}} + + {\overset{\cdot \cdot}{I I}}_{I I - - 11,, {P P}_{I I - - 11}} = = {\overset{\cdot \cdot}{I I}}_{{P P}_{11}} + + \\ {\overset{\cdot &Center Dot;}{I I}}_{f f} cosh cosh {γ γ}_{11} {l l}_{{P P}_{11},, {P P}_{I I - - 11}} cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{I I + + 11},, {P P}_{I I}}))]] \end{matrix} - - - - - - ((1111))$

按式(11)依次递推，继续向P_T(T＜I≤K)节点推算，此时P_T节点电压和出口电流存在式(12)关系。According to the formula (11), it is recursive in turn, and continues to calculate to the node _{of PT} (T<I≤K), at this time, the voltage of the node of _PT and the outlet current have the relationship of formula (12).

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T},, {P P}_{T T - - 11}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11}} - - {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{{P P}_{I I},, {P P}_{I I - - 11}} + + {l l}_{{P P}_{I I - - 11},, {P P}_{I I - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{I I + + 11},, {P P}_{I I}}))]] \\ {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11}}^{' '} = = {\overset{\cdot \cdot}{I I}}_{{P P}_{T T - - 11}} + + {\overset{\cdot \cdot}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{I I},, {P P}_{I I - - 11}} + + {l l}_{{P P}_{I I - - 11},, {P P}_{I I - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{{P P}_{K K + + 11},, {P P}_{K K}} - - {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} - - . . . . . . - - {l l}_{{P P}_{I I + + 11},, {P P}_{I I}}))]] \end{matrix} - - - - - - ((1212))$

其中，T＝I，I-1，…，2；l_f表示故障点f距P_K+1节点的距离。Among them, T=I, I-1,..., 2; l _f represents the distance between the fault point f and the node P _K+1 .

由式(12)和式(9)可得 $χ_{IR} = l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R}, I \leq K - - - (13)$ From formula (12) and formula (9) can get $χ_{IR} = l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R}, I \leq K - - - (13)$

综上式(10)和式(13)可得，线路P_K+1P_K故障时，由各端电量向参考端R推算所得故障线路选择方程的解之间存在关系：To sum up the above equations (10) and (13), it can be obtained that when the line P _K+1 P _K is faulty, there is a relationship between the solutions of the faulty line selection equation calculated from the power at each end to the reference end R:

χ_1R＜χ_2R＜...＜χ_KR＜χ_K+1R＝...＝χ_NR (14)χ _1R <χ _2R <...<χ _KR <χ _K+1R =...=χ _NR (14)

2)KP_K支路故障2) KP _K branch fault

当由I(I≥K+1)端向参考端R推算求故障点距参考端R的距离χ_IR时，式(5)中r点选为P_T点时可得When the distance χ _IR between the fault point and the reference terminal R is calculated from the I (I≥K+1) terminal to the reference terminal R, when the r point in the formula (5) is selected as the P _T point, it can be obtained

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T},, {P P}_{T T - - 11}}^{' '} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11}} - - {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] cosh cosh [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}}))]] cos cos [[{γ γ}_{11} (({l l}_{f f} - - {l l}_{K K,, {P P}_{K K}}))]] \end{matrix} - - - - - - ((1515))$

其中，T＝K，K-1，…，2；l_f表示故障点f距K端节点的距离。Among them, T=K, K-1, ..., 2; l _f represents the distance between the fault point f and the K terminal node.

由式(15)和式(9)可得From formula (15) and formula (9) can get

${χ χ}_{IR IR} = = {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{22},, {P P}_{11}} + + {l l}_{{P P}_{11},, R R},, I I &GreaterEqual; &Greater Equal; K K + + 11 - - - - - - ((1616))$

当由K端向参考端R推算求故障点距参考端R的距离χ_KR时，由式(4)可得P_T节点电压和出口电流如式(17)所示。When the distance χ _KR between the fault point and the reference terminal R is calculated from the K terminal to the reference terminal R, the P _T node voltage and the outlet current can be obtained from the formula (4) as shown in the formula (17).

$\{\begin{matrix} {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T},, {P P}_{T T - - 11}} = = {\overset{\cdot &Center Dot;}{U u}}_{{P P}_{T T - - 11}} - - {\overset{\cdot &Center Dot;}{I I}}_{f f} {Z Z}_{} c c 11 sinh sinh [[{γ γ}_{11} (({l l}_{K K,, {P P}_{K K}} + + {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}} - - {l l}_{f f}))]] \\ {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}}^{' '} = = {\overset{\cdot &Center Dot;}{I I}}_{{P P}_{T T - - 11}} + + {\overset{\cdot &Center Dot;}{I I}}_{f f} cosh cosh [[{γ γ}_{11} (({l l}_{K K,, {P P}_{K K}} + + {l l}_{{P P}_{K K},, {P P}_{K K - - 11}} + + {l l}_{{P P}_{K K - - 11},, {P P}_{K K - - 22}} + + . . . . . . + + {l l}_{{P P}_{T T},, {P P}_{T T - - 11}} - - {l l}_{f f}))]] \end{matrix} - - - - - - ((1717))$

由式(17)和式(9)可得 $χ_{KR} = l_{K, P_{K}} + l_{P_{K}, P_{K - 1}} + . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R} - l_{f} - - - (18)$ From formula (17) and formula (9) can get $χ_{KR} = l_{K, P_{K}} + l_{P_{K}, P_{K - 1}} + . . . + l_{P_{2}, P_{1}} + l_{P_{1}, R} - l_{f} - - - (18)$

当由I(I＜K)端向R端推算求故障点f距参考端R的距离χ_IR时，P_T节点电压和出口电流为 $\{\begin{matrix} {\overset{\cdot}{U}}_{P_{T}, P_{T - 1}} = {\overset{\cdot}{U}}_{P_{T - 1}} - {\overset{\cdot}{I}}_{f} Z_{c 1} \sinh [γ_{1} (l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} + . . . \\ + l_{P_{T}, P_{T - 1}})] \cosh γ_{1} (l_{f} - l_{K, P_{k}}) \cosh γ_{1} (l_{P_{k}, P_{k - 1}} - l_{P_{k - 1}, P_{k - 2}} - . . . - l_{P_{I + 1}, P_{I}}) \\ {\overset{\cdot}{I}}_{P_{T - 1}}^{'} = {\overset{\cdot}{I}}_{P_{T - 1}} + {\overset{\cdot}{I}}_{f} \cosh [γ_{1} (l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} + . . . \\ + l_{P_{T}, P_{T - 1}})] \cosh γ_{1} (l_{f} - l_{K, P_{k}}) \cosh γ_{1} (l_{P_{k}, P_{k - 1}} - l_{P_{k - 1}, P_{k - 2}} - . . . - l_{P_{I + 1}, P_{I}}) \end{matrix} - - - (19)$ When the distance χ _IR between the fault point f and the reference terminal R is calculated from the I (I<K) terminal to the R terminal, the voltage of the P _T node and the outlet current are $\{\begin{matrix} {\overset{&Center Dot;}{u}}_{P_{T}, P_{T - 1}} = {\overset{&Center Dot;}{u}}_{P_{T - 1}} - {\overset{&Center Dot;}{I}}_{f} Z_{c} 1 \sinh [γ_{1} (l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} + . . . \\ + l_{P_{T}, P_{T - 1}})] \cosh γ_{1} (l_{f} - l_{K, P_{k}}) \cosh γ_{1} (l_{P_{k}, P_{k - 1}} - l_{P_{k - 1}, P_{k - 2}} - . . . - l_{P_{I + 1}, P_{I}}) \\ {\overset{&Center Dot;}{I}}_{P_{T - 1}}^{'} = {\overset{&Center Dot;}{I}}_{P_{T - 1}} + {\overset{\cdot}{I}}_{f} \cosh [γ_{1} (l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} + . . . \\ + l_{P_{T}, P_{T - 1}})] \cosh γ_{1} (l_{f} - l_{K, P_{k}}) \cosh γ_{1} (l_{P_{k}, P_{k - 1}} - l_{P_{k - 1}, P_{k - 2}} - . . . - l_{P_{I + 1}, P_{I}}) \end{matrix} - - - (19)$

其中，T＝I，I-1，··，2；l_f表示故障点f距P_K+1节点的距离。Among them, T=I, I-1, ··, 2; l _f represents the distance between fault point f and P _K+1 node.

由式(19)和式(9)可得 $χ_{IR} = l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} . . . + l_{P_{2}, P_{1}} + l_{P_{I}, R}, I < K - - - (20)$ From formula (19) and formula (9) can get $χ_{IR} = l_{P_{I}, P_{I - 1}} + l_{P_{I - 1}, P_{I - 2}} . . . + l_{P_{2}, P_{1}} + l_{P_{I}, R}, I < K - - - (20)$

上述分析中的N、T、T-1、I、I-1、K+1、K、K-1、H、H-1表示多端高压输电区域外端口节点的编号；P_K+1、P_K、P_K-1、P₁、P_1-1、P_T、P_T-1、P_H、P_H-1表示多端高压输电区域内部节点的编号。N, T, T-1, I, I-1, K+1, K, K-1, H, H-1 in the above analysis represent the numbers of port nodes outside the multi-terminal high-voltage transmission area; P _K+1 , P _K , P _K-1 , P ₁ , P _1-1 , _PT , PT _-1 , _PH , PH _-1 represent the numbers of internal nodes in the multi-terminal high-voltage transmission area.

综上式(16)、式(18)和式(20)可得，线路KP_K故障时，由各端电量向参考端R推算所得故障线路选择方程的解之间存在关系：To sum up the above equations (16), (18) and (20), it can be obtained that when the line KP _K is faulty, there is a relationship between the solutions of the faulty line selection equation calculated from the electricity at each end to the reference end R:

χ_1R＜χ_2R＜...χ_K-1R＜χ_K+1R＝...＝χ_NR＜χ_KR (21)χ _1R <χ _2R <...χ _K-1R <χ _K+1R =...=χ _NR <χ _KR (21)

图6给出了P_K+1P_K支路、KP_K支路故障时χ_IR(I＝1，2，3，......，N)之间满足的关系。由图6和式(14)、式(21)关系可知，通过分析χ_IR(I＝1，2，3，......，N)之间的关系即可准确确定具体的故障线路。Fig. 6 shows the satisfying relationship between χ _IR (I=1, 2, 3, . . . , N) when the P _K+1 P _K branch and the KP _K branch fail. From Figure 6 and the relationship between formula (14) and formula (21), it can be seen that the specific fault line can be accurately determined by analyzing the relationship between χ _IR (I=1, 2, 3, ..., N) .

三、计算结果和分析3. Calculation results and analysis

图7为5端高压输电单相仿真模型示意图，利用PSCAD仿真软件搭建此模型。5端高压输电系统内发生不同类型故障时，本发明主站决策服务器的计算分析结果见表1所示。Figure 7 is a schematic diagram of a 5-terminal high-voltage transmission single-phase simulation model, which is built using PSCAD simulation software. When different types of faults occur in the 5-terminal high-voltage transmission system, the calculation and analysis results of the master station decision server of the present invention are shown in Table 1.

由表1结果可以看出，在保护区内不同线路发生不同类型故障时，本发明能准确确定保护区内的过渡电阻情况、具体故障相别和故障线路，具有良好的可靠性、选择性、速动性和灵敏性。As can be seen from the results in Table 1, when different types of faults occur in different lines in the protected area, the present invention can accurately determine the transition resistance situation, the specific fault phase and the faulted line in the protected area, and has good reliability, selectivity, Quickness and sensitivity.

(3)执行子站结构见图2所示。在执行子站控制装置处，其跳闸执行装置的核心由与逻辑跳闸控制器构成，其输入是断路器的开合状态(开为0，合为1)和来自于广域后备保护主站的跳闸信号(正常为0，跳闸为1)，只有当断路器的开合状态和来自于广域后备保护主站的跳闸信号输入全为1时，与逻辑跳闸控制器输出为1，才跳开相应的线路断路器。(3) The structure of the execution substation is shown in Figure 2. At the execution substation control device, the core of its trip execution device is composed of a logic trip controller, and its input is the opening and closing state of the circuit breaker (open is 0, closed is 1) and the signal from the wide-area backup protection master station Trip signal (normal is 0, trip is 1), only when the open and close state of the circuit breaker and the trip signal input from the wide-area backup protection master station are all 1, and the output of the logic trip controller is 1, it will trip Appropriate circuit breaker.

由于网络数据传输延时以及主站集中计算延时，来自于广域线路后备保护主站的即刻跳闸命令会比就地的线路主保护延迟约300毫秒。传统线路后备保护为了实现选择性而采取分段阶梯时延的方法，通常一级阶梯时延就需要500毫秒，多级时延可能高达数秒。因此，本发明动作速度慢于线路主保护，快于基于本地量决策的传统线路后备保护。由此实现线路主保护、本发明和传统线路后备保护的配合。Due to the network data transmission delay and the centralized calculation delay of the master station, the immediate trip command from the master station of the wide-area line backup protection will be delayed by about 300 milliseconds compared with the local line master protection. In order to achieve selectivity, traditional line backup protection adopts the step-by-step delay method. Usually, the delay of one step is 500 milliseconds, and the delay of multiple steps may be as high as several seconds. Therefore, the action speed of the present invention is slower than the line main protection, and faster than the traditional line backup protection based on local quantity decision-making. In this way, the cooperation of the line main protection, the present invention and the traditional line backup protection is realized.

表1：保护区内发生各种故障类型时后备保护决策服务的计算分析结果Table 1: Calculation and analysis results of backup protection decision-making service when various fault types occur in the protection zone

故障类型Fault type 内部故障检测情况 Internal Fault Detection Conditions χ_5R/(km)χ _5R /(km) χ_4R/(km)χ _4R /(km) χ_3R/(km)χ _3R /(km) χ_2R/(km)χ _2R /(km) χ_1R/(km)χ _1R /(km) 故障支路选取 Fault branch selection Bus1-P1支路距P1点35km处BCG，10Ω BCG at 35km from P1 point of Bus1-P1 branch road, 10Ω BC相故障 BC phase failure 149.967149.967 149.976149.976 150.008150.008 149.937149.937 173.708173.708 Bus1-P1Bus1-P1 Bus4-P4支路距P4节点5km处AB故障 Bus4-P4 branch road AB fault at 5km away from P4 node AB相故障 AB phase failure 350.254350.254 355.26355.26 250.048250.048 249.841249.841 149.803149.803 Bus4-P4Bus4-P4 Bus5-P4支路距P4节点125km处AG，300Ω AG at 125km away from the P4 node of the Bus5-P4 branch, 300Ω A相高阻故障 Phase A high resistance fault 474.997474.997 350.002350.002 250.016250.016 249.956249.956 149.94149.94 Bus5-P4Bus5-P4 Bus5-P4支路距Bus5端45km处AG，250Ω AG at 45km from the Bus5-P4 branch to the Bus5 terminal, 250Ω A相高阻故障 Phase A high resistance fault 454.997454.997 350.002350.002 250.023250.023 249.934249.934 149.912149.912 Bus5-P4Bus5-P4 Bus2-P3支路距P3节点15km处CG，200Ω CG at the point 15km away from the P3 node of the Bus2-P3 branch, 200Ω C相高阻故障 C phase high resistance fault 249.845249.845 249.844249.844 349.798349.798 364.785364.785 147.970147.970 Bus2-P3Bus2-P3 Bus2-P3支路距P3节点35km处AG，200Ω AG at 35km from the P3 node of the Bus2-P3 branch, 200Ω A相高阻故障 Phase A high resistance fault 249.884249.884 249.882249.882 349.848349.848 384.825384.825 148.460148.460 Bus2-P3Bus2-P3 Bus2-P3支路距P3节点15km处CG，10Ω CG at the point 15km away from the P3 node of the Bus2-P3 branch, 10Ω C相故障 Phase C failure 249.845249.845 249.844249.844 349.798349.798 364.784364.784 147.970147.970 Bus2-P3Bus2-P3 Bus2-P3支路距P3节点35km处AG，300Ω AG at 35km from P3 node on Bus2-P3 branch, 300Ω A相高阻故障 Phase A high resistance fault 249.884249.884 249.882249.882 349.848349.848 384.825384.825 148.46148.46 Bus2-P3Bus2-P3 Bus3-P3支路距Bus3节点35km处BC，50Ω Bus3-P3 branch 35km away from Bus3 node BC, 50Ω BC相故障 BC phase failure 249.808249.808 249.812249.812 394.693394.693 349.174349.174 147.556147.556 Bus3-P3Bus3-P3 Bus3-P3支路距P3节点35km处CG，300Ω CG at the point 35km away from the P3 node of the Bus3-P3 branch, 300Ω C相高阻故障 C phase high resistance fault 249.747249.747 249.738249.738 391.387391.387 347.061347.061 147.481147.481 Bus3-P3Bus3-P3 P1-BusR支路距P1节点3km处AG，300Ω P1-BusR branch is 3km away from P1 node AG, 300Ω A相故障 Phase A failure 146.966146.966 146.971146.971 147.013147.013 146.921146.921 146.119146.119 P1-BusRP1-BusR P1-BusR支路距R端15km处AG，300Ω AG at 15km from the R terminal of the P1-BusR branch, 300Ω A相故障 Phase A failure 15.19015.190 15.25115.251 15.65615.656 15.25615.256 14.95814.958 P1-BusRP1-BusR P1-BusR支路距R端30km处AG，250Ω AG at 30km from the R terminal of the P1-BusR branch, 250Ω A相故障 Phase A failure 30.25630.256 30.34630.346 30.95030.950 30.32730.327 29.93529.935 P1-BusRP1-BusR P2-P4支路距P4节点2.5km处BC，10Ω BC at 2.5km from P2-P4 branch to P4 node, 10Ω BC相故障 BC phase failure 347.742347.742 347.739347.739 249.294249.294 249.595249.595 149.751149.751 P2-P4P2-P4 P2-P4支路距P2节点2km处BC，10Ω P2-P4 branch 2km away from P2 node BC, 10Ω BC相故障 BC phase failure 252.396252.396 252.631252.631 250.100250.100 249.731249.731 149.586149.586 P2-P4P2-P4 P1-P2支路距P2节点18km处AB相间短路 Short circuit between A and B phases at 18km away from P2 node of P1-P2 branch road AB相故障 AB phase failure 231.954231.954 231.649231.649 232.012232.012 231.858231.858 149.363149.363 P1-P2P1-P2 P1-P2支路距P1节点5km处CAG CAG at 5km distance from P1 node of P1-P2 branch road AC相故障 AC phase failure 154.920154.920 154.440154.440 154.684154.684 154.428154.428 149.186149.186 P1-P2P1-P2

以上所述，仅为本发明较佳的具体实施方式，但本发明的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本发明揭露的技术范围内，可轻易想到的变化或替换，都应涵盖在本发明的保护范围之内。The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present invention can easily think of changes or Replacement should be covered within the protection scope of the present invention.

Claims

1. A method for backup protection of multi-terminal high-voltage transmission areas based on a wide-area measurement system. The wide-area backup protection includes fault detection and fault branch selection in the protection area, and realizes the backup protection of multi-terminal high-voltage transmission areas based on wide-area information. The existing wide-area measurement system in the multi-terminal high-voltage transmission area realizes the synchronous real-time measurement of the voltage and current phasors of all nodes installed with phasor measurement units in the area, and the calculation and analysis of the main station and the wide-area backup protection server accurately determine Specific faulty phases and faulty lines, and issue control commands to the execution sub-stations of each line in the area; it is characterized in that the implementation method is as follows:

a) The wide-area backup protection server uses the wide-area current differential protection to detect whether a fault occurs in the protection area according to the voltage and current phasors at the installation points of each phasor measurement unit collected by the main station in real time. For faults, determine the specific fault phase difference and transition resistance;

b) The wide-area current differential protection in the above step a) includes wide-area full-current differential protection and wide-area fault component differential protection, and the two complement each other to undertake the task of internal fault detection in the multi-terminal high-voltage transmission area. Wide-area full-current differential protection means that the wide-area backup protection server directly performs phase sequence transformation on the real-time measurement data sent by each phasor measurement unit, and selects the center of the multi-terminal high-voltage transmission area as the reference point. Based on the distributed parameter model, the The sequence components at the beginning and end of the multi-terminal high-voltage transmission area are respectively calculated from the reference point to obtain the differential current of each sequence and the braking current of each sequence at the reference point, and then synthesized to obtain the corresponding differential current and braking current, and finally use the ratio Braking characteristics constitute full current differential protection; wide-area fault component differential protection refers to the calculation of positive, negative and zero-sequence voltage fault components and positive, negative and zero-sequence current fault components at the installation points of each phasor measurement unit by the wide-area backup protection server The center position of the multi-terminal high-voltage transmission area is selected as the reference point. Based on the distributed parameter model, the differential current of each sequence fault component at the reference point and each Sequence fault component braking current, and then synthesized to obtain the corresponding fault component differential current and fault component braking current, and finally use the ratio braking characteristic to form the fault component current differential protection;

c) When a fault occurs in the protected area, the faulty line is accurately determined according to the faulty line selection method, and then the master station sends an action command to the execution sub-station of the faulty line; wherein, the faulty line selection method refers to a distribution parameter model based on each The positive sequence components of the terminal are respectively calculated to the reference terminal to obtain the solution χ _IR of the fault line selection equation, where I=1,...,N; if χ _IR satisfies χ _IR <χ _2R <...<χ _KR <χ _K+1R = ...=χ _NR , then the P _K+1 P _K line is faulty; if χ _IR (I=1,...,N) satisfies χ _1R <χ _2R <...χ _K-1R <χ _K+1R ＝...＝χ _NR <χ _KR , then the KP _K line is faulty; R is the reference terminal, and N is the total number of nodes in the outermost periphery of the multi-terminal high-voltage area; K+1, K, K-1 represent the port nodes outside the multi-terminal high-voltage transmission area number; P _K+1 , P _K , P _K-1 indicate the number of internal nodes in the multi-terminal high-voltage transmission area;

d) The fault line selection equation in the above-mentioned step c) refers to the double-ended line synchronous fault location method based on the distributed parameter model, and its expression is in

χ _IR is the solution of the fault line selection equation calculated from the positive sequence component of terminal I to the reference terminal R, is the positive sequence voltage and current of the reference terminal R;

is the distance from _P1 node to the reference terminal R; are the _P1 node voltage and the _P1 node outlet current calculated from the positive sequence component of the I terminal to _P1 ; Z _c1 and _γ1 are the positive sequence wave impedance and propagation constant of the transmission line.