CN112531661B - A station domain failure protection method and system based on switch signal - Google Patents

Abstract

The invention discloses a station domain failure protection method and system based on switching value signals, and belongs to the field of relay protection of power systems. The method comprises the following steps: according to the action state of the protection, the state of the starting element and the switching value signals of adjacent protection, the action logic combination and the secondary loop switching value signals are utilized to realize a failure protection function which is matched step by step according to the adjacent relation for various multi-port protected equipment in a station domain. The invention aims at the station domain protection of the alternating current and direct current power system, does not need complex setting, and can solve the problem that the main protection can not rapidly remove the fault due to the failure of adjacent circuit breakers, the failure of adjacent protection including the voltage loss of adjacent protection control equipment and the like related to the far backup protection.

Description

A station domain failure protection method and system based on switch signal

technical field

The invention belongs to the field of power system relay protection, and more particularly, relates to a method and system for station domain failure protection based on switch signal.

Background technique

Relay protection is the first line of defense to ensure the safety of large power grids. If the protection device fails to act correctly, quickly and reliably when the fault occurs, it will easily lead to the expansion of the accident and even cause a large-scale power outage. In recent years, the continuous expansion and complexity of power grids and the construction of smart grids have put forward higher requirements for power system relay protection, especially backup protection.

When the main protection fails or the circuit breaker fails, the fault must be reliably removed by the backup protection. Traditional backup protection generally adopts staged distance protection or zero-sequence overcurrent protection, which has defects such as complex setting, difficult coordination, slow action speed, poor selectivity, and inability to adapt to changes in complex operating modes. As a near-backup protection, traditional failure protection cannot solve the problem of refusal to move caused by secondary equipment failures such as protection pressure loss. Many researchers have proposed wide-area protection as a backup protection method, but there are also problems such as synchronization of measurement information, delay in information transmission, high dependence on communication, and low reliability.

SUMMARY OF THE INVENTION

Aiming at the defects of the prior art, the purpose of the present invention is to provide a method and system for site domain failure protection based on switch signal, the method does not rely on the communication master station and setting, and aims to solve the problem of remote backup protection due to adjacent The failure of the circuit breaker and the failure of the adjacent protection include the problem that the main protection cannot reliably remove the fault caused by the loss of voltage of the adjacent protection and control equipment.

In order to achieve the above purpose, the present invention provides a switch signal-based station domain failure protection method, comprising the following steps:

S1. Obtain the state of the starting element of the protection device, and send a switch signal to the adjacent protection device according to the state of the starting element, and the switch signal is used to block the adjacent protection device;

S2. Obtain the starting state of the main protection of the protection device, and judge whether the main protection of the protection device should act. If the main protection should act, the protection device will send a trip command to the circuit breaker in the protection zone where the protection device is located, and stop sending to the circuit breaker. The adjacent protection device sends a switch signal, if not, then go to step S3;

S3. Obtain the digital signal sent by the adjacent protection device and the fault characteristic information of the protection zone where the adjacent protection device is located, and determine whether the protection device should be As a failure protection action, if the protection device should act as a failure protection, it will send a trip command to the circuit breaker in this protection zone, and stop sending digital signals to the adjacent protection devices to realize the station domain failure protection, if not, wait to start After the element is returned, the protection device is reset.

Further, the main protection device covers 100% of the protected area, and all protection devices and adjacent protection devices exchange digital signals through the secondary circuit.

Further, all protection devices are equipped with starting elements that respond to system disturbances. For AC systems, the action criteria can be various typical protection starting elements, such as starting elements based on phase current sudden changes, negative sequence starting elements, zero-sequence starting elements, and zero-sequence starting elements. Sequence starting element, differential current starting element, etc.; for the DC system, the starting logic of the starting element can be QD=(Δi>k ₁ I _N )∪(i>k ₂ I _N ), where QD is the action signal of the starting element , Δi is the current sudden change, k ₁ and k ₂ are the reliability coefficients, and I _N is the rated current. If any of the two criteria is satisfied, the protection device will be activated.

其中j为差动保护端口数，

为端口n流入的电流向量，K为差动制动系数，取值根据不同的保护对象及其差流不平衡情况来整定，以保护对象为母线为例，一般K可取0.4左右。Further, the main protection device can be a differential protection device that adopts the principle of ratio braking, and its action criterion is:

where j is the number of differential protection ports,

is the current vector flowing into port n, K is the differential braking coefficient, and the value is set according to different protection objects and their differential current imbalance.

Further, the fault feature does not disappear. For the AC power system, the feature is that the fault current always exists, which satisfies any one of the formulas (1) to (3); for the DC power system, it satisfies (4) to (6) Any one of them, that is, it is determined that the fault feature has not disappeared.

I ₊ ＞I _+.set ∩U ₊ <U _+.set (4)

I _- ＞I _-.set ∩U _- <U _-.set (5)

I _± ＞I _±.set ∩U _± <U _±.set (6)

为被保护范围各间隔流过的A、B、C三相电流的模值，I₀、I₂为被保护范围各间隔流过的零序、负序电流，I₊、U₊、I_-、U_-、I_±、U_±分别为直流正极、负极以及极间的电流、电压。

I_0.set、I_2.set、I_+.set、U_+.set、I_-.set、U_-.set、I_±.set、U_±.set分别为整定值。in,

are the modulo values of the three-phase currents A, B, and C flowing through each interval of the protected range, I ₀ , I ₂ are the zero-sequence and negative-sequence currents flowing through each interval of the protected range, I ₊ , U ₊ , I _- , U _- , I _± , U _± are the current and voltage of the positive, negative and inter-pole DC currents, respectively.

I _0.set , I _2.set , I _+.set , U _+.set , I _-.set , U _-.set , I _±.set , U _±.set are set values respectively.

Further, when a fault occurs in the protection zone where the protection device is located, the starting element starts in response to the disturbance of the fault, and sends a switch signal to other protection devices adjacent to the protection device; When the trip order is issued and the switch signal is stopped at the same time, the adjacent protection devices will no longer receive the switch signal sent by the protection device.

Further, in step S3, when a fault occurs in the protection zone where the adjacent protection device is located, the adjacent protection device sends a trip order and stops sending the switch signal; if the adjacent protection device fails, the fault cannot be removed and cannot be Send the switch signal to the protection device. After the protection device starts, it is judged as an external fault, and the switch signal sent by the failed protection device has not been received. The start delay time is counted, and the connection with the adjacent protection device is continuously monitored. Whether the fault characteristic of the connecting branch disappears or not, if the fault characteristic does not disappear, after the set time T _set delay, the protection device will issue a trip order and stop sending the switch signal. The devices return one after another.

Further, in step S3, when a fault occurs in the protection zone where the adjacent protection device is located, the adjacent protection device sends a trip order and stops sending the switch signal; if the corresponding circuit breaker fails, so that the fault cannot be removed all the time, the protection device starts. After receiving the digital signal sent by the adjacent protection device first, the adjacent protection device will no longer receive the digital signal after the action, the protection is judged as an external fault, start the delay time, and continuously monitor the connection with the adjacent protection device. Whether the fault characteristic of the connecting branch disappears or not, if the fault characteristic does not disappear, after the set time T _set delay, the protection device will issue a trip order and stop sending the switch signal. return successively.

Another aspect of the present invention provides a switch signal-based station domain failure protection system, comprising: a computer-readable storage medium and a processor;

the computer-readable storage medium for storing executable instructions;

The processor is configured to read the executable instructions stored in the computer-readable storage medium, and execute the above-mentioned switch signal-based station domain failure protection method.

Through the above technical scheme conceived by the present invention, compared with the prior art, the following beneficial effects can be achieved:

1. The station domain failure protection method based on the switch signal provided by the present invention can effectively deal with the technical problem that the main protection cannot reliably remove the fault caused by the failure of the circuit breaker and the protection failure, and can ensure the selectivity, so that the power loss range is minimized .

2. The switch signal-based station domain failure protection method provided by the present invention does not require complicated setting, and mainly relies on logic to realize step-by-step coordination.

3. The switch signal-based station domain failure protection method provided by the present invention does not depend on communication, and only needs to obtain the status information of adjacent protection devices, which is simple and reliable.

Description of drawings

FIG. 1 is a schematic diagram of a substation system with a single busbar segment structure to which a switch signal-based station domain failure protection method provided by an embodiment of the present invention is applied;

FIG. 2 is a protection action logic diagram of a switch signal-based station domain failure protection method provided by an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

All protection devices are equipped with actuating elements that respond to system disturbances and main protection covering 100% of the protected area. All protections and adjacent protections within the station domain are through the secondary circuit to exchange digital blocking signals. When a fault occurs in the main protection zone, the corresponding starting element acts and sends a blocking signal to the adjacent protection. When the main protection quickly acts and sends a trip command, it stops sending the signal.

Specifically, the system shown in FIG. 1 can be divided into eight protection zones P1 to P8. Among them, P1 and P5 are transformer protection areas, P2 and P6 are bus protection protection areas, and the rest are outlet protection protection areas. Taking protection P2 as an example, protection P2 and protection P1, P3, P4 and P6 all exchange switching quantities through the secondary circuit.

The present invention provides a station domain failure protection method based on switch signal, as shown in FIG. 2 , which specifically includes:

S1. Obtain the state of the starting element of the protection device, and send a switch signal to the adjacent protection device according to the state of the starting element, and the switch signal is used to block the adjacent protection device.

S2. Obtain the starting state of the main protection of the protection device, and judge whether the main protection of the protection device should act. If the main protection acts, the protection device sends a trip command to the circuit breaker in the protection zone where the protection device is located, and stops sending the The adjacent protection device sends a switch signal, and if the main protection does not act, it goes to step S3.

都向各自的邻接保护发送闭锁信号，并各自起动延时计时，持续监视故障电流是否消失。当P2主保护判断出内部发生故障后，主保护起动MP_QD＝1，主保护动作MP_OP＝QD∩MP_QD＝1，发出跳闸指令并切除故障。随后，各保护起动元件返回，各保护陆续复归。Taking a fault in the P2 area as an example, the starting element of the P2 protection zone senses the fault and starts QD=1, and the protections of other protection zones start successively after sensing the fault. P2 Protection vs Adjacent Protection

They all send blocking signals to their respective adjacent protections, and start their respective delay timings to continuously monitor whether the fault current disappears. When the P2 main protection judges that an internal fault occurs, the main protection starts MP_QD=1, the main protection action MP_OP=QD∩MP_QD=1, issues a trip command and removes the fault. Subsequently, each protection starting element returns, and each protection returns one after another.

S3. Obtain the switch signal sent by the adjacent protection device and the fault characteristic information of the protection zone where the adjacent protection device is located, and determine whether the protection device should be As a failure protection action, if the protection device acts as a failure protection, it will send a trip command to the circuit breaker in this protection zone, and stop sending digital signals to the adjacent protection devices to realize the station domain failure protection. If not, the components to be started will be activated. After returning, the protective device will return.

保护P1动作于断路器Brk1和Brk8，有选择性地切除故障，即实现失灵保护的功能。同理，保护P3动作于断路器Brk2，保护P4动作于断路器Brk3，保护P6动作于断路器Brk4、Brk5、Brk6和Brk7。故障被切除后各保护在起动元件返回后整组复归。Specifically, for the situation of protection failure, take the failure of the protection in the P2 area as an example. The failed protection P2 cannot send a blocking signal to the adjacent protection. After the protection P1 senses the fault, the starting element action QD = 1, the main protection action MP_OP = 0, and the fault feature does not disappear FLT_NOTGONE = 1, and the blocking signal RES_SIG = 0 sent by the protection P2 has not been received, after the set time T _set After the delay, it is judged that the protection P2 fails, and the failure protection starts

The protection P1 acts on the circuit breakers Brk1 and Brk8 to selectively remove the fault, that is, to realize the function of failure protection. Similarly, the protection P3 operates on the circuit breaker Brk2, the protection P4 operates on the circuit breaker Brk3, and the protection P6 operates on the circuit breakers Brk4, Brk5, Brk6 and Brk7. After the fault is removed, the protection of the whole group will be reset after the starting element returns.

此时保护P6不再接收到保护P2发送的闭锁信号，即RES_SIG＝0，且主保护动作MP_OP＝0，故障特征未消失FLT_NOTGONE＝1，经过整定的时间T_set延迟后，判断为断路器Brk4失灵，失灵保护起动

保护P6动作于断路器Brk4、Brk5、Brk6和Brk7。故障被切除后各保护在起动元件返回后整组复归。Specifically, for the situation in which the main protection operates and the circuit breaker fails, take the failure of the circuit breaker Brk4 as an example when a fault occurs in the P2 area. The protection P2 sends a blocking signal to the adjacent protection after starting, and the protection P6 starts and receives the blocking signal sent by the protection P2. After the protection P2 judges that there is an internal fault, the circuit breaker TRIP=1 on each side will be tripped, and a blocking signal will be sent

At this time, the protection P6 no longer receives the blocking signal sent by the protection P2, that is, RES_SIG=0, and the main protection action MP_OP=0, the fault feature does not disappear FLT_NOTGONE=1, after the set time T _set delay, it is judged as the circuit breaker Brk4 failure, failure protection start

Protection P6 operates on circuit breakers Brk4, Brk5, Brk6 and Brk7. After the fault is removed, the protection of the whole group will be reset after the starting element returns.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (4)

1. a station domain failure protection method based on switching quantity signal, is characterized in that, comprises the following steps: S1. Obtain the state of the starting element of the protection device, and send a switch signal to the adjacent protection device according to the state of the starting element, and the switch signal is used to block the adjacent protection device; S2. Obtain the starting state of the main protection of the protection device, and judge whether the main protection of the protection device should act. If the main protection should act, the protection device will send a trip order to the circuit breaker in the protection zone where the protection device is located, and stop sending to the circuit breaker. The adjacent protection device sends a switch signal, if not, then go to step S3; S3. Obtain the digital signal sent by the adjacent protection device and the fault characteristic information of the protection zone where the adjacent protection device is located, and determine whether the protection device should be As a failure protection action, if the protection device should act as a failure protection, it will send a trip order to the circuit breaker in this protection zone, and stop sending digital signal to the adjacent protection device to realize the station domain failure protection, if not, wait to start After the components are returned, the protection device will return; In the step S3, when a fault occurs in the protection zone where the adjacent protection device is located, the adjacent protection device issues a trip order and stops sending the switch signal; if the adjacent protection device fails, the fault cannot be removed and cannot be sent all the time. The switch signal is sent to the protection device. After the protection device is started, it is judged as an external fault, and the switch signal sent by the failed protection device has not been received. The start delay time is counted, and the connection with the adjacent protection device is continuously monitored. Whether the fault feature of the branch has disappeared or not, if the fault feature has not disappeared, after the set time

After the delay, the protection device issues a trip order and stops sending out the switch signal. After the fault is removed, the starting elements of each protection device return, and the protection devices return one after another; In the step S3, when a fault occurs in the protection zone where the adjacent protection device is located, the adjacent protection device issues a trip order and stops sending the switch signal; The switch signal sent by the adjacent protection device is received first, and the switch signal is no longer received after the adjacent protection device operates. The protection is judged as an external fault, and the start delay timing, and continuously monitor the connection with the adjacent protection device. Whether the fault feature of the branch has disappeared or not, if the fault feature has not disappeared, after the set time

After the delay, the protection device sends out the trip order and stops sending out the switch signal. After the fault is removed, the starting element of each protection device returns, and the protection returns successively. 2. The switch signal-based station domain failure protection method according to claim 1, wherein the main protection of the protection device covers 100% of the protected area, and all the protection devices and adjacent protection devices are The switching signal is exchanged through the secondary circuit. 3. The station domain failure protection method based on switch signal as claimed in claim 1, it is characterized in that, when a fault occurs in the protection zone where the protection device is located, the starting element starts in response to the disturbance of the fault, and is directed to the protection device in phase with the protection device. The other adjacent protection devices send digital signals; when the protection device determines that there is an internal fault, it will issue a trip order and stop sending digital signals, and the adjacent protection devices will no longer receive the digital signals sent by the protection device; After the protection device is removed, the starting element returns, and the protection device returns successively. 4. A station domain failure protection system based on switching quantity signal, characterized in that, comprising: a computer-readable storage medium and a processor; the computer-readable storage medium for storing executable instructions; The processor is configured to read the executable instructions stored in the computer-readable storage medium, and execute the switch signal-based station domain failure protection method according to any one of claims 1 to 3.

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