RU2572364C1 - Method for determination of damaged section in branched distributing network - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to relay protection and automatics of distribution networks characterized low steady-state currents at single-phase short-circuiting in the network of complex configuration with a large number of branches. The known way to detect short-circuiting is to perform distributed observation in multiple points of the network with concentration of information at several points and their further transmission to the control room. The network is observed only at inputs, i.e. at busbars of the feeding substation, and at outputs, i.e. by the consumer. The key idea is related to detection of two new components for emergency elements in observed current and voltage. The first component is the response of a normal, i.e. undamaged, network model to all observed sources of voltage. The second component being the most crucial from informative point of view forms a special emergency element. Mode of special component currents occurs in the network model with shunted inputs and outputs. Detection of the damaged network section is possible due to development of new operations on shunt transfer from the feeder input to the closest node and further, when required, to other nodes in sequence. At that each time the level of special current components specifies, which branches are undamaged. Time after time the procedure shortens the model until the damaged section in the network is detected.

EFFECT: by this method the task is solved in a simple way without prejudice for consumers.

12 dwg

Description

The invention relates to electric power and electrical engineering, namely to relay protection of distribution networks. These are networks with isolated or compensated neutral, which are characterized by low earth fault currents. Distribution network - multi-feeder; There is a problem of determining a damaged feeder in which a single-phase circuit has occurred [1]. The problem is exacerbated in networks where the feeders branch, and from the first branches there may be other branches and so on. In this case, the problem arises of determining the portion of the network in which a single-phase circuit has occurred.

A technical solution is known that makes it possible to determine a damaged line in a power transmission linking several supply nodes. It is assumed multilateral observation of power transmission with the exchange of information between places of observation [2].

The development of communication technology has made possible multilateral surveillance in distribution networks [3]. However, the solution to the problem of determining the damaged area here cannot be as simple as in high voltage systems operating in a mode with a grounded neutral, where currents and voltages contain significant steady-state sinusoidal components. Information about the sinusoid is concise; it's just a pair of orthogonal components. Another thing is intense, but short-term transients in distribution networks. After the damping of the transient process, the steady process is often so weak that it cannot be separated from the noise. Consequently, the determination of a damaged distribution network feeder, not to mention the location - determining the location of a circuit, is a difficult task associated with the processing of transients of arbitrary shape.

A technical solution is known that makes it possible to determine a damaged feeder based on the analysis of voltage and transient currents in each of the feeders of the distribution network [4]. This method uses feeder models for zero sequence components. Its distinctive feature is that each feeder is modeled in an intact state. A fixed transient voltage is applied to such a model. The reaction of the model is determined - the zero sequence current. The following pattern holds. If the processes taking place in the network are determined by the ground capacitance and the intrinsic inductance of each feeder, and the influence of the mutual inductance of the feeders is insignificant, then the ratio between the observed values of each intact feeder is determined only by its own normal model and does not depend on the situation in the damaged feeder.

In this method, the root causes of the discovered pattern were left out of sight and therefore it was used only to solve the particular problem of determining a damaged feeder in an unbranched distribution network. Meanwhile, the more general task of determining the damaged branch (section) of a branched network, for example, supplying oil fields or other dispersed enterprises for the extraction of raw materials, is relevant.

The purpose of the invention is the expansion of the functionality of the known method for determining a damaged feeder in such a way that the improved method becomes suitable for determining the portion of the branched network on which an earth fault has occurred. An additional goal is to simplify the operation of recognizing a damaged part of the network. If the prototype uses the discrepancy criterion for the observed and simulated processes, then the proposed method aims to recognize the damaged part according to the simplest criterion for generating a signal of zero level, regardless of the size and nature of the damaged part.

This goal is achieved by the fact that a branched network is observed at the entrances and exits, and although observation is not supposed at intermediate points - network nodes, the information is sufficient to identify the damaged area, wherever it is. Of course, the solution to the problem became possible thanks to the discovery of special informational components of electrical quantities. As in the prototype, a controlled network model is used, in this case branched; An intact network is simulated. From the observed values, the usual informational components are first distinguished - zero sequence or non-zero emergency terms. For those or other information components, a two-wire network model is intact in an intact state. As in the prototype, sources of the observed voltages are applied to the network model in the places where the observation was carried out. The reactions of the model are determined in the form of second currents at the observation sites. The first currents are those recorded during observation.

A distinctive feature of the proposed method is the full-scale use of new information components, called here the third currents and representing the differences between the first and second currents in the places where the network is monitored. It is established that the third currents, which can be called special emergency components of the observed currents, are created by a single source - an unknown earth fault current. The location of the circuit, as well as the damaged part of the network, is also unknown. The search for the damaged section is carried out on the basis of the criterion arising from the property of third currents to bypass the model of the undamaged part of the network. The essence of the invention lies in such transformations of the network model and the observed values that allow you to control the levels of third currents in the branches extending from any node of the model. A new method of transforming the model is used, which can be called a way to move the shunt. Whenever the shunt, moving from the model input to one of the outputs, hits the next node, the third currents are eliminated from all undamaged branches of this node, and only in that branch, which itself is damaged or leads to the place of damage, a third current of non-zero level is detected . Of course, it is not enough to know the path leading to the place of damage. It is necessary to isolate from the general direction a truly damaged area. For this reason, it is necessary to observe the network not only at the entrance, but also at the outputs. If, on its way to the next node, the shunt passes through the circuit, then all the outputs of the branches coming from this node will show non-zero third currents, which directly indicates damage to the branch along which the shunt was moving.

In FIG. 1 shows a structural diagram of the observed distribution network; in FIG. 2 - network model in normal condition, but with sources reproducing observed voltages; in FIG. 3 - model in a special emergency mode created by the source of the circuit with shunted inputs and outputs; in FIG. 4 is an illustration of a conversion made at the beginning of the next step of searching for a damaged branch; in FIG. 5 - a shortened network model without those parts of it that were recognized as intact at the previous stage of the transformation; in FIG. 6 - a shortened model of the network in the normal state, activated by a single source that reproduces the voltage generated at the beginning of this stage; in FIG. 7 - a shortened network model in a special emergency mode; in FIG. 8 - illustration of the initial operation of the next stage of the search for a damaged branch; in FIG. 9 - network model after the next shortening; in FIG. 10 - this model is in normal condition; in FIG. 11 - it is in a special emergency mode and in FIG. 12 is a model of the identified damaged area, designed to search for the place of damage.

, $${\text{i}}_{\text{b}}^{\left(\text{1}\right)}$$

, $${\text{i}}_{\text{c}}^{\left(\text{1}\right)}$$

, где верхние индексы указывают тип тока, индекс (1) говорит о том, что это исходный ток на предстоящем этапе преобразования модели. Для краткости будем исходные токи каждого этапа преобразования называть первыми токами. На выходах ответвлений 8-13 наблюдаются $${\text{i}}_{\text{d1}}^{\left(\text{1}\text{,0}\right)}$$

, $${\text{i}}_{\text{d2}}^{\left(\text{1}\text{,0}\right)}$$

, $${\text{i}}_{\text{d3}}^{\left(\text{1}\text{,0}\right)}$$

, $${\text{i}}_{\text{e1}}^{\left(\text{1}\text{,0}\right)}$$

, $${\text{i}}_{\text{e2}}^{\left(\text{1}\text{,0}\right)}$$

, $${\text{i}}_{\text{e3}}^{\left(\text{1}\text{,0}\right)}$$

, где второй верхний индекс указывает этап преобразования модели сети. Нулевой индекс соответствует начальному этапу. На каждом последующем этапе модель становится короче, пока не сократится до размера поврежденного участка. Всего для преобразования рассматриваемой сети потребуется три этапа - начальный (нулевой), первый и заключительный второй. В сети по фиг. 1 имеет место замыкание на землю в ответвлении 8; замыкание произошло вместе с координатой x_f. Замыкание сопровождается током i_f. Ни поврежденный участок сети, ни место x_f и ток i_f наблюдателю не известны. Стоит задача выявить поврежденный участок и подготовить модель к определению места повреждения.The controlled distribution network includes a substation 1 supplying the common buses 2 shown in a single-line version. Feeders 3-5 depart from common tires. Feeders branch. The branching of feeder 3 is shown in detail, because a short circuit has occurred in its direction. Without prejudice to the consumer, it is assumed that branches 6 and 7 depart from feeder 3, and three more branches from each branch: 8-10 from branch 6 and 11-13 from branch 7. The structure of feeders with their branches and branches includes nodes 14-16. The observation points are assigned indices a, b, c, d, e, the first three - at the inputs of feeders 3-5, the last - at the outputs of branches 8-13 from branches 6, 7 of feeder 3. The outputs of the branches are assigned their numbers: d1, d2, d3 - outputs of branches 8-10; e1, e2, e3 - branches 11-13. On tires 2, a voltage common to all feeders 3-5 is observed. In addition, currents are observed at the inputs of the feeders $${\text{i}}_{\text{a}}^{\left(\text{one}\right)}$$

, $${\text{i}}_{\text{b}}^{\left(\text{one}\right)}$$

, $${\text{i}}_{\text{c}}^{\left(\text{one}\right)}$$

, where the superscripts indicate the type of current, index (1) indicates that this is the initial current at the upcoming stage of the model transformation. For brevity, we will call the initial currents of each stage of the conversion the first currents. At the outputs of branches 8-13 are observed $${\text{i}}_{\text{d1}}^{\left(\text{one}\text{0}\right)}$$

, $${\text{i}}_{\text{d2}}^{\left(\text{one}\text{0}\right)}$$

, $${\text{i}}_{\text{d3}}^{\left(\text{one}\text{0}\right)}$$

, $${\text{i}}_{\text{e1}}^{\left(\text{one}\text{0}\right)}$$

, $${\text{i}}_{\text{e2}}^{\left(\text{one}\text{0}\right)}$$

, $${\text{i}}_{\text{e3}}^{\left(\text{one}\text{0}\right)}$$

where the second superscript indicates the step of transforming the network model. Zero index corresponds to the initial stage. At each subsequent stage, the model becomes shorter until it is reduced to the size of the damaged area. In total, the transformation of the network in question will require three stages - the initial (zero), the first and final second. In the network of FIG. 1 there is a ground fault in branch 8; the closure occurred with the x _f coordinate. Closing is accompanied by current i _f . Neither the damaged part of the network, nor the location x _f and current i _f are known to the observer. The task is to identify the damaged area and prepare the model for determining the location of the damage.

, $${\text{i}}_{\text{b}}^{\left(\text{2}\right)}$$

, $${\text{i}}_{\text{c}}^{\left(\text{2}\right)}$$

, $${\text{i}}_{\text{d1}}^{\left(\text{2}\text{,0}\right)}$$

, $${\text{i}}_{\text{d2}}^{\left(\text{2}\text{,0}\right)}$$

, $${\text{i}}_{\text{d3}}^{\left(\text{2}\text{,0}\right)}$$

, $${\text{i}}_{\text{e1}}^{\left(\text{2}\text{,0}\right)}$$

, $${\text{i}}_{\text{e2}}^{\left(\text{2}\text{,0}\right)}$$

, $${\text{i}}_{\text{e3}}^{\left(\text{2}\text{,0}\right)}$$

. Входные токи i_a, i_b, i_c не нуждаются в указании этапа преобразований, так как свою роль они выполняют только на одном, а именно на начальном этапе. Третьи токи - разности между первыми и вторымиIn FIG. 2 to normal, i.e. intact network model included voltage sources (EMF) 17-23, each of which repeats the voltage observed in the corresponding place. A model with zero initial conditions uniquely responds to the action of sources 17-23 by second currents $${\text{i}}_{\text{a}}^{\left(\text{2}\right)}$$

, $${\text{i}}_{\text{b}}^{\left(\text{2}\right)}$$

, $${\text{i}}_{\text{c}}^{\left(\text{2}\right)}$$

, $${\text{i}}_{\text{d1}}^{\left(\text{2}\text{0}\right)}$$

, $${\text{i}}_{\text{d2}}^{\left(\text{2}\text{0}\right)}$$

, $${\text{i}}_{\text{d3}}^{\left(\text{2}\text{0}\right)}$$

, $${\text{i}}_{\text{e1}}^{\left(\text{2}\text{0}\right)}$$

, $${\text{i}}_{\text{e2}}^{\left(\text{2}\text{0}\right)}$$

, $${\text{i}}_{\text{e3}}^{\left(\text{2}\text{0}\right)}$$

. Input currents i _a , i _b , i _c do not need to indicate the stage of transformations, since they fulfill their role only at one, namely at the initial stage. Third currents - differences between the first and second

They are the result of the distribution of the current of the only one not present in the model of FIG. 2 sources i _f . Instead of the EMF of the model of FIG. 2 in the model of FIG. 3 install shunts 24-30.

Shunt 24 on buses 2 robs current of undamaged feeders 4 and 5 -

as a result, the feeders 4 and 5 cease to have any effect on the current distribution i _f and it becomes possible to eliminate them from the model by making its first shortening.

, поступающий из поврежденной части сети - из какой, неизвестно. Однако становится понятной последовательность, в которой следует преобразовывать модель. Ток $${\text{i}}_{\text{a}}^{\left(\text{3}\right)}$$

определяет состояние узла 14, так как напряжение u_de этого узла и подтекающий к нему ток $${\text{i}}_{\text{de}}^{\left(\text{1}\right)}$$

при зашунтированном входе фидера 3 зависят только от входного тока $${\text{i}}_{\text{a}}^{\left(\text{3}\right)}$$

.The input of feeder 3 is also shunted, but current flows in it $${\text{i}}_{\text{a}}^{\left(\text{3}\right)}$$

coming from the damaged part of the network - from which is unknown. However, the sequence in which the model should be transformed becomes clear. Current $${\text{i}}_{\text{a}}^{\left(\text{3}\right)}$$

determines the state of the node 14, since the voltage u _{de of} this node and the current flowing to it $${\text{i}}_{\text{de}}^{\left(\text{one}\right)}$$

with shunted input of feeder 3 depend only on the input current $${\text{i}}_{\text{a}}^{\left(\text{3}\right)}$$

.

говорит о том, что, во-первых, этот ток имеет отношение к ветвям 6 и 7, от которых идут ответвления с индексами d и е. А во-вторых, что на следующем этапе преобразования модели этому току отводится такая же роль, какую на начальном этапе сыграли наблюдаемые токи

. В следующий этап модель сети входит не только без фидеров 4 и 5, но и без фидера 3 (фиг. 5). Шунты 25-30 остаются на своих местах, место действия тока i_f и он сам по-прежнему не известны, зато известны квазинаблюдаемые величины $${\text{i}}_{\text{de}}^{\left(\text{1}\right)}$$

и u_de, а еще третьи токи в выходных шунтах 25-30

,

на значение которых укорочение модели не повлияло. На следующем этапе преобразований этим токам отводится та же роль, которую играли наблюдаемые токи на выходе модели по фиг. 1. Поэтому для них теперь вводятся новые обозначенияDesignation $${\text{i}}_{\text{de}}^{\left(\text{one}\right)}$$

says that, firstly, this current is related to branches 6 and 7, from which branches with indices d and e go. And secondly, that at the next stage of the model transformation, this current plays the same role as on the initial stage played by the observed currents

. In the next stage, the network model is included not only without feeders 4 and 5, but also without feeder 3 (Fig. 5). Shunts 25-30 remain in their places, the place of action of the current i _f and he himself is still not known, but the quasi-observable quantities are known $${\text{i}}_{\text{de}}^{\left(\text{one}\right)}$$

and u _de , and still third currents in output shunts 25-30

,

the value of which the shortening of the model did not affect. At the next stage of transformations, these currents play the same role that the observed currents played at the output of the model of FIG. 1. Therefore, they now introduce new notation

where the first superscript indicates the type of current, and the second is the stage number.

(фиг. 6). Режим третьих токов, определяемых какThe voltage u _de at this next stage is the only known model voltage. Namely, it determines the EMF 31, which creates the mode of second currents in a normal, albeit shortened network model

(Fig. 6). Third current mode, defined as

takes place in the model, where the source 31 is replaced by a shunt 32, and the model is activated by the fault current i _f (Fig. 7). In this model, the same phenomenon is observed that occurred with feeders 4, 5 in the third current model of FIG. 3. In the latter case, the shunting of node 14 leads to the fact that the paths of the flow of currents of branch 7 and branches 11-13 are lost

устремляется в ветвь 6, появляется возможность определить напряжение u_dd узла 15 и подходящий к нему ток

(фиг. 8).As a result, the model is even more localized relative to the damaged area. As soon as it becomes known that all current

rushes to branch 6, it becomes possible to determine the voltage u _dd node 15 and the current suitable for it

(Fig. 8).

To the next stage (with the second number), the network model fits even shorter without branches 6, 7 and branches 11-13 (Fig. 9). Currents reassigned in the accepted form

и выходные $$i_{d\nu }^{\left(\mathrm{2,2}\right)}$$

. Далее следует очередной переход к особому аварийному режиму с очередными третьими токамиthose. the third output currents of the first stage of model transformation at the second stage begin to play the role of the first quasi-observed currents. The second currents of the new stage are determined by the response of the normal network model, shortened to three branches 8-10 (Fig. 10), to the action of the source u _dd . Four currents are reactions - input current $$i_{dd}^{\left(2\right)}$$

and weekend $$i_{d\nu }^{\left(2.2\right)}$$

. Then follows the next transition to a special emergency mode with the next third currents

which occur in the model with a shunt 34 instead of the EMF 33 and the only source i _j (Fig. 11). All undamaged branches 9, 10 in this model are shunted on both sides, as a result of which they are de-energized

и

After removing the de-energized branches 9, 10, the only part remains in the network model (Fig. 12), which solves the task of finding the damaged part. His model 8 is fully prepared for solving the next problem - determining the coordinate x _f : at the input and output, shunts 34 and 25 are installed, in which known currents flow

and

на входах фидеров 3-5, напряжения u_dν, u_eν и токи

на входах сети. Наблюдаемые величины фиксируются в цифровой форме и сохраняются в памяти микропроцессорной системы релейной защиты. Из зафиксированных величин выделяют информационные составляющие - величины нулевой последовательности i₀, u₀ или фазные безнулевые компоненты аварийных составляющихThe proposed method includes several operations of the same type performed in a certain sequence. They are preceded by preparatory operations for fixing currents and voltages observed at the inputs and outputs of the network. In the network of FIG. 1 voltage u is observed on buses 2 of substation 1, currents

at the inputs of feeders 3-5, voltage u _dν , u _eν and currents

at the network inputs. The observed values are recorded digitally and stored in the memory of the microprocessor relay protection system. From the recorded values, information components are distinguished - values of the zero sequence i ₀ , u ₀ or phase non-zero components of emergency components

σ = A, B, C - phase designation, the indices "PD" and "TC" denote the values of the modes - preceding the closure and occurred after the closure. The upper roof-shaped symbol marks the values of the previous mode, extrapolated to the time after closure. The indices “0”, σ, “ав” are then omitted and all values indicated in FIG. 1-12, present their informational components.

$$u_{\sigma ,ав}^{\text{'}}.$$

The microprocessor relay protection system has a two-wire network model, presented in the basis of information components with passive parameters of zero or direct sequence, respectively, for values of i ₀ , u ₀ or $$i_{\sigma ,\mathrm{but}\mathrm{at}}^{\text{'}\text{'}},$$

$$u_{\sigma ,\mathrm{but}\mathrm{at}}^{\text{'}\text{'}}.$$

The key idea of the proposed method is to separate the information component of the current into two components. The information component is the first current i ⁽¹⁾ , its components i ⁽²⁾ and i ⁽³⁾ . When searching for damage, the information delivered by component i ^{(3) is used} . It is defined as the difference (1) after a preliminary determination of the currents i ⁽¹⁾ and i ⁽²⁾ .

At the initial stage of operation of the relay protection system, the voltage and the first currents give observation of a real network (Fig. 1). Next, perform operations with the network model. An intact network model is available for relay protection. In order to obtain the second components of currents i ^(2,0) , an original mode is created in the existing model by acting on it with sources of known voltages 17-23 (Fig. 2). The second currents are fixed at the points of this normal model corresponding to the observation points of the network a, b, c, dν, eν. Third currents are defined as the differences between the informational components of the observed currents and the reactions of the normal model. The next operation is to control the level of each of the third currents, identify feeders with zero currents; in the illustration, condition (2) is accepted.

By the next step in the implementation of the method, the model is simplified. Submodels of intact feeders 4 and 5 are disconnected, shunts 24-30 are installed at the observation sites (Fig. 3). At a new stage, an assumption is made that feeder 3 is not damaged. If in fact it is damaged, this circumstance will become clear at the end of the stage. An intact feeder 3 makes it possible to determine the state of its output - node 14 (Fig. 4). The output current and voltage of the feeder is expressed through the current of its shunted input 24 using known operations [5]

where R _B is the wave resistance of the feeder, R ⁰ , L ⁰ , C ⁰ are its primary parameters of zero or direct sequence depending on the type of information components of electrical quantities, l is the length of the feeder 3, τ is the travel time along the feeder of the zero or direct wave sequence.

и выходным

получающим свои обозначения согласно равенству (3), придается статус квазинаблюдаемых, т.е. первых токов. Вторые токи определяют в нормальной модели остающейся части сети (фиг. 6). Источником 31, воздействующим на модель, служит единственное известное здесь напряжение u_de. Фиксируемые реакции - токи

Главные информационные компоненты - третьи токи - определяют как разности (4)-(6). Модель, в которой они протекают, содержит шунт 32 на месте источника 31 и активизируется неизвестным током i_j. Анализ уровней третьих токов

на выходах модели подсказывает, в какой части модели произошло замыкание. Если выходные токи как ответвлений 25-27, так и 28-30 ненулевого уровня, то это говорит о том, что замыкание находится на фидере 3 и гипотеза, на основании которой производились операции (12), (13), неверна. Если же имеет место ситуация, показанная на фиг. 7, то гипотеза была верна и обнаружится признак (7) - нулевой уровень токов в участках 7, 11-13.At the current stage of the search for the damaged area, node 14 serves as the input to the remaining model, at the outputs of which shunts 25-30 and currents flowing in them are stored. It remains to be seen where the closure occurred - in the feeder 3 or in the direction of one of the branches 6 or 7 (Fig. 5). All known model currents, input $${\text{i}}_{\text{de}}^{\left(\text{one}\right)}$$

and weekend

receiving their designations according to equality (3), the status of quasi-observables is given, i.e. first currents. The second currents are determined in the normal model of the remaining part of the network (Fig. 6). The source 31 acting on the model is the only voltage u _de known here. Fixed reactions - currents

The main information components - the third currents - are defined as the differences (4) - (6). The model in which they flow contains a shunt 32 in place of the source 31 and is activated by an unknown current i _j . Analysis of the levels of third currents

at the outputs of the model, it tells in which part of the model a circuit has occurred. If the output currents of both branches 25-27 and 28-30 are of nonzero level, then this indicates that the circuit is on feeder 3 and the hypothesis on the basis of which operations (12), (13) were performed is incorrect. If the situation shown in FIG. 7, then the hypothesis was true and the sign (7) is revealed - a zero level of currents in sections 7, 11-13.

и на этот раз будет принята гипотеза о том, что ветвь 6 не повреждена. Определение ее выходных величин

выполняют с помощью операций, аналогичных (12), (13), но с теми значениями параметров, которые присущи ветви 6 (фиг. 8). На этом последнем этапе модель состоит только из ответвлений 8-10 (фиг. 9). Известно состояние квазинаблюдаемого узла 15 и выходные токи

переобозначенные по правилу (8). Модель тестируют в нормальном состоянии источником 33, развивающим напряжение u_dd (фиг. 10). Токи

, возникающие в этой модели, позволяют совершить операции (9), (10) и найти третьи токи, протекающие в модели с шунтом 34 на входе и неизменно зашунтированными выходами (фиг. 11). Контролируют уровни выходных токов

и судят по ним о поврежденном участке. В первую очередь необходимо проверить справедливость гипотезы о том, что ветвь 6 не повреждена. Если уровни всех выходных токов ненулевые, гипотеза отвергается и поврежденным участком сети признается ветвь 6. Если же выполняется условие (11), говорящее о том, что ненулевой уровень у единственного выходного тока

то, наконец, выявляется поврежденный участок 8, что и является целью обсуждаемого способа. Токи

на обеих зашунтированных сторонах поврежденного участка известны (фиг. 12), что делает возможным решение последующей задачи определения места повреждения.By the next step, the model is simplified even further. Branch 7 and branches 11-13 are turned off, the input current of branch 6 is equal

and this time, the hypothesis that branch 6 is not damaged will be accepted. Determination of its output values

performed using operations similar to (12), (13), but with those parameter values that are inherent in branch 6 (Fig. 8). At this last stage, the model consists only of branches 8-10 (Fig. 9). The state of the quasi-observable node 15 and the output currents are known

reassigned by rule (8). The model is tested in the normal state by a source 33 developing a voltage u _dd (Fig. 10). Toki

arising in this model allow you to perform operations (9), (10) and find the third currents flowing in the model with a shunt 34 at the input and permanently shunted outputs (Fig. 11). Monitor output current levels

and judge by them about the damaged area. First of all, it is necessary to verify the validity of the hypothesis that branch 6 is not damaged. If the levels of all output currents are nonzero, the hypothesis is rejected and branch 6 is recognized as a damaged part of the network. If condition (11) is satisfied, which means that the only output current has a nonzero level

then, finally, the damaged area 8 is revealed, which is the purpose of the discussed method. Toki

on both shunted sides of the damaged area are known (Fig. 12), which makes it possible to solve the subsequent problem of determining the location of damage.

Thus, it is proved that the separation of the informational components of currents and voltages into specific components leads to a regular way of identifying a damaged section of a branched distribution network. It is significant that there are no restrictions due to the nature of the observed processes.

Information sources

1. Popov I.N., Lachugin V.F., Sokolova G.V. Relay protection based on transient monitoring. - M .: Energoatomizdat, 1986.

2. RF patent No. 2033623, G01R 31/11, H02H 3/28, 1989.

3. Jen-Hao Teng, Wei-Hao Huang. Automatic and fast faulted line-section location method for distribution systems based on fault indicators. - IEEE Trans, on Power Systems, 2014, V. 29, No. 4, P. 1653-1662.

4. RF patent No. 2516371, G01R 31/08, 2013.

5. Lyamets Yu.Ya., Belyanin A.A., Voronov P.I. Algorithmic modeling of the feeder in transition mode. - Izv. universities. Electromechanics, 2013, No. 5, S. 49-56.

Claims (1)

The method for determining the damaged section of a branched distribution network, consisting of feeders with inputs connected to common buses, and branches whose outputs are connected to the loads, when monitoring currents and voltages at the inputs and outputs of the network using the network model in the normal state, according to which information components of currents and voltages, make up a normal two-wire network model for information components, fix the first currents as information components of the observed currents, p give the inputs and outputs of the normal network model the observed voltages and determine its reactions at all inputs and outputs in the form of second currents, characterized in that they determine the third currents as the difference between the corresponding first and second currents, control the levels of third currents at the supply inputs of the distribution network feeders , identify the feeder with a non-zero level of the third current, while other feeders have a zero level, and note the closure in the detected feeder or in its branches, shunt all inputs of the model of the said feed ra and its branches, transfer the power input of the shunted model to the nearest node, for which they convert the third feeder current to the node voltage and the current suitable for the node, thereby shortening the model by the feeder length, take the current and currents in the shunted outputs as the first ones to the node currents of the shortened model, feed the node voltage to the input of the shortened normal network model, determine the response of this model to the shunted outputs in the form of second currents, find the third currents as the difference between the first and second currents, the controller comfort levels of the third currents, and if all the output third currents have a non-zero level, they check the circuit in the feeder, and if the third currents of one of the branches have a non-zero level and the rest are zero, they check the circuit in the branch with non-zero levels of third currents and repeat the indicated operations until the network model is reduced to one damaged section.

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