RU2107304C1 - Method of determination of damaged place in power line with two-way supply - Google Patents

Abstract

FIELD: electrical engineering. SUBSTANCE: for method realization moment of damage is recorded. Voltages and currents of fundamental harmonic of emergency and preemergency modes are measured at the beginning of line, and emergency components of measured voltages and currents are separated. Measured values and their emergency components are converted to voltages and currents of supposed damaged places by means of formed line voltage and current models. Reactive parameter of supposed damaged places is formed, and place of damage is determined by zero value of the above-indicated parameter. For conversion of voltage and current of preemergency and emergency modes measured at input, as well as of their components, to voltages and currents of supposed damaged places, inherent and reciprocal parameters of power line model are determined relative to group of its inputs in emergency mode, and elementary models with respective inherent and reciprocal parameters are formed. Then emergency voltage and current models are composed of different pairs of elementary models. In this case, emergency voltage model is composed of first and second elementary models, and emergency current model is composed of third and fourth elementary models. First elementary model is formed of inherent and mutual conductances of line inputs. Second elementary model is formed of inherent and mutual conductances between beginning of line and supposed damaged place. Third elementary model is formed of inherent and mutual conductances between supposed damaged place and line beginning, and fourth elementary model is formed of inherent and mutual conductances of inputs of supposed damaged places. Emergency components of measured voltages are passed through first elementary model. Its output values are passed through second elementary model in reverse direction. Thus emergency components of voltage at place of supposed damage are obtained. Emergency components of measured voltages are passed through third elementary model, and output values of emergency voltage model are passed through fourth elementary model. Output values obtained are summed up with opposite sign, thereby obtaining output values of emergency current models (full currents) at supposed damaged place. EFFECT: reduced time of damage place determination. 2 tbl, 11 dwg

Description

 The invention relates to electrical engineering, namely to relay protection and automation of electrical systems, is intended to identify the location of damage to power lines by the results of a one-sided measurement of its voltages and currents, in addition, can be used for remote protection of power lines based on microprocessor technology.

 Known methods for determining the location of damage to the power line with two-way power according to the results of one-way monitoring using its models [1]. According to these methods, the fact of damage is recorded, voltage and emergency currents are measured on one (observed) side of the line, they are converted into input resistances, the ratio of which determines the distance to the place of damage.

 The indicated methods are characterized by a methodological error, in particular, the dependence of the result on the transition resistance of a short circuit.

 Closest to the claimed technical essence is a method for determining the place of damage of a line with double-sided power supply, by which the moment of damage is recorded, the voltages and currents of the main harmonic of the pre-emergency and emergency modes are measured, the emergency components of the measured voltages and currents are isolated, the measured values are converted and their emergency components using the formed voltage and current line models into the voltages and currents of the places of the alleged damage, form a reactive th position parameter assumed damage, for example the total reactive power consumed at these locations, and determining the fault location for a zero value of said parameter [2].

 In fact, in the prototype the pre-emergency voltage model and combined emergency voltage and current models are formed, which together allow converting the voltage and currents of the pre-emergency and emergency modes measured at the beginning of the line, as well as their emergency components, to the voltage and current of the places of the alleged damage, from which it is then formed reactive parameter of the sites of the alleged damage. In the pre-emergency voltage model, the pre-emergency components of the measured voltages and currents are converted to the pre-emergency components of the voltage of the places of the alleged damage, in the combined emergency voltage and current models, the emergency components of the measured voltages and currents are converted to the emergency components of the voltage and the total currents of the places of the alleged damage, and then, summing the output values pre-emergency stress model, receive full stress at the site of the alleged damage. The transformations begin with the fact that in the pre-emergency stress model the equivalent EMFs are tuned on the unobservable side of the line and the pre-emergency components of the voltage of the places of the alleged damage are measured. Then, specific transformations are made in the combined emergency models: they supply the emergency component of the measured voltage to their inputs and balance the emergency components of the currents by connecting and regulating the complex load at the site of the alleged damage. The currents in the resistances of the complex load and the voltage on them are the result of the conversion of emergency models: emergency voltage components and total currents of the places of the alleged damage.

 The disadvantage of this method is that a significant number of operations are performed after the occurrence of damage, which excessively increases the time required to determine the location of the damage. As follows from the foregoing, the formation of a reactive parameter of the places of alleged damage is fundamentally possible only after fixing the moment of damage and measuring the currents and voltages of the pre-emergency and emergency mode at the beginning of the line, as well as after highlighting their emergency components, since only then it becomes possible to compare the model currents and measured currents. In addition, the complexity of converting the measured (and isolated) values to the voltages and currents of the locations of the alleged damage associated with the use of a full model of the power line, taking into account the influence of cables, parallel lines, solders, bypasses, only exacerbates this drawback.

 In the proposed method, places of damage to a power line with two-way power supply fix the moment of damage, measure the voltages and currents of the main harmonic of the emergency and pre-emergency modes at the beginning of the line, isolate the emergency components of the measured voltages and currents, convert the measured values and their emergency components using the generated voltage and current models lines in the voltages and currents of the locations of the proposed damage, for which they determine their own and mutual parameters of the model of the electric line cottages relative to the groups of its inputs in emergency mode and form elementary models with corresponding own and mutual parameters, make emergency voltage and current models from different pairs of elementary models, and the emergency voltage model from the first and second elementary models, the emergency current model from the third and fourth elementary models, while the first elementary model is formed from the intrinsic and mutual conductivities of the line inputs, the second from intrinsic and mutual conductivities between the beginning scrap of the line and the location of the alleged damage, the third - from the intrinsic and mutual conductivities between the location of the alleged damage and the beginning of the line, the fourth - from the intrinsic and mutual conductivities of the inputs of the locations of the alleged damage, the emergency components of the measured voltages are passed through the first elementary model, its output values are subtracted from the emergency components of the input currents, difference values are passed in the opposite direction through the second elementary model, receiving the output values of the emergency on of the breeding model - emergency voltage components at the site of the alleged damage, emergency components of the measured voltages are passed through the third elementary model, the output values of the emergency stress model are passed through the fourth elementary model, and the output values of the third and fourth elementary models are summed with opposite signs, obtaining the output values of the emergency current models - total currents in the place of the alleged damage, form the reactive parameter of the places of the supposed damage and determining the fault location for a zero value of said parameter.

 As a result, the prototype is supplemented by a series of operations that reduce the time spent on determining the place of damage after fixing the moment of the accident, since the problem of converting the measured (and selected) values at the beginning of the line into currents and voltages of the place of the alleged damage is solved in a new way, so the most complex operations can be performed in advance, even before damage occurs. If the method is implemented on a multiprocessor controller, then operations can be performed in parallel, without increasing the total processing time of information about the status of the power line. Such operations include determining their own and mutual parameters with respect to the input groups of the power line model in emergency mode, the formation of elementary models, the compilation of current and emergency voltage models from elementary ones. After a short circuit occurs, only a limited number of operations are performed: the conversion of the measured voltages and currents, as well as emergency components using the appropriate emergency and pre-emergency voltage and current models, into the voltages and currents of the locations of the proposed damage, the formation of a reactive parameter, the search for the location of damage by zero value last one.

 The method, as can be seen, reduces the time to determine the location of damage, since the most time-consuming operations are performed on models in advance, before the occurrence of damage. The accuracy of determining the location of damage due to the fact that when compiling line models does not make any restrictions on the consideration of its features, remains high.

 An illustration of the method are the circuit (Fig. 1-11) and table. 12.

 Figure 1 shows a functional diagram of a power line; in FIG. 2 - model of this line in pre-emergency mode; in FIG. 3 - line model in pure emergency mode (for emergency components of voltages and currents); in FIG. 4-9 are diagrams of operations with the model for determining intrinsic and mutual conductivities between the place of observation and the site of the alleged damage in emergency mode; FIG. 10-11 - two structures, either voltage or current, formed from elementary models, depending on the type of which and the nature of the input quantities supplied to them, they can form various voltages and currents; in table 1 shows the composition of the input and output values of current and voltage models, their pairs of elementary models as applied to the structures of the models of FIG. 10 and 11; in table 2 summarizes the operations performed in the models.

 The place of observation of the line (Fig. 1) and at the same time its beginning are considered to be the input terminals 1, 2, 3. The distance x, counted from this place, is interpreted here as the place of the alleged damage and is marked by terminals 4, 5, 6. Another group of terminals 7, 8, 9, the three-wire part of the unobservable side of the power transmission is marked. In addition to the phase conductors of line 10, the power transmission circuit includes a lightning protection cable 11, a tap 12, one or more parallel circuits and bypass connections shown in the form of an integrated circuit 13, areas of convergence with other lines, for example, 14. In addition, it includes an unobservable system 15 and damage as a separate unit 16, creating an emergency mode.

 The power transmission is characterized by a pre-accident model 17, consisting of a model of line 18, which is generally active, that is, containing sources, and a model of an unobservable system 15 (Fig. 2).

 Power transmission model 19 for emergency components (pure emergency mode) differs from model 17 in the absence of sources (Fig. 3). The passive model of line 20 is obtained from the model of line 18 by excluding sources in blocks 13, 14 and at the receiving end of solder 12, if any. The passive model 21 of the unobservable system differs from the original model 15 only in the level of the emf of the sources: in 15 they are non-zero, and in 21 they are zero.

 When determining the intrinsic and mutual conductivities in emergency mode, for each place of the alleged damage, a maximum of six connections of the power transmission model 19 for emergency components (Fig. 4-9) are made using one of the six terminals to a single voltage source 22, while all the other five terminals are closed to a common the bus.

 According to their own and mutual parameters of the passive models 19 and 20, various elementary models 23, 24 are formed (Figs. 10, 11, Tables 1, 2), of which they are then composed using the summation operation of 25 tension 26 and current 27 models.

 Further, the following notation and concepts are used (as for currents and voltages, then we are always talking about the values of the fundamental harmonic).

 I.

- вектор фазных напряжений;

- вектор фазных токов;
т - индекс транспонирования;

- напряжения (полное и доаварийная составляющая) и ток в месте предполагаемого повреждения x;

- измеренные напряжение и ток доаварийного режима в начале линии;

- измеренные напряжение и ток аварийного режима в начале линии;

- аварийные составляющие наблюдаемых напряжения и тока (напряжение и ток чисто аварийного режима) в начале линии, определяются путем обработки измеренных доаварийных и аварийных входных величин

,

- аварийные составляющие напряжения в месте предполагаемого повреждения x.

- vector of phase voltages;

- vector of phase currents;
t is the transpose index;

- voltage (full and pre-accident component) and current at the site of the alleged damage x;

- the measured voltage and current of the pre-emergency mode at the beginning of the line;

- measured voltage and emergency current at the beginning of the line;

- emergency components of the observed voltage and current (voltage and current of pure emergency mode) at the beginning of the line, are determined by processing the measured pre-emergency and emergency input values

,

- emergency voltage components at the site of the alleged damage x.

- собственных и взаимных проводимостей (параметров), определенных в предположении, что в месте с координатой x произошло трехфазное металлическое короткое замыкание: зажимы 4-6 соединены с землей; блоки матрицы есть элементарные модели

(фиг. 4-9),

.II. Matrices:

- intrinsic and mutual conductivities (parameters), determined under the assumption that a three-phase metal short circuit occurred at a location with coordinate x: terminals 4-6 are connected to ground; matrix blocks are elementary models

(Fig. 4-9),

.

- первая, составлена из собственных и взаимных проводимостей входов места наблюдения (зажимы 1-3);

- вторая, составлена из взаимных проводимостей между местом наблюдения и местом предполагаемого повреждения (зажимы 1-3 и 4-6);

- третья, составлена из взаимных проводимостей между местом предполагаемого повреждения и местом наблюдения (зажимы 4-6 и 1-3);

- четвертая, составлена из собственных и взаимных проводимостей места предполагаемого повреждения (зажимы 4-6).III.Elementary models:

- the first, composed of intrinsic and mutual conductivities of the inputs of the observation site (clamps 1-3);

- the second, made up of mutual conductivities between the site of observation and the site of the alleged damage (clamps 1-3 and 4-6);

- the third, composed of mutual conductivities between the site of the alleged damage and the site of observation (clamps 4-6 and 1-3);

- fourth, composed of intrinsic and mutual conductivities of the site of the alleged damage (clamps 4-6).

- модель

, включенная в обратном (инверсном) направлении.Other designations;

- model

included in the reverse (inverse) direction.

в месте предполагаемого повреждения x можно получить полное напряжение как наложение доаварийной и аварийной составляющих напряжений

.IV. According to the method of reducing to zero initial conditions [3] after determining separately the voltage of the emergency and pre-emergency modes

in the place of the alleged damage x, the total voltage can be obtained as the superposition of the pre-emergency and emergency components of the voltage

.

подобного напряжения не требуется, поскольку в предшествующем режиме тот отсутствовал:

.For current at location x

such voltage is not required, since in the previous mode it was absent:

.

,

.The complete passive power transmission model 19, considered with respect to the clamps of the observation site 1-3, the clamps of the site of the alleged damage 4-6 and two earth clamps connected to a common bus, is a 2x4 pole. It is known that the currents and voltages at the terminals in this case are related by the relation [3]:

,

.

.In the short circuit mode, the difference in the resistance of the forward and reverse sequence of electrical machines is usually not manifested, and then the reciprocity property is satisfied:

.

- симметрическая, и из тридцати шести ее элементов независимых остается только двадцать один.If property (5) holds, then the matrix

- symmetric, and out of thirty-six of its independent elements, only twenty-one remain.

.Equation (4) can be converted to two matrix equations connecting the observation current and the fault current with the observation voltage and the damage voltage:

.

Преобразование входных величин

в доаварийные составляющие напряжения мест предполагаемого повреждения

производится традиционно с использованием доаварийной напряженческой модели [2].Considering observation clamps 1–3 as input terminals of an eight-terminal device, and 4–6 as output terminals, one can transform equation (6) into a reverse gear form by expressing the emergency voltage component at location x through the emergency input voltage and current components:

Convert Input Values

in pre-accident voltage components of the locations of the alleged damage

traditionally produced using the pre-emergency stress model [2].

 For the proposed method, it is fundamentally important that the intrinsic and mutual conductivities depend neither on the type of short circuit nor on the values of the transient resistances and can be determined before damage is detected, moreover, independently of each other.

 The proposed method for determining the location of damage to the power line with two-way power is as follows.

 1. The moment of damage is recorded, separating the pre-emergency and emergency modes, for which starting bodies are used, for example [4].

и аварийного

режимов в начале линии.2. Measure the voltage and currents of the fundamental harmonic of the pre-emergency

and emergency

modes at the beginning of the line.

согласно (1).3. The emergency components of the measured voltages and currents are isolated

according to (1).

и их аварийные составляющие

с использованием образованных напряженческих и токовых моделей линии в напряжения

и токи

мест предполагаемого повреждения, для чего
4.1. определяют взаимные и собственные проводимости модели линии электропередачи относительно двух групп зажимов: начала линии и мест предлагаемого повреждения.4. Convert measured values

and their emergency components

using educated voltage and current line voltage models

and currents

places of alleged damage, for which
4.1. determine the mutual and intrinsic conductivities of the power line model with respect to two groups of clamps: the beginning of the line and the locations of the proposed damage.

 Note that the operations that make up this subparagraph are associated with testing the model of line 19, which can be performed at any time, regardless of the current state of the line and its load.

 To determine all conductivities, it is necessary to carry out six inclusions of the full passive power transmission model 19 (Fig. 4-9). Each time, one of the six terminals of power transmission 1-6 is supplied with a unit voltage from source 22. All the other five terminals are shorted to a common bus. By measuring the currents flowing into the clamps, the corresponding conductivities are obtained. The reciprocity property (5) makes it possible to reduce the number of measured currents: at the first turn-on (Fig. 4), six of them are measured, at the second - five, and at each subsequent one - one less. A total of six inclusions of the full model measures a maximum of 21 currents. Each inclusion is independent of five others, i.e. six relative models 19, can be turned on independently at the same time.

.Tests of model 19 in accordance with the diagrams of FIG. 4-9 are carried out for a given number of places of the proposed closure x in order to form a matrix for each of them

.

 4.2. Four elementary models are formed with the corresponding intrinsic and mutual parameters (see point III. Elementary models).

 The first elementary model is formed from the intrinsic and mutual conductivities of the inputs of the beginning of the line, the second from the mutual conductivities between the beginning of the line and the places of the supposed damage, the third elementary model is formed of the intrinsic and mutual conductivities between the places of the supposed damage and the beginning of the line, the fourth from the intrinsic and mutual conductivities entrances of places of alleged damage.

 4.3. They compose an emergency stress model from the first and second, emergency current - from the third and fourth elementary models.

и

в выходную

(фиг. 10, 11):

они охватывают операции (7), (8) если параметры

и входные величины задаются согласно табл. 1. Полное описание всех применяемых в данном способе моделей видно из табл. 2.Two types of dressing and current models are compiled from elementary models; they transform input quantities

and

on the weekend

(Fig. 10, 11):

they cover operations (7), (8) if the parameters

and input values are set according to table. 1. A full description of all the models used in this method can be seen from table. 2.

а памяти микропроцессорного контроллера.Models should be performed on the elements of digital technology, recording matrices

and the memory of the microprocessor controller.

.The output value of the emergency stress model (8) is the emergency component of the voltage at the site of the alleged damage

.

.The output value of the emergency current model (7), (10) is the total current at the site of the alleged damage

.

формируется доаварийная составляющая

с помощью настроенной на текущий доаварийный режим с напряжением

и током

доаварийной напряженческой модели (фиг.2).4.4. The full voltage at the site of the alleged damage [U (x)] is generated based on overlay (2), for which, in addition to the emergency component of the voltage at the site of the alleged damage

pre-accident component is formed

using the voltage set for the current pre-emergency mode

and current

pre-emergency stress model (figure 2).

.5. After the formation of voltages and damage currents, the reactive parameter of each location of the alleged damage is determined, for example, the reactive power consumed by the damage as a kind of load 16:

.

The location of the power line is determined in which the reactive parameter Q (x) passes through a zero value. It is the place of true damage x _f :
Q (X _f ) = O,
which follows from the resistive nature of the damage [5].

 As you can see, the most time-consuming operations associated with determining the location of damage to the power line in the proposed method are performed before the damage occurs on the line: determining the parameters of the model of the line 19 or 20 itself, drawing up voltage and current models corresponding to the places of the alleged damage.

в уже готовых моделях, определение реактивного параметра (11) и операция (12) определения места, в котором этот параметр изменяет свой знак, переходя через нулевое значение.In the post-accident period, the much less laborious part of the transformations remains: the formation of quantities

in ready-made models, the determination of the reactive parameter (11) and the operation (12) of determining the place where this parameter changes its sign, passing through the zero value.

 The method, thus, reduces the time to determine the location of the damage. The accuracy is also increased due to the fact that when drawing up a line model, no restrictions are made on taking into account its features.

 Sources of information.

 1. Eisenfeld A.I., Shalyt G.M. Definition of places of short circuit on lines with branches. M .: Energoatomizdat. 1988.

 2. RF patent N 2033622, cl. G 01 R 31/11, H 02 H 3/28, 1989. Bulletin of the invention, 1995, N 11 (prototype).

 3. Neyman LR, Demirchyan KS Theoretical foundations of electrical engineering. Volume 1. L.: Power Publishing. Leningrad. Separation. 1981

 4. RF patent N 2012971, cl. H 02 H 3/38, H 01 H 83/20. Bull. Inventor, 1994, N 9.

 5. Lyamets Yu. Ya., Ilyin V.A. Three-phase adaptive resistance relay. / Electrical Engineering 1994. N 1. C. 36-47.

Claims (1)

 A method for determining the place of damage of a power line with double-sided power supply by fixing the moment of damage, measuring the voltages and currents of the main harmonic of the emergency and pre-emergency modes at the beginning of the line, highlighting the emergency components of the measured voltages and currents, converting the measured values and their emergency components using the generated voltage and current models lines of voltage and currents of places of alleged damage, formation of a reactive parameter of places of alleged damage and determining the location of damage according to the zero value of the specified parameter, characterized in that they determine the own and mutual parameters of the power line model relative to the groups of its inputs in emergency mode and form elementary models with the corresponding own and mutual parameters, make emergency voltage and current models from different pairs of elementary models, the emergency stress model from the first and second elementary models, the emergency current model from the third and fourth elementary models, while the first elementary model is formed from the intrinsic and mutual conductivities of the line inputs, the second from intrinsic and mutual conductivities between the beginning of the line and the place of the alleged damage, the third is from intrinsic and mutual conductivities between the site of the alleged damage and the beginning of the line, the fourth is from the intrinsic and mutual conductivities of the inputs of the places of the alleged damage, emergency components of the measured voltages are passed through the first elementary model, its output values are subtracted and emergency components of the input currents, difference values are passed in the opposite direction through the second elementary model, receiving the output values of the emergency stress model - emergency voltage components at the site of the alleged damage, emergency components of the measured voltages are passed through the third elementary model, the output values of the emergency voltage are passed through the fourth elementary model models, and the output values of the third and fourth elementary models are summed up with the opposite bubbled signs, yielding output values emergency current models - full currents at the site of the intended damage.

Images