CN116298682A - Power distribution network fault positioning system and method - Google Patents

Abstract

The invention discloses a distribution network fault location system and method, comprising the following steps: using the voltage and current information generated in the fault loop after a fault, to perform a certain calculation and finally deduce the total impedance of the loop; When precise positioning, the precise positioning of distribution network faults is finally successfully realized. First, a large number of low-cost and low-cost fault indicators are used in the distribution network. Because of its reliable principle and reliability, it is especially suitable for complex distribution networks. Combined with the use of FTU, the location of the fault section can be well realized, and the change of electrical quantity in the power system before and after the fault recorded by the FTU is fully utilized. After analyzing it with the symmetrical component method, according to the relevant principles of the impedance method, deduce Based on the accurate fault distance formula under section location, finally with the support of power system automation technology, the precise fault location is completed only by using the data of the measurement points.

Description

A distribution network fault location system and method

technical field

The invention belongs to the technical field of distribution network fault location, and in particular relates to a distribution network fault location system and method.

Background technique

The distribution network refers to the power network that receives electric energy from the transmission network or regional power plants, and distributes it locally through power distribution facilities or distributes it to various users step by step according to voltage. It is composed of overhead lines, cables, towers, distribution transformers, isolating switches, reactive power compensators and some auxiliary facilities, etc., and plays an important role in distributing electric energy in the power network.

At present, there are still several problems in the fault location of distribution network:

(1) At present, the structure of the distribution network is complex and the number of measurement points is limited. How to use limited fault information to accurately locate faults under the condition of limited measurement points;

(2) The current distribution network automation level is not high, and sufficient fault information cannot be obtained in the actual distribution network. How to accurately locate faults in the distribution network under the condition of limited fault information;

(3) The distribution network is oriented to complex and diverse users, and its load current has a great impact on fault location due to different load conditions. How to accurately locate the fault of the power grid under various load currents.

Contents of the invention

The purpose of the present invention is to overcome the complex structure of the current distribution network existing in the prior art and the limited number of measurement points. How to use limited fault information to accurately locate faults under the condition of limited measurement points; current distribution network automation The level is not high, and enough fault information cannot be obtained in the actual distribution network. How to accurately locate the fault in the distribution network under the condition of limited fault information; the distribution network is oriented to complex and diverse users, and its load current Due to the different load conditions, it has a great impact on fault location. How to accurately locate the fault of the power grid under various load currents provides a distribution network fault location system and method. The distribution network fault location The system and method have the effect of accurately locating distribution network faults.

In order to achieve the above object, the present invention provides the following technical solutions: a distribution network fault location system and method, comprising the following steps:

Step 1: Use the voltage and current information generated in the fault loop after the fault to perform a certain calculation to finally derive the total impedance of the loop, and then divide the loop impedance value by the unit impedance length of the line to achieve the fault distance measurement;

Step 2: According to the number of measurement ends, it can be roughly divided into single-end distance measurement method and double-end distance measurement method;

Step 3: Compared with the single-ended ranging method, the double-ended ranging method is completely unaffected by factors such as system impedance and fault resistance, and the accuracy of the ranging result is higher, but it is difficult to achieve when used in distribution network lines, and it is economical not applicable;

Step 4: For the precise location of phase-to-phase short-circuit faults, the impedance method still has good applicability, in view of the complex and diverse actual conditions of the current distribution network;

Step 5: The positioning method based on segmental switches and reclosers has great advantages, low cost, and can be especially suitable for economically underdeveloped, especially remote and backward mountain villages. In addition, it has a simple structure, high reliability, and does not need to Specially set up information channels;

Step 6: The structure of the distribution network is complex, how to effectively perform topology analysis is the focus of fault location, and the matrix method makes full use of the topological characteristics of the distribution network, with the help of relevant theoretical knowledge of graph theory, to generate a description matrix for the distribution network, The description matrix can accurately describe the characteristics of the distribution network;

Step 7: Considering the wide use of FTU in the distribution network, when a fault occurs, the FTU will record a large number of electrical quantities that change in the system, making full use of these electrical quantities can be used for accurate fault location, through the analysis of the impedance method can be Realize accurate fault location.

Preferably, in step two, the single-ended ranging method is to use only the data of the single-ended electrical measurement of the transmission line to complete the distance calculation of the fault point. This method is simple to implement and does not need to consider information synchronization, but there are differences between the measured distance and the actual distance. large error.

Preferably, in step 3, in the precise fault location in the transmission network, the double-terminal method is often used for fault location, but the distribution network is different from the simple structure of the transmission network, and there are many problems when using the double-terminal method to locate the fault. The problem needs to be solved and the cost is high. The fault location accuracy of the distribution network is more easily affected by the line parameters. Aiming at the single-side power distribution network, a fault location method using double-terminal impedance is analyzed. The method is not limited by clock synchronization, and it is proposed on the basis of fully analyzing the fault location information platform. Based on the information platform in the multi-branched power grid, a group of single-phase distribution network lines without branches is sorted out. Ground fault location equations.

Preferably, in step three, this method only requires two steps, the first step: setting a sinusoidal signal of suitable frequency and the detection resistor at the beginning of the line; the second step: after the system reaches a steady state, measure the conditions at the beginning and end of the line And some necessary electrical quantities, so that all types of faults can be analyzed according to the symmetrical component method to obtain the positive sequence component, and the fault distance measurement equation can be further derived from the characteristics of the positive sequence component. On the one hand, this distance measurement method can Overcoming the positioning dead zone in the traveling wave method, on the other hand, the positioning is accurate and reliable, even if the line parameters are not accurate enough or the information is not synchronized, it will not be affected.

Preferably, in step 6, at the same time, the fault-related information is uploaded to the main station at the FTU, and the fault information matrix is regenerated, and the fault location can be located by analyzing and calculating the matrix.

Compared with the prior art, the present invention provides a distribution network fault location system and method, which has the following beneficial effects:

When the present invention accurately locates the fault of the distribution network, it finally successfully realizes the precise positioning of the fault of the distribution network. First, a large number of fault indicators with low price and low operating cost are used in the distribution network. It is especially suitable for complex distribution networks. With the use of FTU, it can well realize the location of the fault section, make full use of the changes in the electrical quantities in the power system before and after the fault recorded by the FTU, and analyze it with the symmetrical component method. According to the relevant principles of the impedance method, the precise fault distance formula based on section location is deduced. Finally, with the support of power system automation technology, the precise fault location is completed only by using the data of the measurement point.

The parts not involved in the device are the same as the prior art or can be realized by adopting the prior art. The present invention has scientific and reasonable structure, safe and convenient use, and provides great help to people.

Detailed ways

It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

In the description of the present invention, it should be noted that, unless otherwise specified and limited, the terms "installed", "set with", "connected", etc. should be understood in a broad sense, such as "connected", which may be a fixed connection , can also be a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

The present invention provides a technical solution: a distribution network fault location system and method, including the following steps:

Step 1: Use the voltage and current information generated in the fault loop after the fault to perform a certain calculation to finally derive the total impedance of the loop, and then divide the loop impedance value by the unit impedance length of the line to achieve the fault distance measurement;

Step 2: According to the number of measurement ends, it can be roughly divided into single-end distance measurement method and double-end distance measurement method;

Step 3: Compared with the single-ended ranging method, the double-ended ranging method is completely unaffected by factors such as system impedance and fault resistance, and the accuracy of the ranging result is higher, but it is difficult to achieve when used in distribution network lines, and it is economical not applicable;

Step 4: For the precise location of phase-to-phase short-circuit faults, the impedance method still has good applicability, in view of the complex and diverse actual conditions of the current distribution network;

Step 5: The positioning method based on segmental switches and reclosers has great advantages, low cost, and can be especially suitable for economically underdeveloped, especially remote and backward mountain villages. In addition, it has a simple structure, high reliability, and does not require Specially set up information channels;

Step 6: The structure of the distribution network is complex, how to effectively perform topology analysis is the focus of fault location, and the matrix method makes full use of the topological characteristics of the distribution network, with the help of relevant theoretical knowledge of graph theory, to generate a description matrix for the distribution network, The description matrix can accurately describe the characteristics of the distribution network;

Step 7: Considering the wide use of FTU in the distribution network, when a fault occurs, the FTU will record a large number of electrical quantities that change in the system, making full use of these electrical quantities can be used for accurate fault location, through the analysis of the impedance method can be Realize accurate fault location.

In the present invention, preferably, in step 2, the single-ended ranging method is to use only the data of the single-ended electrical measurement of the transmission line to complete the distance calculation of the fault point. This method is simple to implement and does not need to consider information synchronization, but the measured distance There is a large error with the actual distance.

In the present invention, preferably, in step 3, in the precise fault location in the transmission network, the double-terminal method is often used for fault location, but the distribution network is different from the simple structure of the transmission network. When using the double-terminal method to locate the fault There are many problems to be solved and the cost is high when locating. The fault location accuracy of the distribution network is easily affected by the parameters of the line. Aiming at the single-side power distribution network, a fault location using double-terminal impedance is analyzed. method, this method is not limited by clock synchronization, it is proposed on the basis of fully analyzing the fault location information platform, and based on the information platform in the multi-distributed power grid, a group of distribution networks without branches is sorted out Line single-phase ground fault location equations.

In the present invention, preferably, in step 3, this method only needs two steps, the first step: setting the sinusoidal signal of suitable frequency and detection resistance at the beginning of the line; the second step: after the system reaches a steady state, measure the beginning of the line And terminal conditions and some necessary electrical quantities, so that all types of faults can be analyzed according to the symmetrical component method to obtain the positive sequence component, and the fault location equation is further derived from the characteristics of the positive sequence component. On the one hand, the method can overcome the positioning dead zone in the traveling wave method, and on the other hand, the positioning is accurate and reliable, even if the line parameters are not accurate enough or the information is not synchronized, it will not be affected.

In the present invention, preferably, in step 6, at the same time, the fault related information is uploaded to the main station at the FTU, and the fault information matrix is regenerated, and the fault location can be located by analyzing and calculating the matrix.

When the present invention accurately locates the fault of the distribution network, it finally successfully realizes the precise positioning of the fault of the distribution network. First, a large number of fault indicators with low price and low operating cost are used in the distribution network. It is especially suitable for complex distribution networks. With the use of FTU, it can well realize the location of the fault section, make full use of the changes in the electrical quantities in the power system before and after the fault recorded by the FTU, and analyze it with the symmetrical component method. According to the relevant principles of the impedance method, the precise fault distance formula based on section location is deduced. Finally, with the support of power system automation technology, the precise fault location is completed only by using the data of the measurement point.

The preferred embodiments of the present invention have been described in detail above, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the disclosed content of the present invention. All belong to the protection scope of the present invention.

Claims (5)

1. A distribution network fault location system and method, characterized in that: comprise the following steps: Step 1: Use the voltage and current information generated in the fault loop after the fault to perform a certain calculation to finally derive the total impedance of the loop, and then divide the loop impedance value by the unit impedance length of the line to achieve the fault distance measurement; Step 2: According to the number of measurement ends, it can be roughly divided into single-end distance measurement method and double-end distance measurement method; Step 3: Compared with the single-ended ranging method, the double-ended ranging method is completely unaffected by factors such as system impedance and fault resistance, and the accuracy of the ranging result is higher, but it is difficult to achieve when used in distribution network lines, and it is economical not applicable; Step 4: For the precise location of phase-to-phase short-circuit faults, the impedance method still has good applicability, in view of the complex and diverse actual conditions of the current distribution network; Step 5: The positioning method based on segmental switches and reclosers has great advantages, low cost, and can be especially suitable for economically underdeveloped, especially remote and backward mountain villages. In addition, it has a simple structure, high reliability, and does not need to Specially set up information channels; Step 6: The structure of the distribution network is complex, how to effectively perform topology analysis is the focus of fault location, and the matrix method makes full use of the topological characteristics of the distribution network, with the help of relevant theoretical knowledge of graph theory, to generate a description matrix for the distribution network, The description matrix can accurately describe the characteristics of the distribution network; Step 7: Considering the wide use of FTU in the distribution network, when a fault occurs, the FTU will record a large number of electrical quantities that change in the system, making full use of these electrical quantities can be used for accurate fault location, through the analysis of the impedance method can be Realize accurate fault location. 2. distribution network fault location system and method according to claim 1, is characterized in that: in step 2, single-ended ranging method is exactly the distance calculation that only completes fault point with the data of transmission line single-ended electrical measurement, This method is simple to implement and does not need to consider information synchronization, but there is a large error between the measured distance and the actual distance. 3. The distribution network fault location system and method according to claim 1, characterized in that: in step 3, in the precise fault location in the transmission network, the double-ended method is often used for fault location, but the distribution network has Different from the simple structure of the transmission network, there are many problems to be solved and the cost is high when using the double-ended method to locate the fault. The fault location accuracy of the distribution network is more easily affected by the line parameters. Research and analysis of a fault location method using double-terminal impedance, this method is not limited by clock synchronization, it is proposed on the basis of fully analyzing the fault location information platform, using the information platform in the multi-branch power grid On the basis of , a set of single-phase ground fault location equations for distribution network lines without branches is sorted out. 4. The distribution network fault location system and method according to claim 1, characterized in that: in step three, the method only requires two steps, the first step: setting a sinusoidal signal of suitable frequency and a detection resistor at the beginning of the line ;The second step: After the system reaches the steady state, measure the conditions of the beginning and end of the line and some necessary electrical quantities, so that all types of faults can be analyzed according to the symmetrical component method to obtain the positive sequence component. The characteristics are further deduced to obtain the fault distance measurement equation. On the one hand, this distance measurement method can overcome the positioning dead zone in the traveling wave method, and on the other hand, the positioning is accurate and reliable, even if the line parameters are not accurate enough or the information is not synchronized. will not be affected. 5. The distribution network fault location system and method according to claim 1, characterized in that: in step 6, at the same time, upload fault-related information to the master station at the FTU, regenerate the fault information matrix, and analyze the matrix And calculation, you can locate the fault location.