Method for identifying internal and external faults of bus area through simulation after test

A technology of post-test simulation and busbar area, applied in the fault location and other directions, can solve problems such as protection malfunction and refusal to operate

Active Publication Date: 2015-04-22
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The current differential principle is greatly affected by the load current, and the current phase comparison principle can only operate when the bus current exists, and these two principles are not applicable to the internal fault of the 3 / 2 circuit breaker when there is current in the bus Outflow may cause false action and refusal of protection

Method used

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  • Method for identifying internal and external faults of bus area through simulation after test
  • Method for identifying internal and external faults of bus area through simulation after test
  • Method for identifying internal and external faults of bus area through simulation after test

Examples

Experimental program
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Effect test

Embodiment 1

[0061] Example 1: The system is single-bus connection, three-circuit outgoing line, and the line is a split conductor. A distributed parameter model considering the influence of frequency variation (J.Marti line model according to frequency) is adopted, and the length of the outgoing line is 300km. Among them, , , , , , , A phase ground fault occurs in the system, and the grounding resistance is 10 ohms.

[0062] When an internal fault occurs in the bus, the power network is equivalent to a Circuit model, in a short time window, at the measured bus Modulus fault component voltage and component current , and then analyze Model the fault component network properties, using Kirchhoff's voltage theorem (The current direction is positive when flowing into the busbar), and the voltage at the busbar is simulated and calculated , and then calculate the analog voltage Waveform and measured voltage Correlation coefficient of waveform , will simulate the volt...

Embodiment 2

[0069] Embodiment 2: The structure and parameters of the system bus are the same as those in Embodiment 1. A phase-to-ground fault (A-G) occurs on outgoing line 1, the fault location is 200km away from the busbar, and the transition resistance is 10 ohms. The length of the short data window (time window) is 3ms, and the sampling frequency is 20kHz.

[0070] The sampling frequency is 20kHz, the short time window is 3ms, and the data length is measured N =60. After the failure of outgoing line 1, according to the same method as in embodiment 1, according to the measured Modulus fault component current and system positive sequence resistance value , Positive sequence inductance value , calculate the analog voltage at the busbar and the correlation coefficient between the analog voltage waveform and the measured voltage waveform, and get =-0.5815<0, according to which it is judged as non-bus fault;

Embodiment 3

[0071] Embodiment 3: The structure and parameters of the system bus are the same as in Example 1. A phase-to-ground fault (A-G) occurs on outgoing line 2, the fault location is 150km away from the busbar, and the transition resistance is 10 ohms. The length of the short data window (time window) is 3ms, and the sampling frequency is 20kHz.

[0072] The sampling frequency is 20kHz, the short time window is 3ms, and the data length is measured N=60. After the failure of outgoing line 2, according to the same method as in embodiment 1, according to the measured Modulus fault component current and system positive sequence resistance value , Positive sequence inductance value , calculate the analog voltage at the busbar and the correlation coefficient between the analog voltage waveform and the measured voltage waveform, and get =-0.6348<0, according to which it is judged as non-bus fault;

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Abstract

The invention provides a method for identifying internal and external faults of a bus area through simulation after test, and belongs to the technical field of power system relay protection. The method comprises the following steps of: when an internal fault of a system bus occurs, making a transmission line equivalent to a resistor-inductor (RL) circuit model, and in a short-time window, measuring a voltage fault component and a current fault component of an alpha modulus at a bus; analyzing fault component network characteristics of the RL model, listing an equation according to the Kirchhoff's voltage law, and performing analog calculation to obtain voltage at the bus; calculating a related coefficient r between an analog voltage waveform and the measured voltage waveform; and comparing analog voltage with the measured voltage, and judging and identifying the internal and external faults of the bus area according to the similarity and the related coefficient of the two waveforms. According to the method, the current fault component of the alpha modulus at the bus is utilized, and the analog voltage is calculated according to the Kirchhoff's voltage law and is subjected to correlation comparison with the measured voltage waveform, so that the internal and external faults are identified; and the method has the advantages of sensitivity and reliability for identifying the internal and external faults of the bus area, and the like, and is suitable to be promoted and used in electric power systems.

Description

technical field [0001] The invention relates to a method for simulating and identifying faults inside and outside a busbar area after measurement, and belongs to the technical field of fault identification and protection inside and outside the busbar area of ​​a power system. Background technique [0002] The busbar is the hub of power transmission and distribution in the power system. Generators, transformers, transmission lines, distribution lines and other equipment are connected to the busbar. Failures of the busbar may damage a wide range of electrical equipment, disrupt the stable operation of the power system, and damage power generation. The normal operation of the plant even caused the disintegration of the power system and large-scale power outages for users. Compared with the development of line protection, the development of busbar protection is relatively slow. Therefore, it is necessary to strengthen the research on busbar protection. [0003] The current bus...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/08
Inventor 束洪春何廷一董俊
Owner KUNMING UNIV OF SCI & TECH
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