Power distribution network fault protection method and system based on system resistance-capacitance ratio

A distribution network fault and distribution network technology, applied in the direction of fault location, emergency protection circuit device, fault detection according to conductor type, etc., can solve the problem of low security and stability of distribution network, low security, distribution network Problems such as low fail-safe efficiency

Inactive Publication Date: 2020-09-18
ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY +1
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Problems solved by technology

[0005] This application provides a distribution network fault protection method and system based on the system resistance-capacity ratio to solve the problem of low eff

Method used

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  • Power distribution network fault protection method and system based on system resistance-capacitance ratio
  • Power distribution network fault protection method and system based on system resistance-capacitance ratio
  • Power distribution network fault protection method and system based on system resistance-capacitance ratio

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Embodiment 1

[0049] see figure 1 , figure 1 It is a schematic flowchart of a distribution network fault protection method based on the system resistance-capacity ratio provided by the embodiment of the present application. Depend on figure 1 It can be seen that the distribution network fault protection method based on the system resistance-capacity ratio in this embodiment mainly includes the following process:

[0050] S1: Calculate the zero-sequence current of the non-faulted line when a single-phase ground fault occurs in the neutral point through a small resistance grounding system.

[0051] The operations in this embodiment are performed after a single-phase ground fault occurs in the neutral point grounded system through a small resistance. Specifically, step S1 includes:

[0052] S11: Use the formula Calculate the sum of the three phase-to-ground capacitance currents.

[0053] where n represents a non-faulty line, is the zero-sequence current of the non-fault line, j is the...

Embodiment 2

[0073] exist figure 1 and figure 2 On the basis of the illustrated embodiment see image 3 , image 3 It is a schematic structural diagram of a distribution network fault protection system based on the system resistance-capacity ratio provided by the embodiment of the present application. Depend on image 3 It can be seen that the distribution network fault protection system based on the system resistance-capacity ratio in this embodiment mainly includes: a first zero-sequence current calculation module, a second zero-sequence current calculation module, a unified format module, a resistance-capacity ratio coefficient calculation module, and a resistance-capacity ratio coefficient calculation module. A capacity ratio coefficient threshold calculation module and a line selection module.

[0074] Among them, the first zero-sequence current calculation module is used to calculate the zero-sequence current of the non-fault line when a single-phase ground fault occurs in the n...

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Abstract

The invention discloses a power distribution network fault protection method and system based on a system resistance-capacitance ratio. The method comprises the following steps that when a single-phase grounding fault occurs in a neutral point grounding system through a small resistor, the zero-sequence current of a non-fault line and the zero-sequence current of a fault line are calculated; formats of the zero-sequence voltage and the zero-sequence current of each feeder line are unified; a resistance-capacitance ratio coefficient of each feeder line is calculated by using a formula, then a resistance-capacitance ratio coefficient threshold value is calculated by using the formula according to the total capacitance-to-ground current level of a system; and finally lines are selected by using a resistance-capacitance ratio-based zero-sequence overcurrent protection criterion. The system comprises a first zero-sequence current calculation module, a second zero-sequence current calculation module, a format unification module, a resistance-capacitance ratio coefficient calculation module, a resistance-capacitance ratio coefficient threshold value calculation module and a line selectionmodule. The reliability and safety of grounding fault protection can be effectively improved, and the safety and stability of power distribution network operation are further improved.

Description

technical field [0001] The present application relates to the technical field of distribution network relay protection, in particular to a distribution network fault protection method and system based on system resistance-capacity ratio. Background technique [0002] In the urban distribution network, the distribution network in which the neutral point is grounded through a small resistance is widely used. Especially with the expansion of the grid scale, the capacitive current of the system to the ground continues to increase, resulting in insufficient compensation capacity of the arc suppression coil. Some substations gradually transfer the neutral point through the arc suppression coil system due to difficulties in expanding the arc suppression coil. The neutral point is grounded through a small resistance. With the application of the neutral point grounding method through small resistance in the distribution network more and more widely, when a single-phase ground fault ...

Claims

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Application Information

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IPC IPC(8): H02H7/26G01R31/08G01R19/175
CPCH02H7/26G01R31/086G01R19/175
Inventor 孙孔明李玉敦张国辉张婉婕赵斌超杨超史方芳李宽刘萌李娜王昕李乃永范荣奇
Owner ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID SHANDONG ELECTRIC POWER COMPANY
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