DC power distribution network fault disturbance identification method based on mutation integral product

A DC distribution network, fault disturbance technology, applied in the fault location, detecting faults according to conductor types, measuring electricity and other directions, can solve the problem of inability to distinguish the power fluctuation of DC line faults, shorten the protection delay, compensate for the selectivity and Insufficient reliability, effect of improved selectivity and reliability

Active Publication Date: 2019-08-16
ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

When the fault resistance is large or the power fluctuation amplitude is large, single-ended protection will not be able to reliably distinguish between DC line faults and DG (microgrid) power fluctuations

Method used

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  • DC power distribution network fault disturbance identification method based on mutation integral product
  • DC power distribution network fault disturbance identification method based on mutation integral product
  • DC power distribution network fault disturbance identification method based on mutation integral product

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0043] according to Figure 4 The flow chart shows the fault and disturbance identification of DC distribution network at both ends in detail.

[0044] S1. Set the DC microgrid to put 5MW loads in at 3s. The MMC of the converter station at both ends of the DC feeder and the connected DC microgrid will preliminarily determine the occurrence of a fault based on low voltage and current change rate protection, and quickly start the line fault disturbance identification element. Specifically The start criteria are as follows:

[0045] u dp -u dn set_S or d(i dp -i dn ) / dt>I set_S ,

[0046] Among them, u dp , u dn are the positive and negative voltages of the DC line, respectively; i dp i dn are the positive and negative currents of the DC line, respectively; U set_S It is the low voltage action threshold value, which is set to 0.9U in this embodiment dc (U dc is the rated inter-electrode voltage 20kV); I set_S Is the current differential action threshold value, which...

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Abstract

The invention discloses a DC power distribution network fault disturbance identification method based on a mutation integral product. According to the method, mutation integral operation of a mode current at two sides of a DG or a micro-power-grid in a DC power distribution network is performed during a fault transient-state period, an operation result is regarded as identification basis of line fault and power disturbance of the DC power distribution network based on the mutation direction and a product result, a disturbance identification signal is transmitted to a converter station, protective maloperation caused by power fluctuation of the DG (micro-power-gird) can be effectively avoided, and the determination of a fault occurrence section is assisted. According to the method, comparedwith non-unit protection, selectivity and reliability are further achieved, only identification information during the transient-state period needs to be transmitted, the communication traffic is small, the time delay is short, speed is further achieved compared with differential protection, and a certain application value is provided in the DC power distribution network with short lines.

Description

technical field [0001] The invention belongs to the field of identification of faults and disturbances in flexible direct current distribution networks, and relates to a reliable identification method for faults and disturbances in direct current distribution networks with distributed power generation devices or microgrids connected, in particular to a direct current system based on mutation integral products Distribution network fault disturbance identification method. Background technique [0002] At present, the protection configuration of the DC distribution network is not complete. Common single-ended quantity protections such as traveling wave protection and differential undervoltage protection have poor applicability to complex DC distribution networks with distributed generation (Distributed Generation, DG) or micro-grid access. Out-of-area faults, complex setting and coordination. The current differential protection based on double-terminal quantity can meet the s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 章雷其张雪松赵波林达徐珂李志浩汪湘晋祝旭焕叶雨晴马啸王子璇林湘宁李正天
Owner ELECTRIC POWER RES INST OF STATE GRID ZHEJIANG ELECTRIC POWER COMAPNY
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