A single-phase ground fault line selection method for DC transmission lines
A single-phase ground fault, DC transmission line technology, applied in the direction of the fault location, etc., can solve the problems of insufficient ability to withstand transition resistance and reduced protection reliability
Inactive Publication Date: 2017-02-22
EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID +1
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Problems solved by technology
[0008] The purpose of the present invention is to overcome the determination that the reliability of the existing DC line protection is reduced and the ability to withstand the transition resistance is insufficient during the step-down operation, and to provide a line selection method for single-phase grounding faults of the DC transmission line
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[0079] Such as Figure 6 , a high-voltage direct current transmission line traveling wave protection method with high sensitivity, comprising the steps in the following order:
[0080] 1) Power on the relay protection device;
[0081] 2) Assign value to traveling wave protection fixed value Δ 1 ,Δ 2 ; where Δ 1 It is the start-up setting value of the ground electrode voltage of this fault line selection method; Δ 2 It is the judgment value for the unidirectional change time of the ground electrode voltage;
[0082] 3) Measure the ground electrode line voltage U dN ;
[0083] 4) Calculate the average value U of the ground electrode voltage dN-AVG ;
[0084]
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The invention discloses a single-phase earth fault selection method of a DC (Direct Current) transmission line. The method comprises the following sequential steps: electrifying a relay protection device; assigning traveling wave protection constant values [delta] 1 and [delta] 2; measuring a grounding electrode circuit voltage UdN at a protection and installation side; calculating an average value of the grounding electrode voltage to be UdN-AVG; judging whether the formula that the UdN-AVG is more than [delta]1 or 1 -UdN-AVG is more than [delta] 1 is met; entering a next step if the formula is met, and repeating the step if the formula is not met; measuring the voltage one-way change time TUdn of the grounding electrode; judging whether a formula that TUdN is more than [delta] 2 is met; if the formula that TUdN is more than [delta] 2 and UdN-AVG is more than [delta] 1, a fault electrode is a cathode; if the formula that the TUdN is more than [delta] 2 and the -UdN-AVG is more than [delta] 1, the fault electrode is an anode; if the formula is not met, the fault electrode is a transient disturbance. The method provided by the invention is fast and reliable in action without a convertor station or a communication between the cathode and anode wires, and is capable of ensuring higher transition resistance when single electrode depressurization is operated.
Description
technical field [0001] The invention relates to the field of direct current transmission of power systems, in particular to a line selection method for single-phase grounding faults of direct current transmission lines. Background technique [0002] With the rapid development of my country's economy, the characteristics of energy demand and uneven distribution of natural resources have become increasingly prominent, and the demand for long-distance, high-power high-voltage direct current transmission projects has continued to increase. Therefore, in recent years, a number of high-voltage direct current transmission projects have been put into operation or operation in my country. The high-voltage direct current transmission projects include: Tianguang, Guiguang, Xing’an, Liangdu, etc., and the UHV direct current projects include: Yunnan-Guangzhou, Xiluodu-Zhexi , Hami-Henan, Jiuquan-Hunan, Xiangjiaba-Shanghai, Jinping-Southern Jiangsu, etc., it can be seen that DC transmissio...
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IPC IPC(8): G01R31/08
Inventor 陈伟武霁阳卢文浩汪凤娇刘金平龙启王钢李海锋
Owner EXAMING & EXPERIMENTAL CENT OF ULTRAHIGH VOLTAGE POWER TRANSMISSION COMPANY CHINA SOUTHEN POWER GRID