A single-phase-to-ground fault line selection method for distribution networks grounded by arc-suppressing coil devices based on gray relational analysis
A technology of gray relational analysis and single-phase ground fault, which is applied in the direction of fault location, fault detection according to conductor type, short circuit test, etc., can solve problems such as lack of consensus, and achieve effects of eliminating influence, strong adaptability, and small amount of calculation
Active Publication Date: 2022-02-01
WUHAN UNIV OF TECH
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Problems solved by technology
[0003] However, there is still no consensus on how to adjust the arc suppression coil to further improve the reliability of the ground fault line selection by the residual current incremental method
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[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0028] Step 1. Once a permanent single-phase ground fault occurs, adjust the arc suppressing coil device to change the overcompensation degree p of the distribution network. At five different overcompensation degrees (respectively p 1 ,p 2 ,p 3 ,p 4 ,p 5 ) to measure the power frequency magnitude of the zero-sequence current flowing through each feeder respectively to form the following matrix:
[0029]
[0030] where x i * (k) represents the zero-sequence current amplitude of the i-th feeder at the k-th compensation degree, and l represents the number of feeders connected to the same bus.
[0031] The second step is to use gray correlation analysis to carry out dimensionless processing on the measured zero-sequence current power frequency amplitude change sequence of each feeder, as shown in formula (2).
[0032]
[0033] where x i *(k) i...
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The invention relates to a new method for single-phase grounding fault line selection based on gray relational analysis. Firstly, adjust the arc suppressing coil device to change the overcompensation degree of the distribution network, and measure the faults flowing through each under five different overcompensation degrees respectively. Feeder zero-sequence current power frequency amplitude; perform dimensionless processing on the zero-sequence current power frequency amplitude change sequence of each feeder, and calculate the correlation between any feeder and the reference feeder zero-sequence current power frequency amplitude change sequence degree; calculate the average value of the sum of the correlation degrees between one feeder and all other feeders and the feeder fault evaluation index; finally determine the fault feeder judgment threshold, if the fault evaluation indexes of all feeders are lower than the fault feeder judgment threshold, the single-phase The ground fault occurs on the busbar, otherwise the feeder whose fault evaluation index is higher than the judgment threshold of the faulted feeder is a faulted feeder. The invention requires less sample size, strong adaptability, and small calculation amount, and can greatly reduce or eliminate the influence of small current measurement errors on line selection results.
Description
technical field [0001] The invention belongs to the technical field of non-effectively grounded distribution networks, and in particular relates to a new method for single-phase ground fault line selection based on gray relational analysis. Background technique [0002] The existing single-phase ground fault line selection methods of non-effectively grounded distribution network can be roughly divided into two categories according to the information used: one is the fault line selection method based on external injection signals; The fault line selection method can be divided into the fault line selection method based on the fault steady state component, the fault line selection method based on the fault transient component and the comprehensive line selection method. According to the actual application experience in the field, the residual current incremental method based on the fault steady-state component creatively uses the dynamic process of overcompensation degree adju...
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IPC IPC(8): G01R31/52G01R31/08
CPCG01R31/086G01R31/50
Inventor 唐金锐
Owner WUHAN UNIV OF TECH