Transient Steady Line Selection Method Based on Comprehensive Weight of Voltage Calculation
A technology of comprehensive weight and line selection method, applied in the direction of measuring electricity, measuring electrical variables, instruments, etc., can solve the problems of accuracy influence, almost no, small steady-state components, etc., and achieve the effect of improving accuracy
Active Publication Date: 2019-01-04
STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO +2
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[0003] The existing line selection methods are mainly divided into the following categories: one is to use the zero-sequence fundamental wave steady-state component after the ground fault to realize the line selection. Its accuracy will be greatly affected in the event of a failure
One is to use zero-sequence transient components to realize line selection, but when a steady-state ground fault such as high-resistance occurs in the power grid, the steady-state components are small or almost non-existent, resulting in the failure of this type of method
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[0017] A transient steady-state line selection method based on voltage calculation comprehensive weight of the present invention detects and analyzes the fundamental wave components of the three-phase voltage and the zero-sequence voltage of the small-current grounding system, and determines the relative time of the fault, the relative magnitude of the zero-sequence voltage, On the basis of the change of zero-sequence voltage wave head, the weights of steady-state line selection criteria and transient line selection criteria for single-phase-to-ground faults in small current grounding systems are determined comprehensively, so as to realize comprehensive line selection. Concrete steps of the present invention are as follows:
[0018] Step 1. Determine whether a single-phase ground fault occurs in the low-current grounding system by detecting the magnitude of the zero-sequence voltage. If so, execute the next step, otherwise end; specifically:
[0019] Let U 0 is the monitored...
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The invention relates to a transient and steady state line selection method based on a voltage calculation comprehensive weight. The method determines a transient state fault criterion and a steady state fault criterion weight in a single-phase grounding fault comprehensive line selection method through employing the generation relative time of a single-phase grounding fault of a small-current grounding system, the relative size of a zero sequence voltage and the change of a zero-sequence voltage wave head, calculates the comprehensive criteria of all lines, and determines the line with the maximum comprehensive fault criterion as the fault line. During weight calculation, the method just needs to analyze the voltage component of a fundamental wave, effectively solves a problem of difficult calculation caused by the changes of the frequency, amplitude and phase of a transient component of the small-current grounding system during the single-phase grounding fault, improves the accuracy of line selection, and is good in application prospect for a power distribution network.
Description
technical field [0001] The invention belongs to the technical field of power system automation, and in particular relates to a transient steady-state line selection method based on voltage calculation comprehensive weight. Background technique [0002] Single-phase grounding fault line selection in small current grounding system has always been a difficult point in relay protection. Due to the complex fault characteristics and many fault types when a single-phase ground fault occurs in a small current grounding system, the fault component is relatively small, which seriously affects the accuracy of ground fault line selection. For this reason, a large number of power workers have also proposed some line selection methods based on the characteristics of zero-sequence components after a ground fault. [0003] The existing line selection methods are mainly divided into the following categories: one is to use the zero-sequence fundamental wave steady-state component after the g...
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IPC IPC(8): G01R31/02
CPCG01R31/50
Inventor 瞿天易屈卫锋杨宏宇吴蕾
Owner STATE GRID JIANGSU ELECTRIC POWER CO LIANYUNGANG POWER SUPPLY CO