Single-phase grounding fault wire selection method based on improved HHT

Abstract

The invention discloses a single-phase grounding fault wire selection method based on improved HHT. According to the method, a zero sequence current sensor is mounted at each output line in a system close to a bus end, a zero sequence current of each line is acquired in real time, when the zero sequence current signal surpasses a threshold, sampling data is stored; traveling wave signals of the stored data are filtered, a maximum value point and a minimum value point are rapidly acquired according to rules that inherent system oscillation frequency and high frequency signal amplitude satisfy index attenuation, initial values of three-times batten interpolation function coefficients are selected, an improved EMD decomposition method is employed, IMF1 of zero sequence currents of lines are respectively calculated, namely a 1-order modal function. IMF1 of the lines of one same output wire are compared, the line of which an IMF amplitude absolute value is the largest one, and polarity is opposite to other lines is a fault line. The method is advantaged in that through improving the EMD algorithm of HHT transformation, computational complexity is reduced, and a fault inspection and sorting speed is further improved.

Description

technical field [0001] The invention relates to a single-phase ground fault line selection method based on the improved HHT. Background technique [0002] According to the national coal mine safety regulations, large and medium-sized mines use 10KV, 35KV and 66KV voltage levels for power supply, and the neutral point is grounded through the arc suppression coil, which is referred to as the small current grounding (resonant grounding system) power supply network. When faults such as single-phase grounding or short circuit occur in this power supply network, the inductance current of the arc suppression coil will compensate the capacitive current in the system, so that the fault residual current is very small, the arc is suppressed, and the switch will not trip, and the system can continue Run for 1-2 hours. But when a single-phase ground fault occurs, since the single-phase ground is an asymmetrical fault, the non-fault phase-to-ground voltage is the original times, if the...

AI Technical Summary

Problems solved by technology

However, the existing HHT transformation has problems such as long EMD empirical modal analysis time and end-point effects, and cannot overcome the problems of slow speed and large amount of calculation in the single-phase ground fault detection of the existing resonant grounding system.

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