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

A single-phase ground fault, line selection method, applied in fault location, fault detection by conductor type, measurement device, etc., can solve the problems of slow speed, long analysis time, and large amount of calculation. , Overcome the large amount of calculation and meet the effect of production needs

Active Publication Date: 2017-04-26
SHANDONG UNIV OF SCI & TECH +1
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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 overco...

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

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Embodiment Construction

[0049] Below in conjunction with accompanying drawing and embodiment the present invention will be further described

[0050] Figure 1-Figure 5 In the process of HHT transformation, in the process of solving the classic empirical mode decomposition algorithm, the envelope of the original signal needs to be calculated dozens of times every time the first-order IMF is obtained, and the envelope is the extreme envelope of the original signal , is all the extreme point segments of the original signal, which are fitted based on the cubic spline interpolation function. Each fitting needs to go through sample selection, initial value setting, calculation step size and step-by-step iteration. In this way, the amount of calculation is too large, and in actual use, the line selection time is long and the speed is slow.

[0051] In this paper, on the basis of analyzing the zero-sequence current signal of single-phase-to-ground fault in the resonant grounding system, it decomposes vario...

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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...

Claims

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Application Information

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IPC IPC(8): G01R31/08
CPCG01R31/086G01R31/088
Inventor 李文宏亓学广郭斌费立伟
Owner SHANDONG UNIV OF SCI & TECH
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