Grounding fault start method based on power grid characteristic parameter continuous increment

Abstract

The invention discloses a grounding fault start method based on power grid characteristic parameter continuous increment, and the method comprises the steps: detecting the displacement voltage U<N> of a neutral point in a distribution network and the zero sequence current I<0N> of each feed line in real time; determining that a power grid has a single-phase grounding fault if, in a time period delta T, the stable increment of the voltage of the neutral point in the distribution network accords with a formula: delta U<N> >= delta U<NL>, and the stable value of the zero sequence current of any one feed line accords with a formula: I<0N> >= I<0E>, and enabling a grounding fault processing device to carry out the fault start at this moment, and to process the single-phase grounding fault; determining that the changes of power grid parameters cause the change of the displacement voltage U<N> of the neutral point if, in a time period delta T<1>, the stable increment of the voltage of the neutral point in the distribution network accords with the formula: delta U<N> >= delta U<NL>, but the maximum zero sequence current of the feed lines accords with a formula: I<0N> <= I<0E>, and enabling the grounding fault processing device not to start; and determining that the fault is an instable disturbance grounding fault or an intermittent grounding leakage fault if, in a time period delta T, the stable increment delta U<N> of the voltage of the neutral point in the distribution network does not stably accord with the formula: delta U<N> >= delta U<NL>, or the maximum zero sequence current I<0N> of the feed lines does not stably accord with the formula: I<0N> <= I<0E>.

Description

technical field [0001] The invention belongs to the field of single-phase grounding fault processing of distribution network, and is mainly used for determining the fault starting method of a grounding fault processing device when single-phase grounding occurs in the distribution network. Background technique [0002] When a single-phase ground fault occurs in the distribution network, different ground fault processing devices need to set an entry fault start value when performing fault processing. Generally, the absolute value of the neutral point displacement voltage of the power grid is used as the single-phase ground fault fault. Starting value, for a power grid that uses arc suppression coil compensation, the neutral point displacement voltage is generally used ( is the fault starting voltage when the ground fault is handled as phase voltage), but due to the different parameters of the power grid, the asymmetry coefficient of the power grid Also different. When th...

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Problems solved by technology

However, the high-resistance grounding faults caused by personal electric shock or wire disconnection are basically within this range. The high-resistance grounding fault caused by wire disconnection basically cannot reach the fault start value of the grounding fault processing device and cannot be processed

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