Dispatching side transformer substation small-current single-phase grounding automatic line-selection method

Abstract

The invention discloses a dispatching side transformer substation small-current single-phase grounding automatic line-selection method. The method comprises the following steps: judging whether one ofthe following three conditions is satisfied: zero-sequence voltage 3U0 is greater than 15V, phase voltage (U1, U2) is greater than 7kV and U3 is less than 5kV, or a bus is in grounding action and thesustained computing period is equal to 2; if one of the three conditions is satisfied, storing bus voltage, recording line load and zero sequence current of the line under each of a running state anda fault state; performing running line comparison satisfaction: enabling the difference obtained by subtracting IN0 initialization from IN0 fault to be unequal to 0, and the MAX(IN0 fault) and MAX(IN0 fault-IN0 initialization), or MAX(2*IN0 fault-IN0 initialization), outputting a line ID, and giving an alarm instruction, ending the operation. The method disclosed by the invention has the advantages that the ground fault line can be quickly and accurately determined when the system is in single-phase grounding, the accident processing efficiency is improved, the power grid supply stability isimproved; the power supply reliability of the electric user is guaranteed, and the comprehensive economic loss caused by power failure or unqualified electric energy quality is reduced.

Description

technical field [0001] The invention relates to an automatic line selection method for small current single-phase grounding of a substation at a dispatching end. Background technique [0002] With the continuous development of the power grid, the safe operation of the power grid has become the focus of attention. Any failure of the power system will inevitably lead to inestimable losses. How to accurately process the obtained information and timely eliminate faults has become the key to the stable operation of the power system. where. In addition, people put forward higher requirements for the safe operation of the power grid and the reliability of power supply. When the power system fails, it is necessary for the staff to be able to accurately locate and restore the stable operation of the power grid as quickly as possible. [0003] In our country, most of the 6~35kV medium voltage distribution network system adopts the non-direct grounding method of the neutral point, whi...

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Problems solved by technology

[0007] The purpose of the present invention is to provide an automatic line selection method for small-current single-phase grounding of substations at the dispatching end, which can effectively solve the problem that the faulty line cannot be quickly and accurately determined when the substation at the dispatching end is grounded with small currents and single-phase

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