Safe operation method of active voltage reduction for ground fault phase of non-effective grounding system

Abstract

The invention discloses a safe operation method of active voltage reduction for a ground fault phase of a non-effective grounding system, and the safe operation method is applied to the ground fault safe operation of a neutral point non-effective grounding generator or power distribution network. When a single-phase ground fault occurs, an adjustable current source is applied additionally between a bus at a non-effective grounding system side and the ground, or between a circuit and the ground, or between a neutral point and the ground, or between a shunting tap at a transformer non-effective grounding system side winding and the ground, to adjust the injected current magnitude and phase and further reduce the fault phase voltage, so that the fault point voltage is lower than the ground arc continuous combustion voltage to meet the long-term non-stop safe operation requirement. According to the invention, the fault phase voltage is reduced to a non-zero safe operation value, so the permanent single-phase earth fault current is suppressed, the rising amplitude of the non-fault phase voltage is limited, the risk of non-fault phase insulation breakdown is reduced, the personal safety and equipment security risks are reduced, the occurrence of power outages is effectively prevented, and power supply reliability and security are greatly improved.

Description

technical field [0001] The invention relates to the technical field of grounding fault suppression in electric power systems, in particular to an active step-down safe operation method for a grounding fault phase of an ineffective grounding system. Background technique [0002] Generating sets and distribution networks at home and abroad generally adopt the neutral point non-effective grounding method, and the non-effective grounding system constitutes more than 95% of my country's 6kV and above voltage level power grids. Nearly 70% of blackouts are caused by failure of this system. The average annual loss caused by power outages across the country is hundreds of billions of yuan. The non-effectively grounded system is different from the power transmission system, the ground fault resistance can be as high as tens of kiloohms, and it is difficult to sense and protect. Long-term operation with faults will endanger personal and equipment safety and cause serious social and e...

AI Technical Summary

Problems solved by technology

[0009] In order to overcome the defects of the above-mentioned prior art and effectively solve the problem that the prior art cannot take into account the reliability and safety of power supply at the same time, the present invention provides a method for actively stepping down and safely operating the ground fault phase of the non-effectively grounded system. The fault phase voltage is reduced to achieve the goal of safe and stable operation of the system for a long time

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