基于电网自然5次谐波的接地保护方案分析

Analysis on the Earth-fault Protection Scheme Based on the Naturally 5^(th) Harmonic in the Electric Network

在经消弧线圈接地方式的电网中,基于自然5次谐波的接地保护方案存在运行效果不佳的问题。利用室内接地故障动模试验的波形图进行了研究,建立了不同接地故障情况下的5次谐波波形的统一物理模型并进行理论分析,提出了该接地保护方案失效的根本原因。通过在两个真实电网的接地试验分析,进一步验证了所得结论的客观性和真实性。

In the earthed system via the Petersen coil , the earth fault protection scheme based on the naturally 5^th harmonic has the problem of undesirable performance. This paper studies the oscillogram of the dynamic model experiment of the indoor earth fault, establishes the uniformed physical model for the 5th harmonie under the various accidental conditions and analyzes it theoretically, and presents the fundamental causes of the failure of this scheme. Through the analysis on the network grounding test in the two real cases, we further prove the objectivity and facticity of this conclusion.