HIGH VOLTAGE GROUND RELAY FOR DC RAILWAY SUBSTATION

PROBLEM TO BE SOLVED: To perform segmentation in the case where a ground fault occurs in a connection line between a rectifier and a transformer for rectifier in a DC railway substation and in the case where a ground fault occurs in a DC bus.SOLUTION: A high voltage ground relay 1 for DC railway substation comprises a potential difference measurement section 5 which is provided between a ground mat of a DC railway substation and a fly-back line and measures a potential difference between the ground mat and the fly-back line, and discriminates a ground fault using the measured potential difference. The high voltage ground relay for DC railway substation also comprises: a current measurement section 11 for measuring a current flowing through a ground line 10 to which a cable run support or a shield layer of a connection line between a transformer for rectifier and a rectifier is connected; a tertiary harmonic wave extraction section 12 for extracting a tertiary harmonic component from a measurement of the current; an AC-side ground discrimination output section 6B for discriminating a ground fault in a primary-side cable run (AC side) of the rectifier between the transformer for rectifier and the rectifier in the case where the extracted tertiary harmonic component exceeds a threshold value; and an AC-side ground display section 13B for displaying the AC-side ground discrimination.SELECTED DRAWING: Figure 2 【課題】直流電鉄用変電所の整流器用変圧器と整流器の間の接続線で地絡故障が発生した場合と直流母線で地絡故障が発生した場合の切り分けを行う。【解決手段】直流電鉄用変電所の接地マットと帰線の間に設けられ、接地マットと帰線の間の電位差を測定する電位差測定部５を有し、測定された電位差を用いて地絡故障を判定する直流電鉄変電所用高圧接地継電器１において、整流器用変圧器と整流器の間の接続線の電路支持具または遮蔽層が接続された接地線１０に流れる電流を測定する電流測定部１１と、この電流の測定値から第３次高調波成分の抽出を行う第３次高調波抽出部１２と、この抽出された第３次高調波成分が閾値を超過するときに整流器用変圧器と整流器の間の整流器の１次側電路（交流側）の地絡故障を判定する交流側地絡判定出力部６Ｂと、この交流側地絡判定を表示する交流側地絡表示部１３Ｂとを備える。【選択図】図２