[电] open-delta ground potential transformer

kāi jiǎo jiē dì bǐ yā qì ㄎㄞ ㄐㄧㄠˇ ㄐㄧㄝ ㄉㄧˋ ㄅㄧˇ ㄧㄚ ㄑㄧˋ