... ISO9001,ISO14001,OHSAS18001 4.Apply for IEC,ANSI,GB. The three-phase oil-immersed distributing transformer applies new ... (7, 8, 9, 10, 11, 12)---------------------------------special usage or special structure code (M-hermetically sealed R: wound core ... special application environment code (GY: plateauWF: anticorrosion TA: dry tropics TH: humid tropics) 6.6KV S9/S11 series oil ...