7.1.3 Connection examples for high impedance differentialprotection GUID-8C58A73D-7C2E-4BE5-AB87-B4C93FB7D62B v5WARNING! USE EXTREME CAUTION! Dangerously highvoltages might be present on this equipment, especially on the platewith resistors. De-energize the primary object protected with thisequipment before connecting or disconnecting wiring or performingany maintenance. The plate with resistors should be provided with aprotective cover, mounted in a separate box or in a locked cubicle.National law and standards shall be followed.7.1.3.1 Connections for three-phase high impedance differential protectionGUID-C12CCAAF-5AE5-4A9C-AC9C-F56A66FD2C14 v8Generator, reactor or busbar differential protection is a typical application for three-phase high impedance differential protection. Typical CT connections for three-phase high impedance differential protection scheme are shown in figure 50.L1(A)L2(B)L3(C)Protected ObjectCT 1200/1Star/WyeConnectedL1(A)L2(B)L3(C)CT 1200/1Star/WyeConnected789101112123456AI01(I)AI02(I)AI03(I)AI04(I)AI05(I)AI06(I)76X1R4R5R612121211 12 13 14UUUR1134213R22413R3241 2 3 4 5 6 7L1 (A)L2 (B)L3 (C)N3-Ph Plate with Metrosils and Resistors2354X XL1 (A)L2 (B)L3 (C)N1IEDIEC07000193-5-en.vsdxSMAI2BLOCKREVROT^GRP2L1^GRP2L2^GRP2L3^GRP2NG2AI3PG2AI1G2AI2G2AI3G2AI4G2NIEC07000193 V5 EN-USFigure 50: CT connections for high impedance differential protectionPos Description1 Scheme earthing pointIt is important to insure that only one earthing point exist in this scheme.1MRK 511 401-UEN A Section 7Differential protectionBay control REC670 2.2 IEC 131Application manual
