GE Multilin L60 Line Phase Comparison System 5-1735 SETTINGS 5.5 GROUPED ELEMENTS5Figure 5–79: GROUND DISTANCE ZONES 2 AND HIGHER SCHEME LOGICGROUND DIRECTIONAL SUPERVISION:A dual (zero-sequence and negative-sequence) memory-polarized directional supervision applied to the ground distanceprotection elements has been shown to give good directional integrity. However, a reverse double-line-to-ground fault canlead to a maloperation of the ground element in a sound phase if the zone reach setting is increased to cover high resis-tance faults.Ground distance zones 2 and higher use an additional ground directional supervision to enhance directional integrity. Theelement’s directional characteristic angle is used as a maximum torque angle together with a 90° limit angle.The supervision is biased toward operation in order to avoid compromising the sensitivity of ground distance elements atlow signal levels. Otherwise, the reverse fault condition that generates concern will have high polarizing levels so that a cor-rect reverse fault decision can be reliably made.The supervision for zones 2 and 3 is removed during open pole conditions.837011AL.CDRANDANDANDORQuadrilateralcharacteristiconlyANDORMEMORYV_1 > 0.80 puI_1 > 0.025 puSETTINGEnabled = 1GND DIST Z2 FUNCTIONSETTINGOff = 0GND DIST Z2 BLKSETTINGIAIBDISTANCE SOURCEICVAGVBGVCGV_1I_1WyeVTsSETTINGSGND DIST Z2 ZOM/Z1 ANGRUNA ELEMENTRUNB ELEMENTRUNC ELEMENTGND DIST Z2 POL CURRENTGND DIST Z2 NON-HOMGEN ANGGND DIST Z2 COMP LIMITGND DIST Z2 DIR RCAGND DIST Z2 DIR COMP LIMITGND DIST Z2 VOLT LEVELGND DIST Z2 QUAD RGT BLDGND DIST Z2 QUAD RGT BLD RCAGND DIST Z2 QUAD LFT BLDGND DIST Z2 QUAD LFT BLD RCATIMER1 cycle1 cycleSETTINGGND DIST Z2 SUPVRUN| IN – 0.05 × I_1 | > PickupFLEXLOGIC OPERANDSGND DIST Z2 PKP AGND DIST Z2 DPO AFLEXLOGIC OPERANDSGND DIST Z2 PKP BGND DIST Z2 DPO BFLEXLOGIC OPERANDSGND DIST Z2 PKP CGND DIST Z2 DPO CFLEXLOGIC OPERANDGND DIST Z2 PKPFLEXLOGIC OPERANDSOPEN POLE OP ФAOPEN POLE OP ФBOPEN POLE OP ФCD60, L60, and L90 onlyGND DIST Z2 SUPN INGND DIST Z2 DIR SUPNFLEXLOGIC OPERANDOPEN POLE OP **INI_2I_0GND DIST Z2 REV REACHGND DIST Z2 REV REACH RCAGND DIST Z2 REACHGND DIST Z2 RCAGND DIST Z2 ZOM/Z1 MAGGND DIST Z2 Z0/Z2 ANGGND DIST Z2 Z0/Z2 MAGGND DIST Z2 SHAPEGND DIST Z2 DIROR** D60, L60, and L90 only
