8-4 D60 Line Distance Relay GE Multilin8.1 DISTANCE ELEMENTS 8 THEORY OF OPERATION8g) DIRECTIONAL CHARACTERISTICThe directional characteristic is achieved by checking the angle between:AB phase element: (IA – I B) × ZD and (VA – VB)_1MBC phase element: (I B – I C) × Z D and (VB – VC)_1MCA phase element: (I C – I A) × Z D and (VC – VA)_1MA ground element: I_0 × Z D and VA_1MI A_2 × Z D and VA_1MB ground element: I_0 × Z D and VB_1MI B_2 × Z D and VB_1MC ground element: I_0 × Z D and VC_1MI C_2 × ZD and VC _1MThe characteristic and limit angles of the directional comparator are adjustable independently from the mho and reactancecomparators. The directional characteristic improves directional integrity of the distance functions.h) RIGHT BLINDERThe right blinder characteristic is achieved by checking the angle between the following signals:AB phase element: (IA – I B) × ZR – (VA – VB) and (IA – IB) × ZRBC phase element: (I B – I C) × Z R – (VB – VC) and (IB – I C) × Z RCA phase element: (I C – I A) × Z R – (VC – VA) and (I C – IA) × Z RA ground element: I A × ZR + I_0 × K0 × ZR + I G × K0M × ZR – VA and I A × Z R + I_0 × K0 × Z R + IG × K0M × Z RB ground element: I B × ZR + I_0 × K0 × ZR + I G × K0M × ZR – VB and I B × Z R + I_0 × K0 × ZR + IG × K0M × Z RC ground element: I C × Z R + I_0 × K0 × Z R + I G × K0M × Z R – VC and I C × ZR + I_0 × K0 × ZR + I G × K0M × ZRThe blinders apply to the Quad characteristic only.i) LEFT BLINDERThe left blinder characteristic is achieved by checking the angle between the following signals:AB phase element: (IA – I B) × ZL – (VA – VB) and (IA – I B) × ZLBC phase element: (I B – I C) × Z L – (VB – VC ) and (I B – I C) × Z LCA phase element: (I C – I A) × Z L – (VC – VA) and (I C – IA) × ZLA ground element: I A × ZL + I_0 × K0 × ZL + IG × K0M × Z L – VA and IA × Z L + I_0 × K0 × ZL + IG × K0M × Z LB ground element: I B × ZL + I_0 × K0 × ZL + IG × K0M × Z L – VB and I B × Z L + I_0 × K0 × ZL + I G × K0M × ZLC ground element: I C × Z L + I_0 × K0 × Z L + I G × K0M × ZL – VC and IC × Z L + I_0 × K0 × Z L + I G × K0M × ZLThe blinders apply to the Quad characteristic only.j) FAULT-TYPE CHARACTERISTICThe fault-type characteristic applies to ground elements only and is achieved by checking the angle between:A ground element: I_0 and IA_2;B ground element: I_0 and IB_2C ground element: I_0 and IC _2The limit angle of the comparator is not adjustable and equals 50°. The fault-type characteristic is intended to block theground distance elements during double-line-to-ground faults.k) ZERO-SEQUENCE DIRECTIONAL CHARACTERISTICThe extra zero-sequence characteristic applies to ground Zones 2 to 4 only and is achieved by checking angles between:A ground element: I_0 × Z D and –V_0B ground element: I_0 × Z D and –V_0C ground element: I_0 × Z D and –V_0
