CHAPTER 10: THEORY OF OPERATION DISTANCE ELEMENTSL90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL 10-2310• C ground element — IC × Z + I_0 × K0 × Z + I G × K0M × Z – VC and I_0 × ZIf the mho characteristic is selected, the limit angle of the comparator is adjustable concurrently with the limit angle of themho characteristic, resulting in a tent shape complementing the lens characteristic being effectively applied.10.3.3.5 Quadrilateral reactance characteristic for directional applicationsThe quadrilateral reactance characteristic is achieved by checking the angle between• AB phase element — (IA – I B ) × Z – (VA – VB ) and (IA – IB ) × Z• BC phase element — (IB – IC ) × Z – (V B – VC) and (IB – IC ) × Z• CA phase element — (IC – I A) × Z – (VC – VA) and (IC – IA ) × Z• A ground element — IA × Z + I_0 × K0 × Z + I G × K0M × Z – VA and (j × I_0 or j × I_2A) × e jΘ• B ground element — I B × Z + I_0 × K0 × Z + IG × K0M × Z – V B and (j × I_0 or j × I_2B) × e jΘ• C ground element — IC × Z + I_0 × K0 × Z + I G × K0M × Z – VC and (j × I_0 or j × I_2C) × e jΘThe ground elements are polarized from either zero-sequence or negative-sequence current as per user-settings tomaximize performance in non-homogenous systems. The polarizing current is additionally shifted by the user-selectablenon-homogeneity correction angle.10.3.3.6 Reverse quadrilateral reactance characteristic for non-directional applicationsThe reverse quadrilateral reactance characteristic is achieved by checking the angle between• AB phase element — (IA – I B ) × ZREV – (VA – VB ) and (IA – I B ) × ZREV• BC phase element — (IB – IC ) × Z REV – (VB – VC ) and (I B – I C) × ZREV• CA phase element — (IC – I A) × ZREV – (VC – VA ) and (IC – IA) × ZREV• A ground element — (IA × ZREV + I_0 × K0 × ZREV + I G × K0M × ZREV – VA and (j × I_0 or j × I_2A) × ej(180 + Θ)• B ground element — (IB × ZREV + I_0 × K0 × ZREV + IG × K0M × ZREV – VB and (j × I_0 or j × I_2B) × ej(180 + Θ)• C ground element — (IC × ZREV + I_0 × K0 × ZREV + IG × K0M × ZREV – VC and (j × I_0 or j × I_2C) × e j(180 + Θ)The ground elements are polarized from either zero-sequence or negative-sequence current as per user-settings tomaximize performance in non-homogenous systems. The polarizing current is additionally shifted by the user-selectablenon-homogeneity correction angle.10.3.3.7 Directional characteristicThe directional characteristic is achieved by checking the angle between• AB phase element — (IA – I B ) × ZD and (VA – VB )_1M• BC phase element — (IB – IC ) × Z D and (V B – VC )_1M• CA phase element — (IC – I A) × ZD and (VC – VA )_1M• A ground element — I_0 × ZD and VA _1MIA _2 × ZD and VA _1M• B ground element — I_0 × ZD and VB _1MIB _2 × ZD and VB _1M• C ground element — I_0 × ZD and VC _1MIC _2 × ZD and VC_1MThe characteristic and limit angles of the directional comparator are adjustable independently from the mho andreactance comparators. The directional characteristic improves directional integrity of the distance functions.10.3.3.8 Right blinder characteristicThe right blinder characteristic is achieved by checking the angle between the following signals:• AB phase element — (IA – I B ) × ZR – (VA – VB ) and (IA – I B ) × ZR• BC phase element — (IB – IC ) × Z R – (VB – VC ) and (I B – I C) × ZR
