GE L60 Instruction Manual

Also see for L60: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-160 L60 Line Phase Comparison System GE Multilin5.5 GROUPED ELEMENTS 5 SETTINGS5on the parallel line. Mutual coupling compensation is applied when distance source is assigned with 8F or 8L type DSPmodule only and when the ratio of the protected line ground current to parallel line ground current is greater than 1.22.• GND DIST Z1 ZOM/Z1 ANG: This setting specifies the angle difference between the mutual zero-sequence imped-ance between the lines and the positive-sequence impedance of the protected line.• GND DIST Z1 REACH: This setting defines the reach of the zone for the forward and reverse applications. In non-directional applications, this setting defines the forward reach of the zone. The reverse reach impedance in non-direc-tional applications is set independently. The angle of the reach impedance is entered as the GND DIST Z1 RCA setting.The reach impedance is entered in secondary ohms.To achieve specified operating speed of distance elements, the relay internally calculates source to line impedanceratio (SIR) from fault phasors. In these calculations, line impedance is estimated based on the zone 1 reach setting.Therefore, in order to calculate the SIR value properly and to maintain the optimal operating speed of the distance ele-ments, you need to set zone 1 reach with a regular 80 to 85% of the line impedance reach setting, even when zone 1is disabled.• GND DIST Z1 RCA: This setting specifies the characteristic angle (similar to the maximum torque angle in previoustechnologies) of the ground distance characteristic for the forward and reverse applications. In the non-directionalapplications this setting defines the forward reach of the zone. The reverse reach impedance in the non-directionalapplications is set independently. This setting is independent from the GND DIST Z1 DIR RCA setting (the characteristicangle of an extra directional supervising function).The relay internally performs zero-sequence compensation for the protected circuit based on the valuesentered for GND DIST Z1 Z0/Z1 MAG and GND DIST Z1 Z0/Z1 ANG, and if configured to do so, zero-sequence com-pensation for mutual coupling based on the values entered for GND DIST Z1 Z0M/Z1 MAG and GND DIST Z1 Z0M/Z1ANG. The GND DIST Z1 REACH and GND DIST Z1 RCA should, therefore, be entered in terms of positive sequencequantities. Refer to chapters 8 for additional information• GND DIST Z1 REV REACH: This setting defines the reverse reach of the zone set to non-directional (GND DIST Z1 DIRsetting). The value must be entered in secondary ohms. This setting does not apply when the zone direction is set to“Forward” or “Reverse”.• GND DIST Z1 REV REACH RCA: This setting defines the angle of the reverse reach impedance if the zone is set tonon-directional (GND DIST Z1 DIR setting). This setting does not apply when the zone direction is set to “Forward” or“Reverse”.• GND DIST Z1 POL CURRENT: This setting applies only if the GND DIST Z1 SHAPE is set to “Quad” and controls thepolarizing current used by the reactance comparator of the quadrilateral characteristic. Either the zero-sequence ornegative-sequence current could be used. In general, a variety of system conditions must be examined to select anoptimum polarizing current. This setting becomes less relevant when the resistive coverage and zone reach are setconservatively. Also, this setting is more relevant in lower voltage applications such as on distribution lines or cables,as compared with high-voltage transmission lines. This setting applies to both the zone 1 and reverse reactance linesif the zone is set to non-directional. Refer to chapters 8 and 9 for additional information.• GND DIST Z1 NON-HOMOGEN ANG: This setting applies only if the GND DIST Z1 SHAPE is set to “Quad” and providesa method to correct the angle of the polarizing current of the reactance comparator for non-homogeneity of the zero-sequence or negative-sequence networks. In general, a variety of system conditions must be examined to select thissetting. In many applications this angle is used to reduce the reach at high resistances in order to avoid overreachingunder far-out reach settings and/or when the sequence networks are greatly non-homogeneous. This setting applies toboth the forward and reverse reactance lines if the zone is set to non-directional. Refer to chapters 8 and 9 for addi-tional information.• GND DIST Z1 COMP LIMIT: This setting shapes the operating characteristic. In particular, it enables a lens-shapedcharacteristic of the mho function and a tent-shaped characteristic of the quadrilateral function reactance boundary. Ifthe mho shape is selected, the same limit angle applies to mho and supervising reactance comparators. In conjunctionwith the mho shape selection, this setting improves loadability of the protected line. In conjunction with the quadrilat-eral characteristic, this setting improves security for faults close to the reach point by adjusting the reactance boundaryinto a tent-shape.• GND DIST Z1 DIR RCA: Selects the characteristic angle (or ‘maximum torque angle’) of the directional supervisingfunction. If the mho shape is applied, the directional function is an extra supervising function, as the dynamic mhocharacteristic itself is a directional one. In conjunction with the quadrilateral shape selection, this setting defines theonly directional function built into the ground distance element. The directional function uses memory voltage for polar-ization.NOTE