5-74 L90 Line Current Differential System GE Multilin5.4 SYSTEM SETUP 5 SETTINGS5b) VOLTAGE BANKSPATH: SETTINGS SYSTEM SETUP AC INPUTS VOLTAGE BANK F5(L5)Because energy parameters are accumulated, these values should be recorded and then resetimmediately prior to changing VT characteristics.Two banks of phase/auxiliary VTs can be set, where voltage banks are denoted in the following format (X represents themodule slot position letter):Xa, where X = {F, L} and a = {5}.See the Introduction to AC sources section at the beginning of this chapter for additional details.With VTs installed, the relay can perform voltage measurements as well as power calculations. Enter the PHASE VT F5 CON-NECTION made to the system as “Wye” or “Delta”. An open-delta source VT connection would be entered as “Delta”.The nominal PHASE VT F5 SECONDARY voltage setting is the voltage across the relay input terminals when nominalvoltage is applied to the VT primary.For example, on a system with a 13.8 kV nominal primary voltage and with a 14400:120 volt VT in a delta connec-tion, the secondary voltage would be 115; that is, (13800 / 14400) × 120. For a wye connection, the voltage valueentered must be the phase to neutral voltage which would be 115 = 66.4.On a 14.4 kV system with a delta connection and a VT primary to secondary turns ratio of 14400:120, the voltagevalue entered would be 120; that is, 14400 / 120.5.4.2 POWER SYSTEMPATH: SETTINGS SYSTEM SETUP POWER SYSTEMThe power system NOMINAL FREQUENCY value is used as a default to set the digital sampling rate if the system frequencycannot be measured from available signals. This may happen if the signals are not present or are heavily distorted. Beforereverting to the nominal frequency, the frequency tracking algorithm holds the last valid frequency measurement for a safeperiod of time while waiting for the signals to reappear or for the distortions to decay. VOLTAGE BANK F5PHASE VT F5CONNECTION: WyeRange: Wye, DeltaMESSAGE PHASE VT F5SECONDARY: 66.4 VRange: 25.0 to 240.0 V in steps of 0.1MESSAGE PHASE VT F5RATIO: 1.00 :1Range: 1.00 to 24000.00 in steps of 0.01MESSAGE AUXILIARY VT F5CONNECTION: VagRange: Vn, Vag, Vbg, Vcg, Vab, Vbc, VcaMESSAGE AUXILIARY VT F5SECONDARY: 66.4 VRange: 25.0 to 240.0 V in steps of 0.1MESSAGE AUXILIARY VT F5RATIO: 1.00 :1Range: 1.00 to 24000.00 in steps of 0.01 POWER SYSTEMNOMINAL FREQUENCY:60 HzRange: 25 to 60 Hz in steps of 1MESSAGE PHASE ROTATION:ABCRange: ABC, ACBMESSAGE FREQUENCY AND PHASEREFERENCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4MESSAGE FREQUENCY TRACKING:EnabledRange: Disabled, EnabledNOTE3
