5-94 L30 Line Current Differential System GE Multilin5.4 SYSTEM SETUP 5 SETTINGS5• PMU 1 VA... IG CALIBRATION MAGNITUDE: These settings recognize applications with protection class voltage andcurrent sources, and allow the user to calibrate each channel (four voltages and four currents) individually to offseterrors introduced by VTs, CTs. The setting values are effectively a multiplier of the measured magnitudes. Therefore,enter a multiplier greater than 100% of the secondary signal increases the true signal; and a multiplier less than 100%value of the secondary signal reduces the true signal.• PMU 1 SEQ VOLT SHIFT ANGLE: This setting allows correcting positive- and negative-sequence voltages for vectorgroups of power transformers located between the PMU voltage point, and the reference node. This angle is effectivelyadded to the positive-sequence voltage angle, and subtracted from the negative-sequence voltage angle. Note that:1. When this setting is not “0°”, the phase and sequence voltages will not agree. Unlike sequence voltages, thephase voltages cannot be corrected in a general case, and therefore are reported as measured.2. When receiving synchrophasor data at multiple locations, with possibly different reference nodes, it can be morebeneficial to allow the central locations to perform the compensation of sequence voltages.3. This setting applies to PMU data only. The L30 calculates symmetrical voltages independently for protection andcontrol purposes without applying this correction.4. When connected to line-to-line voltages, the PMU calculates symmetrical voltages with the reference to the AGvoltage, and not to the physically connected AB voltage (see the Metering Conventions section in Chapter 6).• PMU 1 SEQ CURR SHIFT ANGLE: This setting allows correcting positive and negative-sequence currents for vectorgroups of power transformers located between the PMU current point and the reference node. The setting has thesame meaning for currents as the PMU 1 SEQ VOLT SHIFT ANGLE setting has for voltages. Normally, the two correctingangles are set identically, except rare applications when the voltage and current measuring points are located at differ-ent windings of a power transformer.e) PMU TRIGGERING OVERVIEWPATH: SETTINGS SYSTEM SETUP PHASOR... PHASOR MEASUREMENT UNIT 1 PMU 1 TRIGGERINGEach logical phasor measurement unit (PMU) contains five triggering mechanisms to facilitate triggering of the associatedPMU recorder, or cross-triggering of other PMUs of the system. They are:• Overfrequency and underfrequency.• Overvoltage and undervoltage.• Overcurrent.• Overpower.• High rate of change of frequency.The pre-configured triggers could be augmented with a user-specified condition built freely using programmable logic of therelay. The entire triggering logic is refreshed once every two power system cycles. PMU 1 TRIGGERING PMU 1 USER TRIGGER See page 5-95.MESSAGE PMU 1 FREQUENCY TRIGGER See page 5-95.MESSAGE PMU 1 VOLTAGE TRIGGER See page 5-96.MESSAGE PMU 1 CURRENT TRIGGER See page 5-97.MESSAGE PMU 1 POWER TRIGGER See page 5-98.MESSAGE PMU 1 df/dt TRIGGER See page 5-100.
