GE Multilin G30 Generator Protection System 5-2115 SETTINGS 5.6 GROUPED ELEMENTS5• DIR POWER 1 RCA: Specifies the relay characteristic angle (RCA) for the sensitive directional power function. Appli-cation of this setting is threefold:1. It allows the element to respond to active or reactive power in any direction (active overpower/underpower, etc.).2. Together with a precise calibration angle, it allows compensation for any CT and VT angular errors to permit moresensitive settings.3. It allows for required direction in situations when the voltage signal is taken from behind a delta-wye connectedpower transformer and the phase angle compensation is required.For example, the active overpower characteristic is achieved by setting DIR POWER 1 RCA to “0°”, reactive overpower bysetting DIR POWER 1 RCA to “90°”, active underpower by setting DIR POWER 1 RCA to “180°”, and reactive underpower bysetting DIR POWER 1 RCA to “270°”.• DIR POWER 1 CALIBRATION: This setting allows the relay characteristic angle to change in steps of 0.05°. This maybe useful when a small difference in VT and CT angular errors is to be compensated to permit more sensitive settings.This setting virtually enables calibration of the directional power function in terms of the angular error of applied VTsand CTs. The element responds to the sum of the DIR POWER 1 RCA and DIR POWER 1 CALIBRATION settings.• DIR POWER 1 STG1 SMIN: This setting specifies the minimum power as defined along the relay characteristic angle(RCA) for the stage 1 of the element. The positive values imply a shift towards the operate region along the RCA line;the negative values imply a shift towards the restrain region along the RCA line. Refer to the Directional power sampleapplications figure for details. Together with the RCA, this setting enables a wide range of operating characteristics.This setting applies to three-phase power and is entered in per-unit (pu) values. The base quantity is 3 x VT pu base xCT pu base.For example, a setting of 2% for a 200 MW machine is 0.02 × 200 MW = 4 MW. If 13.8kV is line voltage and 10 kA is aprimary CT current, the source pu quantity is 239 MVA, and thus, SMIN should be set at 4 MW / 239 MVA = 0.0167 pu≈ 0.017 pu. If the reverse power application is considered, RCA = 180° and SMIN = 0.017 pu.The element drops out if the magnitude of the positive-sequence current becomes virtually zero, that is, it drops belowthe cutoff level.• DIR POWER 1 STG1 DELAY: This setting specifies a time delay for stage 1. For reverse power or low forward powerapplications for a synchronous machine, stage 1 is typically applied for alarming and stage 2 for tripping.If the VTs are located on the high-voltage (HV) side of the transformer, then the source should be configured usingCTs that are also on the HV side. Correspondingly, if the VTs are located on the low-voltage (LV) side of the trans-former, then the source should be configured using CTs that are also on the LV side. In both cases, the CT polarityshould produce a positive power measurement when the machine is generating.Figure 5–96: SENSITIVE DIRECTIONAL POWER SCHEME LOGICNOTE842003A3.CDRDIR POWER 1 BLK:SETTINGOff = 0DIRECTIONAL POWERCHARACTERISTICSRUNFLEXLOGIC OPERANDSDIR POWER 1 SOURCE:SETTINGThree-phase active power (P)Three-phase reactive power (Q)DIR POWER 1 STG1SMIN:DIR POWER 1CALIBRATION:SETTINGDIR POWER 1 STG1DELAY:tPKP100 msDIR POWER 1FUNCTION:SETTINGEnabled = 1SETTINGDIR POWER 1 STG2DELAY:DIR POWER 1 STG1 OPDIR POWER 1 STG2 PKPDIR POWER 1 STG2 DPODIR POWER 1 STG2 OPDIR POWER 1 PKPDIR POWER 1 DPODIR POWER 1 OPFLEXLOGIC™ OPERANDSDIR POWER 1 STG1 PKPDIR POWER 1 STG1 DPO100 msORSETTINGSDIR POWER 1 RCA:ORtPKPDIR POWER 1 STG2SMIN:AND
