GE F60 Instruction Manual

Also see for F60: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-214 F60 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUALGROUPED ELEMENTS CHAPTER 5: SETTINGS5• If “Dual” polarizing is selected, the element performs both directional comparisons as described. A given direction isconfirmed if either voltage or current comparators indicate so. If a conflicting (simultaneous forward and reverse)indication occurs, the forward direction overrides the reverse direction.• If "Dual-V" polarizing is selected, "Voltage" polarizing is performed and "Current" polarizing is ignored if the voltagepolarizing signal is valid; otherwise "Current" polarizing is performed if the current polarizing signal is valid. If neither ofthem is valid, neither forward nor reverse indication is given.• If "Dual-I" polarizing is selected, "Current" polarizing is performed and "Voltage" polarizing is ignored if the currentpolarizing signal is valid; otherwise "Voltage" polarizing is performed if the voltage polarizing signal is valid. If neither ofthem is valid, neither forward nor reverse indication is given.NEUTRAL DIR OC1 POL VOLT — Selects the polarizing voltage used by the directional unit when "Voltage," "Dual," "Dual-V," or"Dual-I" polarizing mode is set. The polarizing voltage can be programmed to be either the zero-sequence voltagecalculated from the phase voltages ("Calculated V0") or supplied externally as an auxiliary voltage ("Measured VX").NEUTRAL DIR OC1 OP CURR — This setting indicates whether the 3I_0 current calculated from the phase currents, or theground current is used by this protection. This setting acts as a switch between the neutral and ground modes of operation(ANSI devices 67N and 67G). If set to “Calculated 3I0,” the element uses the phase currents and applies the positive-sequence restraint. If set to “Measured IG,” the element uses ground current supplied to the ground CT of the CT bankconfigured as NEUTRAL DIR OC1 SOURCE. If this setting is “Measured IG,” then the NEUTRAL DIR OC1 POLARIZING setting mustbe “Voltage”, as it is not possible to use the ground current as an operating and polarizing signal simultaneously. IG currenthas to be above 0.05 ps to be used as operate quantity.NEUTRAL DIR OC1 POS-SEQ RESTRAINT — This setting controls the amount of the positive-sequence restraint. Set it to 0.063for backward compatibility with firmware revision 3.40 and older. Set it to zero to remove the restraint. Set it higher if largesystem unbalances or poor CT performance are expected.NEUTRAL DIR OC1 OFFSET — This setting specifies the offset impedance used by this protection. The primary application forthe offset impedance is to guarantee correct identification of fault direction on series compensated lines. In regularapplications, the offset impedance ensures proper operation even if the zero-sequence voltage at the relaying point is verysmall. If this is the intent, the offset impedance is not to be larger than the zero-sequence impedance of the protectedcircuit. Practically, it shall be several times smaller. Enter the offset impedance in secondary ohms.NEUTRAL DIR OC1 FWD ECA — This setting defines the characteristic angle (ECA) for the forward direction in the "Voltage"polarizing mode. The "Current" polarizing mode uses a fixed ECA of 0°. The ECA in the reverse direction is the angle set forthe forward direction shifted by 180°.NEUTRAL DIR OC1 FWD LIMIT ANGLE — This setting defines a symmetrical (in both directions from the ECA) limit angle for theforward direction.NEUTRAL DIR OC1 FWD PICKUP — This setting defines the pickup level for the overcurrent unit of the element in the forwarddirection. When selecting this setting, keep in mind that the design uses a positive-sequence restraint technique for the“Calculated 3I0” mode of operation.NEUTRAL DIR OC1 REV LIMIT ANGLE — This setting defines a symmetrical (in both directions from the ECA) limit angle for thereverse direction.NEUTRAL DIR OC1 REV PICKUP — This setting defines the pickup level for the overcurrent unit of the element in the reversedirection. When selecting this setting, keep in mind that the design uses a positive-sequence restraint technique for the“Calculated 3I0” mode of operation.