5-178 L60 LINE PHASE COMPARISON SYSTEM – INSTRUCTION MANUALGROUPED ELEMENTS CHAPTER 5: SETTINGS55.6.3.3 Advanced fault detectorsMenuSETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) PHASE COMPARISON ELEMENTS ADVANCED FAULTDETECTORSFive advanced fault detectors are provided, which are supervised by the condition that the magnitude of mixed currenthas to be above 0.02 pu.The negative-sequence voltage element responds to the I × Z – V term for negative-sequence voltage and current and ismeant to detect faults under weak system conditions.The negative-sequence current rate of change element responds to the vector difference of the negative-sequencecurrent over a half-a-cycle moving data window, and is meant to detect faults under load unbalance, such as onuntransposed high voltage transmission lines or in a vicinity of electrical traction systems causing significant negative-sequence current unbalance.The positive-sequence current rate of change element responds to the vector difference of the positive-sequence currentover a half-a-cycle moving data window, and it is meant to detect three-phase balance faults under high load conditions.The negative-sequence current overcurrent element responds to the increment of the negative-sequence current abovethreshold.The positive-sequence current overcurrent element responds to the increment of the positive-sequence current abovethreshold.All advanced fault detectors operate independently from each other, and independently from the mixed signal overcurrentFDL and FDH comparators embedded in the 87PC function. Each detector supports the low and high setting levels tofacilitate starting and supervise tripping. When enabled, a given detector is automatically used to control the 87PCfunction. Effectively all detectors are ORed before they are routed to the 87PC element.The overcurrent fault detectors respond to the effective operating current of the 87PC function, which includes chargingcurrent compensation. The advanced fault detectors respond to their operating signals irrespective of the configured 87PCcurrent.5.6.3.4 Negative-sequence voltage fault detectionSETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) PHASE COMPARISON ELEMENTS ADVANCED FAULTDETECTORS NEGATIVE SEQUENCE VOLTAGE ADVANCED FAULT DETECTORS NEGATIVE SEQUENCE VOLTAGESee below RATE OF CHANGE OF NEG SEQ CURRENTSee page 5-180 RATE OF CHANGE OF POS SEQ CURRENTSee page 5-181 NEGATIVE SEQUENCE CURRENTSee page 5-182 POSITIVE SEQUENCE CURRENTSee page 5-183 NEGATIVE SEQUENCE VOLTAGE NEG SEQ VOL FDFUNCTION: DisabledRange: Disabled, Enabled NEG SEQ VOL FDIMPEDANCE: 10.0%Range: 0.0 to 100% in steps of 0.1 NEG SEQ VOL FDLPICKUP: 0.010 puRange: 0.005 to 3.000 pu in steps of 0.001 NEG SEQ VOL FDHPICKUP: 0.050 puRange: 0.005 to 3.000 pu in steps of 0.001
