GE c60 Instruction Manual

Also see for C60: Communications manual Communications guide Instruction manual Instruction manual Instruction manual

Contents

5-234 C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUALCONTROL ELEMENTS CHAPTER 5: SETTINGS55.8.8.2 Breaker arcing currentSETTINGS  CONTROL ELEMENTS  MONITORING ELEMENTS  BREAKER 1(4) ARCING CURRENTThere is one breaker arcing current element available per CT bank, with a minimum of two elements. This elementcalculates an estimate of the per-phase wear on the breaker contacts by measuring and integrating the current squaredpassing through the breaker contacts as an arc. These per-phase values are added to accumulated totals for each phaseand compared to a programmed threshold value. When the threshold is exceeded in any phase, the relay can set anoutput operand to “1.” The accumulated value for each phase can be displayed as an actual value.The operation of the scheme is shown in the following logic diagram. The same output operand that is selected to operatethe output relay used to trip the breaker, indicating a tripping sequence has begun, is used to initiate this feature. A timedelay is introduced between initiation and the starting of integration to prevent integration of current flow through thebreaker before the contacts have parted. This interval includes the operating time of the output relay, any other auxiliaryrelays, and the breaker mechanism. For maximum measurement accuracy, measure the interval between change-of-stateof the operand (from 0 to 1) and contact separation for the specific installation. Integration of the measured currentcontinues for 100 ms, which is expected to include the total arcing period.The feature is programmed to perform fault duration calculations. Fault duration is defined as a time between operation ofthe disturbance detector occurring before initiation of this feature, and reset of an internal low-set overcurrent function.Correction is implemented to account for a non-zero reset time of the overcurrent function.Breaker arcing currents and fault duration values are available under the ACTUAL VALUES  RECORDS  MAINTENANCE BREAKER 1(4) menus.BKR 1 ARC AMP INT-A(C) — Select the same output operands that are configured to operate the output relays used to trip thebreaker. In three-pole tripping applications, configure the same operand to initiate arcing current calculations for poles A,B, and C of the breaker. In single-pole tripping applications, configure per-pole tripping operands to initiate the calculationsfor the poles that are actually tripped.BKR 1 ARC AMP DELAY — This setting is used to program the delay interval between the time the tripping sequence isinitiated and the time the breaker contacts are expected to part, starting the integration of the measured current.BKR 1 ARC AMP LIMIT — Selects the threshold value above which the output operand is set.  THERMAL OVERLOAD PROTECTIONSee page 5-245 BREAKER 1 ARCING CURRENT  BKR 1 ARC AMPFUNCTION: DisabledRange: Disabled, Enabled BKR 1 ARC AMPSOURCE: SRC 1Range: SRC 1, SRC 2, SRC 3, SRC 4 BKR 1 ARC AMP INT-A:OffRange: FlexLogic operand BKR 1 ARC AMP INT-C:OffRange: FlexLogic operand BKR 1 ARC AMPDELAY: 0.000 sRange: 0.000 to 65.535 s in steps of 0.001 BKR 1 ARC AMP LIMIT:1000 kA2-cycRange: 0 to 50000 kA 2 -cycle in steps of 1 BKR 1 ARC AMP BLOCK:OffRange: FlexLogic operand BKR 1 ARC AMPTARGET: Self-resetRange: Self-reset, Latched, Disabled BKR 1 ARC AMPEVENTS: DisabledRange: Disabled, Enabled