ABB RELION 630 Series Applications Manual

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Contents

ABB RELION 630 Series Applications Manual Manual pdf 38 page image

3.2.6.2 Thermal overload protection T2PTTRThe three-phase thermal overload protection function is used for thermal protection ofgenerators. The function has adjustable temperature limits for tripping, alarm andreclose inhibit. The applied thermal model uses two time constants and a true RMScurrent measuring principle. A set of three phase currents, I3P, is connected to theinputs.The thermal overload alarm and trip signals provide a LED indication on the LHMI.The thermal overload alarm and thermal overload trip are also connected to thedisturbance recorders, as well as to common start and common operate respectively.3.2.6.3 Non-directional overcurrent protection PHxPTOCThe three-phase non-directional overcurrent functions are used for non-directionalone-, two- and three-phase stator overcurrent and short-circuit protection withdefinite-time or various IDMT characteristic. The stage operation is based on threemeasuring principles: DFT, RMS or peak-to-peak values.The configuration includes two variants of non-directional overcurrent functionblocks: low and high. A set of three phase neutral side currents, I3P_N, is connectedto the inputs. The low stage can be used for overcurrent protection, and the high stagesprotect against short circuit.A common operate and start signal from the both non-directional overcurrentfunctions is connected to an OR-gate to form a combined non-directional overcurrentoperate and start signal which provides a LED indication on the LHMI. Also aseparate start and operate signal from the both overcurrent functions is connected tothe disturbance recorder.3.2.6.4 Machine negative-sequence overcurrent protection MNSPTOCTwo instances of negative-sequence overcurrent function are provided for statorprotection against single-phasing, unbalance load or unsymmetrical voltage with DTor IDMT characteristics. A set of three phase neutral side currents, I3P_N, isconnected to the inputs.A common operate and start signal from the both negative-sequence overcurrentfunctions is connected to an OR-gate to form a combined negative-sequenceovercurrent operate and start signal, which is used for providing a LED indication onthe LHMI. Also a separate start and operate signal from the both MNSPTOC functionsis connected to the disturbance recorder.Section 3 1MRS757582 CREG630 variants32 REG630Application Manual