MODULE : TB6 

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GENERATOR AND GENERATOR PROTECTION 

COURSE DESCRIPTION :

• Operation of Generator

• Capability curve, efficient real and reactive power loading, feasible operating regions

• Fundamental concepts in {P(kW) – F(Speed)} and {Q(kVAR) – V(Voltage)} loop controls

• Recommended Governor control modes and AVR control modes for isolated operation and parallel operation with grid

• Generator protection elements

• Over load protection, RTD, insulation class, loss of insulation life

• Stator earth fault, core damage curve, effect of neutral grounding, voltage based and current based schemes

• Differential protection

• Over fluxing protection: generator withstand curve

• Field over heating   

• Rotor earth fault: effects, Stage 1(Alarm) and Stage 2(Trip), special remarks - monitoring through slip rings in brushless excitation system,

• Loss of excitation: unit behavior, off set mho relay with and without under voltage, complementary to pole slipping relay

• Reverse power: unit behavior, influence of prime mover (Steam, Hydro, Gas, Diesel), application of low forward power, measuring CT requirement, testing relay operation on line

• Unbalanced current (Negative Sequence) protection: source of unbalance, effect on rotor, I₂²t relation, influence of machine cooling, Negative sequence loading on captive units in presence of non-linear loads when operating in parallel with grid and in isolation.

• Voltage controlled and voltage restrained over current protections: where useful and where not useful, DMT and IDMT characteristics

• Under frequency protection : Steam, Hydro, Gas and Diesel 

• Pole slipping: Critical Clearing Time and loss of synchronism, mho relay with blinders  

• Inadvertent energizing : scheme and precautions

• PT fuse failure schemes : with one PT, with three PTs

• Recommended protections for small, medium and large generating units

•  Load and no load dynamics and testing of following protection schemes at site:

• Differential : Stability and sensitivity checks

• Stator earth fault

• Negative sequence

• Case study : Typical calculation procedure for setting Generator numerical protection relay (e.g. REM 543)

• Case studies / discussions on reported abnormal occurrences: Reverse power, Differential, Over Frequency.