Rotor Earth Fault Protection of Alternator or Generator

The rotor of an alternator is wound by field winding. Any single earth fault occurring on the field winding or in the exciter circuit is not a big problem for the machine. But if more than one earth fault occur, there may be a chance of short circuiting between the faulty points on the winding. … Read more

Stator Earth Fault Protection of Alternator

This is to be noted that, the star point or neutral point of stator winding of an alternator is grounded through an impedance to limit the ground fault current. Reduced ground fault current causes less damage to the stator core and winding during ground or earth fault. If the ground impedance is made quite high, … Read more

Loss of Field or Excitation Protection of Alternator or Generator

Loss of field or excitation can be caused in the generator due to excitation failure. In larger sized generator, energy for excitation is often taken from a separate auxiliary source or from a separately driven DC generator. The failure of auxiliary supply or failure of driving motor can also cause the loss of excitation in … Read more

Motor Protection Circuit Breaker or MPCB

Motor protection circuit breakers are a specialized type of electrical protection device that is designed specifically for electric motors, like their name implies. Electric motors have plenty of applications and are used to drive mechanical devices of all types, so it is very important to protect them adequately with MPCBs. The following are just a … Read more

Busbar Protection | Busbar Differential Protection Scheme

In early days only conventional over current relays were used for busbar protection. But it is desired that fault in any feeder or transformer connected to the busbar should not disturb busbar system. In viewing of this time setting of busbar protection relays are made lengthy. So when faults occurs on busbar itself, it takes … Read more

Overvoltage Protection

There are always a chance of suffering an electrical power system from abnormal over voltages. These abnormal over voltages may be caused due to various reason such as, sudden interruption of heavy load, lightening impulses, switching impulses etc. These over voltage stresses may damage insulation of various equipments and insulators of the power system. Although, … Read more

Protection of Lines or Feeder

As the length of electrical power transmission line is generally long enough and it runs through open atmosphere, the probability of occurring fault in electrical power transmission line is much higher than that of electrical power transformers and alternators. That is why a transmission line requires much more protective schemes than a transformer and an … Read more

Protection of Capacitor Bank

Like other electrical equipments, shunt capacitor may also be subjected to internal and external electrical faults. Hence this equipment is also to be protected from internal and external faults. There are numbers of schemes available for protection of capacitor bank, but during applying any of the schemes, we should remember the initial investment on that … Read more

Annunciation System Alarm Annunciator

In electrical and electronics systems, the word Annunciator means a device which announces the faults or unusual activities coming from the system or process associated with it. What is Alarm Annunciator? It is basically an audio visual warning system, which highlights the fault or mishap which is going on, or even before it happens. This … Read more

Differential Protection of Generator or Alternator

Any internal fault inside the stator winding is cleared by mainly differential protection scheme of the generator or alternator. The differential protection is provided in the generator by using longitudinal differential relay. Generally instantaneous attracted armature type relays are used for this purpose because all they have high speed operation and also they are free … Read more