What causes over excitation?

Overexcitation of transformers in transmission and distribution networks is caused by overvoltages in the network. For step-up transformers connected to generators during start-up, overexcitation can occur since the flux is dependent of the factor voltage/frequency.

What is Overfluxing protection in generator?

Over Fluxing relay is used to protect the generator against overheating and the winding insulation failure. Over fluxing protection is a popular protection in transformers, which is mainly used in power transformer.

What is over excitation and under excitation?

The over-excitation limiter protects the generator against over-temperature caused by high field current for long time. Under-excitation limiter prevents the decrease of generator field current to the values lower than the stability margin or the thermal limit of end side of the stator core.

What is Overfluxing in transformer?

In transformer over fluxing is the dangerous situation in which magnetic flux density increases to extremely high level. The high flux density increases core loss which may lead to overheating of components which in turn may result into internal fault.

What is overexcitation relay?

RXLK 2H overexcitation relay monitors the magnitude of excitation by measuring the relationship between the voltage and the frequency. When the set operate value is exceeded, an alarm and delayed tripping is obtained.

What are the causes of bus zone faults?

The bus zone fault occurs because of various reasons likes failure of support insulators, failure of circuit breakers, foreign object accidentally falling across the bus bar, etc., For removing the bus fault, all the circuits connecting to the faulty section needs to be open.

Will happen if generator is over excited?

When overexcited, the inductive reactive power is emitted, and the armature reaction is demagnetization; when the excitation is weak, the generator emits capacitive reactive power, and the armature reaction may increase. A normal excitation generator only outputs active power with a power factor of 1.

How do you protect a transformer from Overfluxing?

The flux density in the core should not increase above the rated flux density of the core to avoid over fluxing in the core. Therefore the designed flux density of the core is always kept below the maximum rated flux density of the core. The over fluxing relay is used to protect the transformer against over fluxing.

What does Overflux mean?

noun Excess; exuberance: as, “an overflux of youth,”