Turbo Generators can be supplied with any of the following conventional excitation systems as per customer requirements.
a) Conventional excitation system:-
The system consists of D.C exciter directly connected to the generator field the field of the exciter is controlled by an automatic conventional voltage regulator.
b) Static excitation system:-
The system consists of a thirstier convertors field breaker rectifier transformer and AVR. This system is chosen where fast response is called for since all equipment is static and calls for less maintenance.
c) Brushless excitation system:-
This system comprises of shaft drives AC minimum maintenance and suitable for explosive atmosphere with a spark-free operation.
d) Protection system:-
Following protections are generally recommended for air-cooled turbogenerators of higher sizes the exact scheme of protection will be finalised with reference to axillaries on the basis of rating and application.
– Differential protection.
– Stator earth fault.
– Generator overcurrent.
– Generator overvoltage.
– Rotor earth fault.
– Protection against negative sequence currents.
– Low/ forward power relay in case of generators for parallel operation with either set.
– Back up impedance relay.
– Protection against over fluxing under frequent operation and thermal overload.
– Protection against loss of excitation.
– Protection against motoring / reverse power relay.