- With reference to two identical generators operating in parallel supplying a switchboard that automatically shares load equally, explain EACH of the following:
(a) the effect of the excitation of one generator reducing while the load remains constant;(5)
(b) the possible effects of closing the main circuit breaker when frequency and voltage are equal but phases are out of phase. (5)
- With reference to load sharing of a.c. generators:
(a) state the meaning of the term speed droop;(3)
(b) explain the effect of running generators in parallel with different speed droop settings for EACH of the following:
(i) when the generators are sharing the load equally;(3)
(ii) when the load suddenly increases.(4)
- With reference to AVRS:
(a) explain their purpose;(4)
(b) explain the effects that would be observed should an AVR give a low output when the generator is:
(i) running on its own;(2)
(ii) running in parallel with a second generator whose AVR has no fault.(4)
- Describe, with the aid of a sketch, the operation of a diesel generator speed and load sensing electronic governor, labelling the MAIN components.(10)