Table of Contents
Synchronous generators or alternators are synchronous machines used to convert mechanical power to ac electric power. Nowadays, an isolated synchronous generator supplying its own load independently of other generators is very rare. Such a situation is found in only a few out-of-the-way applications such as emergency generators. For all usual generator applications, there is more than one generator operating in parallel to supply the power demanded by the loads. There are several major advantages to synchronous generators that operated in parallel. * Several generators can supply a bigger load than one machine by itself * Having many generators increases the reliability of the power system, since the failure of any one of them does not cause a total power loss to the load * Having many generators operating in parallel allows one or more of them to be removed for shutdown and preventive maintenance * If only one generator is used and it is not operating at near full load, then it will be relatively inefficient. With several smaller machines in parallel, it is possible to operate only a fraction of them. The ones that do operate are operating near full load and thus more efficiently There are necessary conditions for paralleling two synchronous generators such as : * The rms line voltages of the two generators must be equal * The 2 generators must have the same phase sequence
* The phase angles of the 2 a phases must be equal
* The frequency of the new generator, called the oncoming generator, must be slightly higher than the frequency of the running system The oncoming generator on a power system must be paralleled at a higher frequency than that of the running system because if the frequency of the generators is not nearly equal when they are connected together, large power transients will occur until the generators stabilize at a...
Please join StudyMode to read the full document