Synchronization

No.

Next question.

Another homework? To synchronized gen sets considered as follows;

1. must be the same RPM.

2. must be the same voltages.

3. must be the same phase sequence.

yes synchronization is possible becaz most of industries make there own electricity and these industries have 3-to-4 units i.e 1 generator to 3 generators in which two units operates and 1 generator is in reserve but if there is any problem in one unit (generator) then the reserve unit is switched on and operatings is offed........synchronization will be done only when all generators are same power rating same voltage phase sequence must be checked otherwise short circut problem will be experinced

Yes, they're of the same voltage, frequency, phase sequence, the problem at issue is that, the generators voltages had been change from 220/400v to 112/231v, those that have any effect. which type, kind of synchronizing unit recommend.

Initial rating of generators are...200kva, 220/400v, 289Amp 50hz

The summary here is that you can synchronize these two units with a synchronisation panel. (or a lamp, a multimeter,a screwdriver, a barrow load of confidence and real necessity)

Can you tell us why you opted to alter the gensets rather than replace them with units that were factory configured (new or secondhand/surplus) for your required operating voltage?

What is the public supply voltage at your location?

Mr. King Faisal correction please. The generators can be synchronized though their power rating means in kilowatt or megawatt are not the same. The power rating does'nt matter for example one generator rated 30MW and the rests of three are rated 20MW. One of these example are Saudi Electricity Co(SEC) Power Plant PP9 54km east of Riyadh, K.S.A. with gen.sets of different power rating capacities, the combined generators capacity on transmission lines is 5,980megawatt/132kv. with an area of 3.2million square meter. What matters in sychronization to put all those gen set. on operation in a substation bus bars, the gen.sets 1.)must be symetrical or in-phase. 2.) must be of the same frequency(say 60Hz.),3.) must be of the same output voltages(say 2.40kv, 3-phase), 4.)must be of the same RPM(say 1,800RPM). For example one gen. set is out of phase and gonna be put on parallel operation along with other gen. sets it will not cause a short circuit because the out of phase gen.set will be denied or will not be recognized by PLC incomer sensors. Means this out of phase gen. set will never be a friend of other generators unless basically will become one of them in operational characteristic charts.. shall i say birds of the same feather will flocks together.

My answer is NO.

Ask yourself "What has to happen in order for two or more sources to be connected to the same bus"? or "What does synchronized mean"? and you will have your answer.

The only "special" requirement is that the generator frequency and excitation can be externally controlled.

Not the generators but the Operators should be trained and experienced even though sets are similar.

There are devices out there to sync generators that work on output, the synchronizer adjusts the speed of the Genny's to give the same output, you simply enter the loading and then it will synchronize as many sets as you want. It is not as simple as I've put it here you need sensors and governors on each Gen-set but thats the gist of the idea.

Bazzer

Please note that it is NOT necessary for generators to have same revolutions/minute.

Any Power Grid will have a mix of generators with 2 pole, 4 pole, 6 pole generators etc depending on the power of the prime mover and its type and speed. And unit power can vary from kW to GW - all synchronized.

Diesels and water turbines in particular can have many poles for low speeds.

About 120 years ago, when AC was new - there were parallel operation problems. These were traced to poor generator voltage/current waveform, which was not sinusoidal.

Any good modern generator will be made to an international standard which ensures adequate waveform quality.