When consumers generate electricity to sell to the utility company, how are the phase differences handled?

Question

In some areas of the country, a consumer can install a windmill that generates electricity and sell that electricity to the utility (which then sells it to other consumers). If there were hundreds of individuals in an area, each with a windmill generating electricity, how would the utility handle the fact that each windmill generates AC electricity that is not in phase with the electricity generated by the other windmills?

I understand that there are methods for "shifting" the phase of AC electricity. But would each windmill have its own phase shifter, in order to provide "in-phase" electricity to the system? Or could each windmill sense the phase of the system and generate its electricity in phase?

Please help me understand how this works.
Thanks.

Answer 1

The phases are locked together before significant current is allowed to flow, and continue to remain locked by adjustment of the field current or the torque applied to the generator. You start the generator turning, switch on the field, and as the generator reaches speed, watch phase comparison lamps. When the lamps go out (indicating phase synchronization), you connect the generator to the network, and adjust the field current so that the proper current is generated.

Answer 2

When you shut the output breaker of the turbine the phases will get locked together if the frequency of the induced voltage of your windmill faster than the frequency of the power line or if your windmill is trying to output a higher voltage than the power line then power will flow out of your windmill and onto the grid. So if you try to "slip" a phase would require a large amount of output current from your windmill which would thus induce a large counter electromotive force which would slow down your windmill until it was in phase with the power line grid system or until you fried your generator in you windmill. Power is measured with a power meter.

Answer 3

The info in the above answers about how to tweak the phase to synchronize is perfect. However the practical consequences were not mentioned. It is not the utility that needs to handle synchronization - it is each incoming generator.

The electrical grid that the new generator is going to connect to is infinite in size compared to those generators. If they are not synchronized closely when they are connected to the grid they will, within a fraction of a second, be jerked into a synchronized position of phase locking. The incredible force of that corrective synchronization is enough to twist-off the shaft of the new generator (no matter how large its capacity).

Answer 4

First let us talk about putting 2 generators on line together ,u want to close the switch when the generator is slightly faster than the other . When u close the switch the load will slow it down pulling it in sync . U would need a good speed control to help do this but if u are leading the grid the load will slow u down to fall in sync.