In power stations require electricity for use in the power station. Electric power for use in the power station is used for:
1. Lamp lighting
2. Conditioning air
3. Starting aids generating units, such as cooling water pump, lubricating oil pump, fuel oil transfer pump, lifting machines, and others.
4. Charging batteries battery which is a source of direct current for power plants. II.73a image illustrates the use of its own installation of the central power plant generator unit capacity is relatively small, for example less than 5 MW.
Description:
G = generator
PS = transformer for own use
Block = block transformer Tr
In large generating units, each generating unit has its own usage transformer (Tr PS) are supplied directly by the generator (G). But at the start, the generator (G) is not spinning so immature voltage.
While at the time it was necessary power to run the props, the first power usage is taken from the transformer itself together. After the generator (G) rotates and generates a voltage, PMT B is closed. This was followed by the opening of a PMT so that the power supply assistive devices switch to the generator (G).
At the time of PMT PMT B before A is closed and opened, there was a series of ring closure. It should be noted that the existing transformer-transformer in the ring does not cause phase shifts the voltage so that no problems arise.
The amount of energy needed for their own consumption ranged between 1-10% of the energy production centers generated electricity. It really depends on the type of electrical center, where most ketch generally hydropower and most major power plants generally use coal fuel.
In the event of a major disruption, and all generating units trip, then no voltage available to run the props in order to start again. In an ian demik required delivery outside the center voltage of electricity or inside. electrical center, where there should be units that can start generating its own (black start) without any external voltage. Generally, you can do most of whom are black start unit hydroelectricity (hydro) or diesel power units (diesel).