Aboutcleggsan Expertise All technical areas of Electronics Engineering.
Experience BSEE, MBA, Design, R&D, University Research.
Senior Life Member of IEEE. Life Fellow of AES.
Organizations IEEE, Consumer Electronics Society, Audio Engineering Society.
Broad teaching experience; work experience mostly in consumer electronics and conversion from analog to digital technologies. Pioneer in digital audio at all levels.
Question 1.In the protection system of generator, there is under/over frequency relay. How does this relay detects the under/over frequency? Does it has anything to do with the load demand?
2.For generator, the speed is constant. Let say 15000rpm. this is the speed of the turbine that drive the generator. When there is a demand for more power, how can the generator do it. What are the factors that can increase the generation since the speed is fix, the frequency is fix. Or how can the generator increase the power generated? If we increase the fuel, the speed that rotates the turbine hence the generator is still constant. So how can generator do it?
3.Which one comes first. We increase the generation to cater to the load demand. For example,early generation is 4MW, then suddenly the operation guy said want to start 3 big motors with total 2.5MW. So we need to adjust the generator to increase another 2.5MW which at the end the total generation will be 6.5MW. So we are providing the power first prior to motor starting. If we do not increase it at first, and then the motor starts, the power might not be sufficient ie 4.5MW only.And can cause tripping
Or generation will automatically increase when the 3 big motors been started? So at the end the total will be 6.5MW. The load is increasing simultaneously with the starting.Actually I do not know how to ask this question.
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4.When the load on the systems increases, the frequency tends to lower, so more power (steam flow through the turbin) is needed. The opposite happens when the load decreases.Why it happpens like this ie the load increase, f will decrease vice versa?
Answer I think my previous question answered this. The automatic controls are very sophisticated electronic (mostly computer) now days and use complicated calculation tools to increase energy input (whether it is water driven, steam, etc.) and how quickly it can respond. In multi systems it may drop one out of the line until the inputs can be cranked up; then when it reaches the energy input that is necessary it cuts it back on line. The system prevents a generator from loading down the system when it should be adding power to the bus line, and so on.
If sufficient energy is available at all time, like in water driven units (from water fall of fixed distance) then running a generator at less than output capability is a simple matter of not using all the output. But once it reaches its maximum it can not longer keep up and demand must be meet by adding more generators to the system.
Control theory is beyond my expertise and I can only give you general answers......... I am not a power engineer, just an engineer!
