Why Power Plant Capacity Rated in MW and not in MVA?

For the following reasons, a Power plant capacity rating may be expressed in MW instead of MVA.

In a Generating station, the prime mover (Turbine) generates only and onlyActive Power. That’s why we rated a power plant capacity in MW instead of MVA. Its mean no matter how large your generator is, but it depends on the capacity of the  engine (Prime mover/Turbine) I.e. a 50MW turbine connected to a 90MVA alternator in a power plant will generate only 50MW at full load. In short, a power plant rating is specified in terms of prime mover /Turbine (Turbine rating may be seen by nameplate rating which is in MW or Horsepower (HP) not in MVA) and not by the alternator set coupled to it.

Another thing is that, electric power company charges their consumer for kVA while they generate kW (or MW) at the power station (Power plant).They penalize their consumer for low Power factor because they are not responsible for low power factor and kVA but you. Moreover, in power plant, power factor is 1 therefore MW is equal to MVA …… (MW = MVA x P.f).

 I am just posting some sample posts ........ but will write more datas in forth coming months

question?
Why Motor rated in kW/Horsepower instead of kVA?
Answer:

We know that Transformer rating may be expressed in kVA as well as Generator and Alternator rated in kVA Designer doesn’t know the actual consumer power factor while manufacturing transformers and generators i.e. the P.F (Power factor) of Transformer and Generator/Alternator depends on the nature of connected load such as resistive load, capacitive load, and inductive load as Motors, etc. But Motorhas fixed Power factor, i.e. motor has defined power factor and the rating has been mentioned in KW on Motor nameplate data table. That’s why we are rated Motor in kW or HP (kilowatts/ Horsepower) instead of kVA.

In addition, Motor is a device which converts Electrical power into Mechanical power. In this case, the load is not electrical, but mechanical (Motor’s Output) and we take into the account only active power which has to be converted into mechanical load. Moreover, the motor power factor does not depend on the load and it works on any P.F because of its design.

What is the difference between AC and DC resistance?

                 The property of a substance or material which oppose the flow of electricity through it is called resistance.

                 In Simple words, Resistance in AC circuits is called Impedance. Or

The Overall resistance (Resistance, Inductive reactance and Capacitive reactance) in AC circuits is called Impedance (Z).

Explanation:

When AC Current pass through a wire (resistor, inductor), then current produces a magnetic field across that wire which opposes the flow of AC Current in it along with the resistance of that wire. This oppose cause is called Inductance or Inductance is the property of Coil (or wire) due to which opposes any increase or decrease of current or flux through it. Also, we know that inductance is only exist in AC because the magnitude of current continuously changing

Inductive Reactance X_L, is the property of Coil or wire in an AC circuit which opposes the change in the current. The unit of Inductive reactance is same as Resistance, capacitive reactance i.e. Ohm (Ω) but the representative symbol of capacitive reactance is X_L.

Likewise,

Capacitive Reactance in a capacitive circuit is the opposition to current flow in AC circuits only. The unit of capacitive reactance is same as Resistance, Inductive reactance i.e. Ohm (Ω) but the representative symbol of capacitive reactance is X_C.

QUESTION:

what is the difference between the Kvar and farads, Rating on Power capacitor is for eg: x kvar, and normal capacitor is eg: x farads.

what is the relation between these two?

ANSWER

KVAR : stands for Kilo Volt Ampere Reactance , used to measure maximum reactive power (imaginary) that can the capacitor stands

Farad : unit of measuring the capacitance of the capacitor

No relation between them !

QUESTION :

According to ohms law V=IR that is Voltage and Current are directly proportional to each other but whenever load increases the current increases and the voltage reduces which means inversely proportional how?

ANSWER:

According to ohm's law voltage and current are directly proportional keeping resistance as constant but whenever load increases the current increases and the voltage reduces because Power=V*I so for maintaining constant power when current increases the voltage reduces.so both the conditions are different.