20-11-2012, 04:25 PM
REACTIVE POWER COMPENSATION
reactive_power_compensation.ppt (Size: 125.5 KB / Downloads: 44)
INTRODUCTION
Major industrial loads e.g. induction motors,
furnaces, transformers, etc. need reactive power for
sustaining the magnetic field.As in case of induction
machine the reactive power is needed just to
create air gap magnetic field.Series inductance in
transmission lines implies consumption of reactive
power. Reactors, fluorescent lamps and all
inductive circuits on the whole require a certain
amount of reactive power to work. Thus reactive
power is not delivered as effective mechanical
power output of motor unlike the real power which
is effectively converted as mechanical output.
Definition:
Any device which is connected in shunt or series with the load and which is capable of supplying the reactive power demanded by the load is called a Reactive power compensation device.
NEED FOR REACTIVE POWER COMPENSATION
The power supplier charges penalty for excessive consumption of reactive power.
Reduced energy losses make reactive power profitable.
Additional machines are to be connected to already fully loaded substations, cables or transformer.
The power transmission for a new plant can be planned more economically if power factor correction is taken into consideration.
TYPES OF COMPENSATION
There are different types of compensation:
(1)Individual compensation:
limitation:-compensation value limited by the no load KVA of the motor.
Risk of the high inrush currents due to parallel switching.
Not feasible to design an effective harmonic filter.
Advantage:-Additional control and protection equipments not required.
Overcompensation are avoided.