USE OF SHUNT CAPACITORS IN TRANSMISSION LINES
During power transmission, there will be problems like poor voltage regulation and power factor, poor efficiency and less reliability shunt capacitive compensation is a method to avoid these problems by using this we could get better power factor. Most of the power systems are loaded with an inductive load to compensate the inductive load shut capacitor will be applied to the load. This type of compensation could be done to substation level or the transmission level
The advantages of shunt capacitive compensations are • Transmission power loss is decreased by reducing reactive current • More capacity is available to supply the power to the load • Better regulation due to less voltage drop • Due to less loading, the life of power system equipment increased • It could achieve peak load demand • There will be reduced stress for generator excitation system • Source generator’s power factor increased
OPERATION If an inductive load is connected to a transmission line the power factor lags and it is because of the lagging of the load current as a solution for this problem a shunt capacitor is connected which draws the current leading the source voltage and the result will be better power factor Low power factor causes low voltage regulation the capacitor causes the current to lead the voltage the inductive resistance of the system will be canceled by the capacitive reactance it will be good to use a capacitor bank instead of a single capacitor Capacitor can’t be installed for small loads instead of that it could be connected to medium and large loads so it is difficult to connect capacitor at each load instead of that it will be connected to main distribution substation or secondary grid substation
In order to increase the power factor a certain amount of leading reactive power “Qc” must be added this is usually done by the shunt capacitor
Compensation of the line per unit= series capacitive resistance ÷ inductive reactance
