Reactive Compensation Advantages And Disadvantages

The low power factor is mainly due to the fact that most of the loads are inductive and, therefore, take lagging current, in order to improve the power factor, some device taking leading power should be connected in parallel with the load. One of such devices can be a capacitor. The capacitor draws a leading current and partly or completely neutralizes the lagging reactive component of load current. This rises the power factor of the load. This is known as reactive compensation. [30]

1.7 Reactive compensation Electrical energy is generated, transmitted, distributed, and utilized as alternating current (AC). However, alternating current has several distinct disadvantages. One of these is the necessity of reactive power that needs

to provide leading volt-ampere-reactive and thus to reduce the line current and total KVA loading of the substation transformer. By using shunt capacitors line drop is reduced and the voltage regulation is improved. Shunt capacitors are switched-in when KVA demand on the distribution system rises and voltage of the bus drops.

1.7.3 Shunt Reactive Compensation

Since most of loads are inductive and consume lagging reactive power, the compensation required is usually to supply leading reactive power. Shunt compensation of reactive power can be implemented either at load level, substation level, or at transmission level.

It can be capacitive (leading) or inductive (lagging) reactive power, although in most cases compensation is capacitive. The most common form of leading reactive power compensation is by connecting shunt capacitors to the line.

1.7.4 Shunt capacitors are employed at substation level for the following reasons:

1.7.4.1 Voltage

Load current is inversely proportional to power factor. So by installing shunt capacitor at the bus, improves the power factor and reduces the load current which is flow in the transmission lines, transformers, alternators etc. It also increases efficacy.

1.7.4.3 Increased Utilization of Equipment

Shunt compensation with capacitor banks reduces kVA loading of lines, transformers, and alternators, because the reactive component of current prevents the full utilization of installed capacity. So it means with compensation reactive component partly neutralized and equipment can be used for delivering more power without overloading the equipment. Reactive power compensation in a power system can be done by placed shunt capacitor or series capacitor. Shunt compensation can be installed near the load, in a distribution substation, along the feeder, or in a transmission