Power factor capacitor installation

Last time i already discuss about how to sizing the power factor capacitor.After we got a figure and corrected size for capacitor,the next step is what is types for installation of capacitor?

The installation of power factor capacitor have several method that commonly used around the world.This time i want share some information about types of power factor capacitor installation method.

This part is critical and important because if we wrong to choose the installation method,it can cause a damage for our equipment or machine.It also can effected all equipment in our placed.

Types of power factor capacitor installation

Basically it have 3 types or option to install capacitor for power factor correction.Following listed are common practice for installation :-

1) Install capacitor between overload relay and magnetic contactor

– This method suitable for single capacitor for individual equipment such as induction motor or compressor.We can set the overload relay following the FLA of motor name plated.

– The capacitor only activated when magnetic contactor energized to start the equipment.That mean capacitor have a long life span and made a power factor correction during operation only.

Advantage

• A capacitor can switch on or off depend on magnetic contactor operation.It also can avoid another switching device for pf capacitor.
• Power factor correction activated when it needed,voltage drop and lines losses can be minimized and system capacity is maximized

Disadvantage

• Highly installation cost when we have a lot of equipment or induction motor for power factor correction.
• We need to setting the overload relay for lower motor current draw.

2) Install between upstream circuit breaker and magnetic contactor

– This method usually used for large banks of fixed kVAR with fusing on each phase or power factor regulator automatically switched banks.This method is recommended for jogging motors, multi speed motors and reversing applications

Advantage

• For the larger system,the cost for installation is more effective because it can supply the capacitance value to several induction motor or machinery.

Disadvantage

• If power factor capacitors are not switched with the induction motors,it can cause the  over correction if all motors are not operated or running.
• The reactive current must be carried a greater distance,it will cause the higher line losses and larger voltage drops.

3) Install at the main distribution power supply

– This method is common practice for industry and manufacturing sector around the world for power factor correction.It used a power factor regulator to control the correction and value of kVAR for the distribution supply.

Advantage

• Lower installation cost because with build a 1 unit of capacitor bank completed with regulator to produce large kVAR value.It cover for a hole of distribution system.
• We can easier manage and maintenance the capacitor bank very effective and it can done the power factor correction more accurate.

Disadvantage

• We need to install the over current and separate disconnection system for power factor capacitor.