Basics of Electrical Reactors, Their Working Principle and Applications

  • 22 May, 2019

When it comes to protecting power equipment and circuit breakers, electrical reactors come into the picture. Electrical reactors are simply coils that have a large number of turns and have greater Ohmic resistance. They are mainly used for the purpose of limiting short circuit currents in the whole circuitry. Short circuit currents are the big reason behind the damage of equipment of power systems. Since they provide additional reactance when added in series with the system (for protection), these devices are named as reactors.

Depending upon their function, there are several types of electrical reactors available in the market such as:

  • Neutral grounding reactors
  • Thyristor controlled reactors
  • Smoothing reactors
  • Test reactors
  • Current limiting reactors
  • Damping reactors
  • Shunt reactors
  • Filter reactors

Among all of them, the current limit reactor is the most commonly used reactor in the electrical industry. It is designed to limit the heavy flow of current through particular sections of an entire system. So, when some problem occurs, a repairing technician doesn’t have to shut down the whole system as with a current limiting reactor, the faulty section can be easily isolated.

As previously mentioned, current limiting reactors are also employed in the power systems to protect circuit breakers with different ratings. They are helpful in limiting the short circuit currents depending upon the capacity of circuit breakers. Therefore, while making changes in the system, there is no need to replace the circuit breakers just for matching current limit and rating. Rather, you can add reactors and make use of the same circuit breaker. So, by using electrical reactors, you can also save time as well as money.

Now, you know what they are and why they are used. Let’s discuss their working principle.

Working Principle of Current Limiting Reactors

Assume that the reactance of a circuit during fault is X and given voltage value is E. The short current value can be easily calculated using the below formula:

Isc = E/X

This means the reactance of a circuit is inversely proportional to the short circuit current flowing in the circuit. Thus, when reactance increases, short circuit current decreases and vice versa.

Short circuit currents depend on:

  • Generation capacity
  • Fault point voltage
  • Reactance of the circuit

The rating of reactors is labeled in KVA and formula for reactance % is as follows:

%X= KV drop/ KV (phase voltage)

Applications of Reactors

  • Arc suppression
  • Filter the harmonic currents
  • Protect against high voltage waves, surges and lightning
  • Control starting currents of motors
  • Connected in series with auto transformers of low reactance
  • Connected in series with induction regulators of low reactance

Are you looking for electrical reactors? Check out websites of reputed electrical reactor manufacturers and place your order.