Protective Relays that help you at the time of need

Protective Relay is the device that trips the circuit breaker when any kind of fault is detected. The first relay was based on coils that operate on moving parts to detect any abnormal conditions like over-voltage, over-current, frequency change and other electric faults. These used to be generally electromagnetic in nature.

But now, many types of advanced electrical protection relays are formed which work in a fraction of second so as to maintain the safety of appliances installed in the premises.

• Electromechanical Protective: These can further be classified as attracted Armature, mechanical, induction, moving coil, thermal and motor operated. All these relays have specific uses and these work differently with different applications.
• Induction Disc over Current: These work on alternative current and a rotating disc which is connected to contacts. These are made to check the over current flow in a circuit and warn earlier so that it can be checked and rectified in a proper and timely manner.
• Static Protective: These use the power to transistors with no or few moving parts. They have an advantage of higher sensitivity over electromechanical relays. The static ones reduce the changes of contact bounce and provide long life, faster operation and low maintenance.
• Digital Protective: They have replaced the use of electromechanical protective relays. A single digital relay can have features of many electromechanical ones. These operate by converting voltage and current in digital form which makes it easier to operate and work more efficiently.
• Numerical: Digital and numerical relays can only be distinguished by technical details and are mostly used in protection of circuits. 

Well, relays are also classified according to the functions performed by them. Some of them are:

• Distance Relay
• Current Differential Protection
• Over Current Relays
• Directional Relay
• Synchronism Relay         

Irrespective of the various types, one thing is sure that these are indeed one of the most important innovations that have ensured our safety.