Relays

1. Relying on Relays
By
NKV. Sai Suneel
I/II M.Tech (PS&A)
GIT

2. Abstract
Relays are the devices which actually sense the
fault and play a very vital and key role in the
protection schematics used in a power system.
This presentation is an attempt to share my views
regarding the topic of relays.

3. Introduction
• Relay is an electrical device designed to initiate
isolation of a part of an electrical installation or to
operate an alarm signal, in the event of an abnormal
condition or a fault.
• On a broad perspective, relays are generally divided as :
• Primary Relays
• Secondary Relays (or) Back-Up Relays
• Relay malfunction is due to failure of supply to its trip
coil, bad contacts and open circuit in relay coil.
• The later have longer operating time even though they
sense the fault along with the primary relays.

4. Complexified

5. In fact…..

7. A world of relays

8. Basic Operation

9. The Operation

10. What’s Inside

11. Distance Protection
• Impedance type distance relay
• Reactance type distance relay
• Admittance type distance relay