What are relay settings?

What are relay settings?

The current setting of relay is expressed in percentage ratio of relay pick up current to the rated secondary current of CT. That means, For example, suppose, you want that, an over current relay should operate when the system current just crosses 125% of rated current.

How do you calculate relay settings?

Calculation of Over Current Relay Setting:

1. Over Load Current (In) = Feeder Load Current X Relay setting = 384 X 125% =480 Amp.
2. Required Over Load Relay Plug Setting= Over Load Current (In) / CT Primary Current.
3. Required Over Load Relay Plug Setting = 480 / 600 = 0.8.

What is TMS in relay settings?

Time Multiplier Setting used to change the value of operation of the relay. If it is more the relay will take more time to operate and vice versa. Changing the position of TMS setting, changes the distance between the contact of the rotating disk and the coil.

How do I select a pickup value of a relay?

The first step in setting the relay is selecting the CT so that the pickup can be set for the desired primary current value. The primary current rating should be such that a primary current of 110 to 125% of the expected maximum load will produce the rated 5A secondary current.

What is an IDMT relay?

IDMT relay is inverse definite minimum time relay. It is one in which Time of operation is inversely proportional to magnitude of fault current near pickup value and becomes substantially constant slightly above the pickup value of the Relay.

What is time dial setting?

The time dial setting adjusts the time delay before the relay operates whenever the fault current reaches a value equal to, or greater than, the relay current setting.

What is the IDMT relay?

What is TMS setting?

What is TMS or Time setting multiplier: The time setting multiplier is nothing but an adjusting or speeds up the tripping mechanism of the relay (it is called as the dial). The dial is nothing but a rotating disc, which rotates when the fault current in the relay coil reaches the pickup current.

What is TMS in power system?

Time Multiplier Setting (TMS) or Time Dial. Page 1. Effect of Distributed Generation on Protective. Device Coordination in Distribution System.

What is Idmt?

What is the use of IDMT relay?

What is idmt relay: The IDMT relays are protection relays. They are used in the transmission lines to see that the line current does not exceed the safe values and, if necessary, operates the circuit breaker. IDMT means the minimum minimum time spent.

Why IDMT relays are better?

The IDMT relay uses the electromagnetic core because it can easily saturate for the current having larger magnitude than pick up current. The relay is used for the protection of the distribution line. The inverse characteristic of the relay is more than the IDMT.