What is definite time over current relay?
A definite time over-current (DTOC) relay is a relay that operates after a definite period of time once the current exceeds the pickup value. Hence, this relay has current setting range as well as time setting range.
What is over and under current relay?
It senses the current flowing through a totally electrically isolated circuit and energizes the electromagnetic relay when the current crosses the set value. …
What is the function of over current relay?
The function of Over Current relay is to sense the current and gives the information to the Circuit Breaker, so that the Circuit breaker will open its contacts when any abnormal condition occurs in a system. Over Current relay is very videly use in Electrical Power transmission systems.
How do you calculate current relay setting?
Calculation of Over Current Relay Setting:
- Over Load Current (In) = Feeder Load Current X Relay setting = 384 X 125% =480 Amp.
- Required Over Load Relay Plug Setting= Over Load Current (In) / CT Primary Current.
- Required Over Load Relay Plug Setting = 480 / 600 = 0.8.
What is current setting?
The current setting of relay is expressed in percentage ratio of relay pick up current to the rated secondary current of CT. Then, the relay will be operated when the current of CT secondary becomes more than or equal to 1.25 A. As per definition, The current setting is sometimes referred as current plug setting.
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 TMS and PMS?
phanibabu January 20, 2020 January 20, 2020 1 Comment. PSM and TMS settings that is Plug Setting Multiplier and Time Multiplier Setting are the settings of a relay used to specify its tripping limits. To understand this concept easily, it is better to know about settings of the Electromechanical Relays.
What is an over current device?
An overcurrent protection device (OCPD) is a piece of equipment used in electrical systems that are at risk of experiencing overcurrent due to overloads, short circuits, or ground faults. In overcurrent situations, an OCPD will re-route or disable current flow through the system to make it safe.
What is time multiplier setting?
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 TSM and PSM?
TSM is time setting multiplier which comes into role only when pick-up value is reached. Practically PSM tell us about the magnitude of fault. The more the value of fault current, the more will be the PSM and hence the relay should clear the fault more quickly.