Master Trip Relay 86 Working Function and Significance of Master Trip Relay


Master Trip Relay 86 Working Function and Significance of Master Trip Relay?

A master trip relay is a type of protective relay that is used to trip a breaker in the event of an abnormal electrical condition. This relay is typically used in conjunction with other protective relays, such as overcurrent relays or undervoltage relays, to provide a level of protection for electrical systems and equipment.

The primary function of a master trip relay is to monitor the electrical system for abnormal conditions and to initiate the tripping of the breaker if a problem is detected. This is done by comparing the current or voltage levels in the system to preset values, and if these values are exceeded, the relay will send a signal to the breaker to trip, isolating the faulted part of the system.

The significance of a master trip relay is that it provides an extra level of protection for an electrical system. By monitoring the system for abnormal conditions and tripping the breaker in the event of a problem, the master trip relay helps to prevent damage to equipment and minimize the risk of electrical fires. This is especially important in industrial settings where equipment failures can be costly and dangerous.

Master trip relay also provide protection for generator against over current, over voltage, under voltage and unbalanced current. They also helps to protect generator from short circuits and overloading.

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Additionally, master trip relay also used for protection for motor when over loading and short circuit happens, it helps to protect the motor from damage, ensure the power supply is stable and improve the safety of the motor system.

Master trip relays are classified in to three categories according to the level of fault detection:

  • Low level trip— ANSI Code => 86 L
  • Medium level trip —- ANSI Code => 8M
  • Heavy trip—– ANSI code => 86 H

Master Trip circuit

Low Level Trip 86L:

A “Low Level Trip” is a type of protection mechanism used in electrical power systems to prevent damage to equipment and ensure safe operation. The specific reference to “86L” likely indicates that it is a specific type or model of low level trip relay.

A low level trip relay is a protection device that monitors the level of a liquid in a tank or reservoir, such as oil or water. When the liquid level drops below a certain predetermined point, the relay will trip and shut off the flow of liquid to the tank to prevent it from running dry. This is important to prevent damage to pumps or other equipment that may be damaged by running dry, or to prevent a loss of liquid from a process that is critical to the operation of the system.

Medium level master trip relays 86M:

A master trip relay is a type of protection relay that is used in electrical power systems to trip a breaker if a fault is detected. The “medium level” designation likely refers to the current level at which the relay is rated to operate. The “86M” designation is likely a specific model or part number.

In general, master trip relays are connected to a current transformer (CT), which measures the current flowing in a power system. The relay compares this current to a set point and if the current exceeds the set point, the relay will trip the breaker, effectively disconnecting the faulted portion of the power system from the rest of the system.

The 86M may be specific to a manufacture product that is medium level master trip relay. You would need more details about the product and its characteristics to understand its specific operation or function.

Heavy Trip 86H:

If the fault is heavy, then the relay operates. These relays are called as Lock out relays. These relays only operate when the fault is heavy or might have chance to damage the electrical or mechanical equipment. 86H output is wired with turbine tripping, Grid breaker tripping and Generator breaker tripping.

Tripping equipments: Generator Breaker, Turbine trip, Annunciation alarms

The relay operates when..

  • Instantons Earth Fault
  • Restricted Earth Fault
  • Standby Earth fault
  • Differential relay
  • 86 H- Turbine Side


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