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# What is the best example of distance relay?

## What is the best example of distance relay?

The admittance relay is the most commonly used distance relay. It is the tripping relay in pilot schemes and as the backup relay in step distance schemes.

### What are the different types of distance relays?

There are two types of distance relays in use for the protection of power supply, namely ;

• Definite-Distance relay which operates instantaneously for fault up to a pre-determined distance from the relay.
• Time-Distance relay in which the time of operation is proportional to the distance of fault from the relay point.

What are the characteristics of distance relay?

Distance Relay Characteristics They compare the measured fault voltage with a replica voltage derived from the fault current and the zone impedance setting to determine whether the fault is within zone or out-of-zone.

Why do we need distance relay?

Distance relays are used for both phase fault and ground fault protection, and they provide higher speed for clearing the fault. Thus, they eliminate long clearing times for the fault near the power sources required by overcurrent relay if used for the purpose.

## How do distance relays work?

Distance relays are the protecting equipment that functions based on the distance of the fault point on the transmission line. The distance is calculated from the generating unit. Based on the distance, the impedance is calculated by evaluating the fault voltage and fault current.

### What is the principle of distance relay?

Distance Relay Principle The distance relay working principle is very simple and it is based on the ratio of voltage and current i.e, impedance. This relay contains a potential transformer to supply voltage and current transformer for the current element, which is connected in series with the entire circuit.

What are the advantages of distance protection?

Selective and dependable tripping for line faults without the need for a pilot channel, as well as simple time coordination of distance relays across the system, are great advantages of distance protection.

What is the the distance relay explain with diagram?

The characteristics of the distance relay can be explained using the RX diagram. The impedance of the transmission line is represented by the radius of the circle. In the first quadrant, R is positive, X is positive, which means the fault impedance is greater than the normal impedance. Hence the relay will operate.

## What are the two main types of relays?

Types of Relays – A Thomas Buying Guide

• Relays are electrically operated switches.
• Electromechanical relays have an electromagnetic coil and a mechanical movable contact.
• Solid-state relays are solid-state electronic components that do not have any moving components, which increases their long-term reliability.

### What are the different types of Distance relays?

This impedance between the relay and the fault depends on the electrical distance between them. The principal type of distance relays is impedance relays, reactance relays, and the reactance relays.

How are distance relays used in fault protection?

Distance Protection Relay. Distance relays are used for both phase fault and ground fault protection, and they provide higher speed for clearing the fault. It is also independent of changes in the magnitude of the short circuits, current and hence they are not much affected by the change in the generation capacity and the system configuration.

How are distance relays related to apparent impedance?

Distance relays calculates the ratio of voltage (V) to current (I) and calculates the apparent impedance. In relation to distance relays ‘Reach’ is a common term used. Reach defines how far down the line the relay detects the fault.

## When to use trip command on distance relay?

If the impedance that the relay calculates falls within the distance relay impedance circle, then trip command is issued. For impedance outside the circle no trip is issued. Notice that a basic distance relay is not directional sensitive and is not useful for many common applications.