Category: Numerical Relays

Application of ABB Over current Relay

Application of Relays – Relay Selection Method:

Application of various relays used in the power system network depends upon various factors like the amount of fault current, protection methods, etc. We know that there are different types… Read more »

Directional Over Current Relay Characteristics

Directional Over Current Relay [67]:

In this post operation of Directional current relay along with its settings explained. The detailed explanation about Directional relay settings with Characteristic angle, Maximum Torque angle and Polarisation voltages are… Read more »

Line Differential Relay 87L Protection Scheme

Line Differential Relay [87L]:

The principle of operation of line differential protection is same as transformer differential protection. The only difference is transformer differential protection uses only one differential relay whereas line differential protection… Read more »

Numerical Under-Over Voltage Relay Configuration

Under voltage [27]/Over voltage [59] Relay:

In this post we can learn the working and configuration of Numerical Under voltage [27] /Over voltage [59] protection relay. These relays measure either phase to phase (Ph-Ph) or phase… Read more »

Differential Protection Relay-87

Differential Protection Relay [87]:

Differential Protective Relay is a protective relay that functions on a percentage or phase angle or other quantitative difference of two currents. Differential relaying provides selectivity by providing a zone… Read more »

Numerical Motor Protection Relay

Motor Protection Relays [50/51]:

Motor protection relays are used to provide various protections for the motors. These differ from the over current relays in terms of protections they offer. To understand the working of… Read more »

Trip time formulae for Over Current Relay-50/51

Over current/Earth fault Relays [50/51]:

Over current/Earth fault relays are the basic protection relays. Used for protection of transformers and feeders from over current and earth faults. When excessive current flows in a circuit, it… Read more »

Numerical Relay Connections

Working of Numerical Relays:

Numerical Relays working explained in this post with the help of a Numerical relay used in industrial applications. Brief Introduction about Relay: RELAY: A Relay is a protection device that… Read more »