Numerical Relay Working Pdf

A typical numerical relay can store as much as 520 events and 50 disturbances.

Numerical relay working pdf.

Module 5 directional overcurrent protection. Such relays are also termed as microprocessor type protective relays. In utility and industrial electric power transmission and distribution systems a numerical relay is a computer based system with software based protection algorithms for the detection of electrical faults. Numerical relays working explained in this post with the help of a numerical relay used in industrial applications.

Rom is used to store software needed for the working of relay. Each relay element is in software so with modular hardware the main signal processor can run a vast variety of relay elements. Lecture 19 directional overcurrent relay coordination tutorial lecture 20 directional overcurrent relay coordination in multi loo. Numerical relay is actually the digital relay as.

Lecture 16 psm setting and phase relay coordination tutorial lecture 17 earth fault protection using overcurrent relays. Rom is also needed for storing event and disturbance data. Event and disturbance recording is a must feature for a digital relay because these data are used for troubleshooting any event. Numerical relays are based on the use of microprocessors.

A relay is a protection device that senses the fault in the circuit and gives a trip signal to the circuit breaker to isolate the faulty circuit. Numerical relay is the relay in which the measured ac quantities are sequentially sampled and converted into numerical data that is mathematically and or logically processed to make trip decisions. Lecture 18 directional overcurrent relaying. And the same relay can be used for analysing and monitoring multiple faults such as over current over fluxing different current and more.

Academia edu is a platform for academics to share research papers. Brief introduction about relay. A numerical relay has the functionality that previously required several discrete relays therefore the relay functions such as overcurrent or earth fault are referred to as relay elements. θ is the angle by which s 2 lands s 1 if β 1 β 2 90 o the comparator is called cosine comparator and if β 1 0 and β 2 180 o it is a sine comparator.

Electromechanical and static relays have fixed wiring and the setting is manual. In short a phase comparator compares two input quantities in phase angle vertically irrespective of the magnitude and operates if the phase angle between them is 90o. Numerical relay working and hardware architecture. The first numerical relays were released in 1985.

There are two types of phase comparators.