Numerical Relay Working Pdf

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 relay working pdf.

Each relay element is in software so with modular hardware the main signal processor can run a vast variety of relay elements. Numerical relays working explained in this post with the help of a numerical relay used in industrial applications. 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. Electromechanical and static relays have fixed wiring and the setting is manual.

And the same relay can be used for analysing and monitoring multiple faults such as over current over fluxing different current and more. 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. Academia edu is a platform for academics to share research papers. Rom is also needed for storing event and disturbance data.

Numerical relay is actually the digital relay as. Numerical relays are based on the use of microprocessors. Numerical relay working and hardware architecture. Lecture 19 directional overcurrent relay coordination tutorial lecture 20 directional overcurrent relay coordination in multi loo.

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. 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. Such relays are also termed as microprocessor type protective relays. A big difference between conventional electromechanical and static relays is how the relays are wired.

A single numerical relay can monitor multiple parameters like current voltage frequency onset time offset time etc. There are two types of phase comparators. Module 5 directional overcurrent protection. 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 16 psm setting and phase relay coordination tutorial lecture 17 earth fault protection using overcurrent relays. The first numerical relays were released in 1985. A typical numerical relay can store as much as 520 events and 50 disturbances. They are functional replacements for electro mechanical protective relays and may include many protection functions in.

Brief introduction about relay.