Numerical Relay Working Pdf

Electromechanical and static relays have fixed wiring and the setting is manual.

Numerical relay working pdf.

The first numerical relays were released in 1985. Such relays are also termed as microprocessor type protective relays. 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. Numerical relay working and hardware architecture.

Academia edu is a platform for academics to share research papers. Lecture 16 psm setting and phase relay coordination tutorial lecture 17 earth fault protection using overcurrent relays. Brief introduction about relay. Rom is also needed for storing event and disturbance data.

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. Module 5 directional overcurrent protection. 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. A typical numerical relay can store as much as 520 events and 50 disturbances.

Event and disturbance recording is a must feature for a digital relay because these data are used for troubleshooting any event. There are two types of phase comparators. 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.

Each relay element is in software so with modular hardware the main signal processor can run a vast variety of relay elements. 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. Numerical relay is actually the digital relay as.

A single numerical relay can monitor multiple parameters like current voltage frequency onset time offset time etc. 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. Lecture 18 directional overcurrent relaying. They are functional replacements for electro mechanical protective relays and may include many protection functions in.

A big difference between conventional electromechanical and static relays is how the relays are wired.