A digital rate-of-change underfrequency protective relay for power systems

What is a protective relay?

A protective relay in which the response to the input quantities is primarily a function of the electrical circuit distance between the relay location and the point of fault. Drop out protective relaying of utility-consumer interconnections) Contact operation (opening or closing) as a relay just departs from pickup.

What are repeat relays & hard wired logics used for?

Repeat relays and hard wired logics were used to provide interlocking and control functionality. In Section 15.2 of the IEEE Brown BookTM (IEEE Std 399) it was stated that whether the coordination is done manually or by computer, it is necessary for the engineer to “describe” the system.

What is a drop out protective relay?

Drop out protective relaying of utility-consumer interconnections) Contact operation (opening or closing) as a relay just departs from pickup. The value at which dropout occurs is usually stated as a percentage of pickup.

What is the dropout ratio of an instantaneous overvoltage relay?

For example, dropout ratio of a typical instantaneous overvoltage relay is 90 percent. (of a relay) A term for contact operation (opening or closing) as a relay just departs from pickup. Also identifies the maximum value of an input quantity that will allow the relay to depart from pickup.

What is a measuring relay?

A generic term covering those forms of measuring relays in which the response to the input quantities is a function of the electric circuit distance (impedance) between the point of measurement and the point of fault.

What is a directional relay?

A qualifying term that indicates a means of controlling the operating force in a nondirectional relay so that it will not operate until the two or more phasor quantities used to actuate the controlling means (directional relay) are in a predetermined band of phase relations with a reference input.