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  2. Protective relay - Wikipedia

    en.wikipedia.org/wiki/Protective_relay

    Distance relays, also known as impedance relay, differ in principle from other forms of protection in that their performance is not governed by the magnitude of the current or voltage in the protected circuit but rather on the ratio of these two quantities. Distance relays are actually double actuating quantity relays with one coil energized by ...

  3. Power system protection - Wikipedia

    en.wikipedia.org/wiki/Power_system_protection

    If the ratio of voltage to current measured at the relay terminals, which equates to an impedance, lands within a predetermined level the circuit breaker will operate. This is useful for reasonably long lines, lines longer than 10 miles, because their operating characteristics are based on the line characteristics.

  4. Electrical impedance - Wikipedia

    en.wikipedia.org/wiki/Electrical_impedance

    In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]

  5. Characteristic impedance - Wikipedia

    en.wikipedia.org/wiki/Characteristic_impedance

    The input impedance of an infinite line is equal to the characteristic impedance since the transmitted wave is never reflected back from the end. Equivalently: The characteristic impedance of a line is that impedance which, when terminating an arbitrary length of line at its output, produces an input impedance of equal value. This is so because ...

  6. Relay - Wikipedia

    en.wikipedia.org/wiki/Relay

    A relay Electromechanical relay principle Electromechanical relay schematic showing a control coil, four pairs of normally open and one pair of normally closed contacts An automotive-style miniature relay with the dust cover taken off. A relay is an electrically operated switch. It consists of a set of input terminals for a single or multiple ...

  7. Numerical relay - Wikipedia

    en.wikipedia.org/wiki/Numerical_relay

    Protective relay. 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. [1] Such relays are also termed as microprocessor type protective relays.

  8. Hedges Amicus Brief FINAL - HuffPost

    images.huffingtonpost.com/2013-02-01-ThreeAmigos...

    Nos. 12-3176, 12-3644 IN THE UNITED STATES COURT OF APPEALS FOR THE SECOND CIRCUIT CHRISTOPHER HEDGES, et al., Plaintiffs-Appellees, v. BARACK OBAMA, individually and as

  9. Voltage regulator - Wikipedia

    en.wikipedia.org/wiki/Voltage_regulator

    The relay(s) modulated the width of a current pulse to regulate the voltage output of the generator by controlling the average field current in the rotating machine which determines strength of the magnetic field produced which determines the unloaded output voltage per rpm. Capacitors are not used to smooth the pulsed voltage as described earlier.