static var compensator

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static var compensator

[′stad·ik ′vär ‚käm·pən‚sād·ər]
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Static var compensator

A thyristor-controlled (hence static) generator of reactive power, either lagging or leading, or both. The word var stands for volt ampere reactive, or reactive power. The device is also called a static reactive compensator.

Need for reactive compensation

Reactive power is the product of voltage times current where the voltage and current are 90° out of phase with one another. Thus, reactive power flows one way for one-quarter of a cycle, the other way for the next quarter of a cycle, and so on (in contrast to the real power, or active power, which flows in one direction only). This back- and-forth flow results in no net power being delivered by the generator to the load. However, current associated with reactive power does flow through the conductor and creates extra losses. See Alternating current, Electric power measurement

Most loads draw lagging reactive power, which causes electric power system voltage to sag. On the other hand, under light loads, the capacitance of high-voltage lines can create excessive leading reactive power, causing the voltage at some locations to rise above the nominal value. Finally, it is prudent to keep reactive power flows to a minimum in order to allow the lines to carry more active power.

Mechanical versus static compensation

Utilities frequently install capacitors connected from line to ground to compensate for lagging reactive power and reactors connected from line to ground to compensate for leading reactive power. These reactors and capacitors are switched in and out with mechanical switches based on the level of line loading as it varies throughout the day. However, frequent operation of these mechanical switches may reduce their reliability. See Capacitor, Reactor (electricity)

It is desirable to have a controllable source of reactive power (leading or lagging); and the static var compensator, controlled with static switches, called thyristors, for higher reliability, fulfills this function. It is more expensive than mechanically switched capacitors and reactors (due to the cost of thyristor valves and associated equipment), and hence its use is based on an economic trade-off of benefits versus cost. See Semiconductor rectifier

McGraw-Hill Concise Encyclopedia of Engineering. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
[5] Lu J, Nehir M.H, Pierre D.A, A fuzzylogic based adaptive damping controller for static VAR compensator, International journal of Electric Power System Research, 2004, 68 (113-118).
The nine contracts include the turnkey installation of six new 110 kV gas-insulated substations - four in Jeddah and two in Madinah; the turnkey supply of a Static VAr Compensator designed to improve power stability for Quwayyah 132 kV substation; supply of four auto-transformers for the substation of Ashbliyah; installation of three complete automation and protection systems for three 380 kV substations in the central region; supply and installation of a new iDMS control centre to manage the Madinah's electricity distribution network; and supply and installation of a turnkey telecom system to connect the Al Masher 380 kV substation to SEC's telecoms network.
A rapidly operating Static Var Compensator (SVC) can continuously provide the reactive power required to control dynamic voltage swings under various systems conditions.
ABB will design, supply, install and commission a flexible alternating current transmission systems (FACTS) system, including a static var compensator (SVC), to optimise the transmission network in the region.
American Superconductor Corporation says it is preparing four distribution voltage Static VAR Compensator (SVC) solutions for a major oil pipeline company to manage power demand at pumping stations.
utility for AMSC's Static VAR Compensator, which regulates and stabilizes power grid voltage.
Dubai Electricity and Water Authority (DEWA) has launched two Static VAR Compensator (SVC) stations in Al Nahda and Ras Al Khor at a cost of AED 236mn ($64mn).
Dynamic reactive power control at the AC bus at or near the HVDC Substation by some form of power Electronic reactive Power Controller such as a Static var Compensator (SVC) or Static Synchronous Compensator (STATCOM) may be necessary (L.
Static Var Compensator (SVC) is an early type of the shunt connected FACTS devices, which controls its connection point voltage by adjusting its susceptance in order to supply or absorb the reactive power.
Mitsubishi Electric has announced that it has won a $55m (AED 198m) turnkey order from Dubai Electricity and Water Authority (DEWA) for two large Static VAR Compensator (SVC) systems, for use at the Nahda Substation and Car Complex Substation.
Compared with the static var compensator (SVC), the STATCOM has advantages such as fast, continuous reactive power output ability, high efficiency and low harmonic distortion in the output current [2].
ABSTRACT: This paper proposes a new method to small signal stability improvement using controlled static VAR compensator (SVC).