static var compensator

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static var compensator

[′stad·ik ′vär ‚käm·pən‚sād·ər]

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

References in periodicals archive ?
Devaraj, "Fuzzy Logic Control of Static Var Compensator for Power System Damping", International Journal of Electrical and Electronics Eng.
Static VAr Compensators (SVC) is the most popularly used FACTS device.
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.
ABSTRACT: This paper proposes a new method to small signal stability improvement using controlled static VAR compensator (SVC).
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.
Tenders are invited for Design, Manufacturing, Supply, Erection, Testing And Commissioning Of + 120Mvar, 220Kv Static Var Compensator (Svc) At Existing 220Kv Timbdi Substation On Turnkey Basis Including All Civil Work
5 million in new orders since late April for its Power Quality Static VAR Compensator, a power technology that helps electric companies and manufacturers eliminate voltage sags and flickers.