353 articles
Static synchronous compensator
A static synchronous compensator, also written static synchronous condenser, is a shunt FACTS device that supplies or absorbs reactive power on an AC grid to regulate voltage.
Static synchronous series compensator
The static synchronous series compensator (SSSC) is a converter-based FACTS device that injects a controllable voltage in quadrature with line current, controlling power flow like a series capacitor or reactor.
Static VAR compensator
A static VAR compensator (SVC) is a shunt-connected power-electronic device regulating voltage on AC networks through thyristor-controlled reactive compensation, a standard FACTS controller first applied commercially in 1964.
Station post insulator
A station post insulator is a rigid insulator used in high-voltage substations to support bus bars, conductors, and disconnect switches, made in porcelain, composite, and toughened glass.
Station service transformer
A station service transformer (SST), also called a station auxiliary transformer, supplies a power plant's own auxiliary loads from the high-voltage transmission network, independent of generator status.
Step-voltage regulator
A step-voltage regulator (SVR) is a tap-changing autotransformer installed on medium-voltage distribution lines that adjusts voltage in 32 steps, boosting or bucking it up to 10%.
Stockbridge damper
A Stockbridge damper is a dumbbell-shaped tuned mass damper with two masses on a short steel cable, clamped to overhead conductors to dissipate wind-induced vibration, patented in the 1920s.
Stray voltage
Stray voltage is a small voltage between two surfaces an animal touches at once, such as a water trough and barn floor, giving dairy cows a mild shock.
Stress grading
Stress grading, also called field grading or electric field grading, controls the electric field distribution within or around a high-voltage device, most commonly in the terminations and joints of power cables.
Submarine power cable
A submarine power cable is an insulated cable laid on or buried in the seabed to transmit power across water, first installed in Germany in 1811.
Substation
A substation is a node in the electrical grid where voltage is transformed between levels and circuits are switched, connecting generation, transmission, and distribution; the US grid has over 55,000 transmission substations.
Substation automation
Substation automation applies microprocessor-based intelligent electronic devices, communication networks, and software to monitor, control, and protect power substation equipment, replacing electromechanical relays and governed by the IEC 61850 standard.
Subsynchronous resonance
Subsynchronous resonance (SSR) is a power system condition where a series-compensated transmission line exchanges energy with a generator below rated frequency, potentially damaging the shaft.
Superconducting cable
A superconducting cable is a power transmission cable whose superconducting conductor, cooled below its critical temperature, conducts with essentially zero resistance, carrying up to seven times the power of a conventional cable.
Supergrid
A supergrid is a long-distance electricity transmission network, mainly high-voltage direct current lines at 500 kV or more, connecting remote renewable generation to demand centers and interconnecting national grids.
Switchgear
Switchgear is the combination of disconnect switches, circuit breakers, fuses, and protective relays used to control, protect, and isolate electrical power circuits, often in substations.
Symmetrical components
Symmetrical components decompose unbalanced three-phase voltage or current phasors into positive-, negative-, and zero-sequence sets, a method presented by C. L. Fortescue in 1918 for unbalanced fault analysis.
Synchronized switching
Synchronized switching, also called controlled switching or point-on-wave switching, times a circuit breaker's poles to close or open at targeted phase angles, minimizing switching transients on the power grid.
Synchronous condenser
A synchronous condenser is a synchronous electrical machine with no prime mover that injects or absorbs reactive power and adds inertia to the power grid.
Synchrophasor measurement
Synchrophasor measurement is a power-system monitoring technique in which phasor measurement units estimate voltage and current magnitude and phase angle, synchronized to UTC, enabling direct comparison across substations.
Talcher converter station
The Talcher converter station in Odisha, India, is the eastern terminal of the Talcher–Kolar HVDC bipole, a ±500 kV, 2,000 MW link commissioned in 2003 and operated by POWERGRID.
Tap changer
A tap changer is a transformer switching device that changes winding turns to regulate output voltage; on-load tap changers switch while energized, de-energized ones only when out of service.
Testing transformer
A testing transformer is a specially designed step-up transformer that generates high alternating test voltages for dielectric testing of electrical equipment such as cables, switchgear, bushings, and insulators.
Three-phase electric power
Three-phase electric power is alternating current carried on three conductors with voltages shifted 120 degrees, delivering constant power and needing no return conductor for balanced loads.
Three-phase inverter
A three-phase inverter is a power-electronic converter that converts DC input into three-phase AC output, used for industrial motor drives, solar and wind generation, and battery storage.
Three-phase transformer
A three-phase transformer changes the voltage of three-phase alternating current, built as one unit on a shared core or as a bank of three single-phase transformers.
Three-winding transformer
A three-winding transformer is a power transformer with primary, secondary, and tertiary windings per phase, connecting three voltage levels or supplying station auxiliaries and voltage control.
Thumper (cable fault testing)
A thumper is a high-voltage surge generator that locates faults in underground power cables by arcing at the fault, producing an audible thump crews pinpoint from the surface.
Thyristor valve
A thyristor valve is the complete engineered assembly of series-connected thyristors with gating, grading, and cooling that performs one switching function in an HVDC converter station.
Thyristor-controlled reactor
A thyristor-controlled reactor (TCR) is a shunt inductor in series with back-to-back thyristors, whose current is varied continuously and forms the core of most static var compensators.