353 articles
Thyristor-controlled series capacitor
A thyristor-controlled series capacitor (TCSC) is a series-connected FACTS device that varies the reactance of an AC transmission line, used for power flow control, damping power oscillations, and mitigating subsynchronous resonance.
Thyristor-switched capacitor
A thyristor-switched capacitor (TSC) is a shunt capacitor bank switched fully on or off by a bidirectional thyristor valve, giving fast, near-transient-free reactive power control in static var compensators.
Tianshan converter station
Tianshan converter station (天山换流站), formerly Hami South, is the sending-end station of the 8,000 MW Hami–Zhengzhou ±800 kV UHVDC line in Hami, Xinjiang, in commercial operation since 2014.
Tianshengqiao converter station
Tianshengqiao converter station (天生桥换流站), also called Mawo, is the ±500 kV rectifier terminal of China's 960 km Tian-Guang HVDC link, transmitting Tianshengqiao hydropower to Guangzhou.
Ton tower
The ton tower, or Tonnenmast, is a lattice steel transmission tower whose three cross-arms form a barrel-like silhouette, the tallest and narrowest of Germany's standard 380 kV tower forms.
Toroidal transformer
A toroidal transformer is a mains or signal transformer wound on a doughnut-shaped steel core with no air gap, giving 95–98% efficiency and low hum in audio and medical equipment.
Touch and step voltage
Touch and step voltage are the shock quantities used to judge whether a grounding system protects people during an earth fault, with limits set by IEEE Std 80 and IEC 60479-1.
Tower earthing
Tower earthing, also called tower grounding, is the system of electrodes and buried conductors that bonds a transmission tower to the earth so lightning current is safely dissipated.
Tower erection
Tower erection is the stage of overhead transmission line construction in which tower steel is assembled and raised on its foundations, using piecemeal, gin pole, crane, or helicopter methods.
Tower foundation
A tower foundation is the buried structure that anchors a transmission tower to the ground, designed mainly for uplift, and accounting for 15% to 35% of an overhead line's cost.
Traction transformer
A traction transformer, also called a railway traction or locomotive transformer, converts high railway supply voltage into lower voltages for train propulsion and auxiliary systems like lighting and HVAC.
Transformer
A transformer, also called an electrical transformer, is a static device that transfers AC electric energy between circuits by magnetic induction, changing voltage levels to transmit power efficiently.
Transformer differential protection
Transformer differential protection is a unit protection scheme for power transformers that compares incoming and outgoing currents and trips when the difference indicates an internal fault.
Transformer oil
Transformer oil, also called insulating oil, is the liquid used inside transformers to provide electrical insulation and transfer heat from the core and windings to the cooling system.
Transformer types
Transformer types are the classes of electrical transformers, distinguished by function, winding and core construction, and insulation and cooling, including distribution, power, instrument, and autotransformers.
Transient recovery voltage
Transient recovery voltage (TRV) is the voltage that appears across a circuit breaker's terminals immediately after it interrupts a current, largely determining whether the breaker can clear a fault.
Transient stability
Transient stability, a branch of rotor angle stability also called large-disturbance angular stability, is a power system's ability to maintain synchronism through a severe disturbance, such as a transmission-line short circuit, and regain equilibrium afterward.
Transient stability analysis
Transient stability analysis is a power systems engineering method that determines whether a grid's synchronous generators remain in synchronism after a large disturbance, such as a short circuit.
Transmission tower
A transmission tower, also known as an electric pylon or by the German name Hochspannungsmast, is a tall structure, usually a steel lattice, that carries high-voltage conductors of an overhead transmission line.
Traveling wave fault location
Traveling wave fault location (TWFL) locates faults on power transmission lines by timing the wavefronts a fault launches, reaching accuracy of a few hundred meters on long lines.
TV pickup
TV pickup is a sudden surge in electricity demand synchronized with breaks in popular TV programs, mainly in the United Kingdom, as millions of viewers boil kettles at once.
Two-phase electric power
Two-phase electric power, or two-phase power, is an AC polyphase system carrying two equal voltages 90 degrees apart, historically over four wires, displaced by three-phase for transmission.
Under-frequency load shedding
Under-frequency load shedding (UFLS) is a last-resort emergency protection scheme that automatically disconnects predetermined blocks of load when power system frequency falls below thresholds, arresting decline and preventing cascading blackouts.
Undergrounding
Undergrounding is the practice of placing electric power lines below ground instead of on poles, improving reliability and reducing wildfire risk at much higher cost.
Undervoltage load shedding
Undervoltage load shedding (UVLS) is an emergency control measure in electric power systems that automatically disconnects selected loads when bus voltages fall below preset thresholds, arresting voltage instability and preventing collapse.
Unified power flow controller
The unified power flow controller (UPFC) is a FACTS device that independently controls active and reactive power on a transmission line by injecting a series voltage.
Unit commitment
Unit commitment is an optimization method in power systems scheduling that decides which generators to switch on and at what output to meet demand at minimum cost.
Unit protection
Unit protection is power system protection that operates only for faults inside a clearly defined zone, such as a transformer or busbar, never for faults outside it.
Utility frequency
Utility frequency, also called mains frequency, is the rate at which alternating current in a power grid oscillates: 50 Hz in most of the world, 60 Hz in North America.
Utility pole
A utility pole, also known as a telephone pole or power pole, is a column, most often treated wood, supporting overhead power lines, communication cables, and streetlights.