Dowei Electric company News and Trends items

245 kV Current Transformer (Hair-pin Type) is an extra-high-voltage (EHV) outdoor instrument transformer used in 220 kV and 245 kV air-insulated substations (AIS). It converts high primary currents into standardized secondary currents (1 A or 5 A) for protection, metering, monitoring, and control while providing complete electrical isolation between the high-voltage prim...

123 kV Current Transformer (Hair-pin Type) is a high-voltage instrument transformer used in 110 kV and 123 kV air-insulated substations (AIS) to accurately transform high primary currents into standardized secondary currents (typically 1 A or 5 A) for protection, metering, control, and monitoring. The hair-pin type uses an integral U-shaped primary conductor that forms a...

72.5 kV Current Transformer (Hair-pin Type) is a high-voltage instrument transformer used in transmission and sub-transmission substations to accurately measure high primary currents and provide isolated secondary currents for protection, metering, monitoring, and control. The hair-pin type incorporates a single U-shaped (hair-pin) primary conductor that passes through t...

Horizontal Knee Disconnector (Horizontal Knee Break Isolator) is a high-voltage disconnector used in air-insulated substations (AIS) to provide a visible isolation point for maintenance and operational safety. It employs a hinged knee-joint mechanism that folds horizontally during operation, making it suitable for substations where vertical clearance is limited. Working...

Vertical Knee Disconnector (Vertical Knee Break Isolator) is a high-voltage disconnector used in outdoor substations to provide visible electrical isolation of equipment after the associated circuit breaker has interrupted the current. It features a hinged "knee" joint that folds upward or downward during operation, making it suitable for substations where horizontal spa...

Double Break Disconnector (Double Break Isolator) is a high-voltage switching device used in transmission and distribution substations to isolate electrical equipment after the associated circuit breaker has interrupted the current. It creates two visible air gaps when opened, providing higher insulation performance than a center break disconnector. Working Principle A ...

Center Break Disconnector (Center Break Isolator) is a high-voltage switching device used in substations to isolate electrical equipment from the power system after the circuit has been de-energized. Unlike a circuit breaker, it cannot interrupt load current or fault current. Its purpose is to provide a visible isolation gap for maintenance and safety. Working Principle...

Indoor Vacuum Circuit Breaker (VCB) is a medium-voltage switching device that uses vacuum interrupters to interrupt normal load currents and fault currents within indoor electrical distribution systems. Because the arc is extinguished inside a sealed vacuum bottle, VCBs provide high reliability, long service life, and very low maintenance. Indoor VCBs are commonly insta...

Dead Tank Circuit Breaker (DTC) is a high-voltage outdoor circuit breaker in which the interrupter tank is at ground potential (earth potential). The energized conductors enter the grounded metal tank through insulated bushings, and the interruption of current takes place inside the grounded enclosure. Dead tank circuit breakers are widely used in transmission and distr...

Live Tank Circuit Breaker is a high-voltage outdoor circuit breaker in which the interrupter chamber (tank) is at the same electrical potential as the energized conductor (line voltage). The interrupter is mounted on an insulated support column, isolating it from the grounded structure below. Live tank circuit breakers are widely used in transmission substations because...

Earthing Transformer, commonly known as a Zig-Zag Transformer, is a special-purpose transformer used to provide a neutral point for grounding in three-phase, three-wire power systems that do not have an accessible neutral. It creates an artificial neutral, allowing the system neutral to be connected directly to earth or through a grounding impedance such as a Neutral Gro...

Traction Transformer is a specialized transformer designed to supply electrical power to railway electrification systems, including electric locomotives, metro systems, light rail, and high-speed rail networks. It converts utility-grid voltage to the voltage required by railway traction systems and is engineered to withstand frequent load fluctuations, short-circuit even...

Rectifier Transformer is a specially designed transformer that supplies AC power to a rectifier system, which converts alternating current (AC) into direct current (DC). Unlike conventional power transformers, rectifier transformers are engineered to withstand harmonic currents, DC bias, unbalanced loading, and severe thermal stresses associated with rectifier operation....

Vacuum Pressure Impregnated (VPI) Dry Type Transformer is a dry-type transformer in which the windings are impregnated with insulating polyester or epoxy varnish under vacuum and pressure, then cured in an oven. Unlike cast resin transformers, the windings are not fully encapsulated in solid epoxy resin, resulting in better heat dissipation, lighter weight, and improved ...

Epoxy Resin Cast (CRT) Dry Type Transformer, also known as a Cast Resin Transformer, is a dry-type transformer in which the high-voltage (HV) windings are encapsulated in epoxy resin under vacuum, while the low-voltage (LV) windings are typically vacuum-pressure impregnated (VPI) or resin-coated. Because the windings are completely enclosed in solid insulation, no insula...

Substation Distribution Transformer is a transformer installed in a distribution substation to reduce medium- or high-voltage electricity to lower distribution voltages for delivery to residential, commercial, and industrial consumers. It serves as the interface between the transmission or sub-transmission network and the local distribution system. Typical Specification...

Pad-mounted transformer is a ground-mounted, enclosed distribution transformer installed on a concrete pad. It is designed for underground electrical distribution systems and provides a safe, tamper-resistant method of stepping medium-voltage power down to low-voltage levels for residential, commercial, and industrial customers. Typical Specifications ·Primary Voltage: ...

23 kV distribution transformer is a medium-voltage transformer designed to step down power from a 23 kV (or 22.9 kV/24.9 kV) distribution feeder to low-voltage levels for residential, commercial, and industrial customers. It is widely used by electric utilities in North America, Asia, and other regions with 23 kV-class distribution systems. Typical Specifications ·Highe...

220 kV power transformer is a high-voltage transformer used in transmission substations to step voltage up or down for efficient long-distance power transmission and distribution. It is a critical component of modern electrical grids. Typical Specifications ·Highest System Voltage: 245 kV ·Rated Voltage: 220/132 kV, 220/110 kV, 220/66 kV, 220/33 kV, etc. ·Rated Power: 1...

A Medium Voltage (MV) Soft Starter is a solid-state motor starting device designed to start and stop medium-voltage AC motors smoothly by gradually increasing and decreasing the applied voltage. It reduces the high inrush current and mechanical stress associated with direct-on-line (DOL) starting. Most MV soft starters use thyristors (SCRs) for voltage control and a bypa...

A Medium Voltage AC Drive (MV AC Drive), also called a Medium Voltage Variable Frequency Drive (MV VFD) or Medium Voltage Adjustable Speed Drive, is a power electronic device used to control the speed, torque, and power consumption of medium-voltage AC motors by varying the output voltage and frequency. It is widely used for large motors in industrial and utility applica...

A Medium Voltage AC Drive (MV AC Drive), also called a Medium Voltage Variable Frequency Drive (MV VFD) or Medium Voltage Adjustable Speed Drive, is a power electronic device used to control the speed, torque, and power consumption of medium-voltage AC motors by varying the output voltage and frequency. It is widely used for large motors in industrial and utility applica...

A Medium Voltage Motor (MV Motor) is an electric motor designed to operate at medium voltage levels, typically from 1 kV to 35 kV (and in some applications up to 69 kV). MV motors are used for driving large industrial loads where high power output, efficiency, and reliability are required. Common applications include: ·Pumps ·Fans ·Compressors ·Conveyors ·Crushers ·Mill...

A Medium Voltage Fault Current Limiter (MV Fault Current Limiter / UFCL) is a protection device designed to rapidly reduce excessive short-circuit currents in medium-voltage electrical networks. It limits fault current magnitude within the first few milliseconds after a fault occurs, helping protect switchgear, transformers, cables, generators, and distribution equipment...

An AAAC (All Aluminum Alloy Conductor) is an overhead electrical conductor made entirely from aluminum alloy strands. It is mainly used for medium-voltage and high-voltage overhead distribution and transmission lines where high strength, corrosion resistance, and reduced weight are required. AAAC was developed as an alternative to AAC (All Aluminum Conductor) and ACSR (...

A Medium Voltage Cable (MV Cable) is a power cable designed to transmit and distribute electrical energy at medium voltage levels, typically from 1 kV up to 35 kV (sometimes up to 69 kV depending on regional classification). MV cables are widely used in distribution networks, industrial facilities, renewable energy plants, substations, and utility power systems. MV cabl...

A Static Var Generator (SVG), also known as a STATCOM (Static Synchronous Compensator), is a power electronic-based FACTS (Flexible AC Transmission System) device used for dynamic reactive power compensation, voltage regulation, power factor correction, and harmonic mitigation. Unlike an SVC, which uses thyristor-controlled reactors and capacitor banks, an SVG uses a vo...

A Static Var Compensator (SVC) is a shunt-connected FACTS (Flexible AC Transmission System) device used to provide fast dynamic reactive power compensation in electrical power systems. It regulates system voltage by rapidly generating or absorbing reactive power (MVAR) through controlled switching of reactors and capacitor banks using thyristors. SVCs are widely used in...

An Active Harmonic Filter (AHF) is a power electronic device used to detect and eliminate harmonic currents in electrical power systems. It injects an equal and opposite compensation current into the network to cancel unwanted harmonics, improve power quality, and reduce distortion. Unlike passive harmonic filters that use fixed combinations of capacitors and reactors, ...

A Line Trap (also called a Wave Trap or Carrier Blocking Coil) is a high-voltage power system component used in Power Line Carrier Communication (PLCC) systems. It is installed in series with a transmission line to block high-frequency communication signals from entering unwanted parts of the power network while allowing 50/60 Hz power frequency current to pass normally....

An Iron Core Reactor is an electrical reactor (inductor) that uses a magnetic iron or steel core to increase inductance and magnetic flux concentration. It is designed to provide controlled inductive impedance for reactive power compensation, current limiting, harmonic filtering, and voltage regulation in power systems. Unlike an Air Core Reactor, the iron core provides...

An Air Core Reactor (ACR) is a type of electrical reactor (inductor) that uses a coil winding without an iron or steel magnetic core. Its inductance is produced by the magnetic field generated in the surrounding air. It is widely used in transmission and distribution systems for current limiting, harmonic filtering, reactive power control, and power quality improvement. ...

A Super Capacitor (also called an Ultracapacitor or Electric Double-Layer Capacitor, EDLC) is an advanced energy storage device that stores electrical energy through electrostatic charge separation rather than chemical reactions used in conventional batteries. Super capacitors provide very high power density, extremely fast charging/discharging capability, and very long...

A Capacitor Bank is an assembly of multiple capacitor units connected together to provide reactive power compensation (kvar/Mvar) in electrical power systems. Capacitor banks are used to improve power factor, voltage stability, system efficiency, and power transmission capacity by supplying leading reactive power to offset inductive loads. They are widely installed in u...

A Capacitor Unit is a power system component used to supply reactive power (kvar), improve power factor, regulate voltage, and increase the efficiency and stability of electrical networks. Multiple capacitor units are typically connected together to form a capacitor bank installed in substations, distribution networks, industrial plants, and renewable energy systems. Ca...

A Mobile Substation is a transportable electrical substation designed to provide temporary, emergency, or rapidly deployable power transformation and distribution capability. It integrates major substation equipment—including transformers, high-voltage switchgear, medium-voltage switchgear, protection systems, control panels, and auxiliary systems—onto a trailer, skid, o...