Large & Medium Power Transformers
Generator step-up transformers (GSU) are the critical link between the power station and the transmission network, often operated day and night at full load. They must be built to withstand extreme thermal loading without ageing prematurely.
GSU take the voltage from the generator voltage level up to the suitable transmission voltage level. These transformers are located in a power station and are built as single-phase or three-phase units. There are two (2) basic technologies for designing and manufacturing: core and shell. With shell-formed transformers, the primary and secondary are on one leg and surrounded by the core. With a core-formed transformer, cylindrical legs windings cover the core legs. Generator step-up transformers (GSU) are the critical link between the power station and the transmission network, often operated day and night at full load. They must be built to withstand extreme thermal loading without ageing prematurely. GSU take the voltage from the generator voltage level up to the suitable transmission voltage level. These transformers are located in a power station and are built as single-phase or three-phase units. There are two (2) basic technologies for designing and manufacturing: core and shell. With shell-formed transformers, the primary and secondary are on one leg and surrounded by the core. With a core-formed transformer, cylindrical legs windings cover the core legs. |
Phase shifting transformers (PST) are crucial components in the ongoing strive for improved AC network efficiency. Increasing amounts of transmitted energy push the networks to the limit, increasing the risk of network instability.
PSTs allow controlling the power flow in the transmission grid independently of the generation. By avoiding system overloads and instabilities protect transmission lines and HV equipment from thermal overload, improve transmission system stability and control the power flow between different networks, for parallel long distance overhead lines or for parallel cables. PSTs are highly specialized pieces of equipment that require leading- edge design and manufacturing skills combined with stringent quality control. They are highly complex power transformers, with more windings and tap changers than traditional power transformers and a large number of connections between the three-phases |
A shunt reactor is an absorber of reactive power, thus increasing the energy efficiency of the system. It is the most compact device commonly used for reactive power compensation in long high-voltage transmission lines and in cable systems. The shunt reactor can be directly connected to the power line or to a tertiary winding of a three-winding transformer.
The shunt reactor could be permanently connected or switched via a circuit breaker. To improve the adjustment of the consumed reactive power the reactor can also have a variable rating. If the load variation is slow, which it normally is (seasonal, daily or hourly), a variable shunt reactor (VSR) could be an economical solution for some customer applications. |
Hitachi Energy's power transformers are key components in power networks. Their availability and longevity have a major impact on grid reliability and profitability. Hitachi Energy does not compromise on quality. We ensure that every one of our 14,500 delivered units has undergone rigorous full-acceptance testing. Hitachi Energy offers a complete range of power transformers and related components and parts. We have delivered more than 14,500 power transformers (over 17,000,000 MVA), including over twenty 800 kV UHVDC and over five hundred 735 - 765 kV AC units, to all major global markets.
Our entire range is the result of our own research, development and manufacturing, which makes us unique in the industry. This has given us extensive experience in every relevant part of power transformer technology. Customers worldwide can securely rely on the quality and reliability of our products. |
Station service voltage transformer SSVT (46 - 362 kV)
Outdoor oil-filled station service voltage transformer for HV to LV/MV substation and remote power needs SSVT inductive voltage transformers consist of a single-phase design intended for connection between phase and ground on 46 kV-362 kV HV grounded neutral networks to supply power to panels at low voltage or medium voltage. The design allows for convenient siting within the substation environment for simple mounting to single phase supports. The SSVT is directly connected to the HV network and provides power to the panel within the substation, or to remote loads directly supplied for the HV service. SSVTs can provide output voltages from 120 V to MV levels (contact factory for specific output voltages). Power levels available range from 10 kVA to 167 kVA single phase supply for all system voltages, and as high as 333 kVA for 245 kV systems. Station service voltage transformers can be supplied for power only, or power plus optional metering windings having either single or two tapped windings for voltage measurement. Hermetic sealing of the design is accomplished using a gas cushion above the oil to prevent free-breathing outside moisture-ladened air. ANSI 70 gray insulators are supplied with high creep and high strike designs. Porcelain insulators are normally standard with polymer offered as an option, except at 362 kV, which has a standard polymer design. |