A phase-shifting transformer for Ghana has passed testing successfully researched and developed by BTW itself

Recently, a 200MVA/330kV phase-shifting auto-transformer passed testing successfully, which is developed independently by Baoding Tianwei Baobian Electric Co., Ltd., (BTW) for Ghana. The unit is one of the two 330kV phase-shifting auto-transformers to be supplied by BTW to Ghana National Power Grid, all the properties of which completely meet the requirements of the contract, and have been approved by the users and Italian experts employed as supervisors by the user.

The HV rated voltage of the phase-shifting auto-transformer is 330kV, and the LV rated voltage is 161kV, so this transformer will be used to connect the two power grids with different voltage levels in Ghana. The product not only has the on- load voltage regulation function at LV which is possessed by ordinary auto-transformers, but also can regulate the phase angles between HV and LV through an OLTC, such a special phase-shifting function can help the user conveniently improve active power distribution between parallel circuits or power grids with different voltages.

Since 2002, according to the actual demands of different grids, BTW has developed nearly 20 phase-shifting transformers with a variety of phase -shifting principles and functions, including such types as the single core, double core, regulating voltage and auto-transformer. These products have been successfully exported to some electrical power companies of the United States, Canada, Ghana and other countries. The maximum capacity among these phase-shifting transformers is 650MVA, the highest rated voltage reaches 345kV and the maximum no-load phase-shifting angle reaches±74.5°. Among them, in 2015, a 400MVA/345kV/±74.5°phase-shifting transformer for American Pacific Electrical Power Company was manufactured, because of its large phase-shifting angle, its excitor weighed shipment 343 tons, and its total weight was 1000 tons, causing an the extensive concern from the international industry, and being reported by some presses of US.

As electrical equipment controlling power flow distribution in the primary circuits of power grids, phase-shifting transformers have been widely used in Europe and the United States to improve power balance between different transmission lines over the years, saving the cost of the construction of power system effectively. As the interconnection of global energy network, phase-shifting transformers are gradually become important power equipment interconnecting between different power grids. Moreover, phase-shifting transformer technology provides a strong technical support for the equipment of transformer category used in conveying flexible AC transmission system (FACTS) which is being rapidly developed. Making use of the design technology of the phase-shifting transformers, BTW has developed 220kV and 500kV series transformers, meeting the requirements of the equipment unified power flow controller (UPFC) that is needed in China’s power grid development. With the development of power system in the direction of intelligentization (getting smart), based on phase-shifting transformer technology accumulation over years, while actively developing new products, it is believed that BTW will have a wider space for development in the field of intelligentization control of power transmission and distribution.