Trench and the companies forming the Trench Group have always been front runners in all three fields of the business. With the patent on Oil impregnated paper condenser type bushings in , Emil Haefele laid the foundation for the Trench Bushing business. In Instrument transformers the Trench Group is a technology leader since years, when in Italy the first paper oil Instrument transformers were produced. And Tony Trench, the founder of the Trench Group was a real pioneer developing Air core reactors in the early s.

The company was founded in in Switzerland by Emil Haefely, an inventor who played a decisive role in the development of the electrotechnical industry at beginning of the th century. With the patent of the OIP Condenser type bushing in by Emil Haefely, the company became a pioneer in Oil type bushings. Trench France is part of the Trench & HSP Bushing group belonging to Siemens with locations in France (Trench France), Germany (HSP) and China (THVS). This close cooperation for innovation and design is supported by Siemens process and manufacturing know how. In , the Trench Group decided for Trench France to focus specifically on bushings by making extensive manufacturing investments and improving all customer relevant processes.

In Trench Austria was established by Alois Esslinger, an electrical engineer known beyond the borders of Austria. The former name of the company until was Spezielektra Esslinger KG. From the very beginning, one focus area of the company was the development and production of reactors for electrical power system. The use of glass fiber reinforced plastic as part of the insulation of reactors was revolutionary in the s . Trench Austria gained significant international reputation in the s when supplying high current and high voltage test reactors for leadin test laboratories like KEMA in Arnheim/The Netherlands. In Spezielektra was merged with Trench Electric Toronto/Canada. This was also the starting point for the foundation of the Trench Group. Today Trench Austria in Leonding near Linz produces reactor/coil products for medium and high voltage electrical systems, both in dry type as well as oil immersed technology and is one of the worldwide leading companies in this special area of the electrical industry.

Trench High Voltage Products Ltd., Shenyang, (THVS) successor of Trench Fushun Bushing Co., Ltd., was established in and is a member of the global Trench Group. Being a member of Trench Group, THVS benefits from strong technical support and global R&D activities and innovations from group to serve local and oversea customers for various HV applications. The factory is well equipped with advanced manufacturing, assembly, testing equipment and HV test labs. A dedicated team of experienced engineers and skilled workers is working hard to meet customers’ satisfaction. THVS is certified for ISO , ISO & OHSAS . THVS is not only a market leader for bushings in China and various export markets, but also a successful manufacturer of oil insulated instrument transformers with customer references worldwide. The Instrument Transformers product portfolio includes: • Oil insulated Current Transformers (up to kV) Oil insulated Capacity Voltage Transformer (up to kV) The Bushings product portfolio includes: • Oil Impregnated Paper Bushings (from . kV &#; kV up to , A) • Epoxy Resin Impregnated Paper Bushings (from . kV &#; kV up to , A)