Power transformer bushings – market trends

Power transformer bushings – market trends

Special Edition – Bushings


Bushings are critical for the safety of power networks. With the power transformer collective market expected to reach around 3.1 billion USD in the European Union over the next ten years, the market for transformer bushings is also developing in parallel. It is expected that the HV bushings market in the EU will reach close to 60 million USD in the same period. Within the EU, Germany is going to be the largest market for the next ten years. Globally, Western Europe remains one of the key markets for bushings, driven by replacements, along with the USA, China, India and Australia.

Keywords: Transformer bushings, market overview, future trends, online condition monitoring, porcelain, composite

1. Introduction

All generated electricity is channelled through power transformers, and every piece of this equipment is critical for its continuous supply. Overloaded grids in developing countries, aging substation infrastructure in mature markets, and increased renewable penetration are all factors that are causing significantly more stress on grid transformers. This stress leads to failures, which in turn not only cause cascaded blackouts, but also may result in catastrophic events like transformer explosions and fires that can cause casualties.

After windings and tap changers, bushings are the third major point of transformer failure [1, 2]. Nearly 20% of all power transformer failures located in transmission substations and generator step-up (GSU) applications are caused by bushings. In the transmission grid, transformer bushing failures dominate in high voltage (HV) and extra-high voltage (EHV) transformers (220 kV to 400 kV), as compared to GSU and distribution transformers. The statistics in Europe shows that bushing failures occur between 12 and 20 years after the installation (midlife of a transformer). In 2012, CIGRE conducted a survey (A2.37 Transformer Reliability Survey) [1] which included 56 utilities from 21 countries. The survey concluded that almost 17% of substation transformers failures are caused by bushings. Additionally, more than 40% of the total bushings failures resulted in either a fire or explosion incident. All these factors indicate a high risk of bushing failure and its impact on the grid through transformers.