Medium Voltage Transformers and Their Application Areas

Transient Voltage Protected (TVP) Transformers

Transient voltage in electrical systems can cause serious damage to electrical equipment and may lead to network failures over time, resulting in costly repairs and downtime. Transformers equipped with Hitachi Energy’s Transient Voltage Protection (TVP) technology protect your network against faults and help you avoid complex system redesigns and expensive interruptions.

Hitachi Energy has spent 15 years researching and perfecting protective solutions for network switching, and TVP technology is the successful result of this effort.

A Complex Problem

Medium voltage fast-acting circuit breakers have become the most widely used switching technology across industries. However, when the current is interrupted, a sudden drop occurs, which creates a short-term overvoltage known as transient voltage. As systems operate more frequently, new failure modes caused by such transients have been observed.

Stress caused by excessive transient voltages can damage various magnetic equipment in the network over time, including transformers, motors, pumps, and measuring devices. Switching transients are among the most severe voltage stresses a transformer can experience.

Due to complex system variables, it is often difficult to predict or even identify the exact nature of the damage. Some solutions such as RC snubber circuits and surge arresters have been proposed, but they are not compatible with all network configurations and are often expensive to install.

TVP Technology – A Simple Solution to a Complex Problem

Hitachi Energy’s transformer with Transient Voltage Protection (TVP) technology provides full protection for your electrical systems during each switching operation. Varistors strategically placed along the transformer windings protect them from all types of overvoltages caused by virtual current interruption and resonance amplification.

This prevents voltage peaks from reaching insulation-damaging levels in TVP-equipped transformers. Moreover, its network-independent design makes it an optimal solution regardless of application requirements.

Comparison with Other Solutions

Our TVP technology is the only solution capable of controlling both internal and external voltage surges in transformer windings. Unlike RC snubber circuits, TVP technology does not increase design complexity.