Advances in MV voltage regulators

Voltage regulators were originally implemented as a cost effective means of improving power quality on network spurs where embedded generation was not considered economically or technically feasible. Their main function in maintaining local network stability is achieved by way of increasing voltage during periods of short-time over-loading and reducing voltage during periods of load shedding. This paper gives a brief introduction to the mode of operation and network installation configuration of voltage regulators. This paper also gives an insight into modern regulator controls which enable voltage regulators to perform a variety of new tasks and functions such as local operation and data storage alongside real-time communication with utility operation centres. One of the latest features of voltage regulation control is voltage reduction mode, which enables utilities to tap down regulators to reduce the local voltage by up to 3% to increase the current available in the network. Voltage regulators are tailor-made for individual utility´s requirements and manufacturers must examine the key internal components of the regulator when designing a regulator for a specific utility. A review of some of the factors utilities must examine when procuring regulators is contained in this paper. New directives which apply to all oil-immersed transformers imported into the EU have come into effect that restrict and regulate the substances contained in transformer mineral oil and the amount of which can be imported into the EU. Certain substances which have been deemed carcinogenic have been subject to heavy restrictions on import into the EU and manufacturers of transformers have introduced new products that not only comply with EU legislation but are also environmentally sound. This paper examines a number of aspects of voltage regulators from the development of new control features, new environmentally-friendly oils and, communication and control design and test criteria.