System planning to achieve automation of network operation and reduction of operation costs

Adam Opel AG operates a large factory in Rüsselsheim, Germany. Following the decision in 1997 to close down the 90 MW company-owned power station it was a huge challenge to develop a new network concept for the 20 kV system with an infeed from a public utility. There were major restrictions on time and budgets and the work had to be carried out without causing any disruption to production. This paper describes in detail the design criteria that were employed for the network, the selection of network components and how the project was implemented. Also described are the selection of a neutral earthing scheme suitable for an industrial environment and the earth fault testing that was carried out during implementation of the project. After more than a year of service, there is little doubt that the new network concept is more reliable and more flexible and that overall operating costs have been reduced