Integrated control and protection solution in 33 and 11 kV package substations

The basis of this paper is a solution engineered and supplied by VA TECH Reyrolle AC&P Ltd, in partnership with FKI switchgear for a number of Scottish Power substations. In general, the overall package substation solution, together with the integrated design of the control and protection system, is successful in significantly reducing both costs and delivery time for new substations. The design of the control and protection system takes full advantage of the flexibility and communication capability of today's numerical relays to provide a convenient and rugged plant interface at the switchgear bay level. The power and flexibility of the modern remote terminal unit (RTU) provides the necessary protocol gateway to interface to legacy SCADA systems, providing any necessary station level functions. The reduced number of physical interfaces leads to a significant reduction of site wiring allowing the system to be delivered to site almost fully pre-tested in its final configuration, hence significantly reducing the testing required. Even within 'nonpackage' substations, e.g. retrofit applications, where switchgear is being replaced, the integrated protection and the control system still provides significant savings in wiring and site testing, making it a viable and economic solution. It is therefore very much envisaged that this type of solution will become increasingly common within power distribution network companies.