Smart HMI tools for numerical relaysmore than just a setting assistant

The liberalization of the electricity market has clearly brought about an increased pressure on the power system management to reduce costs. The pursuit of potential savings through maintenance is of special importance. Standardised concepts are increasingly used as well as multicultural products that cover the complete functional requirements of a feeder circuit. Interdisciplinary beginnings are occurring in the power system management and the asset management areas. A medium sized Distribution System Operator (DSO) maintains an asset population of some 1000 relays. The age of the individual relays in the asset population may vary between 1 and 20 years consisting of numerous models and some makes. Their associated protective schemes have to be engineered, commissioned, routine-tested, administered and their performance analysed after power system fault clearance. The budget for such expenses may amount to some 30% of the total operating costs. For economic and operator reliability reasons, the DSO therefore has a strong interest in smart human-machine interfaces HMIs supporting the vast majority of the relays in the system. Beyond the traditional use as HMI tool, facilities for system fault analysis and quick power system restoration after an outage become vital for efficient system operation management