Quality assurance in the design of protective relays

The functionality of a protective relay is only one, albeit important, aspect of the overall design. Other aspects, such as component reliability and product immunity to interference are equally important for the protective relay to remain stable under adverse conditions. To ensure all aspects are considered during product development requires a development quality system, nowadays this means internationally recognised ISO 9001. The processes discussed only give a partial picture of quality assurance for a protective relay, since manufacturing quality also plays a significant role. Other parts of ISO 9001 will normally be used to audit these processes. The quality assurance measures taken in development must continue throughout the manufacture and service life of the product