Power utilities have for along time relied on protection relays (electromagnetic and first-generation digital relays) to perform only a single isolated task - fault protection. This was for a number of reasons but mainly due to limited process-
ing power. With the advent of second-generation digital relays using powerful high-speed digital signal processors (e.g. DSPs), the protective relay is able to process the usual protection functions safely and effectively with processing overhead to spare. This additional processing capacity permits the relay to do more than just provide standard protection. These digital relays combined with a Windows-driven relay setting environment provides increased input/output capability, digital fault recording and asset management functionality in powerful yet simplified solution. Such asset management functionality allows protection relays, for example, to provide transformer temperature and overload monitoring. This article discusses the use of a “smart” relay that provides both fault and overload protection of a power transformer.
Understanding Relays1
Understanding Relays2
