Disturbance recorders trigger detection and protection

The ability to perform power system measurements synchronously over large areas opens a new window on dynamics occurring within the power system. A number of events were recorded by GPS satellite-locked disturbance recorders, and the records illustrate the frequency variation that exists across a network during transients, the swinging of various points in the system with respect to each other during a disturbance, and the effects of loss of generation or load over extremely long distances. Measurements are made possible by the use of embedded computers and digital signal processing technology. The author discusses the use of phasor measurement unit, a microprocessor based data acquisition system and signal processing platform with an integral GPS clock and multiple inputs. The system allows more accurate recording of power system phenomena that would otherwise remain undetected. System response data permits the validation of models, real-time measurement of protection characteristics, and early detection of potential system instabilities or equipment malfunction.