Time-synchronized multi-phase generator

The advent of precision timesynchronized measuring equipment, necessitates test simulators of comparable accuracy. By utilizing the precise timing signals available from a GPS (Global Positioning System) receiver, real-time digital simulators can be constructed for local or end-toend testing. In the area of transient testing of protective relays, a multiple cycle, phase/transient generator was constructed around the capabilities of a DDS (Direct Digital Synthesis) chip. It offers extremely high phase and frequency resolution. Amplitude control was obtained by use of a D/A converter and multiplier. Transient generation capability is provided by the use of memory arrays and D/A Converters. The combination of DDS and GPS technology allow for the repetitive and time synchronized transient generation necessary for the testing of protective relays. The Phase Generator described, has been utilized extensively for system calibration and test.