A test feeder for DG protection analysis

A new radial feeder model supports comparison testing of distributed generation (DG) protection analysis programs. The software tools need to calculate fault currents, voltages, and certain symmetrical component relaying quantities for a range of fault types and resistance values. The tools need to work with and without a utility source present, and with or without a DG source present. One of the important design questions is how to ground the DG interconnection transformer, so the tools also need to handle a variety of winding connections and neutral impedances. With unbalanced loads, it is necessary to calculate neutral currents whenever the interconnection transformer provides a ground source. IEEE Std. 1547 specifies monitoring of individual phase-phase and/or phase-neutral voltages, so the tools need to provide corresponding outputs.