DISTRIBUTED GENERATION ISSUES Technical Issues Non-Technical Issues

Technical Issues DG Size The greater the DG size, the higher the fault duty capacity Location and type of fault Contribution of DG to fault on the feeder reduces expected current for substation relays. They must be able to see faults at the end of the circuit.

Technical Issues (continued) Configuration of interconnection transformer Ungrounded windings greatly affect relay performance during grounded faults If primary winding is delta and a phase- to-ground fault occurs on the grid, the current relays of the DG will not be as sensitive to it. DG voltage relays on the primary side must see rise in voltage.

Technical Issues (continued) Lowest expected feeder load compared to maximum generator output DG is preferred not to back feed substation bus under minimal circuit loading At all times of year, power must not be pushed back to substation transformer (generator could feed transmission fault)

Technical Issues (continued) Voltage issues near DG site Voltage on feeder must not be outside of allowable range due to presence of DG Undesired voltage regulation on circuit must not result during low circuit loading

Non-Technical Issues Customer’s system configuration and operation with DG Understanding prints and scheme involved Need generator data to model DG Increasing volume of DG applications