The functional levels of interconnection protection vary widely
depending on factors such as: generator size, point of
interconnection to the utility distribution system, type of generator
(induction, synchronous, asynchronous) and interconnection
transformer configuration. As shown in Table 1, specific objectives
of an interconnection protection system can be listed, as well as the
relay functional requirements to accomplish each objective. Other
than a very simplistic discussion of the detection of loss of parallel
with the utility, IEEE 1547 does not address protection areas such
as: use of fault current at the DG facility to detect supply tripping,
abnormal power flow, and damaging system conditions.