Protection of utility-refinery interconnection

This paper discusses the protection requirement to interconnect a typical refinery to the utility system. It covers applications involving service to a refinery that normally require a transformation between the utility´s supply voltage and the refinery´s utilization voltage. The paper specifically addresses refineries with generation that are connected to utility transmission circuits. The protection discussed must protect the refinery from the effects of utility system faults but must also protect the utility from the effects of refinery faults. Coordination between these two systems is essential to minimize the effects of fault-induced outages. This paper specifically addresses typical refinery-utility interconnections system one-line designs, determining utility supply performance expectations, impact of generation on interconnection protection, relay functional requirements for typical interconnections protection, relay communication requirements and grounding of the interconnection transformer(s) and its impact on protection. In addition, the paper will discuss NERC (North American Electric Reliability Corporation) requirements and its effect on refinery interconnection protection.