IEEE C37.95-1989, IEEE Guide for Protective Relaying of Utility-Consumer Interconnections, is intended to cover applications involving service to a consumer that normally requires a transformation between the utility's supply voltage and the consumer's utilization voltage. Interconnections supplied at the ultimate utilization voltage are not covered.

This guide contains information on a number of different protective relaying practices for the utility-consumer interconnection. It is intended to cover applications involving service to a consumer that normally requires a transformation between the utility's supply voltage and the consumer's utilization voltage. Interconnections supplied at the ultimate utilization voltage are not covered. This guide is not intended to supplant specific utility or consumer practices, procedures, or requirements, or any contractual agreement between the utility and consumer. The examples in Section 9 are used for illustrative purposes only and do not necessarily represent the preferred protection trader all conditions. This guide addresses users (consumers), with or without generation, that are connected to utility subtransmission or transmission circuits. The specific control schemes associated with generation are not addressed. It is not intended to apply necessarily to consumer generation connected to utility distribution circuits.

The primary purpose of this guide is to help those who are responsible for the application of protective relaying for the electrical interconnection between utility and consumer systems. It is anticipated that it will be used by representatives of the utility, the consumer, and their consultants who are responsible for the specification, design, and operation of the interconnection. Recognizing the diverse audience being addressed, background information and references are included in Section 4 to direct the reader to more complete treatment of the material.