IEEE 1313.2-1999

The insulation coordination standard and guide apply to three-phase ac systems above 1 kV and are divided into two parts. IEEE Std 1313.1-1996 (Part 1) specifies the procedure for selection of the withstand voltages [basic lightning impulse insulation level (BIL) and basic switching impulse insulation level (BSL)] for equipment phase-ground and phase-phase insulation systems. It also identifies a list of standard insulation levels. Although he principles of this standard also apply to transmission line insulation systems, the insulation levels may be different from those identified as standard insulation levels. This guide (Part 2) is an application guide with practical examples, intended to provide guidance in the determination of the withstand voltages and to suggest calculation methods and procedures. The insulation coordination examples for selected equipment are designed to explain the principles of Part 1. The guide is intended for air-insulated ac systems; caution should be exercised in the case of gas-insulated systems (GIS). It should be recognized that absolute protection of station equipment is theoretically impossible. Even if arresters are located at the terminals of all apparatuses, equipment failures can occur. The probabilistic method, that is, designing for a mean time between failures (MTBF) criterion, is proposed here not only to permit a realistic basis of design, but perhaps more importantly, to form a consistent measure of design based on reliability. New IEEE Standard - Inactive-Reserved. The calculation method for selection of phase-to-ground and phase-to-phase insulation withstand voltages for equipment is presented. This guide gives methods for insulation coordination of different air-insulated systems like transmission lines and substations. The methods of analysis are illustrated by practical examples.