TABLE OF CONTENTS Insulation co-ordination is the technique used to ensure that the electrical strengths of the various items of plant making up the transmission and distribution system and their associated protective devices are correlated to match the system characteristics and expected range of voltages. The objective of the analysis and application of its conclusions are to reduce the probability of plant failure and supply interruptions caused by insulation breakdown to an operationally and economically acceptable level.
IEC 60071 covers the subject of insulation co-ordination as indicated in Table 9.1. The standard recognizes that insulation may occasionally fail since it is not economically feasible to eliminate failure completely. A proposed order of priorities for an insulation co-ordination policy is to:
Ensure safety to public and operating personnel.
Avoid permanent damage to plant.
Minimize interruption of supplies to consumers.
Minimize circuit interruption.
| IEC 60071 insulation co-ordination |
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| 60071 1 Part 1 Terms, definitions, principles and rules |
| Specifies the insulation for the various items of plant used in a given installation. Applies to plant for AC systems having a higher voltage for plant above 1 kV, and covers phase-to-earth insulation. |
| 60071 2 Part 2 Application guide |
| Provides guidance on the selection of the electric strength of plant, of surge arresters or protective spark gaps, and on the extent for which it will be useful to control switching over-voltages. Indicates the lines to be followed to obtain rational and economic solutions. Deals with... |
