CSA C71.2 : 1998

FOREWORD
Clause
1 General
   1.1 Scope
   1.2 Normative references
   1.3 List of symbols and definitions
2 Representative voltage stresses in service
   2.1 Origin and classification of voltage stresses
   2.2 Characteristics of overvoltage protective devices
   2.3 Representative voltages and overvoltages
3 Co-ordination withstand voltage
   3.1 Insulation strength characteristics
   3.2 Performance criterion
   3.3 Insulation co-ordination procedures
4 Required withstand voltage
   4.1 General remarks
   4.2 Atmospheric correction
   4.3 Safety factors
5 Standard withstand voltage and testing procedures
   5.1 General remarks
   5.2 Test conversion factors
   5.3 Determination of insulation withstand by type
        tests
6 Special considerations for overhead lines
   6.1 General remarks
   6.2 Insulation co-ordination for operating voltages
        and temporary overvoltages
   6.3 Insulation co-ordination for slow-front
        overvoltages
   6.4 Insulation co-ordination for lightning
        overvoltages
7 Special considerations for substations
   7.1 General remarks
   7.2 Insulation co-ordination for overvoltages
Tables and Figures
Annexes
A Clearances in air to assure a specified impulse
   withstand voltage installation
B Determination of temporary overvoltages due to earth
   faults
C Weibull probability distributions
D Determination of the representative slow-front
   overvoltage due to line energization and
   re-energization
E Transferred overvoltages in transformers
F Lightning overvoltages
G Calculation of air gap breakdown strength from
   experimental data
H Examples of insulation co-ordination procedure
J Bibliography

Constitutes an application guide and deals with the selection of insulation levels of equipment or installations for three-phase electrical systems. Gives guidance for the determination of the rated withstand voltages for ranges I and II of IEC 71-1 and to justify the association of these rated values with the standardized highest voltages for equipment. Covers three-phase systems with nominal voltages above 1 kV. Covers phase-to-earth, phase-to-phase and longitudinal insulation.