Page 659 - Industrial Power Engineering and Applications Handbook

18/624 Industrial Power Engineering and Applications Handbook
Relevant Standards

IEC Title IS BS
60056/1987 High voltage alternating current circuit breakers 13 11 8/1991 BS 5311/1996
6007 1 - 1/1993 Insulation coordination - Definitions, principles 2165-1/1991, BS EN 60071-
and rules 2 165-2/199 1 1/1996
60071-2/1996 Insulation coordination - Application guide 37 16/1991, RS EN 60071 -2/1997
60099- 1/1991 Surge arrester - Non-linear resistor type gapped 3070-1/1990 BS EN 60099-
surge arresters for a.c. systems. 1/1994
60099-4/1991 Surge arresters - Metal oxide without gaps for a.c. 3070-3/1993 BS EN 60099-
power circuits 4/1993
60099-5/1996 Surge arresters. Selection and application 4004/1990 BS EN 60099-
recommendations 5/1997
6 1024- 1/1993 Protection of structures against lightning ~ 2309/1989 DD ENV 61024-1/1995
General principles BS 6651/1992
Relevant US Standards ANSINEMA and IEEE

ANSI/IEEE-C62.1/1994 Standard for gapped silicon carbide surge arresters for ax. power circuits
ANSI/IEEE-C62.2/1994 Guide for application of gapped silicon carbide surge arrester for a.c. systems
ANSIIIEEE- Metal oxide surge arresters for a.c. power circuits
C62.11/1993
ANSI/IEEE Guide for the application of metal oxide surge arresters for a.c. systems
C 62.22/1997
ANSI/IEEE Insulation coordination, Definitions, Principles and Rules
13 13.1/1996
NEMNLS- 1/1992 Low voltage surge protection devices

Notes
1 In the tables of Relevant Standards in this book while the latest editions of the standards are provided, it is possible that revised editions
have become available. With the advances of technology and/or its application, the updating of standards is a continuous process by
different standards organizations. It is therefore advisable that for more authentic references, readers should consult the relevant
organizations for the latest version of a standard.
2 Some of the BS or IS standards mentioned against IEC may not be identical.
3 The year noted against each standard may also refer to the year of its last amendment and not necessarily the year of publication

List of formulae used Z,, = surge impedance of the incoming circuit
Z,, = surge impedance of the outgoing circuit
Electrical characteristics of a ZnO surge arrester Voltage of the refracted wave,

Characteristic of a ZnO block E" = E + E'
I= K.V" (18.1) (18.4)
K depends upon geometrical configuration, cross-
E = voltage of the incident wave (incoming wave)
sectional area and length of ZnO Block E' = voltage of the reflected wave
a = is a measure of non-linearity between V and I E"= voltage of the refracted (transmitted) wave
When the outgoing circuit is inductive,
Protective margins

BIL of the equipment (18.5)
Protective margin =
ImDulse Drotection level (18.2)
df the arrester (V,, )
L = inductance of the circuit
When the outgoing circuit is capacitive,
Reflection of the travelling waves
Voltage of the reflected wave (18.6)
(1 8.3)
C = capacitance of the circuit