Study Committee C4
Proposal for the formation of a new Working Group
WG No.: WG C4.408
Name of Convener : Alexandre Piantini (Brazil)
Title of the Group: LIGHTNING PROTECTION OF LOW-VOLTAGE NETWORKS
Scope:
In recent years, the growing use of sensitive electronic equipment and the increasing demand of utility
customers for stability of the power supply have highlighted the importance of improving the reliability and
power quality levels of electric systems. As lightning is a major source of faults on overhead lines and
damages to or malfunction of sensitive electronic equipment, it is essential to evaluate the lightning
electromagnetic environment in order to mitigate its effects and improve the power system quality. Due to the
lower withstand capabilities of low-voltage networks (voltages less than 1 kV) in comparison with those of
medium voltage lines (voltages in the range of 1 kV to 69 kV), they are more susceptible to lightning
electromagnetic interferences.
Joint CIRED/CIGRE Working Group 05 "Protection of MV and LV networks against lightning" was
established under SC 33 in 1993 with the task to prepare an application guide for distribution utilities
focusing on practical methods of lightning protection of MV and LV networks, taking also into account
economical aspects and quality of supply. After an interruption in 1997, the working group resumed its
activity in 2002 under SC C4 with the name JWG C4.402 “Protection of MV and LV Networks Against
Lightning” and the following documents have been produced:
• “Protection of MV and LV networks against lightning – Part 1: Common topics”, which is a brochure
that presents basic information and principles related to lightning protection of MV and LV networks;
• “Protection of MV and LV networks against lightning - Part 2: Lightning protection of medium voltage
networks”, which presents an application of the basic information provided in Part 1 to the lightning
protection of MV networks containing overhead lines with system voltage in the range of 1 kV to
36 kV. It is applicable for higher system voltages as well, but it becomes gradually less relevant
when the system voltage increases. This document will be finalized in May 2009.
This new CIGRE working group, with participation of several Cired experts, is proposed in order to
accomplish additional, important activity focused on LV networks, through the following proposed scope of
work:
• to document a careful review of the characteristics of lightning overvoltages (amplitudes, shapes,
etc.) of different origins (cloud-to-cloud and intra-cloud lightning, indirect lightning, direct strikes to
the low voltage conductors, direct strikes to low voltage power installations, transference from the
MV network) in LV networks;
• to investigate the overvoltage characteristics as a function of line and lightning parameters, load
frequency-dependent behaviour and distribution transformer representation;
• to present specific methods of protecting LV networks and relevant equipment.
Deliverable: a technical report/ brochure providing guidelines for lightning protection of LV networks
Time schedule:
Initiation of the WG: February 2009;
Deliverable: May 2011.
Approval by TC Chairman:
Klaus Fröhlich
Date: 07/02/2009