Dependability and LV switchboards

Electrical power availability

This Cahier Technique publication deals with the dependability of commercial and industrial low voltage electrical installations. Its aim is to answer the question “which installation best satisfies our growing needs in terms of electrical power availability?”.
The subject is dealt with for LV switchboards and focuses on the following problems:

• which switchboard functions guard against failure of the LV distribution system?
• how should they be used?
• with what components?
• in what power system environment (number of sources and loads, type of system earthing)?

The reason for this focus is that LV switchboards are vital links in any power distribution system. This document is intended to help operators and designers of electrical installations to:

• determine the points which must be considered. These points are related to the technical choices dealt with in the sub-chapter entitled “industrial dependability concepts” . The discussion is based on reliability levels calculated on concrete cases and yields solutions in terms of equipment type. A summary is given in the subchapter entitled “required dependability levels”.
• realise the increasing influence of power management systems on LV switchboard dependability.

Switchboards Functions

The switchboard is a key part of any electrical installation. It incorporates devices designed to:

• distribute electrical power and protect circuits,
• protect persons,
• control and monitor the installation.

Recent developments in this control and monitoring function have made the switchboard even more vital to the installation. The dependability of the entire installation is largely determined by the dependability of the switchboard.
Moreover, the lasting viability of the associated industrial or commercial activity depends on the capacity of the switchboard to keep pace with future needs.

AUTHOR: Schneider Electric expert | Olivier BOUJU