TABLE OF CONTENTS This chapter introduces the basic items of design and specification for the principal systems and components of an electrical industrial installation. Electrical supply systems are discussed with regard to interface with the supply authorities and the characteristics. Salient features of switchgear, transformers, protection systems, power factor correction, motor control equipment and standby supplies are identified and discussed together with reference to the relevant Codes of Practice and standards. The equipment and systems described are appropriate to industrial plant installations operating at typically 11 kV with supply capacities of around 20 MVA.
The majority of industrial installations will receive all or part of their electrical energy from an area electricity board supply authority. The factors which will affect the way in which this energy is imported to the site and subsequently controlled are:
The voltage and frequency
The load requirements
The fault level
The tariff
Access to equipment
The key parameters for each of these factors are discussed below.
The voltage of the supply will depend upon the load requirements of the site and the relative capability of the local supply system. Voltages typically available are 33 kV, 11 kV, 6.6 kV, 4.16 kV, 415 V and 380 V. For some larger installations 132 kV (or higher) voltage supplies may be provided.
Statutory regulations imposed upon the supply authorities will normally limit variations in...
