Practical considerations (substation earthing)

Prior to the major changes in this industry in the 1970s and 1980s the majority of the work carried out by the British switchgear manufacturers was for the nationalised CEGB and area boards, using CEGB and the company´s own standard equipment and arrangements. Because of subsequent changes in the switchgear business due to privatisation and rationalisation of companies, a lot of these standard layouts now do not apply and the experts who originally designed the systems are no longer with the companies. We found that when completing our own turnkey projects the earthing detail design was being re-engineered for each contract which was costly and time consuming. In order to minimise these problems it was decided to introduce a standard earthing policy which is relatively easy to use, and has the versatility to be easily customised to suit the greater variety of clients and standards which we now have to cater for. This paper covers some of the considerations covered in this standard