Wessex CP-5 Earthing Renewals
RPS designed a new Substation earth farm at Tolworth Substation. The 33kV Substation was deemed a hot site by Network Rail with a ROEP at 1,072V. RPS undertook a comprehensive survey to identify the existing earthing and bonding arrangements of the Substation, in addition we undertook the following tests –
Fall of potential test to determine existing system earth;
Double clamp stakeless method to determine local earth;
Soil resistivity measurements using the 4-pole Wenner method;
Soil analysis test.
RPS then used the CDEGS software package to accurately design a new earth farm, where ROEP, step and touch potential voltages are calculated, in addition we identified any transfer potential issues regarding a steel palisade fence. RPS engaged with the contractor and Network Rail to ensure a valued Engineering approach was used for design and construction, which met the requirements of BSEN-50122-2. Once the new earth farm was installed the ROEP was calculated at 245v.
RPS have undertaken 24No. Wessex earthing designs for McNicholas.