|Project||Onshore Substation Resistance Impedance Measurement|
The onshore substation was constructed as a part of the new extension for the offshore wind farm project, which is an extension to the existing offshore wind farm located in the Irish Sea. The offshore wind farm capacity is approximately 750MW. The power from the offshore wind farm will be exported by undersea high voltage cables to the 400kV onshore substation. It is here the power is fed into the transmission network. ERM was engaged to test the new, onshore substation earthing system in order to verify the earthing installation and the CDEGS model used for earthing design.
ERM’s expertise and experience with earth impedance measurements at large sites was instrumental in delivering this test. ERM was able to liaise effectively with the client and land owners to obtain a test route that would give accurate results and require minimal client planning input. ERM’s uses only pedestrian access in line with our field test policy, which is to leave all third party land in a condition where our presence is undetectable.
Undertaking precise earth impedance measurements at large sites is challenging and often cannot be accomplished using off-the-shelf equipment. The factors below were very important in achieving an accurate result at the substation: