BC Hydro
Mica Ground Grid Measuring Consulting Services
Project Description
The project involves the addition of two (2) new generation turbines at the Mica Dam site. The MCW scope for the project was to provide a grounding study including a review of existing grounding drawings, site investigations, field measurements, calculations, analysis, recommendations and reports as part of the requirement for an extension of the existing 500kV switchgear building. Testing was subcontracted to Kinectrics and directed by MCW staff. Testing included soil resistivity measurements, a fall of potential measurement, step and touch voltage measurements, fault current split measurements, and lab testing by Kinectrics to determine the river water resistivity. The grounding system was modeled and analyzed using CDEGS software, and included the existing grounding system of the underground powerhouse, switchgear building, spillway, penstocks, dam crest, and tourist building. The soil structure was analysed and modeled in CDEGS and included the native soil, river, and the earth-fill dam. Recommendations were provided for the switchgear building extension grounding requirements and to mitigate touch voltages in the designated laydown areas for equipment and trailers related to the switchgear building extension.