This presentation will have a brief introduction to the basics of substation grounding as per IEEE 80 and will describe the analytical methodology, performance results and the grounding system analysis for the Kingston Solar Farm in Ontario. The Kingston Solar Farm saves approximately 14,700 tonnes of carbon dioxide per year, an amount equivalent to planting 3,340 acres of trees and is the largest solar farm ever built in Canada.

The Kingston Solar Farm which is owned by Kingston Solar LP has a generating capacity of 100 MW AC /140 MW DC and consists of six (6) distributed zones interconnected by a 34.5kV distribution network. The solar farm is connected to the Hydro One 230 kV transmission system.

The most advanced grounding software CDEGS was used for the grounding system performance analysis to simulate a ground fault on the 230kV system to induce a GPR at the interconnecting substation and a transfer potential throughout the solar farm.

This presentation will describe the limitations in terms of soil model variations and the maximum number of conductors / elements that were included in the simulation model. As a result, special analysis methods had to be used for this large solar farm which included a simplified overall model and further detailed analysis of the different zones using GPR energization.

This presentation will also describe the final design of the grounding system including a combination of mitigation methods such as neutral grounding resistors, crushed stone layers, gradient control conductors, insulated fence sections as well as different interconnection methods between the zones.