Distributed generation grid connection experiences minimizing high voltage equipments

Since 2007, farm-based biogas utilizing small synchronous generation has emerged in Ontario. Initial attempts at grid connection revealed several costly barriers. First, a requirement for proponents to pay for consequential upgrades to distribution infrastructure was mitigated through an amendment to the Ontario Distribution Code. Second, a requirement for transfer-trip to protect against feeder islanding was removed through the evolution of a low-cost alternative involving passive protections. Third, high-voltage equipments, contained in the standard grid connection designs, were considered disproportionately expensive. To minimize the use of such equipments: For connections to three-wire feeders, fast imbalance protection was employed to avoid using high-voltage potential transformers; For connections to feeders employing single-phase reclosers, the effective grounding requirement was relaxed, enabling high-voltage equipments associated with wye-delta transformation to be avoided; For connections to feeders with ganged three-phase reclosers, high-voltage equipments were avoided through utilizing a low-voltage wye-delta transformer for grounding.