5 MW Flywheel Energy Storage

Guelph Hydro needed to connect a Flywheel Energy Storage System (FESS) at their Arlen Transformer Station (TS). The system would be comprised of ten 500 kW, 480V energy storage flywheels with the ability to inject and store up to 5.0 MW of electrical power to Guelph Hydro’s 13.8 kV distribution system.

Flywheel energy storage systems utilize fast-spinning machines to very quickly inject or absorb reactive and non-reactive power to/from the grid. The fast ramping of these systems can potentially impact the operating conditions of existing power delivery networks thereby requiring a Detailed Connection Impact Assessment (DCIA). We worked with our partner, Teshmont, to perform this DCIA using PSCAD to ensure that the utility’s network would not be compromised with the addition of the FESS.

It was proposed that an underground cable tap connection onto a 13.8 kV feeder of the TS. The interface station would connect the flywheel energy storage facility to the 13.8kV distribution system including a switchgear consisting of a main withdrawable type, primary breaker that would be used as the HV interrupter, and four fused-disconnect switches feeding four padmount transformers. We had previously assisted the client with integration of a current limiting reactor at the station as well as the related grounding system modifications thereby streamlining the assessment process.