IEEE Power & Energy Magazine - May/June 2021 - 71

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NORTH BAY HYDRO SERVICES INC., AN AFFILIATE OF NORTH BAY HYDRO DISTRIBUtion Limited, set out to deploy Canada's first utility-scale microgrid, completing the project in 2019
The North Bay, Ontario, company wanted to build a more resilient grid to support the community in
case of an emergency. In conjunction with the community, the microgrid's development helped form
a community hub that benefits the city of North Bay during both normal and emergency events
(see Figure 1).
A simplified single-line diagram of the North Bay Community Energy Park (CEP) microgrid is
provided in Figure 2. The microgrid has two points of interconnection with the local utility system
providing a redundant supply resilient to some upstream line or transformer faults. Only one of the two
utility interconnection breakers (CB1 and CB2) is closed at any time. The microgrid supplies electricity
and heat to three facilities: the YMCA Aquatic Center, Thomson Park, and Memorial Gardens. In an
emergency, these buildings serve as a gathering space that can supply shelter for members of the community. Examples of the equipment found at the CEP are shown in Figure 3.
To ensure that the microgrid can maintain operations independent from the grid, the microgrid
includes the following distributed energy resources (DERs):
✔ two combined heat and power (CHP) natural gas generators, each rated 265 kW
✔ one battery energy storage system, rated 250-kW ac, 274 kWh
✔ solar photovoltaic (PV) systems totaling 8-kW ac.
In this article, DERs are defined by the IEEE Standard 2030.7 definition: " Sources and groups of
sources of electric power that are not directly connected to the bulk power system; they include both
generators and energy storage technologies capable of exporting power. " The microgrid DERs supply
maximum electrical power of 788 kW. The CHP generators also produce thermal energy, which is used
to heat the community facilities.
The microgrid is capable of operating grid tied (interconnected with the local utility system) and
islanded (separated from the local utility system). The microgrid can seamlessly transition between
these two operational states during both planned (e.g., the operator manually initiating transition)
and unplanned events (e.g., the external utility system faults while grid tied). This feature enables the
CEP's buildings to maintain their critical power supplies, even when the surrounding area experiences an outage.

North Bay CEP Microgrid Protection Challenges
When designing a microgrid, protection challenges are expected because the grid was not initially
designed to support the addition of microgrids. For the CEP microgrid, the major challenges to devising a robust protection plan included the following items:
✔ bidirectional and variable-fault current
✔ power-export restrictions
✔ a need for fast protection operation
✔ an ability to detect utility events promptly
✔ reliably protect the equipment from closing out of phase.
The North Bay CEP microgrid is the fi rst of its kind in Canada. The microgrid's complexity required sophisticated and reliable microgrid protection. Microgrid protection is one of the most critical components of the overall
microgrid. In all power systems, protection is responsible for detecting and isolating faults promptly. Protection functions are critical to guarantee safe operation and minimize damage to equipment when a fault occurs.
Microgrids often include costly DERs and switchgear, which make protection a necessary feature to ensure the
equipment's integrity.
In a microgrid, detecting faults can be more challenging for the reasons outlined in the next section. Protecting this
microgrid involved several challenges typical of microgrids. The following challenges were most significant in shaping the CEP microgrid protection design.

By Michael Higginson, Matt Payne, Keith Moses,
Peter Curtiss, and Stephen Costello
may/june 2021

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IEEE Power & Energy Magazine - May/June 2021

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