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E.C. Drury school for the deaf
An original “non-functional” system existed and ESAC utilized existing field wiring to minimize costing. The facility has numerous unit substations with essential and non-essential loads. The emergency generator impacts essential loading and add or subtracts non-essential loads with automatic management, monitoring frequency with capacity. The project has resulted in a reliable system with strategic power supply prioritization to ensure residents' and staff safety.

Approach and Methodology
The EPLU is located in the main power house and is supplied from a switchgear DC battery bank. This monitors emergency generator frequency, voltage, and loading and interfaces with 4.16kV breakers transfer scheme with distribution circuits. Upon a loss of normal power, the existing transfer scheme starts the emergency generator and is frequency and voltage supervised prior to loading. To ensure minimal impact loading, each 4.16kV feeder is closed in turn permitting load pickup to subside prior to next feeder energization and all non-essential loads tripped off. Pending current emergency power loading, non-essential circuits are added or subtracted as per designated priorities.

Key Challenges
Encountered challenges include field research and checks including main 4.16kV switchgear to defining existing system for EPLU design. Available field wiring was defined and design interface rework performed. Upgrading occurred while the facility was occupied and in-service, requiring scheduling to be done in a way to minimize interruptions. Additionally, ESAC ensured EPLU system reliability for transfer to emergency power with no overload conditions including under frequency and overcurrent trips.

Ongoing Support
The system was upgraded using existing 4.16kV switchgear meters and protection relays. Additionally,  hardware failures have resulted in further upgrades such as replacing IOC relays and analog/transducer metering to digital protection relays. ESAC assists facility staff with operational understanding, offers technical support and system service.


   151 Meg Drive
   London, ON
   N6E 3Z7

   Phone: (519) 686 - 6722
   Fax: (519) 686 - 1486

   Sales: esac.sales@esac.com
   HR: esac.hr@esac.com