System Diagram, circa 1947
Early Mimic Board
In the days before real-time data, before remote monitoring of system status, the City of Edmonton Electric Light & Power Department used this display board to keep track of the status of over 100 various HV switches, air-breaks and oil switches. This System Display (or "Mimic Board", as it mimicked the status of field switches) was mounted in the Rossdale Control Room. If it was necessary to operate a switch, a "Switching Order" would be created by the Control Room Operator. When it was time to execute the Switching Order, a utility employee would approach the operator for the key(s) to operate any devices called for in the Switching Order. The Operator would open the mimic panel cabinet and select the pertinant keys and hand them to the employee (typically a Power Lineman).
The lineman would travel to the switch location, and after receiving clearance from the operator would operate the appropriate switches. He would then contact the Control Room (typically by telephone) to confirm the switch had been operated, and the Operator would move the switch on the mimic board. The lineman could then proceed to the next step on the switching order.
On this mimic board, underground circuits are displayed as chrome bars and overhead lines are shown in copper.
This display is a fascinating snapshot of the history of Edmonton, and icons from the past include the government elevators on 127 St. & 130 Ave. (now Cargill), Aircraft Repair at Blatchford field (later North West Industries), Namao Field (Lancaster Park), Griesbach Barracks (now Village at Griesbach) and Swifts, Burns and Canada Packers that operated meat packing plants in the east end.
