ENWIN Powerlines Ltd., the organization responsible for the distribution of electric power in Windsor, Ontario, Canada, has undertaken a major substation automation initiative that will improve service and reduce maintenance costs. The project is designed to overcome the shortcomings of an outdated 4-kV municipal system and aging substations located throughout this birthplace of Canada's automotive industry.

“The project involves 24 substations located in neighborhoods throughout the city operating at two different voltage levels,” explains Kevin Damphouse, SCADA manager for ENWIN Powerlines, whose department is heavily involved in planning and implementation. “We have two power systems in the city — 4 kV and 27.6 kV — and we're beginning to phase out the 4-kV system. The higher priority is the substation upgrade. Some of those structures are 60 years old and need refitting to meet power system requirements for added reliability, protection and control.”

A key part of the substation project involves replacing electromechanical protective relays, some of which are 40 to 50 years old. Among other deficiencies, those relays are not fully reliable, are not SCADA capable, necessitate high maintenance costs and are labor-intensive, tying up vital human resources. Also, on-hand replacement parts are becoming scarce and many parts are no longer available from the supplier.

The relay selected for the upgrade project is the SEL-551 overcurrent/reclosing relay (67 units total) from Schweitzer Engineering Laboratories Inc. (SEL; Pullman, Washington, U.S.). The SEL-551 is a microprocessor-based multishot reclosing relay with sequence coordination; phase, ground and negative-sequence overcurrent protection; and monitoring, communications, reporting and control features.

Prior to the installation of the SEL-551 relays, the ENWIN Powerlines substations had used thermal-demand ammeters. Many of these old ammeters were not accurate, and there were no graduation marks between 0 and 100 A on the meter scale. Significantly, the planners used those readings to calculate present and future loads and transfers.

Using the accurate metering information in the SEL-551 relay allowed planners to know exactly what load transfers were actually being made, which enabled them to eliminate some processes and to bypass and remove stations earlier than planned.

ENWIN Powerlines also recently installed three major 115-kV transformer stations for the Windsor area's largest automotive customers — Ford, General Motors and DaimlerChrysler — that include SEL equipment.
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