This project included the rebuild of a 115-kV to 12.47-kV substation except for the existing distribution switchgear. The 115-kV included new Pull-Off structures, Circuit Breakers, Metering Units, Circuit Switcher and 20/26/33-37MVA Power Transformer with concrete moat type oil containment.
Completion Date: 2014
COYOTE SPRINGS SUBSTATION Hermiston, Oregon Owner: Umatilla Electric Cooperative
This project included the full rebuild of a 115-kV to 12.47-kV transmission switching substation. The 115-kV was configured as a main and auxiliary bus which initially included three incoming transmission lines. The distribution includes a 25MVA transformer with four (4) feeder breakers and a dedicate bypass breaker. All distribution buss was open-air main and auxiliary with underground getaways.
TriAxis services included the full design except for protection and controls, RUS contract documents assembly, construction bid review, routine construction inspections and management, and RUS contract close-out document preparation.
Completion Date: 2014
Design work for which TriAxis was responsible: All protection except controls
JOHN STREET Longview, Washington Owner: Cowlitz County PUD
TriAxis provided complete design of 138/12.47-kV, 12/16/20 MVA dual transformer distribution substation. The substation supplies power to an aquifer storage and recovery facility.
Substation design features included:
138-kV equipment includes circuit switchers for over-current protection and power-operated switches to initially serve two power transformers, and provide for a future third transformer.
The 12.47-kV bus is designed for 1200-amps and uses 20-kA rated reclosers.
Each transformer and main 12.47-kV breaker serves an outdoor distribution rack with six breaker positions: five for feeder circuits and one for a capacitor bank. The two 12.47-kV racks are separated with a normally-open tie breaker.
Transformer relaying uses a typical differential scheme with current and time-over-current backup tripping.
All power-driven switching devices may be controlled locally or via the SCADA system.
The substation is designed to normally operate with both power transformers in parallel with the 12.47-kV tie breaker closed. However, the transformers can operate un-paralled, or switching can be reconfigured to serve all loads with either transformer. Operating the transformers in parallel requires higher-rated secondary equipment to handle increased fault currents. However, the added flexibility benefits the City through increased reliability. With each transformer sized to serve all loads, outages are minimized when maintenance is performed.
COPCO 2 HYDROELECTRIC SUBSTATION 115/69-kV Copco, California Owner: PacifiCorp
This project consisted of designing a new four position 115-kV ring bus in the same location as the existing radial bus substation. The new generator step-up transformers. ring bus connected two new hydro generator step-up transformers and a new 115/69-kV transformer to replace failing 115/69-kV.
The substation design included provisions for future conversion to a breaker-and-a-half configuration, it was necessary also for the hydro generators to continue operating while the new substation was being constructed. A new control house was designed and installed to contain all the new relaying, metering and SCADA equipment. The existing ground grid was analyzed using CDEGS software to verify safe touch-and-step potentials inside and adjacent to the substation.
TriAxis was responsible for all of the outdoor design, wiring and on-site support during outages. Estimated design cost was $164,000.