STATELINE WIND ENERGY PROJECT
Wallula, Washington
OWNER: FPL ENERGY
Juno Beach, Florida
Wallula, Washington
OWNER: FPL ENERGY
Juno Beach, Florida
The Stateline Wind Energy Project is currently the largest single-owner wind energy project in the world.
It is designed by TriAxis for 454 667-kW Vesta V47 wind turbine generators (300MW). The project is designed to deliver 200 MW at 230 kV to the PacifiCorp Wallula Substation, and 100 MW to BPA’s 115-kV Franklin – Wallula transmission line.
TriAxis Engineering was responsible for the following design components:
- The collection system (95 circuit miles of 34.5-kV, 3-phase, underground cables) connecting the wind turbine generators to the Nine Mile Substation. The collection system consists of 10 main circuits, each with able sizes ranging from 2/0 1000 kcmil. This fully underground system is designed for long life with economical construction and operation. Most circuits are placed in easily dug trenches; some, however, required trenching on ridgelines of fractured rock. Some circuits cross under railroads and gas pipelines. Main concentric neutrals of the main circuit cables are cross bonded to reduce heating in soils with extremely high thermal resistivity.
- 5.5 miles of 115-kV transmission line using wood pole, H-frame structures, and 556.5 kcmil, ACSR, and a Dove conductor. The line includes a 2100-foot-long span crossing a major highway and the Walla Walla River Valley.
- TriAxis was responsible for the design of 2.6 miles of 230-kV, wood pole, H-frame transmission line using 795 kcmil ACSR “Drake”conductor.
- The Nine Mile Substation is essentially two substations in one. It has five 34.5-kV main collection system feeder breakers permanently connected to the 250 MVA, 230-kV step-up transformer, and an outdoor 34.5-kV rack with seven feeder circuit breakers that are switchable between the 230-kV step-up transformer and the 100 MVA, 115-kV step-up. This switching flexibility allows the operator to better match incoming generation to plant output requirements and transformer capacity. The substation also has twelve 2-stage, 9 MVAr capacitor banks to control power factor. TriAxis modified the PacifiCorp Wallula Substation from a 3-position ring bus to a 4-position ring bus to accept the Nine Mile 230-kV transmission line termination. A new circuit breaker was added as well as the foundations, conduit, cabling, buswork, and relay/metering panels necessary to make a complete system.
