Dashiell was awarded this project in July, 2020. The substation is an EPC (engineering, procurement, and construction) greenfield project for a 345-138kV substation. The 345kV station was designed in a ring bus configuration initially with two (2) line nodes and one (1) transformer node with the capabilities of being converted to a five (5) bay breaker-and-a-half (BAAH) arrangement in the future. The project included the installation of one (1) 345kV/138kV/13.2kV 600 MVA (maximum forced air rating) autotransformer (this was the only piece of material for the project that the owner procured). The 138kV station was designed in a ring bus initially with one (1) transformer node and one (1) line node with the capabilities of being converted to a three (3) bay BAAH configuration in the future. The two (2) stations share a common control building designed with floor space and utility capabilities (125VDC and AC station service) for the ultimate arrangement of a five bay 345kV BAAH station and a three bay 138kV station. Our scope of work also included the design-build of 0.15 miles of 345kV Transmission line to cut in the existing WETT Cottonwood to Dermott Line, 0.50 miles of 138kV Transmission line to connect the new WETT Nova Prime 138kV Station to the new Solar Generator’s Collector Substation, and 0.10 miles of 138kV Transmission Line between the 345/138kV Auto yard and the 138kV Yard. The project was successfully completed in April, 2023.
In late summer 2012, Dashiell accepted a project with an aggressive project schedule to design and build a 138 kV generator interconnect substation and a 138 kV interconnecting transmission line for a new peaking power plant being built by NRG at the W.A. Parish power plant near Richmond, Texas. Although the facilities themselves were not technically difficult to design and build, the number of interfaces between existing NRG facilities, the new peaking power plant and Centerpoint created a number of challenges for the project team.
On Thursday, June 6th, Dashiell successfully energized the interconnect substation bus by re-energizing the transmission line from the Centerpoint substation to the NRG W.A. Parish Unit #7 Standby Transformers. On Friday, June 7th, the interconnect breaker to the new generation facility was closed, energizing the transmission line and back-feeding the new power plant through the Generator Step Up Transformer. Even with all of the interface issues that challenged our energization, Dashiell completed this project a full week ahead of our commitment to the customer.
Project Description: Dashiell provided an EPC turnkey project for a 345kV – 138kV substation as part of the Horse Hollow Generation Tie Project. The station consisted of a 2 breaker 345kV tap substation with a single incoming line, two (2) 555MVA 345kV – 138kV transformers and a 3 bay 138kV breaker and a half substation. The switchyard was designed as an interconnect point for the operation of a 1000MW wind park in Kendall County. 100% of the design for this station was by Dashiell, including site grading, structures, foundations, conduit, grounding, lightning protection, station lighting, control building layout and specification, electrical plans and section, installation details, protection and control single line drawings, schematics and wiring, communications/SCADA, relay control panels, relay coordination settings, and equipment specifications. Due to the critical nature of this project, Dashiell completed design and construction in 9 months, from notice to proceed.
