Search Results

Client Challenge In an initiative to improve area reliability on the local distribution system, our client commissioned this substation upgrade project to support a new 34kV distribution feeder out of an existing 115kV switching station. This new feeder allowed an existing distribution circuit to be sectionalized, thus reducing the overall circuit length. Tie capability was also added for additional reliability and maintenance flexibility.   Before this project, this substation consisted of a 115kV three (3) breaker ring bus, initially constructed in 2014 to support utility interconnection of wind generation. It abuts a customer-owned collector substation. To establish the new 34kV distribution circuit, a new 115/34kV power transformer, and a 34kV distribution bay structure were installed.    A new 115kV circuit breaker was installed within the existing ring bus to support the additional node, along with a new 34kV circuit breaker in the distribution bay structure to protect the outgoing circuit.  New disconnect switches, CCVTs, other ancillary equipment, and supporting structures and foundations were also added to support this project.    The new 34kV circuit exits the station underground and is routed to a new manhole outside the fence. It then continues to a riser pole, which connects to the aerial distribution system. Supporting protection and control upgrades were also required for this project, including three (3) new relay cabinets and modifications to multiple existing relay cabinets How We Helped SGC provided the Owner’s Engineering and Engineering Coordinator services for this project, which included reviewing all aspects of the detailed engineering design for accuracy, suitability, and conformance to the client’s standards.  SGC also assisted the client with internal coordination items such as outage sequencing & development, project scheduling & resource planning, document management, procurement support, and relay database updates; SGC also prepared the remote end relay settings required for this project and provided site support during construction.  SGC also supplied high-voltage testing and commissioning services for the project.  Powerful Results SGC supported all technical aspects of the project and provided several value-added services that contributed to the project’s successful completion.  Due to SGC’s familiarity with the client, several aspects of the project could be executed with limited burden on internal client resources.  The project team faced many challenges during the project's construction phase that required close collaboration with multiple project stakeholders and prompt resolution.  Some obstacles included significant equipment issues and, most notably, construction during the COVID-19 pandemic. Our successful collaboration with all project stakeholders was critical in overcoming these challenges.   Read more of our case studies here .

Client Challenge Our client is a leading renewable energy company that designs, develops, manages, and operates power plants. Our client required additional infrastructure to deliver renewable power to the utility grid. For this interconnection, a collector system, collector substation, and transmission line needed to be designed and constructed. How We Helped SGC completed the collector system, collector substation, transmission line designs, and the local utility interconnection substation design and construction at two significant substations. Additional changes were required at another collector substation to facilitate the metering of a new wind farm and proper communication over the three-terminal line.   The collection system consists of five 34.5 kV feeder circuits connecting seven 3.6 MW and twenty-four 4.2 MW Vestas turbines to the collector substations. Two feeder circuits contributed 50.4 MW to one of the existing collector substations, and three circuits contributed the remaining 75.6 MW to a new collector substation.   The new 138/34.5 kV collector substation connects the new collector system to the transmission line. Major high-voltage equipment in the substation includes arresters, current transformers, potential transformers, a circuit breaker, a motor-operated disconnect switch, and a 138/34.5 kV, 55/73/92 MVA transformer.    Major equipment on the low-voltage side includes arresters, potential transformers, disconnect switches, circuit breakers, a station service transformer, and two 12 MVAR capacitor banks with 4.55 ohm outrush reactors. A control shelter design was provided to house the AC/DC systems and protection and control equipment. A 2.9-mile, 138 kV transmission line connects the collector substation to the existing generator lead line as a three-terminal line.   SGC was responsible for the collection system, transmission line, and substation civil, electrical, protection, and control designs. These included a 30% conceptual design, a 75% design for construction contractor bidding, an issue for construction design, and a final record drawing submittal. SGC completed all required studies, including reactive compensation, short circuit analysis, neutral ground reactor sizing, and underground cable sizing. SGC completed equipment specifications and FERC Form 8 documentation and provided construction support.  Powerful Results SGC completed the project on time and under budget, with no significant issues with the final design.  The client was highly satisfied with the final product, which is a testament to the quality of our work, and has continued to engage SGC for subsequent renewable projects. As part of this project, SGC introduced a new “Super Breaker” structure/bus design that simplifies bringing two collection circuits into one breaker. The client was impressed with the design and has since implemented it in multiple subsequent projects.   Read more of our case studies here .

Client Challenge Our client required additional infrastructure to deliver renewable power to the utility grid. For this interconnection, a collector system, collector interconnection substation, transmission line and upgrades to the interconnecting utility substation needed to be designed and constructed. How We Helped Our team were required to complete the collector system, collector interconnection substation, transmission line and the local utility substation upgrade designs. The collector interconnection substation was a greenfield design; however, it was built directly adjacent to the existing 345kV utility substation. This required our team to design a shared fence and new 345kV bus connection over the shared fence to the existing substation to facilitate the interconnection. Major equipment in the interconnecting substation on the 345kV side includes arresters, coupling capacitor voltage transformers, circuit breaker and motor operated disconnect switches along with a 345/115kV, 180/240/300MVA transformer. Major equipment on the 115kV side includes arresters, potential transformers, disconnect switches, circuit breakers, circuit switchers, station service transformer and two 25MVAR capacitor banks each with 75 micro-henry reactors. A control shelter design was provided to house the AC/DC systems as well as the protection and control equipment. A 59-mile, 115kV transmission line connects the collector substation to the collector interconnection substation. The collection system consisted of four 34.5kV feeder circuits connecting forty-eight 3.075MW Vestas V112 turbines to the collector substation. A 115/34.5kV collector substation connects the collector system to the transmission line. The SGC Engineering team were responsible for the collection system and transmission line designs as well as substation civil, electrical, protection and control design. These included a 30% conceptual design, a 75% design for review, an issue for construction design and a final record drawing submittal. SGC completed all required studies, protection settings, equipment specifications and provided construction support. Powerful Results The project was completed on time, on budget and there were no notable issues with the final design. The client was pleased with the final product and has continued to utilize SGC Engineering on subsequent renewable projects. Read more of our case studies here .