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New Substation, Pole Line and Substation Addition in Western Pennsylvania
Project Scope:
Project required an electrical system to interface between the customer's existing 13.8kV system and the utility's 138kV transmission system. Three principal tasks were undertaken:
- 250 MVA substation was designed and constructed near the generation site
- 138 kV pole line was designed and constructed
- 138 kV substation addition involving a power circuit breaker and appropriate relaying was designed and installed in an existing utility substation.
The electrical system serves an existing 154 MW coal fired generation facility which previously provided the customer with all the power required for its smelting operation.
Design Factors:
Continuity of service and system integrity were paramount when the opportunity of lost revenue was factored into the equation. A redundant system with backup transformer capabilities was a significant design decision keeping in mind the cost associated with power equipment of this classification. Secondly, it became obvious that the point of interface was going to take place physically within the confines of an existing utility substation. This required extreme confidence in our engineering capabilities and construction techniques. |
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Key Issues :
The customer's power contracts required the project be completed and on line within a short time, based on the revenue generating capabilities of the existing coal fired plant. The utility required assurances for continuity of service and system integrity. The facility also required a minimum of supervision and maintenance with staffing of the station accomplished by the generating plant personnel.
Engineering & Construction Solutions:
A two-transformer design was selected on the basis of each transformer being dedicated to one 76.8 MW generator but having fan ratings capable of handling the total generation of the facility. Costs were minimized by utilizing remanufactured equipment and implementing a transfer trip scheme between the GSU substation and the utility substation. Substation status and power flow information were integrated into the existing generating facility control and supervisory equipment located in the generation plant control room.
Success:
The project was completed in 32 weeks from initial design to start-up at cost savings, which allowed the facility to pay for itself within a six-month period.
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