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34.5kV Electrical Reliability

Owner:

Webb Electric and Bath Engineering teamed to perform this design/build project at the Naval Station Great Lakes in Illinois. 

The Station receives power from two Commonwealth Edison 138kV transmission lines with two 20 MVA 138/34.5kV step-down transformers that supply two 34.5kV sub-transmission loop feeders.  The scope of work called for the improvement of reliability of the electric power system by adding automatic loop segment sectionalizing, communications assisted relay protection, and SCADA monitoring and control to all the existing loop segments and to a new loop segment. The design added vacuum circuit breakers at three substations so that each loop segment in the double sub-transmission loop has a 34.5kV breaker at each end. In its final configuration, the double 34.5kV sub-transmission loop will have eight step-down substations connected in a double loop configuration using nine 34.5kV line segments.  Bath also designed new single-mode fiber optic communications links between the substations for breaker status, and to control and assist schemes.

The project included:

  • Automatic loop segment sectionalizing of the 34.5KV sub-transmission loop
  • Communications assisted relay protection
  • SCADA monitoring and control to each of nine total loop segments
  • Addition of 34.5KV walk-in, protected aisle vacuum circuit breaker switchgear at three substations
  • Single-mode fiber optic communications links between all substations connected by the 34.5kv loop segments
  • Fiber optic communications links used by SEL 311L line-protection relays in communications assisted protection schemes.
  • Fiber optic communication links used by SEL 2030 communication processors, located at each 34.5kV substation, to communicate substation status and control, to and from the Master SCADA controller.
  • Relaying modifications are implemented at each of five existing 34.5kV substations by the addition of SEL 311L line protection relays, SEL 587 transformer differential relays, and SEL 587Z bus differential relays.
  • Upgrading of the existing SCADA communications system from spread spectrum radio to single-mode fiber optic cabling.
  • Installation of a 30" steel casing bore under a four lane state highway and parallel Union Pacific railroad tracks for 34.5kV and fiber optic circuits
  • Installation of a new 34.5kV underground loop segment between two existing substations
  • Rerouting and reconnection of several other 34.5kV loop segments to improve system reliability
  • Installation of new 34.5kV station circuit breakers at the incoming utility substation
  • Design coordination of the 34.5kV system for paralleling a new customer owned co-generation facility with the incoming utility lines.

Click here to see a letter of commendation for this project.