Southwest Rhode Island Transmission Supply Study Long Term Needs and Solutions

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Southwest Rhode Island Transmission Supply
StudyLong Term Needs and Solutions
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Southwest RI Transmission Supply Study

• Study initiated in 2001 due to recognition of
  voltage and thermal concerns.
• Identified Short-term and Long-term upgrades to
  ensure reliability of service.
• SWRI area supplied primarily by 115 kV lines
  looped between Kent County in RI and Montville in
  CT.

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Geographic Location of Southwest RI

• New England Power Company
• Map redacted due to Critical Energy
  Infrastructure Information
• Available upon request

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Southwest RI Area Reliability Concerns

• Voltage Concerns Loss of G-185S
• Voltages drop to unacceptable values of less than
  0.9 p.u. and potential collapse
• Thermal Concerns Loss of 1280
• G-185S overloads over STE rating for loss of 1280.

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Existing Concerns

• New England Power Company
• Map redacted due to Critical Energy
  Infrastructure Information
• Available upon request

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Short-term Upgrades

• Short Term upgrades addressed immediate voltage
  concerns
• 7 distribution station capacitors
• total of 38.7 MVars
• In service for Summer 2003
• Other Actions
• Planned G-185S Uprate for Summer 2005

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Recommended Solution

• New England Power Company
• Map redacted due to Critical Energy
  Infrastructure Information
• Available upon request

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West Kingston Substation
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Recommended Solution

• Extend L-190 from Davisville Tap to West Kingston
  substation (2007)
• Total of 12.3 miles - 795 ACSR
• Install load break switch at Davisville Tap
• Total 6.0M
• Connect L-190 at West Kingston substation (2007)
• Install new 115 kV bus structure
• Install 2nd Breaker and two disconnect switches
• Reterminate T2 transformer to L-190 for better
  load management
• Replace existing breaker and disconnect switches
  at West Kingston substation
• Install motor operated air break switch on L-190
  within substation fence.
• Replace air break switch on G-185S with a motor
  operated air break switch within substation fence
• Total 2.6M

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Recommended Solution (contd)

• Reconductor L-190 from Kent County to Davisville
  Tap (2007)
• 2 miles of 795 AAC on single circuit towers
  reconductored to 1590 ACSR (2007)
• 3.26 miles of 795 ACSR on DCT reconductored to
  1113 ACSR (2007)
• Total 1.9M
• Future Upgrade Reconductor G-185S from Kent
  County to Davisville Tap by 2012
• 2 miles of 795 ACSR on single circuit towers
  reconductored to 1590 ACSR
• 3.26 miles on DCT reconductored to 1113 ACSR
• Total 2.0M
• Total 14.6M
• TCA Application 10.5M
• Short Term Completed Non-PTF 2.1M
• Future Work 2.0M

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Other Alternatives Studied

• Alternative 2 115 kV Capacitors (6x10 MVAr)
• Reconductor G-185S from Davisville Tap to West
  Kingston to 795 ACSR (2006)
• Reconductor G-185S from Kent County to Davisville
  Tap with 1113 ACSR and 1590 ACSR (2008)
• Additional Reinforcement Reqd by 2016
• Estimated Total 15.7M
• Alternative 3 FACTS Devices (60 MVAr)
• Reconductor G-185S from Davisville Tap to West
  Kingston to 795 ACSR (2006)
• Reconductor G-185S from Kent County to Davisville
  Tap with 1113 ACSR and 1590 ACSR (2008)
• Additional Reinforcement Reqd by 2016
• Total 19.9M

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Other Alternatives Studied (contd)

• Alternative 4 345 kV line Kent County to
  Montville
• Total 108.1M

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Assessment of Alternatives

• Recommended L190 Alternative
• Technically Superior to Alternatives 2 and 3
• Economically preferred least cost
• Future Expansion in-line with long term plans
  to continue 2nd 115 kV tie into Connecticut.
• Potential operational impacts during construction
  less impact than Alternatives 2 and 3.
• West Kingston substation will contain new
  standard equipment for additional breaker and
  replacement of existing breaker and switches.
• Alternatives 2 and 3
• Switching voltage variations are an issue on weak
  system
• Alternative 4
• Cost excessive for local needs
• Longer construction time

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Upcoming Applications

• New England Power Company
• Map redacted due to Critical Energy
  Infrastructure Information
• Available upon request