The Path Operations issues we are experiencing are due in part to the fact that path limits are considered SOLs. The current paradigm marries operating limits and Transfer Capability into a single parameter for WECC paths – the historical OTC. This approach reveals i nconsistencies and conflicts with real-time information and tools. What does it mean to operate a path in the operations horizon? Why do we require WECC Paths to have SOLs? Are there better ways to determine that we have acceptable system performance? History of Path Operations
Current paradigm reveals conflicts between Path SOLs and real-time information and tools: Path XYZ – thermally limited to 650 MW in the E>W direction. 650 MW is the Path SOL. Loss of line A results in line B reaching its emergency Facility Rating at path transfer levels of 650 MW E>W. When path flows exceed 650 MW TOPs mitigate – up to and including shedding load (for TOP-007-WECC-1 paths) When the Path SOL is being exceeded, what if real-time information or RTCA isnt showing that the loss of line A results in line B exceeding its emergency Facility Rating? Is an SOL really being exceeded? NO Inverse is also true – what if the Path SOL is not being exceeded, but the underlying condition driving the establishment of the Path SOL is being violated? YES Issues With Current Paradigm
WECC and the POTF are considering the following: What if a thermally limited Path SOL were not an SOL at all, rather the facility ratings of the impacted facilities were the SOL? What if the Path had a Transfer Capability instead of an SOL? What if the Path Transfer Capability was observed for scheduling purposes but not treated as an operational parameter? Should we be using real-time information and tools such as real-time contingency analysis to determine acceptable pre- and post- Contingency system performance? If a Path does not have an SOL, does a Path really need to be operated? Challenging Questions Brett
Findings Path Operator is in practice responsible for outage reporting to assure correct topology and Path SOLs to the WECC RC per the IRO-10 RC Data Request.
Findings Capital D Directives issued to Path Operator(s) for Path SOL exceedences. Coordinated procedures that have been agreed upon may result in other TOPs receiving Directives.
Issues Identified For Some Paths Path Operator does not have specific authority to direct the TOPs unless contracts provide that authority. Path Operators, have indicated that the counterparties have no incentive to enter into contracts assigning responsibility for path Exceedance. There is no single entity under the NERC Functional Model identified for path management. Path Operators have little Authority for the Path but in some cases have been held responsible for the Path SOL violation.
NERC Functional Model No true definition of Path Operator in Reliability requirements, responsible entities listed are RC, TOP, TO, BA, GO, GOP, LSE………….. No mention of Path Operator