2034 Reference Case Network Reduction Michael Bailey WECC Staff Western Electricity Coordinating Council

Western Electricity Coordinating Council Power Flow History Numerical methods in power flow analysis has dramatically evolved in parallel with advances in computer and computing technologies. Computational burden of solving power flow and optimal power flow equations for large networks still a challenge. Numerical power flow approximation techniques have been developed and used to overcome this computational burden since 1962 when the first optimal power flow formulation was derived by J. Carpentier. Western Electricity Coordinating Council

Power Flow Approximation Techniques Some power flow approximation techniques that are widely used today include: Fast De-coupled Power Flow Linear Approximations Mixed Integer Programming Sparse Matrix Methods Network Reductions Western Electricity Coordinating Council

Full Network Power Flow Equation Fast de-coupled approach to solving the power flow. Basis for DC power flow analysis. Basis for Linear Optimal Power Flows. Power Flow Equations Power Flow Jacobian Zero Approximations Power Flow Decoupling Active Reactive Western Electricity Coordinating Council

Western Electricity Coordinating Council DC Power Flow DC approximation derived from Active Power Sub-problem of the Fast Decoupled Power Flow Approximation. Western Electricity Coordinating Council

Starting with PSA Model Sub-regional focus. Alignment with WECC PSA. Alignment with WECC Paths. Western Electricity Coordinating Council

Starting with PSA Model Continuity with WECC PSA with Regard to Hub Aggregation and Transmission Paths. Continuity with Common Case with regard to Generating resources. Continuity with Power Flow as a reduced nodal network model. Western Electricity Coordinating Council

Western Electricity Coordinating Council Sub-regional Focus Western Electricity Coordinating Council

Transmission Equivalent Links Ɵj ßij Western Electricity Coordinating Council

Western Electricity Coordinating Council Path Focus Western Electricity Coordinating Council

Western Electricity Coordinating Council The Network Reduction Boundary flows match to within 1% of full network model. Focus on paths not corridor siting. Corridor proxies associated with paths. Better traceability to Common Case and the LCRA cases. Western Electricity Coordinating Council

Western Electricity Coordinating Council Accessibility of LTPT Right size the LTPT Modeling focus. Move the Transmission Corridor Optimization into the WECC “Environmental and Cultural Data Viewer” Make the LTPT accessible to stakeholders for their use. Staff (initial) maintains default functionality and modeling data. Western Electricity Coordinating Council

Proposed GIS Data Viewer Enhancements Proposed changes to the “Environmental and Cultural Data Viewer” are: Phase 1 – Provide capability to upload GIS corridors. Phase 2 – Implement a persistent corridor library. Phase 3 – Provide corridor optimization. Western Electricity Coordinating Council

Western Electricity Coordinating Council Top Priority Complete 2034 Long Term Studies. Position for LTPT evolution without distracting from the study program work. Western Electricity Coordinating Council

Western Electricity Coordinating Council Questions? Michael Bailey, P.E. Senior Staff Engineer mbailey@wecc.biz Western Electricity Coordinating Council