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Center for Nonlinear Studies |
The Transmission System Operators (TSOs) plan investments into their transmission grids based on the projected future system loads, among other factors. Many reasons for construction of new equipment exists, but usually motivation is the following - be prepared for future loading conditions which means be feasible in terms of regime existence, minimize operational cost and does not have any overloads. Also, one considers lifetime of currently installed devices and does security analysis. The problem is that such investments are usually performed to resolve local particular problems and not take into account how other equipment will be used together with just installed. New operational aware planning methodology was developed in order to take future power system operations into account during the planning phase. It was demonstrated that such approach allows to reduce investment costs and also obtain cheaper operational costs by considering build capacities of new equipment as additional degrees of freedom together with already available. First, we apply developed approach for placement and sizing of Flexible Alternating Current Transmission System (FACTS) devices, thus allowing delaying or avoiding much more expensive transmission expansion. These devices are capable of utilizing the existing transmission grid more flexibly. However, the locations and sizing of future FACTS devices must be carefully determined during the planning phase. Planning methodology allows to maintain feasible power system operations under multiple future representative scenarios of the projected economic growth (of loads) and minimize sum of investment cost and expected value of operational cost for a given planning horizon. Approach also considers setting all available adjustable equipment additionally to installed FACTS thus using all benefits of extra degrees of freedom. Optimization problem is stated using the most general AC Power Flows modeling for determining suitable locations and sizes of series and shunt FACTS devices. Non-linear, non-convex and multiple-scenario optimization is resolved via efficient heuristics, consisting of a sequence of Quadratic Programming and ACPF solutions in order to maintain feasible (for initial exact problem) scenario states during iterations. Optimality, scalability and benefits of the approach in comparison with more traditional planning is illustrated on IEEE 30-bus and 2736-bus Polish systems. Now, we develop a methodology which considers multi-frame investments (not single but multiple decision points in the future). This could be applied to planning of construction of new generators taking into account lifetime of them or planned retirement of old ones. Also this allows to take into account the fact that uncertainty of future predictions grows with time. Future price changes can be modeled as well. Extensions including accounting for LMPs, chance-constraint investments (taking into account uncertainty or fluctuations) and investor planning will be discussed.
Host: Michael Chertkov