Application Of Robust Optimization For Transmission Network Expansion Planning With Renewable Energy Resources Integrated

With the increasing integration of the new energy resources, the uncertainties in the electric power system will also increase. This will bring significant challenges to the security and stability of the electric power system. So the uncertainties must be considered in the power system operation and planning problem. This paper investigates the transmission network expansion planning(TNEP) considering uncertainties in loads and renewable energy resources. The main contents are as follows:Firstly, the TNEP problem is formulated in this paper. Based on the formulated model whose phase angle and branch flow are eliminated, the TNEP problem considering uncertainties in loads and new energy resources is formulated. In this TNEP, the ramping capabilities of the generators are considered. Eventually, a nonlinear stochastic optimization problem is formulated.Secondly, a method to solve the proposed nonlinear stochastic TNEP problem is proposed, using the decomposition techniques. The problem has been split into two subproblems, namely expansion planning and operation. Then the genetic algorithms and robust optimization algorithm are used to solve this problem. The method proposed in this article not only can obtain cost less results without losing the robustness, but also can optimize the average output level of conventional generators.Thirdly, based on the principle of Monte Carlo simulation, the robustness of the network-planning scheme is checked. By adjusting the robustness index, the optimal tradeoff between robustness requirements and line costs can be achieved.Finally, using the models and methods proposed in this paper, practical studies on the Gansu power grid under the "13th Five Year Plan" are conducted The transmission network planning scheme above 330 k V voltage level in Gansu province are optimized and analyzed. The results showed that Gansu provincial planning renewable energy installed capacity is large, which raises the average loading of the transmission lines. To ensure the consumption of renewable energy resources, we need to add more lines in an optimal way.