The operation of distribution networks differs from the transmission networks due to the radial connection. For this reason, planning of such systems is required to consider different point of views not only for normal operation but also contingency operations. Among the others, N-1 contingency is one of the most important contingency case, which is taken into account in planning problems, either within the problem or as a post-analysis. In the case of renewable generation integration, tractability of this problem can drastically decrease due to the consideration of load flow equations for every single contingency case. In this study, a probabilistic distribution network planning is proposed considering the effects of critical N-1 contingency cases within the optimization framework. By this way, it is aimed to minimize investment and electricity costs along with satisfying chance constraints and minimizing adverse effects of critical contingencies on feeder currents. The advantage of the proposed methodology is to not include the power flow equations for each contingency case separately; instead probability distribution functions of feeder currents are evaluated for N-1 cases using the Monte Carlo Simulation results for normal operating condition. The proposed methodology is applied to the 34-nodes test systems through case studies. The results show that the optimal investment solution is obtained different when the critical N-1 contingencies are dealt with in distribution network planning. On the other hand, it yields higher objective function value while increasing the reliability of the system.

Anahtar Kelimeler: Distribution network planning, Contingency, Renewable generation, Monte Carlo simulation