Available Delivery Capability of General Distribution Networks With Renewables: Formulations and Solutions

The widespread use of distributed generators (DGs) in utility distribution feeders brings about several challenges to the operation, planning, and design of general distribution networks. In this paper, the task of accurate determination of available delivery capability (ADC) subject to thermal limits, voltage limits, and voltage stability limit is formulated. A rigorous numerical method to calculate the ADC of large-scale distribution networks with renewables is presented. This numerical method computes three critical points which are the saddle-node bifurcation point or structure-induced bifurcation point, voltage violation point, and thermal-limit violation point. To gain the speed and robustness for the proposed method, the continuation method is integrated into the proposed numerical method. For illustrative purposes, the proposed method is applied to the IEEE 14-bus test feeder and the IEEE 8500-node test system.