Optimization of Adaptive Current Protection Setting for Distribution Network Considering the Interconnection of PV

The interconnection of photovoltaic (PV) energy to the distribution network has changed the structure of the network and the direction of power flow, making the existing current protection problematic. As the most widely used protection method in the distribution network, the current protection needs to be reset for its existing problems. Firstly, this paper analyzes the controlling strategy of PV under normal operation and fault conditions. The equivalent output expression of PV source under the fault low voltage ride through control strategy is introduced. Secondly, the influence of PV energy on current protection is analyzed. The existing problems of current protection when PV energy is widely connected to the distribution network are analyzed. A setting optimization method based on real-time iterative calculation is proposed. The setting value of the protection scheme is matched with the real time voltage value. An example is given to verify the improvement of protection sensitivity by the proposed method, The error between calculation and simulation results is within 0.1kv, Simulation results show the effectiveness of the proposed scheme.