Research on distribution network optimal operation with a novel medium voltage photovoltaic power generation device with the soft open point function

Abstract

Soft open point (SOP) realizes the normal and flexible interconnection between distribution network feeders, leading to the improvement of the flexibility and rapidity of the distribution network control. However, drawbacks such as high cost and low utilization rate limit its application. A novel medium voltage photovoltaic power generation device with the SOP function is proposed in this paper. There are two grid-connected interfaces, and both of them adopt the cascaded H-bridge topology. A common DC-link is used for both H-bridge inverters belonging to the two grid-connected interfaces respectively. The proposed device eliminates the step-up transformers, and can be connected directly to the medium voltage distribution network. Therefore, advantages such as simple structure, low cost, low power loss and fault-tolerant operation capability are able to be obtained. The stability and flexibility of the distribution network operation are improved. The topology and power flow mode of the proposed medium voltage photovoltaic power generation device with the SOP function are analyzed, and the distribution network multi-objective optimal operation model with the proposed device is established. The proposed medium voltage photovoltaic power generation device with the SOP function is connected to the modified IEEE 33-node distribution network, and the network optimal operation with the device in terms of the power flow optimization and voltage improvement is analyzed.