Reliability And Power Supply Capability Evaluation Of Active Distribution Networks With Multi-Terminal Soft Open Points

As a new power electronic device,multi-terminal soft open points(SOPs)can control and optimize the overall network power flow in a real-time and accurate fashion.Multi-terminal SOPs can overcome the limited service life of traditional tie switches and address the power outage after a fault,thus improving the network reliability and power supply capability(PSC).However,the current research on power supply capability of active distribution networks(ADNs)simplifies the reliability demand into rigid N-1 safety criterion and fails to analyze the relationship between PSC and reliability demand,thus underestimating the power supply potential of ADNs Therefore,with the widespread access of multi-terminal SOPs,DG and energy storage,it is of great practical significance to introduce the flexible reliability constraint into the evaluation of PSC,quantify the improvement effect of multi-terminal SOPs on the reliability and PSC of ADNs,realizing the integrated evaluation of reliability and PSC of ADNs with multi-terminal SOPs.To address the lack of quantitative measures on the benefits of multi-terminal SOPs,a PSC evaluation method for ADNs with multi-terminal SOPs considering reliability constraint is proposed in the expectation of fully tapping the power supply potential of ADNs.The specific solution is as follows:First,the topology of multi-terminal SOPs is investigated from a power electronic perspective,the networking and operation modes of ADNs with multi-terminal SOPs are established in complex feeder connection modes,and the control modes of multi-terminal SOPs in normal operation and fault are analyzed.Second,the influence of multi-terminal SOPs on the power outage duration of different feeder areas after a fault is studied based on the principle of feeder partition,the FMEA model and the post-fault load curtailment and transfer model for ADNs with multi-terminal SOPs are proposed.Then,the reliability evaluation method is developed based on the quasi-Monte Carlo simulation method,and the improvement effects of multi-terminal SOPs on network reliability are quantified.Third,the impact of multi-terminal SOPs on PSC is examined based on the continuous power flow regulation capability,and the PSC evaluation model for ADNs is established with the reliability demand as the main constraint.Next,the model is solved by the genetic algorithm,and the improvement effects of multi-terminal SOPs on PSC are quantitatively measured.Finally,the effectiveness and applicability of the proposed method are verified through a case study.The results of the study show that:(1)after replacing the traditional tie switches,multi-terminal SOPs will impact the power outage/supply status of different feeder areas after a fault,and increase the number of connected feeders which can provide transfer support,thus reducing the power outage duration of feeder areas,and enhancing the network reliability;(2)lowering the network reliability demand can significantly optimize the PSC.Besides,under the same reliability constraint,multi-terminal SOPs can effectively improve the PSC,thus fully developing the power supply potential of ADNs.