To fully leverage the application potential of distributed energy storage systems (DESS) and network reconfiguration, a coordinated optimization method is proposed to enhance the economic efficiency of distribution networks under normal conditions and the reliability of a power supply during fault conditions. First, a scenario-generation method is developed based on Latin hypercube sampling and Kantorovich distance synchronous back-substitution reduction is used to obtain the typical scenario of wind and solar output. Next, a planning operation coordinated optimization framework and model are established, considering both normal and fault states of the distribution network. In the planning layer, the objective is to minimize the annual comprehensive capital expenditures for the distribution network to improve the economic efficiency of the distribution network. The operation layer includes both normal operation and fault operation states, with the optimization goal of minimizing the sum of normal operation costs and the fault costs associated with load shedding. Subsequently, a hybrid optimization algorithm combining an improved Aquila Optimizer-Second-Order Cone Programming (IAO-SOCP) is proposed to solve the coordinated optimization model. Finally, the proposed coordinated optimization method is validated using an enhanced IEEE 33-bus distribution network case study. The results demonstrate that the method effectively reduces network losses and minimizes load shedding costs during fault conditions, thereby ensuring a balance between the economic efficiency and reliability of the distribution network.

This paper presents an advanced dynamic voltage restorer with integrated energy optimal compensation (EOC-DVR), which combines the advantages of pre-sag compensation and energy minimization compensation. The performance parameters of the EOC-DVR, such as the compensatory capability, loss of energy, and duration of compensation, can be balanced by this optimal compensation strategy. Additionally, the impact on the load is further reduced by the proposed method. By analyzing the working process of optimal comprehensive energy, the compensation limit of the strategy is discussed. After that, both the voltage and active power of the system for compensating are obtained by analyzing the compensation characteristics of the strategy. Therefore, the relations of the formula and curve between the related physical quantities can be obtained. Finally, simulation results based on MATLAB/Simulink are provided to verify the effectiveness of proposed compensation method.

A triple-active bridge (TAB) can be used as a power conversion unit in a three-port DC energy router (DCER) such as a triple-active bridge-based DC energy router (TAB-DCER). The operational loss of a TAB can be seen as a key factor affecting the efficiency of a TAB-DCER. However, the RMS value of the inductor current of the TAB-DCER increases under single-phase shift (SPS) control, and this greatly increases the system operating losses. The use of phase-shifted plus PWM (PS-PWM) control can reduce the RMS value of the inductor current, but its mathematical model is complex, and involves difficult calculations. To address this problem, in the study reported here, we developed an optimal control strategy for the RMS value of the inductor current based on TAB-DCER. First, the working principle of a TAB-DCER under PS-PWM control was analyzed, and a circuit decomposition model was established. Second, the operating modes under PS-PWM control were analyzed, and corresponding expressions of port power and the RMS value of the inductor current were obtained. Third, an optimized mathematical model of the sum of squares of the RMS value of the inductor current of the TAB-DCER was constructed. Finally, a genetic algorithm was used to solve the mathematical model and derive the optimal phase shift angle; this resulted in a lower RMS value of the inductor current in the TAB-DCER and reduced the system operating losses. The simulation and experimental results show that the TAB-DCER used in the present study can reduce operating losses, improve system efficiency, and deliver coordinated power control.

Coordinated operation among various converters within a power router (PR) is crucial for ensuring its normal operation. Since the power balance among converters in a DC PR is reflected by the DC bus voltage level, maintaining stable DC bus voltage control is particularly important as it directly affects the coordinated operation of each converter. This study proposes a coordinated control strategy for multi-port power routers based on DC bus voltage droop regulation, addressing the limitations of existing methods that rely on communication and complex control units. Based on DC bus voltage signals, all power ports automatically switch their operating states, ensuring that only one converter operates in voltage source mode at any given time, thereby maintaining the system’s bus voltage and power balance. This enables effective coordination among converters and ensures stable system operation without requiring communication between converters, simplifying control while maintaining internal system stability.

This paper proposes an optimization strategy for Feeder Terminal Unit (FTU) configuration in distribution networks, accounting for the influence of Distributed Generation (DG). Firstly, the impact of different FTU configurations on load interruption duration was analyzed. Regions were divided based on the planned installation locations of FTUs, and a model for calculating load interruption losses in different regions was established. Secondly, an all-probability model was introduced to calculate the probability of DG disconnection during faults. The importance weight of DG was determined based on its capacity, and a loss model for photovoltaic disconnection was constructed accordingly. Then, an optimization configuration model was established with the objective of minimizing the weighted sum of FTU installation costs, load interruption losses, and DG disconnection losses, while constraining the solution by supply reliability. Finally, the accuracy of the proposed optimization model was validated using Particle Swarm Optimization (PSO) through the IEEE 33-node distribution network model.

A fault protection method is proposed for flexible direct-current (DC) power systems based on the cosine similarity of currents in current-limiting reactors. The typical characteristics of external and internal faults in a flexible DC power system were analyzed. The principles of cosine similarity and the fault current characteristics of current-limiting reactors were used to distinguish between internal and external faults. The ratio of the average positive and negative voltages of the current-limiting reactor was then used to distinguish the fault types and fault line. Finally, a simulation model of a circular flexible DC power system was constructed using MATLAB/Simulink software (2018b). The simulation results show that the proposed protection scheme can quickly and accurately identify the location and type of faults, and has a strong ability to withstand fault resistance and is less affected by distributed capacitance, noise, and communication delay.