This study proposes an enhanced particle swarm optimization algorithm designed to overcome the limitations of the traditional particle swarm optimization (PSO) in reactive power optimization, including premature convergence and insufficient search capability. The proposed enhancements enhance global exploration by integrating a competition mechanism with adaptive inertial weights, while optimizing particle distribution through hierarchical congestion and perturbation strategies to improve accuracy. A multi-objective optimization model is established to simultaneously minimize network losses and operational costs. Benchmark function verification, IEEE 14-node case studies, and IEEE 30-node and IEEE 33-node studies have demonstrated the superior performance of the hierarchical mechanism multi-objective particle swarm optimization (LMMOPSO) algorithm: it reduces power losses, accelerates convergence compared to standard PSO, and optimizes voltage distribution and power flow to maintain them within reasonable unit ranges. The algorithm’s robustness in reactive power optimal dispatch confirms its practical applicability to power system optimization.
In recent years,the utilization of renewable energy and the proportion of distributed generation in power grid systems have been increased significantly,and the trend of power electronics in power systems is becoming more and more evident.The problem that arises is that when the grid voltage is unbalanced,the performance of grid-connected inverters decreases which shall be eliminated in the power grid,otherwise it can seriously affect the stability of the power system.Therefore,the control of grid-connected inverters under unbalanced grid conditions is particularly critical.The output power and current quality of the system under unbalanced grid voltage conditions are the main concerned data of grid-connected inverters.In this paper,a three-phase three-wire LCL-type grid-connected inverter is taken as an example,the issues of phase detection inaccuracies and power fluctuations are analyzed,and an improved phase-locked loop(PLL)and power-current cooperative control strategy is proposed.This method can refer to the reference current formula and coordination coefficients to achieve smooth switching among grid-connected current,active power,and reactive power.The feasibility and effectiveness of the proposed strategy are verified through Matlab/Simulink simulations and experiments on the RT-LAB platform.
With the continuous expansion of the application range of self-healing dry metallized film capacitor, its heat dissipation mode and internal temperature-rising have become important theoretical and engineering problems. In view of this, the paper is based on the heating rule of the cylindrical element of the DC-link capacitor. Furthermore, combined with the principle of electro-thermal duality, the thermal calculation model of the cylindrical element is established, and the thermal resistance calculation formula of a cylindrical element is obtained through the integration of the differential cells. Finally, the correctness of the thermal calculation model of cylindrical element is verified through the test, and the verification method of thermal calculation of cylindrical element is proposed, which will provide theoretical and experimental reference for the heating of cylindrical element of DC-link capacitor.
In view of the long period of the current offshore wind power project construction, a self-starting wind turbine grid-connected method is proposed, and a set of wind turbine grid-connected self-starting device is developed based on this method. Through this device, it is available to provide a stable power supply for the wind turbine through the submarine cable before the grid power on the land is delivered to the offshore substation. After the grid power is delivered, the wind turbines are directly connected to the grid, which greatly shortens the construction period of offshore wind power projects, creates considerable economic value. The technology had been applied in many offshore wind farms in Rudong, Jiangsu, and the field test data verified the advancement and effectiveness of the developed system and the proposed method.
研究±500 kV换流站TILP型交流滤波器电容器接线柱频繁发热原因,提出具体的预防解决措施.本文研究新型特殊线夹,为该型设备能够继续良好的运行提供了有力技术支持.通过对不同措施方案进行测试分析和数据研究,对比目前运行情况,得出TILP型交流滤波器电容器频繁发热是由于接线柱结构设计不合理供导流的接触面过小且接触面容易氧化引起,介绍了解决该问题的方案.
