随着分布式光伏并网的比例逐年高升,分布式光伏出力和负荷的不确定性给配电网的稳定运行带来的影响日益显著.文中考虑光伏-负荷的不确定性,提出配电网中光伏接入优化方法,通过构建光伏发电及负荷随机模型,以节点电压方差作为评估指标对光伏出力、负荷进行不确定性评估,同时采用灵敏度分析法分析光伏、负荷随机模型中不同参数对配电网各节点电压的影响,通过评估结果分析可找出配电网中适合接入光伏的节点.采用遗传算法以线损最小为目标函数对节点可接入容量进行评估,找出节点在约束条件下可新增容量的最优值.最后通过IEEE33节点对所提方法进行算例分析,验证该方法的可行性和有效性.

2019年初,国网公司印发《关于服务乡村振兴战略大力推动乡村电气化的意见》,要求围绕国家乡村振兴战略规划的重大工程、重大计划、重大行动,利用2019年至2022年四年时间,全面实施乡村电气化提升工程.如何通过改造升级农村电网、提高农村供电服务水平、推广电能替代技术、推动特色用能项目建设、推介新型用电产品等手段,增强农村用电保障能力,提升农业生产、乡村产业、农村生活电气化水平,是江西农村配电网精细化管理的重点、难点问题.国网江西经研院通过多年的配电网规划管理经验,在规划业务中对规划数据、模型和工具进行统一规范,基于"村级规划"对农村配电网规划进行精细化管理.

The power consumption readings of sub meter and total meter of distribution transformer of low-voltage users follow the law of conservation of energy. The meter power loss rate of abnormal low-voltage users must also be abnormal. This paper studies the solution of the meter power loss rate under the four abnormal power consumption scenarios of single (multi) user and full (partial) period. The traditional linear solution method has accurate identification effect for the abnormal power consumption scenario of full period, but it cannot identify the abnormal power consumption scenario of partial period. In this paper, an improved artificial fish swarm algorithm is proposed. By adjusting the fixed step to the adaptive step, the power loss rate of each sub meter is obtained, and the abnormal power users are pinpointed. The research results are verified by simulation examples on IEEE European Low Voltage Test Feeder. The results show that the improved artificial fish swarm algorithm in this paper can identify abnormal power users for the above four abnormal electric field scenarios. The algorithm provides a new alternative for the identification of abnormal low voltage users.

Aiming at the time-consuming and labor-consuming problem of manually checking the 10kV feeders and transformers relationship in distribution network, this paper proposes a checking method of feeder-transformers relationship based on the characteristic representation of the voltage time series. Firstly, the voltage data is cleaned and preprocessed to obtain the compliant voltage data set and calculation three-phase voltage of ABC into a single-phase voltage. Then, for each transformer, the voltage time data are divided into several sub series of the same length. Each time point of the voltage time subseries is extended to feature vectors containing global and local characteristics. Then calculate the characteristic covariance matrix of the voltage sub series eigenvector matrix, and measure the distance of the characteristic covariance matrix between the two distribution variables, and form the distance matrix of the distribution variables. A class with few clusters is obtained by hierarchical clustering method, and it is judged as wrong distribution of line variable relationship. Experiment shows that the method can be used to verify the correctness of feeder-transformer relationship and has the value of wide application.

用户与电网的互动技术是配电网安全、高效运行的重要内容.首先,提出了采用多功能串联补偿器MFSC(multifunctional series compensator)的感应电机优化控制方法,通过灵活控制MFSC中的串联型电压源变流器,使其能够分别运行在电压补偿模式、自适应柔性软启动模式.在电网电压跌落期间,通过在故障相注入补偿电压快速恢复电机定子并网点电压,保证电机稳定运行;在感应电机启动期间,基于动态分压原理,通过注入变化的虚拟阻抗实现对机端电压的柔性调节,保证电机柔性启动冲击电流和谐波扰动均较小,启动过程平滑.然后提出了MFSC系统的优化控制策略及参数设计方法,仿真和实验结果验证了MFSC系统在感应电机中应用中的有效性和正确性.

The development of smart grid technology has improved the way in which grid companies interact with power users, but there are data breaches when data falls into the hands of malicious attackers. This paper implements a multi-blockchain system based on sovereign blockchain technology for the main body of the power trading market, and designs the data transmission mechanism and system architecture. Through the power data classification index, the effective mining and utilization of intelligent power data is realized. Incorporating national sovereignty constraints into smart contracts ensures that smart grids provide a system of trusted, nationally compliant systems for power users’ electricity transactions. Finally, the advantages of the power data management scheme proposed in this paper are analysed by comparing with the traditional power data management methods.

This paper proposes a wireless charging system powered by DC power module which is currently mature and applied to electric vehicle wired charging. The topological connection diagram between the power module and the main control unit is designed, and the main control unit based on AMR and FPGA is further developed. The CAN communication protocol between the main control unit and the DC power module is analyzed, and the communication protocol between the battery measurement unit and the main control unit is designed. Aiming at the need of three-stage charging of batteries, the charging control flow is analyzed, then the judgment of charging stage and the PID control of charging process are proposed. The prototype system of the laboratory is developed, and the usability and superiority of the wireless charging system based on adjustable DC power module are verified by charging experiments on a group of 1.2 kW power batteries.

Aiming at the possible metal foreign matter mixing and transmission coil offset in the resonant magnetic coupling wireless charging system, this paper establishes a system numerical model based on the two-port network theory to obtain key characteristic parameters, and studies the presence of ferromagnetic and non-ferromagnetic metal foreign bodies between the two coils. At the same time and the influence of the position of the transmission coil on the system, a dual-purpose non-overlapping coil group applied to the surface of the transmitting coil is proposed, which can simultaneously detect metal foreign object detection and transmission coil offset, and conduct feasibility analysis in principle. The finite element simulation software is used to establish the magnetic field simulation model of the two-coil wireless energy transfer system. The influence of metal foreign matter and the positional deviation of the receiving coil on the system magnetic field is analyzed. The induced voltage of the detection coil is obtained through the simulation circuit, and the prototype of the detection device is built. Experimental verification. The feasibility of the metal coil and the transmission coil offset detection is verified by simulation analysis and prototype experiment.

The implementation researches of high power electric vehicle wireless charging (kW) are summarized, and three methods to achieving high power: multiple inverters in parallel wireless power transfer (WPT) system, heterogeneous parallel WPT system and multi-matching transformer parallel WPT system. By comparing the three system's power expansibility, circulation inhibition effect, achievable power level, and the complexity of control system, the applicable scope of the three systems are given. And transfer efficiency and the maximum voltage of reactive power devices along with the change of load resistance among different topology compensation are compared.

This paper proposes a detailed analysis of the incomplete coupling effect in omnidirectional wireless power transfer systems and a compensation method aiming to improve the transmission performance. Recently, omnidirectional wireless charging technologies have been gradually explored and studied. These charging technologies can transmit power to arbitrary directions in three-dimensional space. However, there are still specific regions where the transmitted power capability dramatically drops to an extremely low level due to the incomplete coupling effect. Accordingly, this paper provides a theoretical analysis and compensation of such an effect. The compensation effectiveness is validated by both a simulation and a 7 W experimental prototype. After the compensation, the transmitted power can be improved by 61% to drive the load in a full range of the space.

Induction Power Transfer (IPT) is one of wireless power transfer technologies, which can be applied for a drone's flexible wireless charging in power line inspection applications. However, IPT technology requires precise alignment between transmitting coil and receiving coil to ensure the transmitted power. In order to overcome the transmission power shortage caused by drones landing errors, this paper proposes an optimal design of asymmetric coupling system for drones wireless charging. By comparing the coupling performance and the charging performance, an optimal design is obtained. The optimal design has the better coupling performance and misalignment tolerance, with the received power and transmission efficiency characteristics less affected by landing errors. Finally, the optimal design is verified by simulation that realize a drone 22.2 V battery's wireless charging with a constant current of 12 A.

The zero voltage switching (ZVS) condition should be maintained in the inductive power transfer (IPT) system supplied by inverter. It can be obtained when current lags the voltage of the inverter. In this paper, a modeling and control strategy is presented to maintain the ZVS condition of the IPT system. The equivalent impedance angle of the system can be regulated through adjusting the operation frequency. An equivalent circuit model of the IPT system supplied by a half-bridge inverter is firstly developed for analysis. Then the model is linearized around the operation point using small-signal method and is reduced with balance realization method. Based on this low-order model, the transfer function of this model is obtained and a PI controller is presented in discrete-time domain to stabilize the impedance angle. Finally, the simulation results verify the correctness of modeling and the effectiveness of the proposed controller.

In this paper, an optimal design of magnetic resonance wireless charging coil for unmanned aerial vehicles (UAVs) is proposed to optimally design the structure of charging coupled transmitting coils and vehicle-carrying receiving coils for UAVs(1). A parallel matrix double-layer coil superposition structure is adopted through transmitting coils and the size parameters of vehicle-carrying receiving coils are optimized to match the transmitting coil array, thereby ensuring a relatively high coupling coefficient between the receiving coils and transmitting platform when UAVs are located in any area of the charging platform, so as to improve the transmission efficiency of the UAV wireless charging system. The experiment results show that the transmission efficiency of the optimized designed coupled coil system can be kept stable with the horizontal movement of the receiving coils and transmitting coils.

The flexible connections are frequently applied to connect motor drive and loads devices in industrial control systems,which leads to vibration at the load side.To achieve high-dynamic and high-precise servo control,vibration suppression in two-mass systems is an very important issue to be solved.In this paper,a strategy to suppress vibration based on torque and speed compensation and disturbance torque observer under position closed-loop was presented.Firstly illustrated the problem formulation,then analyzed the different bodes of the system transfer functions under classical PI controller and proposed method which explained the principle of vibration suppression at the same time.Additionally,detected the vibration frequency by FFT and gave some specifications about the design of control parameters based on CDM.Simulation under simulink environment and physical experiments were conducted to test the proposed method.The results illustrate that the method can suppress speed and position vibration successfully.