基于模块化多电平变换器(modular multilevel converter,MMC)的统一电能质量调节器(unified power quality conditioner,UPQC)可用于高电压下电压电流的电能质量综合治理,但当电网电压不平衡时,电流电压相位和幅值发生变化,给综合治理带来困难.将无源控制方法应用到MMC-UPQC中,以解决电网电压不平衡下的电能质量问题.首先,根据MMC-UPQC的拓扑结构,建立其在不平衡电网下的数学模型;然后,根据正负序分离方法,对检测量进行无需锁相环的分离;接着基于无源控制理论,搭建基于E-L模型的无源控制器,并将其应用到多电平、高电压的电能质量补偿系统中;最后,利用串联侧补偿电压和并联侧补偿电流的原理,通过协调控制综合解决不平衡状态下的电网电能质量问题.Matlab/Simulink平台实验结果发现基于所提无源控制器的MMC-UPQC系统响应时间小于0.05 s且总谐波失真度小于5％,验证了其解决电能质量综合治理问题的有效性和优越性.

针对传统的扰动检测法无法区分正常扰动状态与弱故障扰动状态的问题,提出了一种基于dq变换和小波包变换的微网故障检测方法,该方法使用每条母线上d、q轴故障电流的平方和作为解析电流,并利用小波包对其进行分解,进而利用各层小波包系数来构建故障检测判据.仿真试验结果表明,该方法能够有效区分正常运行状态、正常扰动状态和强、弱故障扰动状态,且不受接地电阻、故障类型/时间/相、负荷/DG的投切等各种因素影响,具有很强的适应性与工程应用价值.

电力生产作业历来“重一次、轻二次”,二次系统现场安全作业缺乏规程规范,大多依靠人的主观经验,导致各类二次安全事故频发.探讨构建电力二次系统现场作业本质安全的组织措施和技术措施体系,并将成果作为制定二次专业《安规》的顶层设计,编制了《电力通信安规》《电力监控安规》和《信息安规》.介绍了实际应用的成效,为实现电力二次系统本质安全管控提供有力支撑.

Starting with the global scope of strengthening the enterprise safety management,standardizing the staff behaviors and improving the external environment,the power grid safety risk was analyzed and the enterprise safety risk prevention ability was improved,which promoted the change from the ex-post safety management to prevention first.On the basis of system engineering thought,the overall design idea and system structure of the index system of regional power grid safety risk assessment were proposed.Through analyzing the risk elements which influenced on the power gird safety and combining with the analytical hierarchy process,the quantitative safety risk index and its weight calculation method were proposed.Based on the realization of the computer software programming and its application generalization,the new ideas for establishing of the national standard of the power grid safety risk assessment and the power gird accident insurance were also proposed.

The lessons that can be learned from blackout accidents occurred in European and Russian power grids in recent two years are summarized.Based on the status quo and development trend of East China Power Grid,the weaknesses in the safe and stable operation of the Grid are analyzed.The ideas on enhancing the safety and stability management for the Grid to deal with its complicated operational characteristics as a large receiving-end grid are proposed.

对高水头长隧洞双机组双调压井的水轮机组水、机、电系统进行研究，得出系统数学模型及其稳定性和动态品质；分析有压过水系统、调速器等参数以及机组间水力干扰对稳定性及动态品质的影响；提出改善系统稳定性及动态品质的措施。