基于WAMS的电力系统频率动态时空分布特性分析

发布时间：2018-07-05 06:00

本文选题：频率动态 + 时空分布特性　；参考：《东北电力大学》2016年硕士论文

【摘要】：频率是电能质量的重要指标,也是反映电力系统有功功率供需平衡的重要参量。电力系统中大型发电机运行中突然故障停机时,突发的有功功率缺额会引起系统频率的波动,已有的研究表明,电力系统的频率变化具有时空分布的特性。随着越来越多的大容量发电机组(1000MW火电机组或核电机组)投入运行,电力系统中发生大的功率脱落事件的风险也在增大。频率动态过程的时空分布特性是一个非常复杂的问题,理论分析的方法只能研究几种简化系统的特性。观测手段的不足也是重要的制约因素。基于同步相量测量单元(PMU)的广域量测系统(WAMS)可以实现对全系统动态信息的同步量测,为研究电力系统真实的频率动态过程及其时空分布特性提供了观测手段。深入研究电力系统受扰后的频率动态过程及其时空分布特性对防范频率失稳、改善低频减载控制等均具有重要意义。本文分析了东北电网4次核电机组异常停机导致的功率脱落事件,根据WAMS记录的45个场站的频率变化数据,建立了包括初始响应时刻、初始频率、频率最低值、频率最低值时刻和平均频率变化率等参数的特征量,分析了频率变化主要特征与测点距扰动源距离之间的相关关系,从不同角度揭示了频率动态过程的时空特性。在理论分析方面,通过单机系统频率动态模型研究了频率动态过程的时序特性及其与系统参数的关系;用多机系统机电暂态仿真模型对频率动态过程的时空分布特性进行了研究,分析了有功缺额、惯性时间常数和调速器死区等主要因素的影响,并与实测数据的分析结果进行了比对。由仿真结果可知,有功缺额的增大和惯性时间常数的减小将会导致扰动后频率变化传播速度加快;频率最低值主要与有功缺额和调速器死区范围强相关;频率跌落趋势主要与有功缺额和惯性时间常数强相关,有功缺额的减小,惯性时间常数的增大,调速器死区范围的增大将导致频率最低值出现的延迟。基于WAMS的频率动态过程数据为研究频率动态过程的时空特性提供了重要依据。基于数据的研究和基于仿真的研究相结合可以更好地揭示频率动态过程的机理和主要影响因素。频率动态过程的研究对防范频率失稳以及改善低频减载整定方法均有重要意义。
[Abstract]:Frequency is not only an important index of power quality, but also an important parameter to reflect the balance of supply and demand of active power in power system. The frequency fluctuation of power system will be caused by the sudden active power shortage when the power system is stopped suddenly during the operation of the large generator. The existing researches show that the frequency variation of the power system has the characteristics of space-time distribution. With more and more large capacity generating units (1000MW thermal power units or nuclear power units) put into operation, the risk of large power loss events in power system is also increasing. The spatial and temporal distribution of frequency dynamic processes is a very complex problem. The theoretical analysis method can only study the characteristics of several simplified systems. The shortage of observation means is also an important constraint factor. Wide-area measurement system (WAMS) based on synchronous phasor measurement unit (PMU) can realize synchronous measurement of dynamic information of the whole system, which provides an observation method for studying the real frequency dynamic process and space-time distribution characteristics of power system. It is of great significance to study the frequency dynamic process and its space-time distribution of power system after disturbance for preventing frequency instability and improving low-frequency load reduction control. In this paper, the power shedding events caused by 4 abnormal shutdown of nuclear power units in Northeast China Power Grid are analyzed. According to the frequency variation data of 45 stations recorded by WAMS, the initial response time, initial frequency and minimum frequency are established. The relationship between the main characteristics of the frequency change and the distance between the measured point and the disturbance source is analyzed, and the space-time characteristics of the frequency dynamic process are revealed from different angles. In the aspect of theoretical analysis, the time-series characteristics of frequency dynamic process and the relationship between frequency dynamic process and system parameters are studied by the single-machine system frequency dynamic model. The time-space distribution characteristics of frequency dynamic process are studied by using the electromechanical transient simulation model of multi-machine system. The effects of active power gap, inertia time constant and governor dead time are analyzed. The results are compared with the measured data. According to the simulation results, the increase of active power gap and the decrease of inertial time constant will lead to the acceleration of frequency change propagation speed after disturbance, the lowest frequency value is mainly related to the active power gap and the dead zone range of governor. The trend of frequency drop is mainly related to active power gap and inertia time constant. The decrease of active power gap, the increase of inertia time constant and the increase of dead zone range of governor will lead to the delay of the lowest frequency. The frequency dynamic process data based on WAMS provide an important basis for the study of spatial and temporal characteristics of frequency dynamic process. The combination of data-based research and simulation-based research can better reveal the mechanism and main influencing factors of frequency dynamic process. The study of frequency dynamic process is of great significance for preventing frequency instability and improving low frequency load reduction setting method.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM712

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