次同步振荡动态抑制器控制策略与工程应用研究

发布时间：2018-03-17 10:12

本文选题：次同步振荡动态抑制器　切入点：新能源电力系统　出处：《华北电力大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：随着风力发电等新能源的快速增长,大功率电力电子技术的广泛应用,以复杂交直流系统为组成架构的新能源电力系统逐渐形成。新能源电力系统的多源多变换特性使得次同步振荡新问题不断凸显。为了解决新能源电力系统中存在的次同步振荡新问题,本文基于电压源换流器(Voltage Souce Converter,VSC)技术,提出了次同步振荡动态抑制器(Subsynchronous Oscillation-Dynamic Suppressor,SSO-DS)的新型抑制方法,开展了如下研究:论文首先分析了我国电力系统中近年来出现的次同步振荡若干新问题的产生机理。针对大型火电机群经高压直流输电(High Voltage Direct Current Transmission,HVDC)与交流混合串联补偿线路送出系统的频繁次同步振荡(Frequent Subsynchronous Oscillation,FSSO)问题,提出了系统阻尼特性和基于强迫振荡原理的轴系扭振响应特性的综合分析方法,结果表明,在系统弱阻尼条件下,强制激励与系统自由响应的共同作用,是导致频繁次同步振荡出现的根本原因;针对双馈风电场经串补送出的次同步控制互作用(Subsynchronous Control Interaction,SSCI)问题,基于单机无穷大系统,采用特征值法分析了SSCI的产生机理,指出转子电阻和转子变流器电流内环在次同步频率下的负电阻效应以及变流器有功功率的次同步调制作用是导致系统负阻尼的根本原因;分析了双馈风电场经弱交流系统并网情形下双馈感应发电机(Doubly Fed Induction Generator,DFIG)与静止同步补偿器(Static Synchronous Compensators,STATCOM)的SSCI风险,结果表明弱交流系统中电压的次同步扰动分量有可能感应到STATCOM控制器中,在STATCOM控制环节作用下形成不稳定的闭环,导致SSCI的发生。上述机理分析结果不仅揭示了次同步振荡新问题的产生机理,而且为次同步振荡动态抑制器的阻尼控制器设计奠定了基础。分析了SSO-DS的基本原理与运行特性。针对大型火电机组轴系次同步扭振问题,研究了SSO-DS的阻尼电流调制策略。在已有双频调制策略的基础上,提出了只发次同步电流或超同步电流的单频调制策略,并对其关键参数设计进行了分析;对具有不同分流特性的系统,提出了SSO-DS阻尼电流调制策略的优化设计方法。基于PSCAD/EMTDC的时域仿真平台,对不同的阻尼电流调制策略进行了对比分析,结果表明了SSO-DS阻尼控制策略设计方法的有效性。针对双馈风电场经串补送出系统中SSCI发生频率范围宽的特性,以及传统抑制方法控制输入信号提取困难,鲁棒性差的不足,研究了相应的SSO-DS阻尼控制策略。基于留数分析方法,考虑不同串补度和风速,确定了次同步阻尼控制器(Subsynchronous Damping Contoller,SDC)的最优控制输入信号及SDC接入VSC控制器的位置(d轴或q轴);基于根轨迹分析确定了次同步振荡模态正阻尼的SDC增益范围;最后,针对SDC有可能引起超同步模态失稳的问题,提出了一种改进的设计方案,通过加入带阻滤波器来消除超同步频率分量的影响。采用时域仿真对控制策略和控制参数设计的有效性进行了验证,结果表明所提出的SSO-DS阻尼控制策略能够有效解决风电场中的次同步振荡问题。将研发的10kV/20MVA SSO-DS装置应用于呼贝电厂。基于本文提出的阻尼电流调制方法,设计了其控制策略。采用实时数字-物理闭环仿真研究了其阻尼特性与最优参数。现场试验和工程应用结果表明,SSO-DS成功解决了困扰呼贝电厂多年的FSSO,同时在大扰动下能够明显提高发电机模态收敛速度,从而验证了SSO-DS的有效性。
[Abstract]:With the rapid growth of new energy sources such as wind power, wide application of high power electronic technology, with complicated AC / DC system for the new energy power system structure gradually formed the new energy power system. Multi multi transform characteristics make SSO new problems continue to highlight. In order to solve the existing new energy power system in time a new synchronous oscillation problem, based on voltage source converter (Voltage Souce Converter VSC) technology, the subsynchronous oscillation suppressor (Subsynchronous Oscillation-Dynamic Suppressor, dynamic SSO-DS) the new type suppression method is carried out as follows: firstly, analysis of the mechanism of China's power system in recent years is the emergence of subsynchronous oscillation some new problems. For large fire by HVDC motor group (High Voltage Direct Current Transmission, HVDC) and AC hybrid series compensation Frequent subsynchronous oscillation compensation line system (Frequent Subsynchronous sent Oscillation, FSSO), the damping characteristic of the system and comprehensive analysis method, the characteristics of torsional vibration of the forced oscillation principle based on response results show that in the system with weak damping conditions, strong interaction and incentive system for free response, is the root cause frequent subsynchronous oscillations occur; for doubly fed wind power by the series compensation transmission sub synchronous control interaction (Subsynchronous Control Interaction, SSCI), a single machine infinite bus system based on using the eigenvalues of SSCI generation mechanism analysis, pointed out that the negative resistance effect of rotor resistance and rotor current in the subsynchronous frequency converter the active power converter and sub synchronous modulation system is the fundamental reason for negative damping; analysis of doubly fed wind power system and the weak AC Net under the condition of doubly fed induction generator (Doubly Fed Induction Generator, DFIG) and static synchronous compensator (Static Synchronous Compensators, STATCOM) SSCI risk, results show that the voltage weak AC system subsynchronous disturbance component may be induced to STATCOM controller, to form a closed loop instability in STATCOM control under the action of lead the occurrence of SSCI. The mechanism of the analysis results not only reveal the mechanism of time synchronous oscillation problems, but also lays a foundation for the design of damping controller subsynchronous oscillation dynamic suppressor. Analysis of the basic principle and operation characteristics of SSO-DS. According to the large thermal power unit shaft torsional fatigue problem of damping current modulation strategy SSO-DS. Based on the existing dual frequency modulation strategy, proposed single frequency modulation strategy only time synchronous current or super synchronous current, and the key The design parameters are analyzed; the system has different division characteristics, put forward the optimum design method of SSO-DS damping current modulation strategy. The time domain simulation platform based on PSCAD/EMTDC, the damping current different modulation strategies are analyzed, the results show the effectiveness of SSO-DS damping control strategy. The design method for DFIG wind farm the series compensation SSCI transmission system in a wide range of frequency characteristics, and the traditional method to suppress the control input signal is difficult to extract the robust, short, research on SSO-DS damping control strategy. The corresponding residue analysis method based on the consideration of different series compensation degree and wind speed, the subsynchronous damping controller (Subsynchronous Damping Contoller. SDC) the optimal control input signal and SDC VSC access controller position (D or q axis); based on the root locus analysis to determine the subsynchronous oscillation modal damping The SDC gain range; finally, the SDC may cause the instability of the super synchronous mode, proposes an improved design scheme, by adding a bandstop filter to eliminate the influence of super synchronous frequency component. The time-domain simulation of control strategy and control parameters of the effectiveness of the design is verified, the results show that SSO-DS the control strategy can effectively solve the damping of subsynchronous oscillations in wind farm proposed. The research and development of 10kV/20MVA SSO-DS device used in power plant. Call Bei damping current modulation method is proposed in this paper based on the design of its control strategy was studied. The damping properties and optimal parameters by the simulation of real time digital physical field results in closed loop. Experiment and application shows that SSO-DS successfully solved the problem of Hu Bei power plant of FSSO for many years, while in large disturbance can significantly improve the convergence speed of the generator mode, in order to verify The effectiveness of SSO-DS.

【学位授予单位】：华北电力大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM712

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