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调相机附加电压调节器参数优化研究
Research on Parameter Optimization of Additional Voltage Regulator in Condenser
【作者】 李志远；
【导师】 王克文；
【作者基本信息】 郑州大学 ， 电气工程， 2021， 硕士
【摘要】 特高压直流输电技术得到了快速发展和大规模应用,虽然可以很好地缓解能源分布不均的现状,但也导致系统故障时电压支撑能力不足。大容量调相机的动态无功特性与电力系统故障时动态电压所需无功特性相符,可以为系统提供充足动态无功从而提升系统电压稳定性,因此在电网中得到应用。在调相机上加装电力系统电压调节器(PSVR)可以进一步提升调相机动态特性。本文从小干扰稳定角度分析加装PSVR对调相机和电力系统动态特性产生的影响,并据此形成一种PSVR参数优化方法,最后通过仿真验证PSVR对调相机动态特性和系统电压稳定性的改善作用,主要所做工作如下:(1)建立调相机动态模型,分析调相机动态特性。通过推导确定功角扰动与电磁转矩之间的解析表达,据此在MATLAB软件中建立含PSVR的调相机模型,对比分析不同控制方式下功角特性的变化情况;在未加装PSVR和加装PSVR两种情况下,通过推导得到调相机高压母线电压与无穷大母线电压之间的解析表达,对比分析可得加装PSVR对电压特性的影响。(2)为降低PSVR对功角特性的影响,基于调相机动态特性,形成一种PSVR参数优化方法。电压特性相频值的大小可判断PSVR对功角特性的影响程度,据此构建衡量电压特性幅角相移程度的指标,依据该指标对PSVR超前/滞后时间常数进行调整;根据根轨迹法确定PSVR临界增益系数,选择最佳增益;在MATLAB中搭建单机无穷大系统模型,仿真分析系统受到扰动后无功功率和高压母线电压的响应情况。仿真结果表明,对PSVR进行参数优化后更加有利于调相机无功功率和高压母线电压达到稳定状态。(3)在MATLAB/Simulink环境下搭建五机三区域系统,仿真分析加装PSVR对系统动态特性的改善效果。结合本文所提PSVR参数优化方法,对PSVR进行优化。仿真分析系统在受到不同扰动时,调相机无功功率和高压母线电压的变化情况。仿真结果表明,在调相机上加装PSVR后,提升了调相机无功出力和系统动态电压支撑,系统的电压稳定性得到了改善。
【Abstract】 UHV DC transmission technology has been rapidly developed and applied on a large scale.Although it can alleviate the uneven distribution of energy,it also leads to insufficient voltage support capacity when the system fails.The dynamic reactive power characteristics of large-capacity condensers are consistent with the reactive power characteristics required by the dynamic voltage of the power system when the power system fails,which can provide sufficient dynamic reactive power for the system to improve the voltage stability of the system,so it is applied in the power grid.Installing a power system voltage regulator(PSVR)on the condenser can further improve the dynamic characteristics of the condenser.This thesis analyzes the influence of the condenser on the dynamic power angle and voltage characteristics of the power system from the perspective of small disturbance stability,and forms a PSVR parameter optimization method based on this,and finally verifies the improvement effect of PSVR on the dynamic characteristics of the condenser through simulation.The main work is as follows :(1)Establish a dynamic model of the condenser and analyze the dynamic characteristics of the condenser.The analytical expression between power angle disturbance and electromagnetic torque is determined by derivation.Based on this,a PSVR-containing tuning camera model is established in MATLAB software to compare and analyze the changes in power angle characteristics under different control methods;when PSVR and electromagnetic torque are not installed In the two cases of installing PSVR,the analytical expression between the condenser’s main transformer high-voltage bus voltage and the infinite bus voltage is obtained through derivation,and the influence of installing PSVR on the voltage characteristics can be obtained by comparing and analyzing.(2)In order to reduce the influence of PSVR on the power angle characteristics,based on the dynamic characteristics of the condenser,a PSVR parameter optimization method is formed.The magnitude of the phase frequency value of the dynamic voltage characteristic can judge the influence of PSVR on the power angle characteristics,construct an index to measure the voltage characteristic argument phase shift,and adjust the PSVR lead/lag time constant according to the index;determine the PSVR criticality according to the root locus method Gain coefficient,select the best gain;build a stand-alone infinite-bus system model in MATLAB,simulate and analyze the reactive power output and the response of the high-voltage bus voltage after the system fails.The simulation results show that the PSVR parameter optimization is more conducive to the stable state of the condenser’s reactive power output and the high-voltage bus voltage.(3)Build a five-machine three-area system under the MATLAB/Simulink environment,and simulate and analyze the effect of installing PSVR on the dynamic characteristics of the system.Combining with the PSVR parameter optimization method proposed in this thesis,optimizing the PSVR.the simulation analysis system is subjected to different disturbances,the condenser reactive power output and the change of the high-voltage bus voltage.The simulation results show that after installing PSVR on the condenser,the reactive power output of the condenser and the dynamic voltage support of the system are improved,and the voltage stability of the system is improved.