宁夏交直流电网谐波特性分析

发布时间：2018-07-28 20:42

【摘要】：在多种发电形式和交直流联合输电主体结构下,电网电能质量谐波污染日益恶化。对于交直流互联电网的谐波问题,国内外许多专家学者从不同方面做了分析与研究,取得了突破性进展。目前亟待解决的难题是如何以实测数据为依托建立准确可靠的仿真模型,使计算值能够反映实测值,进而达到把握全电网谐波特性、提供滤波器设计所需数据依据的目的。本文的研究手段可概括为:1)通过对直流线路稳定运行和检修期间全过程谐波的测试,分析交直流电网谐波特性及其主要影响因素,总结谐波的传递规律,并通过对实测数据的提炼分析给出适合计算软件的电网谐波源模型和谐波源数据。2)以ETAP软件进行电网建模,将建立的谐波源注入到等值模型中,采用仿真分析的方法,对比仿真计算值与实测值,验证模型的准确可靠性。3)在电网直流不同运行方式下,计算宁夏电网750k V双环网的谐波值,并对比换流站330k V交流侧和主变750k V的谐波情况,以实现对电网谐波分布的全面把握,在这个背景下,计算出规划网架下的上海庙直流母线侧谐波水平,为上海庙直流输电工程交流滤波器的设计提供背景谐波依据。本文的研究成果可总结为:1)实测数据分析,宁夏电网以5次谐波为主导,银川东主变750k V和330k V侧3、7、11、13次谐波含量较大,换流变330k V侧11、13、23、25次谐波含量较大;直流线路稳定运行时,主变侧的特征谐波幅值增减规律相同;直流检修时,5、7次谐波含量较小,12脉动换流变压器对6k±1次谐波具有抵消的作用。2)以ETAP仿真软件为平台,形成以宁夏电网750k V双环网为主网架的计算等值模型,通过对仿真模型潮流进行调试和测试,使其更加适合不同情况下的谐波潮流计算,计算值与实测值一致,得出可靠的电网谐波仿真计算模型。3)基于等值模型,改变直流运行方式,计算得出无直流时电网谐波畸变率较大,各次谐波幅值也较大;一条直流运行时,电网谐波畸变率较小,各次谐波的幅值也较小;两条直流时电网谐波含量较一条直流时更小。这是由直流配套电源的接入,系统短路容量的增大引起的。4)计算得出上海庙直流输电工程的背景谐波水平,并在此基础上,给出500 k V母线侧推荐值来供设计单位在交流滤波器的设计中采用。
[Abstract]:Under various forms of generation and the main structure of AC-DC combined transmission, harmonic pollution of power quality of power network is worsening day by day. Many experts and scholars at home and abroad have made analysis and research on harmonics of AC / DC interconnected power network from different aspects, and have made breakthrough progress. At present, the problem to be solved is how to build an accurate and reliable simulation model based on the measured data, so that the calculated value can reflect the measured value, and then achieve the purpose of grasping the harmonic characteristics of the whole power network and providing the data basis for the filter design. The research means of this paper can be summarized as follows: (1) by testing the harmonics in the whole process during the steady operation and maintenance of DC lines, the harmonic characteristics of AC / DC power network and its main influencing factors are analyzed, and the law of harmonic transmission is summarized. Based on the analysis of the measured data, the harmonic source model and harmonic source data of the power network are presented. The ETAP software is used to model the power network. The harmonic source is injected into the equivalent model, and the simulation analysis method is adopted. By comparing the calculated value with the measured value, the accuracy and reliability of the model is verified. 3) under different operation modes of DC network, the harmonic value of 750kV double loop network of Ningxia power network is calculated, and the harmonics of 330kV AC side and 750kV main transformer are compared. In order to realize the overall understanding of the harmonic distribution of the power network, the harmonic level of the DC bus side of the Shanghai Temple under the planning grid is calculated under this background, which provides the background harmonic basis for the design of the AC filter for the Shanghaimiao HVDC transmission project. The research results of this paper can be summarized as follows: (1) Analysis of measured data shows that Ningxia power grid is dominated by the fifth harmonic wave, the East main Transformer of Yinchuan has a larger harmonic content of 750kV and 330kV sides, and the 310kV side has a larger harmonic content of 25 times, while the DC line is in stable operation. The amplitude of characteristic harmonics in the main transformer side is the same as that in the main transformer side, and the seventh harmonic content is smaller than that of the 12 pulsating converter transformer when the DC is overhauled. 2) based on the ETAP simulation software, the amplitude of the characteristic harmonics of the main transformer side is equal to that of the 6k 卤1 th harmonic wave. The equivalent model of 750kV double loop network in Ningxia power network is formed. By debugging and testing the simulation model power flow, it is more suitable for harmonic power flow calculation under different conditions, and the calculated value is consistent with the measured value. The reliable harmonic simulation calculation model .3) based on the equivalent model, changes the DC operation mode, and calculates that the harmonic distortion rate is larger and the harmonic amplitude is larger when the DC is not in operation. The harmonic distortion rate of power network is smaller and the amplitude of each harmonic is smaller. This is caused by the connection of the DC power supply and the increase of the short-circuit capacity of the system.) the background harmonic level of the Shanghaimiao HVDC transmission project is calculated, and on this basis, The recommended value of 500 kV bus side is given for the design unit to adopt in the design of AC filter.
【学位授予单位】：北方民族大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM711

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