特高压交流半波长输电系统无功电压特性分析及控制技术初探

发布时间：2018-05-20 10:31

本文选题：无功电压 + 送受端电压模值比　；参考：《东北电力大学》2017年硕士论文

【摘要】：近年来,环保压力越来越大,传统的以煤电为主的电源发展模式已经越来越难以为继。而我国地域辽阔,南北方、中西部与中东部资源分布、全社会的用电量逐年增大,为解决中东部地区负荷中心的电力供给不足的问题,急需解决大容量、超远距离的输电技术问题。此外,根据联合国气候发展峰会《巴黎协定》的要求以及“一带一路”宏伟发展蓝图的构想,为更好的优化资源配置,国与国之间的电力输电走廊建设会越来越多,很多地方的电力传输距离将会超过3000km。半波长交流输电以其显著的技术经济优势,在超远距离点对点输电模式中,具有较强的竞争优势和广阔的工程应用前景。对于特高压交流输电技术而言,类半波长线路、常规的中长线路、短线路的主要电气参数如沿线电压、电流,在输电线路的长度达到某一个量值时就会发生很明显的变化。本文正是以均匀无损传输线理论作为理论基础,参照已经成功投运的特高压远距离交流输电线路示范工程,就特高压交流半波长输电技术的相关问题进行初步探索。分析目前远距离输电的研究现状,并比较了各种远距离输电技术的经济技术的优劣,提出了相应的技术路线。以自然功率为基准,找出了传输功率与沿线电压关系,编程进行求算仿真出了沿线电压、电流随传输功率变化的波形,并提出自然功率和波阻抗这两个关键性的指标,并以送受端无功功率需求量为评价指标,证明了半波长线路阻抗参数的有效性;利用第一章和第二章得出的结论,得出了沿线电压、电流沿线的变化,并且从首末端传输功率的参数方程和静态稳定性两个方面证明了半波长输电线路传输功率的极限值;从功率传输的机理和电气谐振两个方面说明了功率传输对沿线电压的影响;提出评价输电线路经济运行的一个指标—线损率,通过逐步增大传输功率得出了在线路传输自然功率时线损率最低的结论;通过设定不同地点的不同的短路故障类型,得出了沿线过电压的水平并从机理上分析了故障处非故障相电压升高的原因,并做了对应的仿真曲线,进行理论分析验证;在输电线路稳态运行时,穿越无功的多少在一定程度上决定了特高压输电线路运行的经济性,为使得运行经济性最优,必须使得对应的穿越无功最小。因此,将穿越无功进行分解,并找出对应分解的各部分穿越无功与送受端电压模值比的等式关系,以建立相应的目标函数。以沿线电压的峰值、特高压半波长输电系统与下网配合的无功补偿容量等作为不等式或等式的约束条件,得出了最优解,并且和普通控制策略相比证明了此种控制算法的有效性,也为现场的实际运行提供了有益的参考。
[Abstract]:In recent years, the pressure of environmental protection is increasing, and the traditional mode of power supply based on coal power has become more and more difficult to sustain. The vast territory of China, the distribution of resources in the south and north, the central and western regions and the central and eastern parts of China, and the increasing power consumption of the whole society year by year, in order to solve the problem of insufficient power supply in the load centers in the central and eastern regions, it is urgent to solve the problem of large The problem of super long distance transmission technology. In addition, in accordance with the requirements of the United Nations Climate Development Summit Paris Accord and the vision of the "Belt and Road" ambitious development blueprint, there will be more and more power transmission corridors between countries for better resource allocation. In many places the distance between electricity transmission will be more than 3000 km. Half-wavelength AC transmission has strong competitive advantage and broad engineering application prospect in ultra-long distance point-to-point transmission mode because of its remarkable technical and economic advantages. For UHV AC transmission technology, the main electrical parameters such as voltage and current along the transmission line will change obviously when the length of transmission line reaches a certain value. Based on the theory of uniform lossless transmission line and referring to the demonstration project of UHV long distance AC transmission line which has been successfully put into operation, this paper makes a preliminary exploration on the related problems of UHV AC half wavelength transmission technology. This paper analyzes the present research situation of long distance transmission, compares the advantages and disadvantages of various long distance transmission technologies, and puts forward the corresponding technical route. Based on the natural power, the relation between the transmission power and the voltage along the line is found, and the waveform of the voltage and current along the line is simulated by programming. The two key indexes of natural power and impedance are put forward. Taking the reactive power demand of the receiving end as the evaluation index, the validity of the impedance parameters of the half-wavelength transmission line is proved, and the changes of the voltage and current along the line are obtained by using the conclusions obtained in the first and second chapters. The limit value of transmission power of half-wavelength transmission line is proved from the parameter equation of transmission power at the first and end and static stability, and the influence of power transmission on the voltage along the line is explained from the two aspects of power transmission mechanism and electric resonance. This paper puts forward an index to evaluate the economic operation of transmission lines-line loss rate. By increasing the transmission power step by step, the conclusion that the line loss rate is the lowest when the natural power is transmitted on the transmission line is obtained, and different short circuit fault types are set up in different locations. The level of overvoltage along the line is obtained and the cause of the rise of non-fault phase voltage at fault is analyzed from the mechanism, and the corresponding simulation curve is made for theoretical analysis and verification. To a certain extent, the economy of UHV transmission lines is determined by the amount of reactive power traversing. In order to make the operation economy optimal, the corresponding traversing reactive power must be minimized. Therefore, the traversing reactive power is decomposed, and the equality relation between the ratio of traversing reactive power and the voltage mode value ratio of the corresponding decomposition is found, and the corresponding objective function is established. Taking the peak voltage along the line and the reactive power compensation capacity of UHV half-wavelength transmission system as the constraints of inequality or equality, the optimal solution is obtained. Compared with the conventional control strategy, the effectiveness of the proposed control algorithm is proved, and it also provides a useful reference for the practical operation of the field.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM75

【参考文献】