基于机网协调的共振机理低频振荡影响因素分析及对策研究

发布时间：2018-01-23 23:55

本文关键词： 机网协调共振机理低频振荡调速系统汽轮机热力系统 GPSS　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：电力系统互联能有效提高系统的经济性和可靠性，而大电网互联后复杂的网架结构也带来了较多的动态稳定问题。低频振荡问题作为大电网互联后最可能发生的稳定问题，是威胁电网安全稳定运行的重要问题之一。目前，对负阻尼机理的低频振荡较为常见，且相关理论较为成熟。普遍认为装设电力系统稳定器(PSS)为系统提供适当的正阻尼能有效的抑制低频振荡的发生。实际运行经验表明，负阻尼机理在某些类型的低频振荡中将不再适用。本文在分析低频振荡传统机理的基础上，全面的阐述了共振型低频振荡的概念，并对共振机理与负阻尼机理低频振荡的特征判别进行了研究。基于机网协调考虑对电网侧、机组侧各种形式的扰动对低频振荡的影响进行了分析，并综合考虑汽轮机、调速系统和电力系统之间的相互影响，从汽轮机及其调速系统中寻找共振机理低频振荡可能的扰动源，即造成机械功率周期性波动的原因。并通过仿真得出了汽轮机调速系统的摆动以及汽轮机蒸汽压力脉动对机组机械功率的影响及其与电力系统共振机理低频振荡的关系。本文打破以往研究低频振荡时忽略调速系统及汽轮机热力系统对电力系统的影响而孤立的研究电力系统，并通过理论推导、仿真研究和实例分析指出：调速系统及汽轮机的各环节和参数设置不当或者由于某些机械故障可能会造成汽轮机组机械功率发生相应波动，进而可能引发电力系统共振机理的低频振荡；不同位置相同扰动量情况下，机侧较网侧的影响更为严重。这种类型的低频振荡运用PSS进行抑制，，效果不甚理想，需要在调速系统中设计并安装GPSS达到比较好的抑制效果。
[Abstract]:Power system interconnection can effectively improve the economy and reliability of the system. The complex grid structure after the interconnection of large power grid also brings more dynamic stability problems. Low frequency oscillation is the most likely stability problem after the interconnection of large power grid. It is one of the important problems threatening the safe and stable operation of power grid. At present, low frequency oscillation of negative damping mechanism is more common. It is generally considered that the installation of power system stabilizer (PSS) can effectively restrain the occurrence of low frequency oscillation by providing proper positive damping for the system. The negative damping mechanism will no longer be applicable to some types of low frequency oscillations. Based on the analysis of the traditional mechanism of low frequency oscillation, the concept of resonance low frequency oscillation is expounded in this paper. The characteristic discrimination of resonance mechanism and negative damping mechanism of low frequency oscillation is studied. Based on the consideration of power grid coordination, the influence of various types of disturbances on low frequency oscillation on the power grid side and the unit side is analyzed. Considering the interaction among steam turbine, speed regulating system and power system, the possible disturbance source of resonance mechanism low frequency oscillation is found from steam turbine and its governing system. The reason of periodic fluctuation of mechanical power is obtained by simulation, and the influence of turbine governing system swing and steam pressure pulsation on the mechanical power of turbine and the low frequency oscillation of resonance mechanism between turbine and power system are obtained. The relationship. This paper breaks the previous study of low-frequency oscillation ignore the speed control system and steam turbine thermal system on the power system and isolated research power system, and through theoretical derivation. The simulation research and the analysis of examples show that the mechanical power of steam turbine may fluctuate due to the improper setting of various links and parameters of the governing system and steam turbine or because of some mechanical faults. Furthermore, the low frequency oscillation of the resonance mechanism of power system may be initiated. Under the condition of the same disturbance quantity at different positions, the influence of the engine side is more serious than that of the network side. This type of low frequency oscillation is suppressed by PSS, and the effect is not very satisfactory. Need to design and install GPSS in the speed control system to achieve better suppression effect.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM712

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