新能源接入条件下电网频率安全稳定特性与控制研究
发布时间：2018-11-01 14:41
【摘要】：随着石化能源限制问题和环境保护要求日益受到重视,我国风电与光伏新能源接入的规模不断增大。同时,受电力体制改革、厂网分开、管理主体多元化影响,电网频率安全稳定控制面临很大的挑战。一方面,新能源与火电、水电常规电源相比,缺乏惯量效应,并且波动性大,不具备一次调频能力。因此,新能源接入后的电网调频对常规机组的依赖性加大,需要加强对火电和水电常规机组调速器一次调频特性的研究,明确传统和数字电液式两类调速系统的特点和差异,为对新能源接入后的电网频率特性进行准确仿真、科学策略提供指导。另一方面,新能源接入系统与主网间发生解列故障是频率安全稳定研究的重要场景,应全面考虑电源侧频率异常保护和电网侧安全控制措施,研究解列故障面临的高频或低频问题及控制策略。本文首先简要介绍了所用到的新能源和常规机组的数学模型,并梳理总结了其各自的频率异常耐受范围,明确了两类机组的频率异常保护的配置特点和差异。随后,对火电、水电机组的传统和数字电液式两类调速系统的特点和差异进行了对比研究,着重于两类调速系统的结构、死区环节处理、动态调频特性三个方面,分析了在小扰动、大扰动两种工况下两类典型调速器的特性。在此基础上,对新能源接入系统后解列导致的高频问题开展研究,建立了含多类型电源的送端典型系统算例,分析了对火电机组OPC保护定值进行差异化设置的效果;指出新能源高频保护定值过低而无序脱网将导致原高频问题转化为低频问题的严重后果;研究了应对高频问题的连锁切机方案,比较了切除常规机组和切除风电机组对抑制频率波动和最大功角差的不同效果,提出了兼顾频率和功角因素的综合切机策略。最后,对新能源接入系统后解列导致的低频问题开展研究,以有大规模新能源接入的西北某省级电网为实例,研究了动态无功补偿的电压控制、常规机组的旋转备用容量、新能源接入电网比例等因素对电网频率调节特性的影响,并针对新能源接入易导致低频减载轮次增多的问题,提出了低频减载方案的优化策略。
[Abstract]:With the increasing attention paid to the restriction of petrochemical energy and the requirement of environmental protection, the scale of new energy access to wind power and photovoltaic in China is increasing. At the same time, due to the reform of power system, the separation of power plant and power grid, and the influence of diversified management bodies, the frequency security and stability control of power network faces great challenges. On the one hand, compared with conventional power supply of thermal power and hydropower, new energy is lack of inertia effect, and is fluctuating, so it does not have the ability of primary frequency modulation. Therefore, the dependence of power grid frequency modulation on conventional units is increased after the new energy source is connected, so it is necessary to strengthen the study on the primary frequency modulation characteristics of the governor of thermal power and hydropower conventional units, and to make clear the characteristics and differences between the traditional and digital electro-hydraulic speed regulating systems. It provides guidance for accurate simulation of power grid frequency characteristics after new energy access and scientific strategy. On the other hand, the decoupling fault between the new energy access system and the main network is an important scene for the study of frequency security and stability. The frequency abnormal protection on the power side and the safety control measures on the grid side should be considered comprehensively. The problem of high frequency or low frequency and control strategy are studied. In this paper, the mathematical models of new energy sources and conventional units are briefly introduced, and their respective frequency abnormal tolerance ranges are summarized, and the configuration characteristics and differences of frequency abnormal protection between the two types of units are clarified. Then, the characteristics and differences of the traditional and digital electro-hydraulic speed regulating systems of thermal power and hydroelectric generating units are compared and studied, focusing on the structure of the two types of speed control systems, dead zone processing, dynamic frequency modulation characteristics. The characteristics of two kinds of typical governor under small disturbance and large disturbance are analyzed. On this basis, the high-frequency problem caused by the post-de-listing of the new energy access system is studied, and the typical system with multi-type power supply is established, and the effect of differential setting for the OPC protection of thermal power unit is analyzed. It is pointed out that the low fixed value of new energy high frequency protection and disordered disconnection will lead to the serious consequences of converting the original high frequency problem into the low frequency problem. This paper studies the scheme of interlocking cutting machine to deal with the problem of high frequency, compares the different effects of removing conventional unit and removing wind turbine on restraining frequency fluctuation and maximum power angle difference, and puts forward a comprehensive cutting strategy which takes into account the factors of frequency and power angle. Finally, the low-frequency problem caused by the post-de-listing of the new energy access system is studied. Taking a provincial power grid with large-scale new energy access as an example, the voltage control of dynamic reactive power compensation and the rotating reserve capacity of conventional units are studied. The influence of the proportion of new energy access to the power network on the frequency regulation characteristics of the power network is discussed. Aiming at the problem that the low frequency load reduction cycle increases easily due to the new energy access, the optimization strategy of the low frequency load reduction scheme is put forward.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712
本文编号：2304228
[Abstract]:With the increasing attention paid to the restriction of petrochemical energy and the requirement of environmental protection, the scale of new energy access to wind power and photovoltaic in China is increasing. At the same time, due to the reform of power system, the separation of power plant and power grid, and the influence of diversified management bodies, the frequency security and stability control of power network faces great challenges. On the one hand, compared with conventional power supply of thermal power and hydropower, new energy is lack of inertia effect, and is fluctuating, so it does not have the ability of primary frequency modulation. Therefore, the dependence of power grid frequency modulation on conventional units is increased after the new energy source is connected, so it is necessary to strengthen the study on the primary frequency modulation characteristics of the governor of thermal power and hydropower conventional units, and to make clear the characteristics and differences between the traditional and digital electro-hydraulic speed regulating systems. It provides guidance for accurate simulation of power grid frequency characteristics after new energy access and scientific strategy. On the other hand, the decoupling fault between the new energy access system and the main network is an important scene for the study of frequency security and stability. The frequency abnormal protection on the power side and the safety control measures on the grid side should be considered comprehensively. The problem of high frequency or low frequency and control strategy are studied. In this paper, the mathematical models of new energy sources and conventional units are briefly introduced, and their respective frequency abnormal tolerance ranges are summarized, and the configuration characteristics and differences of frequency abnormal protection between the two types of units are clarified. Then, the characteristics and differences of the traditional and digital electro-hydraulic speed regulating systems of thermal power and hydroelectric generating units are compared and studied, focusing on the structure of the two types of speed control systems, dead zone processing, dynamic frequency modulation characteristics. The characteristics of two kinds of typical governor under small disturbance and large disturbance are analyzed. On this basis, the high-frequency problem caused by the post-de-listing of the new energy access system is studied, and the typical system with multi-type power supply is established, and the effect of differential setting for the OPC protection of thermal power unit is analyzed. It is pointed out that the low fixed value of new energy high frequency protection and disordered disconnection will lead to the serious consequences of converting the original high frequency problem into the low frequency problem. This paper studies the scheme of interlocking cutting machine to deal with the problem of high frequency, compares the different effects of removing conventional unit and removing wind turbine on restraining frequency fluctuation and maximum power angle difference, and puts forward a comprehensive cutting strategy which takes into account the factors of frequency and power angle. Finally, the low-frequency problem caused by the post-de-listing of the new energy access system is studied. Taking a provincial power grid with large-scale new energy access as an example, the voltage control of dynamic reactive power compensation and the rotating reserve capacity of conventional units are studied. The influence of the proportion of new energy access to the power network on the frequency regulation characteristics of the power network is discussed. Aiming at the problem that the low frequency load reduction cycle increases easily due to the new energy access, the optimization strategy of the low frequency load reduction scheme is put forward.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM712
【引证文献】
相关硕士学位论文 前1条
1 孙志远;负荷频率特性及建模方法研究[D];西安理工大学;2018年
，本文编号：2304228
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