【作者】 唐利军；

【导师】 余楚中；

【作者基本信息】 重庆大学 ， 控制理论与控制工程， 2010， 硕士

【摘要】 电力系统稳定是电网安全运行的关键,一旦遭到破坏,必将造成巨大的经济损失和灾难性的后果。现代电力系统都是跨区域互联系统,其特征是系统规模大、超高压输电距离远,机组容量大,因此明显改善了电力系统运行的可靠性和经济性,在正常运行条件下,系统频率质量可得到显著提高。但是,系统一旦遭受大扰动,其频率稳定性有可能急剧恶化,因此在系统遭受大扰动时如何维持频率稳定以保证供电质量已成为业界普遍关注的问题。在现代电力系统中,低频减载是保证电力系统正常运行的最后一道防线,是维持电力系统频率稳定的重要措施,无论在国内还是国外,低频减载在电力系统中都获得了广泛的应用。本文在分析国内外低频减载方案及其实现装置现状基础上,研究了电力系统的动、静态频率特性,比较了由单机带集中负荷模型得出的电力系统动态频率特性与实际电力工程系统所测量特性的不一致性,指出了用单机带集中负荷模型分析电力系统动态频率特性的局限性,对比了各种低频减载方法的优缺点,推导提出了本文所推荐的低频减载方法,设计了低频减载装置的软、硬件平台。本文完成了以下研究工作:①分析了电力系统的动、静态频率特性,得出电力系统频率和负载与电网提供的有功功率是否平衡有关的结论,为低频减载装置设计提供了理论依据。②提出了以系统频率及频率变化时间为减载判据构建新型低频减载装置是否减载的量化方法。③设计了一种基于32位嵌入式微控制器MCF52235为核心的新型低频减载装置硬件平台,该平台可在以太网通信环境中使用。④设计了一种基于“主程序+采样中断+低频减载控制中断+通信中断”构建系统软件框架的低频减载系统软件平台。从系统层次保证了系统数据采集的实时性和低频减载控制的及时性。更多还原

【Abstract】 The electric power system stability is the key to realize power network safe operation, once the stability is damaged, it will result in huge economic losses and disastrous consequences. Modern power systems are always the cross-regional interconnected system characterized by large scale, extra high voltage, long distance and large capacity units. It has been obviously improved to the reliability and economy of power system operation. The quality of system frequency of the cross-regional interconnected system can be obviously improved generally, however, once the system is suffered from a large disturbances, the frequency stability would be deteriorated sharply, so how to maintain the frequency stability to ensure the quality of supply during the system being suffered large disturbances has been widely focused.In the modern electric power system, under frequency load shedding is the last defense line that is used for ensuring the normal operation of electric power system, and being as the important measures to maintain the frequency stability of electric power system. Whatever at home or abroad the measures of under frequency load shedding has been widely applied in electric power system. In this paper, firstly it analyzed to the development dynamics of under frequency load shedding scheme and its device at home and abroad. Then it was studied to the dynamic/static frequency characteristics of electric power system and compared the measured frequency response characteristics of actual power system with the dynamic frequency response characteristics obtained by means of single generator with concentrated load analysis model. In the above the frequency response characteristics is different from each other, therefore there are some limitations when using single generator with concentrated load analysis model analyzes the dynamic frequency characteristics of electric power system. After that, it was made the comparison with advantages and disadvantages of various scheme of under frequency load shedding, and proposed a new scheme of under frequency load shedding. Finally it designed to the hardware system platform and software system platform. The following research works has been completed in this paper:①Analyzed the dynamic/static frequency characteristics of electric power system. The conclusion is that the frequency of electric power system is directly related to whether or not the active load balancing with the electric power system supply. It made the substantial foundation for designing a under frequency load shedding device. ②Proposed a quantitative method of whether or not load shedding for the device of under frequency load shedding. The load shedding criterion is that it is responded to system frequency and the time of system frequency change.③Designed a sort of new hardware platform for under frequency load shedding system. The hardware platform is based on 32-bit microcontroller MCF52235, which could be used for Ethernet communication environment.④Designed a sort of software system platform for under frequency load shedding device. The software platform is based on the framework of“main program plus the interrupt for sampling plus the interrupt for the control of under frequency load shedding plus the interrupt for communication”. This framework could ensure the data sampling in real time and the control of under frequency load shedding in time.更多还原