【作者】 马立克；

【导师】 王成山；

【作者基本信息】 天津大学 ， 电力系统及其自动化， 2007， 博士

【摘要】 近些年,电力市场化改革不断深入,燃煤发电和核电的环境成本、经济成本逐渐增大,用户对电力供应的可靠性要求日益提高,随着可再生能源等新的发电技术获得快速发展,分布式发电得到了越来越多的重视。分布式发电具有很多优点,例如,可降低系统损耗,延缓输电网和配电网的升级改造,提高供电可靠性以及降低温室效应等。但同时分布式电源与配电网间的相互作用也将会产生一些问题,如果得不到合理的解决,接入系统的分布式电源可能会降低系统运行可靠性和电能质量,因此开发有效的分析工具对配电网和分布式电源间的相互影响进行全面的研究是很有必要的。本文以间歇式电源对配电网的影响为研究重点。(1)研究了风能/光能混合发电作为电源连接到配电网后对配电网可靠性的影响;(2)建立了风能/光能混合发电系统的模型,发展了配电系统三项潮流计算方法,用于仿真其对配电系统可靠性的影响;(3)建立了用于电压和电能损耗研究的定速风机模型,并验证了模型的有效性;(4)建立了完整的变速异步风力发电系统仿真模型和控制器模型;在电气部分引入了无差控制策略,采用电压分序方法将电压分解为正序和负序两部分进行控制,以提高故障情况下电流控制器的性能;为了避免锁相环自身模型的不准确性影响整个控制系统的控制效果,通过虚拟磁链计算取代了锁相环。通过算例仿真分析,验证了在外部系统短路故障情况下的风力发电系统故障低电压穿越能力和控制器控制效果。本文工作可为电力系统的规划和运行人员提供参考,帮助他们选择可替代能源发电技术以提高系统的可靠性水平,并选择合适的分析方法对间歇式电源进行研究。更多还原

【Abstract】 In the last few years, deregulation of electric power sector, the economic and environmental concerns over electrical energy derived from fossil and nuclear fuels, the advancement in technology, and the growing requirements for high reliability have created renewed interest in smaller distributed generators operating in parallel with the electric distribution networks.There are several benefits associated with the use of Distributed Generation (DG), such as the system power losses reduction, transmission and distribution upgrades deferral, improved supply reliability and green house effects reduction. However, the interactions between DG and the distribution system in which it is embedded involve several phenomena that are worth careful investigations. If not properly handled, the integration of DG can result in lower reliability and even in a reduction in power quality. Hence it is necessary to develop analytical tools and to conduct thorough analyses and careful studies of the interactions between DG technologies and the distribution system.This thesis is concerned with the interactions between DG and the electric power distribution system and the impacts that the first can have on the second one’s performance. The analysis is focused on determining the impacts of Intermittent DGs (IDGs) on distribution network performances i.e. power quality and reliability, power losses, voltage profile, short circuit current levels, protection coordination and the impact of power system events on the operation of IDGs. The thesis first presents the operational and planning impacts of IDGs on the power system. Secondly, model and simulation algorithm of Wind/PV hybrid generation system suitable for reliability impact study are developed. Case studies were carried out to validate the model and to examine the effect that Wind/PV hybrid IDGs had on system reliability. Thirdly, steady state models that support voltage profile and power losses impacts assessment of fixed speed wind turbine systems are presented and validated. Fourthly, model and dead-beat control structures suitable for grid fault response simulations of the fixed speed and variable speed wind turbine systems, and for ride-through capability analysis of variable speed wind turbine units are suggested. Since the induction machine is currently the most widely used electrical generator in wind turbine applications, a big effort has been paid in dynamic and steady state modelling of Wind Energy Conversion Systems (WECSs) based on it. The basic control structure for these generation units in grid-connected mode is treated. A controller design method based on predictive dead-beat control strategy is presented. The target was to develop a control structure for the active and reactive power that achieves fault ride-through capability of Variable Speed Asynchronous Machine (VSAM) WECSs. The response of a VSAM-WECS to grid disturbances is simulated. A 30% voltage dip (70%remaining voltage) is handled very well.From the results of case studies and contribution, this work provides another reference for system planners and operators in choosing the alternative supply source to achieve a desired reliability level for their systems, and in choosing a suitable evaluation methodology when dealing with intermittent distributed generations.更多还原