【作者】 吕志鹏；

【导师】 罗安；

【作者基本信息】 湖南大学 ， 电气工程， 2010， 硕士

【摘要】 新兴的大电网与分布式发电(DG, Distributed Generation)相结合的模式被认为是节省投资,降低能耗,提高供电可靠性和灵活性,实现科学用能的重要形式。对于含有分布式电源(一般包括中压等级的大功率分布式电源组成的集中式电站以及低压等级的配套储能装置、负荷以及电力电子转换装置的可控的,高度自治运行的微网)的配电网来说,分布式发电可以综合利用本地优势资源,向用户提供清洁和可靠的能源,但也带来许多消极影响。配电网作为电力系统的最末端直接与用户(尤其是居民用户)相连,本身的电能质量指标就比较落后,分布式发电引入配电系统后其电能质量水平直接影响到用户的日常生活和经济活动,各种电能质量问题如电压跌落、闪变、短时供电中断、三相不平衡以及谐波等问题使得更易发生供电阻塞以及次生故障的发生。在分布式发电高渗透率情况下的配电网中,如何发挥分布式发电的长处,规避其短处,在不增加原有配电网电能质量治理装置硬件开销的前提下,构建高效、节能、高电能质量水平的配电网是很值得研究的问题。在低压等级的配电网中,由于光伏发电逆变器与有源电力滤波器具备相同的主电路结构,本文提出一种带有滤波功能的光伏发电系统及统一控制方法,系统可发出满足负载需要的有功,同时可发出补偿谐波电流以抵消非线性负载的影响,达到了即供能又改善含分布式电源配网电能质量的目的,节省了硬件开销,使得新能源发电更加绿色环保。同时为使微网更易被配电网接纳并担当更多职责,本文提出了一种由静止同步补偿器(DSTATCOM)和微网构成的无功电压协同控制系统。系统由较小容量的DSTATCOM作为连续子系统,进行快速连续无功调节；由微网作为离散子系统,提供较大容量的分级无功功率,二者协同工作实现无功电压的迅速调整。这种联合运行模式有利于降低微网并入配电网的门槛,实现高品质可靠供电,同时也降低了原有用户电力装置的容量,使分布式发电在供能的同时发挥了电能质量调节的作用。在中压等级配电网中,在分布式发电系统中配置静止无功补偿器(SVC, static var compensator)以稳定电压、提高供电质量是目前广泛采取的有效措施,由于SVC本身也是谐波源,本文通过添加谐波检测和滤波环节,使得并网逆变器同时具备供能和滤波的双重功能,来抑制由本地负载和SVC产生的谐波。考虑到现有SVC控制方法难以适应分布式发电间歇性、波动性大的特点,进行了优化递推积分PI的SVC电压控制研究；对添加滤波环节的系统的控制稳定性进行了分析并提出了改进措施,构建的配置SVC的高品质逆变型分布式系统在供能的同时可快速补偿电压波动和消除本地负载和SVC本身产生的谐波,使得分布式发电系统更容易被配网接纳。针对分布式电源、微网的并入对配网带来的消极影响以及其功率可控调度方便的积极作用,本文提出了一种含分布式电源、微网以及电能质量控制装置的配电网电能质量多代理控制系统结构,建立了以电能质量国家标准为控制目标,综合考虑分布式电源及微网极限出力、电能质量校正装置容量为约束条件的配电网电能质量综合控制模型。构建的含分布式发电与电能质量治理装备的经济高效的电能质量控制平台对目前分布式发电的供电质量治理有较好的借鉴意义。更多还原

【Abstract】 New emerging composite system of large grid and distributed generation is considered as an effective mode of saving investment, reducing energy consumption and increasing the reliability. For the distribution network, the distributed generation could utilize the local superior resource, providing clean and reliable energy to users, but also brought many negative effects. Distribution network is mainly connected near the user at the terminal of the power system and the power quality is not good. Various kinds of power quality problems, such as voltage sag, voltage flicker, supply disruptions, short term three phase unbalanced and harmonics etc, in some degree make the occurrence of the power supply blocking and secondary fault more easier happen. In the distribution network with high penetration of DGs and micro-grids, the problem of how to take advantage of the strongpoint of DGs, to avoid its shortcoming and to construct effective, energy-saving as well as high level power energy distribution network, on the premise of not increasing hardware cost of the power quality correction devices in distribution network, is worthwhile to research.Due to the same circuit configuration of gird-connected inverter of PV and active power filter, the micro-grid PV power system with filtering function which can work as the grid-connected inverter and active power filter simultaneously and its corresponding unified control method are presented. A feasibility study for unified control and the system design parameters are put forward. Theoretic analysis and experiments proved the feasibility of this scheme which increases the advantage of distributed generation by supplying enough active power to the load and improves the power quality by suppressing the harmonics caused by the nonlinear load. In order to let micro-grid be more easily accepted by distribution network and undertook much responsibility, in this paper, reactive voltage collaborative control system consisted of DSTATCOM and micro-grid is proposed. It use small-capacity DSTATCOM as continuous subsystem for rapid continuous reactive power regulation and micro-grid as discrete subsystem to provide large-capacity graded reactive power. Their collaborative working could realize rapid adjustment of reactive power.Configuration of static var compensator (SVC)in the distributed power supply system is a widely adopted and effective measure to improve the quality of power supply. As SVC itself is harmonic source, the paper proposed to add harmonic compensation order in the current regulation loop of grid-connected inverter on the premise of not increasing hardware cost, in order to suppress the harmonic generated by local load and SVC. For the existing SVC control method is difficult to adapt the distributed generation’s characteristics of intermittent and fluctuation, the SVC voltage control strategy based on optimal recursive integral PI is put forward in the paper. The paper analyses the control stability of the adding filtering system and proposes improved measurement. The intelligent and high quality power supply system of inverter-based distributed generation with SVC could not only provide power, but also compensate for voltage fluctuation quickly along with eliminating harmonic produced by local load and SVC.Aiming at the negative impact and the advantage of improving the power quality brought by DGs, the paper puts forward a kind of power quality multi-agent control system. According to the united analysis of example under various kind of conditions, the correction and effectiveness of power quality multi-agent control method in distribution system which contains distributed power supply is verified in the paper.更多还原