Research on Quality Control Center in Power Systems for Coming in Practice

本研究计画的目的在于探讨一种新的配电系统FRIENDS的核心--品质控制中心（Quality Control Center，QCC），以供实际应用。主要结果如下：1.研究了QCC高压侧与网络线路连接的故障，揭示了其特点.研究了实现灵活网络重构的转移交换方法。因此，开发了“单独晶闸管控制方法”和“利用UPS的转换开关”。后者不受切换前后系统电压幅值和相角的影响.在UPS型内部结构中，提出了一种利用PWM控制变换器独立控制三相电压幅值和相位的三相不平衡负载补偿方法.通过将负载变化分为快、慢两部分，提出了PWM变换器与分散储能系统（DESS）的分担与协调方法.为了提高可再生能源系统作为电源的价值，提出了一种与可再生能源系统协同工作的DESS控制方法.提出了统一电能质量控制器（UPQC）型配置作为QCC的内部结构之一，它可以在高压侧电压波动的情况下实现高质量的电能分配，并消除UPS型的谐波失真和三相负载间的不平衡.研究了直流配电的经济性，分析了直流负荷的潜在比例。提出了QCC生产能力需求和设备边际成本的估算方法.研究了QCCs的自主、分散和协作运行，证实了多智能体的概念将是有前途的。

This research project aimed to investigate a Quality Control Center (QCC), the core of a new power distribution system FRIENDS, for coming in practical use. The brief results are as follows :1. Configurations of connection between the high voltage side of QCC and network lines were investigated and the features of them were revealed.2. Transfer switching methods to realize flexible network reconfigurations were investigated. As a result, "Individual Thyristor Control Method" and "Transfer Switching Utilizing UPS" were developed. The latter is not effected by the system voltage magnitudes and phase angles before and after transfer switching.3. In an UPS type interior structure, a compensation method of the unbalanced three phase loads was proposed by controlling three phase voltage magnitudes and phases with PWM controlled converter independently.4. By dividing the load changes into quick and slow elements, a method for sharing and cooperating between PWM convertors and Dispersed Energy Storage Systems (DESS) was developed.5. To improve the value of renewable energy systems as power sources, a control method of DESS for cooperating with them was developed.6. UPQC (Unified Power Quality Controller) type configuration was proposed as one of interior structure of QCC.It can realize high quality power distribution under the voltage fluctuation in high voltage side and cancel the harmonics distortion and unbalances between three phases of loads as UPS type.7. The economical merit of DC power distribution for potential percentage of DC load was investigated. Estimation methods for necessaries of capacities and marginal cost of equipment in QCC were developed.8. Autonomous, decentralized and cooperative operation of QCCs was investigated and it was confirmed that the concept of multi agent would be promising.