Fundamental Study on Comprehensive Multi-Purpose Utilization of Small Hydropower

本研究的目的是提出小水电综合利用的途径，为小水电的各种利用目的提供最合适的水电回收系统和最优控制，在1998-1999年的研究调查期间，表示“交叉”之义选择了结构简单、制造成本低的贯流式涡轮机作为中、低水头小型水轮机的最佳涡轮机水力和彻底的实验研究的涡轮机。通过改变水头和流量，研究了该涡轮机的性能特性，并通过数值模拟对喷嘴内部的导叶进行了优化修改，以简化涡轮机的结构。对于利用小水电的各种目的，如在孤立的地点发电或连接到电力系统等，最合适的发电机 关于我们 由于涡轮机的导叶被去掉，有时会出现飞逸现象。为此，在2000年首次对涡轮机的飞逸转速特性进行了研究，并提出了一种直接向转轮内部送风的新的送风方式。采用这种新的送风方式，通过紧凑涡轮机的转轮室，使涡轮机的结构更加简化。结果，涡轮机的尺寸显着减小，同时最大涡轮机效率提高了1.3%，在高转速范围内效率提高了9%。此外，为了更有效地利用变水头的微型水力资源，开发了两种由低成本商用电力电子元件组成的变速微型水力发电系统。一种是由同步发电机和电子负载调节器组成，用于隔离运行，另一种是由感应发电机组成，用于连接到电力系统。试验结果表明，采用该系统后，涡轮机性能和系统总效率在变工况下有较大提高。通过试验确定了简化贯流涡轮机在变水头下的性能特性，为小水电的有效利用提供了理论依据。少

Purpose of this study is to propose an approach to comprehensive multi-purpose utilization of small hydropower and to provide the most appropriate hydropower recovery system and the optimal control for each purpose of utilizing small hydropower.In the research and investigation period for 1998-1999, a cross-flow turbine that has simple construction and low fabrication cost has been selected as the most appropriate water turbine for medium and low head small hydropower and a thorough experimental investigation of the turbine was made. The performance characteristics of the turbine was investigated by varying head and flow, and for the purpose of simplifying the structure of the turbine, a guide vane in the nozzle inside was removed and the shape of the nozzle was modified optimally by using a numerical simulation. And for each purpose of utilizing small hydropower, such as generating electric power in an isolated site or connecting to power system etc., the most appropriate power genera … More ting system and the optimal operation method have been identified.Because the guide vane of the turbine is removed, at sometime runaway speed phenomena may happen. Therefore in the year of 2000, the runaway speed characteristics of the turbine were firstly investigated, and a new air supply method that supplies air directly into the runner inside was proposed. Using this new air supply method, the turbine structure is more simplified by compacting the runner chamber of the turbine. As a result, the size of the turbine was remarkably reduced and in the meanwhile the maximum turbine efficiency was improved by 1.3%, and a 9% efficiency improvement was obtained in the high rotational speed range.Furthermore, in order to utilize micro hydropower resource that has variable head more effectively, two variable speed micro hydropower systems that consist of low-cost commercial power electronic elements have been developed. One is composed of a synchronous generator and an electronic load governor for the purpose of applying to an isolated operation, and the other is composed of an induction generator for the purpose of connecting to power system. The experimental results showed that turbine performance and total system efficiency at off-design heads are improved much by using these systems. The performance characteristics of the simplified cross-flow turbine under variable head were also determined experimentally.From the above results, the work of the study can contribute to effective utilization of small hydropower. Less