Recently, some good news from Peijiang Hydropower Company Limited of China Huaneng Group Co., Ltd. shows that the Ziyili 70MW Francis hydroelectric generating unit whose capacity expansion and reconstruction were undertaken by HEC has been in stable operation for 90 days. The various parameters of the unit have all reached the expected design values, and the owner has given a high praise for the technical, installation and manufacturing levels of HEC. This is one of HEC's significant breakthroughs in the reconstruction projects for these units not manufactured by HEC.
Two Francis hydroelectric generating units with the rated capacity of 65MW and rated head of 445m were installed in Ziyili hydropower station. However, several problems, such as local overheating of iron core at stators’ edges, severely affected the safe, stable operation of the units. As a result, the owner required to fully solve the technical problem of the power station and complete the fully reconstruction of generators' stators, rotators, upper frame supports and other relevant devices within one year.
Before this, technical reconstruction was a huge challenge because HEC had no operational experience of high-rotation-rate units with 65MW or higher capacities. During the implementation of the project, HEC established a design team with specially-selected key designers of the company to conduct field measurement, structural arrangement and calculation validation and formulate schemes. After that, HEC's technical specialists reviewed and modified the schemes for many times. Then, a complete design scheme was established within only 5 months. With such scheme, the problems, such as iron cores' local overheating at the stators' edges of the former units and the radial vibration of upper frames, were successfully solved base on the required capacity increase.