Application of Online Monitoring Technologies in Hydropower Plants Cases in China Application of Online Monitoring Technologies in Hydropower Plants

Contents 1. Power Generating Equipment Online Monitoring System in CYPC 2. Dam and Hydraulic Structure Online Monitoring System in CYPC 3. 4 Cases about Fault Detection with online monitoring system

1.Power Generating Equipment Online Monitoring System of CYPC About us China Yangtze Power Company ltd (CYPC) takes charge of the operation of six huge hydropower plants on the main stream of the Yangtze River, including Three Gorges, Gezhouba, Xiluodu, Xiangjiaba, Wudongde and Baihetan HPPs. By July 2014, CYPC had operated and managed 81 hydraulic power units, and 58 units have the capacity of 700 Megawatt or above.　 Drawn by: Yang Xu Technical Research Center of CYPC Dam site spacing (river channel) With Wudongde and Baihetan HPPs putting into operation in around 2020, CYPC will manage 107 hydropower units, 84 units have the capacity of 700 Megawatt or above.

1.Power Generating Equipment Online Monitoring System of CYPC 5 goals Early warning of equipment accident Operation with high stability and high efficiency Accident cause analysis Online Monitoring System Maintenance decision making Fault mechanism study Goal No. 1 Accidents of hydropower equipment have their own development process. And most of them have symptoms,can be reflected by some parameters. we can monitor the data and their changes to get the accidents in bud.The abnormal online monitoring data can inform us to do something,such as operation condition changing or inspecting after an active shutoff to avoid the accidents happening or further developing. Goal No. 2 The performance of the hydropower units have close relationship with the operation condition.By monitoring the paramaters such as the stability and efficiency, we can know which operation condition the units can generate more power and prolong the service life. Goal No. 3 Due to complex structures of generating equipment, the faults of different equipment may affect and couple with one anothers. When faults and defects happen, the cause and location often cannot be found directly. The monitoring data can give us firsthand information to find them. Goal No. 4 In traditional scheduled maintenance, the maintenance plan is made according to fixed number of years. It may result in “excessive maintenance”or “insufficient maintenance”,, and both of them will lead to extra cost. we can evaluate the real-time condition and developing trend of equipment in time by analyzing the mornitoring data. And make maintenance plan more reasonable with the help of the online monitoring system. Goal No. 5 The hydropower equipment are affected by the hydraulic, mechanical, electrical joint effect. According to present technology, we have not fully mastered the mechanism for the faults. But the faults will leave marks , so we can monitor the data and analyze by some technology , such as data mining technology and hope to find the connection of the faults and the monitoring data. So that we can improve the fault diagnosis technology for hydropower equipment.

single online monitoring individually 1.Power Generating Equipment Online Monitoring System of CYPC developing history The vibration and runout Online monitoring has been implemented in Gezhouba HPP since the 1990s. Monitoring method stability monitoring only stability, turbine discharge, partial discharge, dissolved gas analysis,... Monitoring objects tubine/generator, main transformer, reactor, GIS/GIL, high-voltage cable, governor system, excitation system, etc. turbine/ generator Data Aanlysis method single online monitoring individually Multiple online monitoring systems integrated and the data analyzed comprehensivly

1.Power Generating Equipment Online Monitoring System of CYPC Current situation Hierarchical structure Diagnostic Center Remote access terminal Center level Plant level Gezhouba HPP Left Bank Station of TGHPP Right Bank Station of TGHPP Xiluodu HPP Xiangjiaba HPP The local-level is composed of various special Online monitoring systems of power plants, including the Online monitoring of stability, air gap, DGA, generator partial discharge, GIS/GIL partial discharge, generating discharge, etc. The plant level is to integrate the data of Online monitoring systems within a hydropower plant. The center level is to integrate the data of Online monitoring systems in all hydropower plants of the company. Stability monitoring DGA Generator partial discharge GIS partial discharge monitoring turbine discharge monitoring .... Local level

Special Online Monitoring System 1.Power Generating Equipment Online Monitoring System of CYPC Current situation Existing special Online monitoring systems No. Special Online Monitoring System 1 Stability 10 GIS partial discharge 2 Generator air gap 11 GIL partial discharge 3 Generator magnetic field intensity 12 HV cable partial discharge 4 Generator stator water cooling state 13 HV cable optical fiber temperature 5 Generator partial discharge 14 Turbine cavitation 6 DGA for transformer oil 15 Trubine discharge 7 Transformer partial discharge 16 Thrust bearing force and components of oil 8 Transformer core and clamp grounding current 17 Governor system condition 9 Transformer DC magnetic biasing 18 Excitation system condition

1.Power Generating Equipment Online Monitoring System of CYPC Application Condition Report One report each month The content and analysis method of the report as following: The operating range, conditions and state The trend of the measured parameters under different operating conditions The operating condition characteristecs The measured parameters of different units The existing problems in the operating process Guidance for long-term and stable operation Other analysis methods will be added with the improvement of the technology and our knowledge. Unit: number of times Startup times Shutdown times Output (Megawatt)

1.Power Generating Equipment Online Monitoring System of CYPC Application Report on generating set operating condition This picture shows the results obtained by the stability parameters under different operating conditions throughout a year. We can give suggestion for the next year operation according to the picture, and also can find whether the stable operation area changes or not based on the area comparision year by year.. 19F operating range Water head (m) Output (Megawatt) Restricted operation area Stable operation area Prohibited operation area

2. Dam and Hydraulic Structure Online Monitoring System in CYPC current situation The system of Gezhouba Project was developed in May 1983 at the beginning and has been developed into a complete and mature automatic safety monitoring system after many times of testing and upgrading Three Gorges Hydropower Project is the first hydropower plant in China that adopts special design, special construction, professional supervision and special acceptance for safety monitoring. In this project, a mature monitoring and management mode has formed and a number of key technologies have been adopted. The mode has been promoted and applied to Xiluodu and Xiangjiaba HPPs. Each of these hydropower plants will have over 6,000 instruments connected to the automation system to become the largest dam safety monitoring automation system cluster in China. The River Basin Dam Safety Monitoring Center set up by CYPC will establish an uniform system to manage the safety monitoring of the six hydropower plants.

3.Four Cases about Fault Detection with online monitoring system Runner Crown wearing ring broken and seperated The turbine guide runout and head cover vibration increased significantly according to the online monitoring system, during the shutdown inspections, the runner crown wearing ring was found broken and separated from the runner. The abnormal acquisition data of the on-line monitoring system has prevented the accident from further development. Parameter Normal Operation Abnormal Situation Active power (Megawatt) 680 Turbine guide bearing runout (μm) 82 117 Head cover horizontal vibration (μm) 18 68 Head cover vertical vibration (μm) 10 125 Tailrace downstream pressure pulsation (%) 0.6 2.4

3.Four Cases about Fault Detection with online monitoring system Spiral case guide plate tearing The vibration of upper and lower brackets and the head cover vibration increase significantly according to the online monitoring system, during the shutdown inspections , the spiral case guide plate was found torn. The abnormal acquisition data of the on-line monitoring system has prevented the accident from further development

3.Four Cases about Fault Detection with online monitoring system troubleshooting of Rotor spider cracking It is a case in a foreign hydraulic power plant, and CYPC went to solve the problem. During shutdown inspections , cracks were found on the rotor spider, and the cracks had tendency of becoming larger. The plant did not know why it happened and how to solve this problem. We did the site stability test, and found the unstable operating area is 30MW -90MW , but the unit had been operated under the condition with 75MW-100MW for a long time. The operation condition is the main cause of cracking on the rotor spider, and we gave the suggestion of the stable operation area Active Power Output

3.Four Cases about Fault Detection with online monitoring system troubleshooting of Rotor spider cracking Active Power Output

3.Four Cases about Fault Detection with online monitoring system Application stator bar insulation damage The maximum discharge intensity (Qm) and discharge quantity (NQN) measured by a generator partial discharge online monitoring system both increased sharply; and it was discovered after shutdown that there was a section of iron hose with a diameter of 10 mm between the upper ends of the two lower stator bars , and the stator bar insulation had been damaged. The partial discharge data was back to normal after the stator bars being replaced. D4-D6: maximum discharge amplitude (Qm) began to increase by about 1.5 times D4-D18: shutdown D4-D6: discharge quantity (NQN) began to increase by about 50 times

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