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

2. 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

3. 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.

4. 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.

5. 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

6. 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

7. 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

8. 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)

9. 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

10. 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.

11. 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

12. 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

13. 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

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

15. 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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