Yang S.,Xiluodu Hydropower Station |
Chen H.,Xiluodu Hydropower Station
Gaoya Dianqi/High Voltage Apparatus | Year: 2015
When outage of a GIS breaker happens, the whole dielectric loss of the parallel capacitor between the circuit breaker contacts cannot be measured because its adjacent circuit breakers at both sides or the busbar still operate with electricity. In this paper, the difficulties in measurement of whole dielectric loss of parallel capacitor between contacts of a GIS circuit breaker in outage state are analyzed. A method of connecting before break to prevent high voltage and ensure safety and forming neutral point to eliminate coupling high voltage and strong electric field interference is proposed. Test results verify that this method is safe, applicable and convenient. ©, 2015, Xi'an High Voltage Apparatus Research Institute. All right reserved.
Zhang F.,China Institute of Water Resources and Hydropower Research |
Geng Z.,Xiluodu Hydropower Station |
Fu J.,China Institute of Water Resources and Hydropower Research |
Pan L.,China Institute of Water Resources and Hydropower Research
Zhendong Ceshi Yu Zhenduan/Journal of Vibration, Measurement and Diagnosis | Year: 2015
In order to achieve online flywheel moment monitoring, formulas to calculate the flywheel are derived and research on the flywheel moment is performed based on the increase in speed in the load rejection mode of a hydro-generator unit. A new method is proposed to monitor the flywheel moment. Speed signal sources are sorted into analog signals from the control system and signals from the toothed disc. For the analog speed signal, the wavelet theory is adopted to de-noise the signal, then the correlation coefficient between the speed and defined time is calculated to determine the effective increase in speed within the defined correlation coefficient. For the signal from the toothed disc, a maximum correlation coefficient between the speed and the limited period of time is calculated to determine the effective speed signal. Finally, the flywheel moment is calculated based on GB/T1029-2005. The effectiveness of this method has been tested and verified through case study. ©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.