Experimental Study On Hydrogenerator Instable Running And Its Improvement Measures In Ankang Hydropower Station

A series problems, such as hydrogenerator vibration, rupture of upper stay column and speed ring, crack of runner vane, damage of the servomotor guide tube and the diversion cover plate & cavation of draft tube, have appeared on 200MW hydrogenerator in Ankang Hydropower station for the reasons of design, manufacture, setting and running.In this paper, test, examination, calculatation, analysis and study has been conducted in the light of some main problems.Through the stability test on different water head and load, it is found that the flow vortex core pulse on low load caused the instability of 200MW hydrogenetor running. The practical stable running range is put forward, i. e, the hydrogenerator shall be running on exceeding 100MW. It has effectively directed the adjusting, overhaul and running of hydrogenetor in Ankang Hydropower station.This paper adopts the 3D finite element analysis program to find the rupture reason of speed ring and screw, i. e, the stress is out of permissiblerange. Those problem has been solved through adjustment and treatment.Using non-destructive test and analysis of material chemical element, the reason of crack runner vane has been found. The internal reason is the content of C and P exceeding standard, the external reason is fatigue damage resulted from the long time vibration. It is suggested to weld and apply anti-abrasion-cavitation material on seriously cavitated area, obvious result has been abtained.The implementation of up-rating and retrofit for hydrogenerator which is most radical and effective to slove the problems is raised at the end of this paper.