HEI can renovate and modify all the systems of hydraulic turbines and generator units, including seat rings, bottom rings, guide vanes, top covers, control rings, guide bearings, runners, main shafts, main shaft seals, runner ventilators, servomotors, stators, stator cores, rotors, pole coils, upper brackets, lower brackets, thrust bearings, braking systems, neutral points, coolers, firefighting devices, illuminating devices, oil and water pipelines, and excitation systems.