HYDRAULIC STUDIES FOR UPGRADING AGING HYDRAULIC GENERATING STATIONS
by
I. Corbu¹, K. Ho², L.M. Lai², C. Zygouris²

ABSTRACT

Ontario Hydro has a total installed generating capacity of 30,200 MW of which 7,100 MW is hydraulic. Many of its 68 hydraulic generating stations are old and the average age of the existing 265 turbine units is about 57 years.
Since the existing generating system will provide the major share of Ontario's growing electricity needs over the next 30 years, Ontario Hydro has given a high priority to the upgrading of its aging hydraulic turbine-generating units.
This paper describes the computing tools and methodology that have been recently applied to calculate the expected increase in energy generation and capacity corresponding to various unit upgrade scenarios. The results of these studies are used to calculate the economic indicators for each upgrade scenario. A study case for upgrading the units of the hydraulic generating stations located on the Nipigon River in Ontario, Canada is presented.

INTRODUCTION

Ontario Hydro is a power utility responsible for the generation of electricity in the province of Ontario. Its installed generating capacity of 30,200 MW consists of 7,100 MW of hydraulic, 10,700 MW of fossil and 12,400 MW of nuclear generation.
The hydroelectric generation is produced by 68 generating stations which are equipped with a total of 265 turbine-generating units having an average age of 57 years. Fifty four units with a capacity of 2,124 MW have been upgraded since 1974. However, there are still one hundred and ninety units with a total capacity of 3,477 MW which are more than 30 years old. Many of these units are potentially upgradable.
Over the last 10 years, hydraulic unit outages have lasted longer, occurred more often, and resulted in increased production losses.
Any loss of hydraulic generation is usually replaced with more costly fossil generation from Ontario Hydro stations. However, an increase in fossil generation may be restricted by the tight acid gas emission limits imposed by government regulations. This may necessitate replacing the lost hydraulic generation with electricity imports from neighbouring utilities at significantly higher costs.
In the future Ontario Hydro will have to satisfy a steadily increasing demand of electricity. This will be met by developing and blending both supply and demand options.
On the supply side, a balanced mix of increasing all means of acceptable sources of generation are being considered. Hydraulic generation will be increased by developing new sites, by promoting non-utility generation and by maintaining and upgrading turbine-generating units.
The need for more efficient and reliable hydraulic units has prompted a corporate program for turbine-generator upgrade.