Assessment of performance of turbo-alternators at the Jebba Hydroelectric Power Station in Nigeria from 2005 – 2014

The Nigerian power system consists of several sets of aged turbo-alternators (TAs) associated with frequent failures and limited installed capacity. This paper presents the results of a study of the performance of the turbo-alternators at one of the most important power stations in the country. The energy conversion characteristic of each of the turbo-alternators is studied by comparing the electrical power output with the total hydro-energy available on a daily basis. Similarly the availability was examined by generating the stochastic sequence of up-times for each TA. The results indicate that energy conversion remained essentially linear throughout the third decade of operations. Availability was however found to vary considerably from year to year with the worst performances occurring in the first five years - an indication of poor state of repair of the machines during that quinquennium. In conclusion, the results indicate that despite their age the TAs have many more years of service left provided maintenance is carried out diligently. Enhanced maintainability will however require both retro-fitting and a forward looking maintainability strategy. Keywords: Hydro–Power, Turbo-Alternators, Energy conversion, Availability, Maintainability, Nigerian Power System