Abstract

This paper presents investigation on availability carried out on six steam unit generators in Egbin Thermal-Power Station in Nigeria. The availability investigation covers from 2005 to 2011 and was done through an exhaustive collection of data from samples of operating facilities in the power station. Data was collected from plant user maintenance log, operation records and manufacturers’ data were also sources of information. This investigation used the IEEE std 762 generator performance indices amongst other calculated key operational availability indices in the evaluations and analysis of the collected data. A software program was developed, ‘Function Outage Parameters (OP)’, using the outage frameworks of data collected from the station. The program was implemented in MATLAB 11.5b which provided user-friendly Graphical User Interfaces (GUI) and corresponding output results in numerical values in tables of values and graphs. The data was used to evaluate all the six generating units available in the station. The result was used to appraise a periodic availability assessment of all the generating units. The study has demonstrated that availability has a very major impact on power generation and plant economy. The investigations ensured quantified (computed) comparative analysis for planned and unplanned outages by using results to estimate unit generators‟ performance capacity credibility. The availability results generated by stations values were: ST01 = 89%; ST02= 89.99%; ST03 =85.24%; ST04 = 87.45%; ST05= 86.50%; ST06 = 29.71% while the overall availability is 88.35%. Result shows reduction in plant availability is caused by increased number and duration of forced outages. The causes and durations of forced outages and unscheduled maintenances were identified through the study of outage causes. The use of a historic failure database to identify critical components for improvement of generating unit availability is demonstrated. While Nigeria is practically hungry for power supply availability to support economic growth and provide basic modern energy services to her people though the energy level is still abysmally low, the facts presented herein are sufficient to exhibit the importance of power availability and unit performance measurement in enhancing the country energy revolution and development.

Key words: Availability, performance, generators, steam turbines, maintenance, reliability.