- At the time of Independence, power generating capacity in the country was 1362 MW only. Many new units were installed after Independence. Up to 1980, the total installed capacity of thermal power stations was 14,250 MW which comprised many imported units of sizes from 30 MW to 120 MW. The average Plant Load Factor (PLF) of thermal power stations during 1976-77 was 56%. However, due to various reasons, the PLF gradually started deteriorating as seen from the table given below:
Year-wise PLF
As a result, thermal generation fell short of the targets, leading to a power shortage of about 11%, as compared to the requirement at that time.Year PLF 1976-77 55.9% 1977-78 51.4% 1978-79 48.3% 1979-80 44.7% 1980-81 4.6% - Roving teams of the Central Electricity Authority (CEA)A number of efforts were made to improve the operation of the units. Task Forces/Roving Teams consisting of experts from CEA, BHEL and ILK were constituted, which went around various thermal stations with a view to identify the defects/reasons for poor performance and to prepare action plans to address the problems. Based on the reports of Roving Teams, many State Electricity Boards (SEBs) prepared schemes for attending to the problems identified and included them in their annual plans. However, lack of adequate funds with some of the States led to lower priority being given to such programmes though there was an urgent need to attend to the problems of the thermal stations.
- Causes for poor performanceThe reasons identified for poor performance of thermal stations included the following:
- Design deficiencies, manufacturing and generic defects.
- The Operation and Maintenance (O&M) deficiencies causing prolonged and repetitive forced outages.
- Inadequate and non timely availability of spare parts especially for imported equipment.
- Lack of resources with SEBs even for making payments to BHEL against supplies & services and for coal supplies to coal companies. Accordingly, they were not able to take up the Renovation & Modernisation programmes to the extent required.
- The quality of coal being supplied had deteriorated as compared to the deigned quality. Besides, the coal had high ash content and contained stones, boulders, shale and sand.
- There was excessive and inadequately trained manpower for the O&M of the plant.
- Stabilisation of 200/210 MW UnitsDuring the early 1970s, it was decided to install bigger units of size 200/210 MW and BHEL started the manufacture of these units. Many such units were installed during 1979-82. Though a large capacity of about 5,000 MW was installed, these units were giving a lot of problems since the beginning and the PLF of these units was as low as 40%. Concerned with this, Stabilisation Teams comprising engineers from CEA, BHEL, ILK and the concerned power utilities were formed. These Stabilisation Teams visited all the stations where 200/210 MW units were installed and identified the problem areas. There were many teething problems and failures due to inherent design defects. These defects were studied and analysed in detail. BHEL and other original equipment manufacturers carried out the required modifications. Most of the modifications were carried out free of cost by the manufacturers on all the existing units irrespective of occurrence of the failure. The modifications were also incorporated for future units. As a result, the performance of these units substantially improved and got stabilised. Because of that efforts, 200/210 MW units are now operating at a level comparable to the of the best in the world. At present, there are about 160 units of 200/210 MW comprising about 44% of the total thermal installed capacity in the country.
