Its All About Power Sector

Central Electricity Authority has done two studies on Design and Performance of Chinese Equipments. The two studies made were, the first one included Design Features of Boilers and Auxiliaries being sourced from Chinese Manufacturers in year 2008. The second one was to Analyze the performance of Chinese equipment vis-a-vis Indian equipment in year 2013
Details of Study on Design Features of Boilers and Auxiliaries from Chinese sources.

• The Study Covered 5 stations with 300/330 MW and 2 stations with 600 MW . units (All Sub-critical)
  • 300/330 MW Units - Yamunanagar- HPGCL, Durgapur- DPL, Sagardighi- WBPDCL, Lanco-Amarkantak, Mundra-Adani Power.
  • 600 MW Units- Lanco Anapara C, Hissar HPGCL.
• Only 3 Commissioned Stations - Yamunanagar, Durgapur & Sagardighi.
• Main Findings in this study.
  • The technical particulars relating to major design features of boiler and their auxiliaries found to be in line with good engineering practices- any generic design issues could be best known after these units operate for an initial period of about one to two years.
  • Initial 1-2 years of operation of any plant are critical and will bring out inherent generic deficiencies, if any.
  • Operational feed back then available indicated milling Constraints in some units
  • Secondary fuel oil consumption has been found to be high in all the three operational projects.
  • Layout constraints Found in some of the plants which may result in difficulties in attending to the equipment during maintenance.
  • Data Gaps- No information from Chinese manufacturers on design features, operational performance, Standards followed during manufacturing & testing procedures. Lack of Sufficient data with plant owners.
  • Some of the utilities did not have complete information about important technical particulars -During interaction with the project authorities of the three operating stations, it has emerged that there has been substantial lack of participation by the utilities in the areas of technical specifications, detailed engineering, quality inspection at works, erection supervision, training of O&M personnel, etc.
  • Important equipment drawings/ technical data/ documents were not available with the projects. Design data was also not available with some IPPs sourcing the equipment from Chinese manufacturers.
• Recommendations - Need for due diligence
  • Due diligence required by the utilities during stage of specification finalization and detailed engineering, inspections/testing etc. to minimize O&M problems
  • Detailed comprehensive quality plans for ensuring quality at works and at site identifying customer hold points and test procedures and Standards needs to be defined and implemented for each major equipment/system. Some of the utilities were found lacking in this regard

Details of study to Analyse the performance of Chinese equipment vis-a-vis India Equipment.

• A study to Analyse the performance of Chinese equipment vis-a-vis Indian equipment was taken up by CEA in 2011 - through a Committee of CEA and NTPC.
  • The Objective of the study was to analyse the performance of Chinese equipment vis-avis Indian equipment (BHEL) including coal consumption patterns, heat rate and efficiency achieved.
  • Areas Covered
    • Operating Load Factor (OLF), Outages/Downtime
    • Design Parameters- Turbine cycle Heat rate & Boiler Efficiency Flow Margins
    • Operating Efficiency - Heat Rate and Specific Fuel Oil Consumption
    • Problems in Erection & Commissioning
• Units Considered in Study 2  
  • The Study covered Chinese Subcritical units of 300 and 600 MW and BHEL Sub-critical units of 250 and 500 MW units commissioned in 11th Plan (2007-08 to 2010-11)
  • Chinese capacity covered - 8200 MW
    • 22 Units across 11 stations
  • BHEL capacity Covered -12480 MW
    • 36 Units across 22 Stations

• Study-2: Details of Manufacturers
  • Manufacturers Wise Break up of Capacity

• Thus Most Chinese Supplies from Dongfang and Shanghai (SEC).
• Main Finding - Steam Parameters & Heat Rate
  • Steam parameters and Design Turbine cycle heat rate

The regenerative system configuration of Chinese machines is different from BHEL machines and Chinese 300 MW units have higher steam Pressure also. Thus on like to like comparison basis the BHEL machines indicate higher cylinder efficiency implying that their design/construction in terms of blading provided, sealing etc. renders higher efficiency
Expected THR of BHEL machine with similar configuration - 1890 (250 MW) and 1932/1920 (500 MW)

• Main Findings - Flow Margins
  

Both, the Chinese 300 & 600 MW and BHEL 250 & 500 MW units have adequate flow margins - VWO and BMCR margins. However the Chinese 330 MW machines have a composite TMCR to BMCR margin of 5.34 % which is very low and not compliant to the CEA Technical Standards and may not meet IEGC provisions.

• Main Findings -Outages and Load Factors
  

CEA Monitoring Data
PLF - 2011-12 (units in Study) - Chinese (D) -66.19, (I) 75.46, BHEL- 76.68
PLF - 2012-13 (units in Study) - Chinese (D) -52.27, (I) 81.57, BHEL- 78.13

• Main Findings - Operating Heat Rate
  

Chinese imported coal based units show much lower heat rate than indigenous coal based units - the difference is far higher than envisaged due to the boiler efficiency difference.
Variations in Operating Heat Rate of BHEL units are seen. Six stations show operating deviation (below 5%, four stations show deviation of around 10-11 %. Rest of the stations show very high deviations of 15-25 % and even higher.
Chinese indigenous coal based units generally show high operating deviations.

• Main Finding - Specific Secondary Fuel Oil Consumption (SFC)
  

SFC for Chinese imported coal based stations is considerably lower than indigenous coal based stations. Indigenous - 2.5 to 5 ml/kWh. Best Yearly values Indigenous- 0.90, Imported- 0.53.
Large number of BHEL supplied stations show very low SFC of below one ml/kWh. The lowest overall (2007-11) SFC is 0.27 ml/kWh followed by 0.47, 0.52, 0.54 and 0.81 ml/kWh.
The yearly SFC for individual BHEL stations are even lower. The best yearly SFC is 0.16 ml/kWh followed by several instances of yearly SFCs in the range of 0.20 to 0.50 ml/kWh.

• Station Visits
  • Visits to Stations

• BHEL stations - Generally satisfied
• Chinese Stations - Mixed Bag. Widely different feedback from two stations visited.

• Main Finding - Turbine Control Systems

The level of automation in Chinese turbines is much less than the BHEL turbines The Chinese turbines do not have many analysis/diagnostic functions and equipment safety features such as Turbine Stress Evaluator (TSE) and Auto Turbine Run-up Systems (ATRS) in their control system. Thus, lot of manual interventions are envisaged during start up as well as during normal operation of Chinese machine contrary to philosophy of fully automated system with minimum manual intervention in BHEL machines.
Thus the control systems of Chinese turbines are not in line with the prevailing modern turbine design/technology. Manual intervention during critical operations gives rise to subjectivity with the possibility of mal-operation and accidents.