Its All About Power Sector

• The Design Turbine Cycle Heat Rate (THR) for Chinese 300 MW units is around 1910 kcal/kWh as compared to around 1945 kcal/kWh for BHEL 250 MW units. However, the Design Heat rate for Chinese units do not correlate well with the steam flows indicated and large variations in design steam flows are seen for similar indicated design THR.
• The Design THR of Chinese 600 MW machines is 1954 kcal/kWh for two stations and 1945 kcal/kWh for one station. However, the Design Heat rates for Chinese machines do not correlate well with the steam flows indicated. The Design THR of BHEL 500 MW machines is around 1944 kcal/kWh for normal reheat temperature and 1932-1936 kcal/kWh for higher Reheat temperature (565 deg C) machines. Thus the Turbine cycle heat rate of BHEL machines is better than the Chinese 600 MW machines - by about 10 kcal/kWh for BHEL normal reheat temperature machines and 22 kcal/kWh for higher reheat temperature machines.
• However, 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
• Amongst the Chinese 600 MW and BHEL 500 MW turbine generators, only the BHEL machines with higher Reheat temperature of 565 deg C comply with the minimum efficiency criteria (maximum THR of 1935 kcal/kWh) prescribed in the CEA Technical Standards for Construction of Electric Plants and Electric Lines Regulations - 2010.
• The anomalies/discrepancies in the design Turbine Cycle Heat Rate, Steam flows design margins of Chinese machines is indicative of lack of due diligence by the suppliers and utilities/generating companies on the above aspects - some of them being mandatory as laid down in the CEA Technical Standards for Construction of Electric Plants and Electric Lines Regulations - 2010.
• It is thus suggested that the generating companies while making Tariff Application to CERC/SERC may be asked to furnish details key design/efficiency parameters with an undertaking certifying compliance to "CEA Technical Standards for Construction of Electric Plants and Electric Lines Regulations 2010". It is suggested that a formal advice to the above effect may be issued to Central Electricity Regulatory Commission.
• The Design boiler efficiency for BHEL units and Chinese units designed for indigenous coal is of the same order. However overall variability of design boiler efficiency amongst stations is higher for Chinese units. Also, apart from the design boiler efficiency, the operating efficiency with coal quality variations within or outside the design coal quality range is important. However such feedback would be available only after sustained operation of stations with different quality coals.
• 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 does not appear to be compliant to the CEA Technical Standards for Construction of Electric Plants and Electric Lines Regulations - 2010 and the provision of instantaneously load picking of the Indian Electricity Grid Code (IEGC).
• Chinese units based on indigenous coal show a much lower Operating Load Factor (OLF) than the Chinese units based on imported coal. The overall average OLF for Chinese stations based on imported coal works out to 80.4 % while for Chinese stations based on indigenous coal it works out to be 57.2 % against 71.6 % for BHEL units. Thus the Operating Load Factor of BHEL units with indigenous coal have been higher than Chinese units based on indigenous coal.
• Total outages for Chinese units based on indigenous/domestic coal are higher than the Chinese units based on imported coal and BHEL units. The overall average of total outages for Chinese units based on indigenous coal is 23.5% while it is 14.1 % for Chinese units with imported coal and 18.7 % for BHEL stations. Excluding stations with very high outages, the total outages are 17.4 %, 7.6 % and 12.6 % respectively for Chinese indigenous coal, Chinese imported coal and BHEL units.
• The Operating Heat Rate (OHR) of Chinese indigenous coal based units is considerably higher than BHEL units and Chinese units based on indigenous coal. The overall Operating Heat Rate is 2719 kcal/kWh for Chinese indigenous coal based units and 2520 kcal/kWh for BHEL indigenous coal based units''. Also the Chinese units indicate higher operating deviation from design heat rate Vis-a-vis BHEL units.
• The OHR for Chinese imported coal based units is 2275 kcal/kWh and the difference vis a vis Chinese indigenous coal is considerably larger than could be accounted for the higher boiler efficiency (due to better coal quality) thereby implying that units with imported coal have been performing better than indigenous coal based units.
• Large number of BHEL stations have shown very low Operating Heat Rate with deviation from Design Heat Rate (DHR) of 2-5 % while most Chinese units with indigenous coal have shown much higher Operating Heat Rate - with deviation from DHR of around 10-12 %. The operating deviation for Chinese units based on indigenous coal is much lower than Chinese indigenous coal based units.
• The BHEL units show remarkably better performance with respect to Secondary Fuel oil consumption as compared to Chinese units based on indigenous coal.
• The overall SFC for Chinese units with indigenous coal is 6.13 ml/kWh and for BHEL indigenous coal based units'' 3.06 ml/kWh. The overall SFC for Chinese units based on imported coal is 1.34 ml/kWh.The level of automation in Chinese turbines is much less than the BHEL turbines. The Chinese turbines do not have many safety and analysis/diagnostic functions 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. Manual intervention during critical operations gives rise to subjectivity with the possibility of mal-operation and accidents

The above facts speak that the control systems of Chinese turbines seem to be not in line with the prevailing modern turbine design/technology. In this view in July 2012, the government had slapped 21 per cent import duty on power equipment. The Cabinet, last year, had approved 5 per cent basic customs duty, 12 per cent counter-veiling duty and 4 per cent special additional duty on import of power gear. As domestic industry has enough capacity to provide after-sales services, the Chinese firms have already captured as much as 40% of the domestic market where an opportunity of annual sales of 17,000 Mw capacity exists at present. India has a current domestic equipment manufacturing capacity of 27,000 Mw. Power equipment worth Rs 130,000 crore was sold in India last financial year. Around 28% of this comprised generation equipment while the rest 72% of the sales occurred in the transmission and distribution sector.

At times it sounds necessary for India to look for import of Chinese Equipment in order to meet its projected capacity additions which is also very vital for the country be to be more energy secured. The Indian government's support to the domestic manufacturers as not been so encouraging with many manufacturers expressing a discomfort from the recent decisions taken by the govt. in respect to Chinese Equipment manufacturers. All these entail the Indian Govt. to provide a more competitive platform so as to balance both these markets.

Content Writer: Sweta Bhattkoti (Research Analyst @ Cerebral Business Research Pvt. Ltd)