Comments on Press Reports comparing Chinese Power equipment with BHEL supplied equipment.

I have started my career as Engineer Trainee in BHEL Haridwar in 1973. I was Erection Engineer and erected 4 out of 5 Turbines of 200 MW at Obra from 1977 to 1982.

Later on I joined NTPC Corporate Office and was involved in Performance Guarantee Tests of Steam Turbines of 200 MW of Singrauli, Korba and Ramagundam. We use to discuss the gap between the Design Heat Rate and actual Station Heat Rate extensively. Being pioneer in India in acceptance testing of Steam Turbines I claim a proficiency and expertise in this area which very few people could match.

I was transferred to Vindhyachal STPS in 1987 and worked in O&M of 6x210 MW Units. In these units I discovered the importance of CW Chlorination in maintaining good Condenser Vacuum which is primarily responsible for Turbine Heat Rate.

I left NTPC in 1996 and worked in DLF Industries, ALSTOM and NASL.

I joined Steag after the company was entrusted with O&M of 4x600 MW IPP at Jharsuguda. I was entrusted with Turbine Maintenance but was also associated with Performance Guarantee Tests of Steam Turbines due to past experience.

My experience at Jharsuguda tells me that Dongfang Steam Turbines are no way inferior to BHEL Steam Turbines and I am shocked to read the following news reports:

Business Standard: CEA shock for Chinese power equipment

The Indian Express: Bhel equipment outperforms Chinese gear on critical parameters, says study

The Financial Express: Bhel equipment outperforms Chinese gear on critical parameters, says study

The Economic Times: Chinese equipment less efficient than supplied by BHEL: Government

I am quoting below from these reports and responding:

The Financial Express: The CEA report found that the operating heat rate of Chinese power equipment works out to 2,719 kcal/kWh compared to 2,520 kcal/kWh for Bhel gear.
The load factor of Chinese equipment averaged 57.2% during the study while it stood at 71.6% for Bhel gear.
Bhel equipment also outdid Chinese hardware on secondary fuel oil consumption. The fuel oil consumption of Chinese equipment was 6.13 ml/kWh while it was just 3.06 ml/kWh for Bhel gear.

The Operating Heat Rate mainly depends upon the Loading Factor. When the Loading Factors are different the comparison is unfair. The Loading Factor does not depend upon the machines but what Load Schedule you get from the grid. The Power Grids are under the control of Government Bodies and give less schedule to Private Companies who are operating the Chinese supplied power plants. Once again the Fuel Oil consumption parameter is based on units generated (kWh) which will be less and the specific fuel oil consumption is more.

As an expert in the field I can say that the report has been prepared just to blackmail the Chinese suppliers and please the Politicians who might be seeking such report.

I am waiting for the Report to be made public and examine it thoroughly.

Important Feed back for KN series Steam Turbines of BHEL.

As per Report of BHEL the KN series Steam Turbines were introduced in 1997. As per the Report there were lot of problems initially and combined HP IP modules called K Turbine were sent back to works and LP Turbine called N turbine were also rectified at site. Thus the KN series.

Recently the combined HP IP module had to be reopened after overhauling due to suspected leakage from Balancing Leak off pipe.

By the way there is a Balance Drum on HP Rotor rear side and a steam pipe called balancing leak of is connected between IP 6th stage and the Balance Drum. There is a sliding joint in the pipe to take care of expansion of inner casing.

The space between inner and outer casing of K Turbine is filled with IP Turbine exhaust steam which is at 302 degC.

Due to leakage in the sliding joint of balancing leak off pipe high temperature steam at 465 degC (full load parameter) was heating the space between inner and outer casing during the cold start causing high HP Top, Bottom and Flange Temperatures, high expansion of HP Outer casing and Rotor expansions. The Top Bottom temperature differential was also high (37 degC).

This is an important feed back for these machines. In case the extraction steam temperature to Deaerator (which should be equal or 1 degC lower than IP Turbine exhaust temperature) is higher than IP Turbine exhaust it indicates leakage in these joints and should be attended by opening the K Turbine.

There are two pipes in lower half of the inner casing and the same has to be removed to attend the leakage.

 

L. P. Turbine Bearings in separate pedestals.

The title may surprise new generation of Turbine Engineers because L. P. Turbine Bearings are mounted in separate pedestals since BHEL the indigenous supplier began manufacturing as per KWU (German) technology.

But if you look at 200/210 MW Steam Turbines manufactured by BHEL as per LMW (Russian) technology the bearing housing is just an extension of lower half of L. P. Turbine. Even the Generator front bearing is placed in L. P. Turbine casing.

Condensers are placed on springs which get compressed due to weight of water in hot well, Condenser Tubes and Water Boxes. This may bring the bearings down and there was a theory that it may affect the alignment between I. P./ L. P. Rotor and L. P./Generator Rotor. Although we did not check the rotor alignment by filling water in hot well (normal level plus additional water equivalent to water in tubes and water boxes) this was done at other power projects. When one such expert visited Obra where I was doing the erection of 200 MW Steam Turbines, I showed him that the alignment was getting affected even due to variation in ambient temperature by taking the alignment readings at 4 PM and 6 AM. This was happening because the L. P. Turbine Casing expands and contracts vertically from its foundation and the height of the bearing from foundation is considerable.

The pedestal mounted bearings have more rigidity and they are not affected by movement of L. P. Turbine Casings due to weight of water or thermal expansion.

Recently I was asked whether 4x600 MW Steam Turbines at Jharsuguda manufactured by Dongfang have bearings in separate pedestals or in the extended portion of L. P. Turbine. The answer is very simple the Steam Turbine at Jharsuguda is state of the art and the bearings are mounted in separate pedestals like BHEL KWU design.