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Vol. 29 No. 2 June 2006

3-D CFD Analysis Results of Modified LP Exhaust Hood

DEVELOPMENT OF A NEW DESIGN VARIANT OF LP TURBINE OF 200/210MW LMW RUSSIAN DESIGN FOR UPRATING

At present,there are 57 Steam Turbines Generatingsets of 200/210 MW of LMW Russian design inoperation,which form the backbone of powergeneration of the country. Design of these sets datesback to early 60s and a majority of them havecompleted more than 20 years out of their servicelife of 25 years. To upgrade these old in-serviceSteam Turbines,a new variant of LP Turbine hasbeen developed by BHEL-Haridwar. State-of-the-artdesign tools have been used in designing of this new

variant: 3-D modellng for design evolution, 3-DFinite Element Method for structural analysis and3-D CFD for flow path analysis. The implementationof new design shall result in gain in output by8.5 MW (204 MW to 212.5 MW) and improvementin heat rate by nearly 86 kcal/kg (from 2142 kcal/kgto 2056 kcal/kg) i.e. by 4%. This new development

will enable BHEL to tap huge business potential inthe retrofit area.

The New Design Features :

New state-of-the-art reaction-type, integral LProtor with advanced class Siemens blading of N302*6.3 sqm., has been incorporated in placeof the existing shrunk-on disc-type impulse rotor

with inefficient bauman penultimate stage.

The new design of LP rotor shall have integralcouplings, instead of semi-flexible coupling.

Shaft sealing glands have been made of see-through type as per Siemens design, whichpermits unrestricted relative expansion betweenrotor and casing.

New liners and guide blade carriers have beendesigned to fit in the existing LP casing.

New exhaust diffuser has been designed to guidethe exhaust flow to the condenser.

Modification of the LP casing front and rearexhaust part has been done by cutting a few platesto accommodate the newly designed LP rotor andflow path.

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The Castings

CASTINGS OF STATE-OF-THE-ARTH-COMPACT MOTOR DEVELOPED

BHEL-Bhopal has successfully developed critical &intricate Siemens design H-Compact ILA435 motorframe, end shield & internal fan patterns & castings.The first H-Compact motor (355 kW, 4 pole, 6.6 kV,50 Hz, SCIM Frame ILA4 352-4), using the above-mentioned castings, has also been successfullymanufactured & tested, and handed over to thecustomer, M/s Chethar Vessels Pvt. Ltd., Trichy.

The frame & end shields are made of IS 210 Gr. 200grey cast iron with external cooling ribs over the entirelength and internal cooling ribs at both DE & NDE.The frame also has box section feet over the entirelength and four axial ducts for internal cooling circuit.The frame pattern & core boxes are made of wood

with cast aluminium LM6 alloy ribs fixed on the wooden base. The frame was cast using 11 cores bycore-in-core assembly in the mould and bottompouring. The internal fan was cast in LM6 aluminiumalloy in shell mould. The end shield metallic pattern

was also developed & manufactured.

operating cost. The higher-reliability bearing designresults in low vibration, long bearing life and lowmaintenance costs. Micalastic insulation with vacuumpressure impregnation results in high reliability, longlife and high-load capability under fault conditions,acceleration & overload.

This development is expected to increase BHELsmarket share in motors business.

SOLAR PHOTOVOLTAIC (SPV)-DIESEL HYBRID SYSTEM SET UP

AT BANGARAM ISLAND OFLAKSHADWEEP

Bangaram Island, located in Arabian Sea, attracts alarge number of international tourists. To cater to theelectrical load requirements of this tourist resort, BHELhad supplied, installed and commissioned a 10kWpstand-alone SPV system in the year 1993. As theelectrical load increased over the period of time,Lakshadweep Electricity Department (LED)subsequently commissioned BHEL to install an SPV-Diesel hybrid system comprising a 50kWp SPV array,240V maintenance-free battery bank, 2 nos., each of 75kVA, 3-phase, 415V, 50Hz, Diesel Generators(DGs) housed in a sound-proof FRP enclosure.

Accordingly, the system was designed & set up by

BHEL, and it has been performing satisfactorily forthe last one year. . Encouraged by the savings of fuel(diesel) and silent operation, LED is planning to installsuch systems in other islands of Lakshadweep as well.

Diesel can be substantially saved by employing theSPV-Diesel hybrid system. The control strategy of thesystem ensures that during the time when the site loadis less than 25kW, supply of power to load is from theSPV source only. This leads to substantial saving of diesel (40%-50% savings). Accordingly, solar arrayof 50kWp has been sized so as to generate an averageof 150 units per day.

System Operation:

The solar PV array also charges the battery bank through charge controller and keeps the battery bank in FLOAT mode, while feeding power to the site load

via a 3-phase, sine wave inverter. During low-sunshineperiods, the battery bank supplies the required power

The cast iron frame & end shield with cooling ribsprovide a rugged, torsionally rigid design, enablingextremely high loading capability & enhanceddamping characteristics, leading to lower noise &

vibration levels compared to the fabricated frame &end shield in conventional motors.

With this development, the era of H-Compact motorshas started in BHEL. The H-Compact motors have amore compact design with higher power density &optimized efficiency, resulting in lower weight-to-output ratio, smaller space requirement and lower

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to the load. As the battery reaches a predetermined vo ltage , one of the di esel gene ra to rs star tsautomatically and gets synchronised to the inverteroutput. Now, the diesel generator charges the batterybank (being a bi-directional inverter) and feeds powerto the site load also, thus ensuring that the DG set isoptimally loaded. Should the site load increase tomore than the capacity of one DG set and theavailable SPV power, another DG set alsoautomatically starts and gets synchronised to therunning generator, thereby meeting the increaseddemand of the site peak load. When the site load getsreduced, the DG sets automatically get switched off,thereby conserving the diesel. If the site load is suchthat the combination of one DG set and SPVgeneration can meet the site load requirements, thenthe operation of the two DGs alternates so that they

will have equal wear and tear. To facilitate solo andparallel operation of the generators in conjunction

with the solar inverter, a parallel generator set controlmodule (PGCM) monitors the parameters of Gensetsand also has a built-in synchroniser. The system hasa built-in SCADA for local and remote data logging

via a telephone line.

The DG Sets

The Solar PV Array

TEST FACILITY FOR DEEPWELL SPV WATER PUMPING SYSTEMESTABLISHED IN-HOUSE

For marketing SPV water pumping system throughMNES / IREDA programme, it is necessary to getempanelled with MNES. For this purpose, it isessential to establish in-house a test facility for the SPVWater Pumping System and collect data over asuitable period. In line with the above requirement, atest facility has been established to carry out long-term testing of the High-Efficiency SPV DeepwellWater Pumping System developed earlier atCorporate R&D Division of BHEL.

The test facility has been established with the followingfeatures :

Two PV arrays, using 12 nos X 75 Wp PV modulesand 8 nos X 100Wp PV modules

Two 500-litre plastic water tanks with piping formeasurements along with pressure gauges and

water flow meters

Two automatic solar tracking structures for the twoPV arrays

The automatic sun-tracking system has been installedfor tracking the sun from East to West everyday so

that the PV array mounted on it keeps receiving themaximum available solar energy daily. . A very smallportion of the power from photovoltaic array is beingused to drive the motor in steps with a small controller,for the tracking system. The tracking structure isdesigned to withstand wind speed of 150 km / hour.

The high-efficiency water pumping system developedearlier using non-tracking, fixed-tilt PV array of 840 Wp rating has been tested with the newly installedautomatic active solar tracker using slightly smallerrating (800 Wp) PV array. Due to the sun trackingsystem, the daily water output has increased from19300 to 26750 litres per day (LPD) at 40m head,i.e. by 38.6%.

The automatic active solar tracker can be usedeffectively for remote stand-alone applications such as

water pumping, battery charging and other PV powersystems. Due to self-standing structure design, theseautomatic solar trackers can be easily installed on theterrace of multi-storeyed buildings and apartments for

water pumping and other PV power applications.

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Issued quarterly by the Corporate Office, Bharat Heavy Electricals Limited, BHEL House, Siri Fort, New Delhi-110049, Website : http://www.bhel.comEditor : R.K. Bhattacharya. Associate Editor : D. Roy. Printed at I G Printers Pvt. Ltd., New Delhi-110020. Phones : 26817927, 26810297. Telefax : 26817927 For Private Circulation only

With this test set-up, it is now possible to collect long-term test data of deep well / high-head SPV pumpingsystems as per MNES / IREDA norms.

STATE-OF-THE-ART INVERTER DEVELOPED FOR INDIAN RAILWAYS FOR 3300 HP DIESEL-ELECTRIC LOCOMOTIVE WITHHOTEL LOAD FEATURE

The hotel load, consisting of fan, light and airconditioner load of passenger coaches of fully air-conditioned trains, is traditionally being catered tothrough two power cars connected on either end of the locomotive. Each power car has two DG sets. Since

Diesel-Electric Locomotives have an arrangement of power generation,Indian Railways approached BHELfor developing a system which can draw power fromdiesel engine and supply it to passenger coaches at3-phase, 750 volts, 50 Hz., resulting in replacementof one power car with passenger coach, therebygenerating extra revenue for the Railways. BHELaccepted the challenge, and consequently Railwaysplaced order for two sets of the electrics onBHEL. Accordingly, the two sets have beenmanufactured,and successfully tested in the presence The Inverter with Covers

of representative of RDSO, Lucknow. One set hasbeen dispatched to Diesel Locomotive Works,Varanasi, for commissioning on 3300 HP Diesel-Electric locomotive specially developed for thisproject. The inverter has been developed for the firsttime in the country.

BHEL-Bhopal and Corporate R&D Division havedeveloped the complete system in-house. The systemincludes: microprocessor-controlled IGBT-basedinverter, choppers for excitation controls of main &companion alternators, software for control, troubleshooting & data logging. The snubber-less, fuel-lessdesign of IGBT inverter results in reduced number of components and leads to higher efficiency andincreased reliability. Microprocessor-based controlsused provide fault monitoring and self-diagnosticsfeatures in addition to controls and protections. Thecontrol philosophy has been developed to ensuresafe working of the hotel load inverter in tandem withpower car to provide redundancy. In case thelocomotive with the new hotel load system is used ingoods train or in multiple-unit operation with aconventional locomotive, the power used for hotelload can be made available for traction by operatinga simple switch.

The total output of the inverter is 290 kW, out of which240 kW i.e. 300 kVA at 0.8 power factor will be usedfor the air-conditioning & other load of passenger

coaches. The remaining 50 kW power is used forexcitation of machines, battery charging and otherauxiliary loads.

This project is very prestigious for both Indian Railwaysand BHEL in view of the novelty and innovativemanner of catering to the hotel load and the locomotiveload through the Diesel-Electric Locomotive.

The Test Facility for SPV Water Pumping System