30-01-2013, 10:14 AM
MANUFACTURE OF TURBO GENERATOR INDUSTRY ORIENTED MINI PROJECT REPORT
MANUFACTURE OF TURBO.doc (Size: 3.3 MB / Downloads: 100)
ABSTRACT
GENERAL ASPECTS deal with the principle on
which a turbo generator works on and the classification of turbo generators basing on drives, speed and cooling system
ELECTRICAL DESIGN AND MANUFACTURE of stator comprises of stator core, stator core, stator coil/bars, stator winding, output leads/brushing and face connectors design and manufacture.
In general the losses in a generator are manifested in the form of heat. This heat must be dissipated out as early as possible, otherwise there may be damage to the stator and rotor parts. Thus a cooling system is provided in the generator to dissipate the heat (losses).
There may be possibility of presence of moisture in stator and rotor parts. Hence flux linkage with the moisture present, which leads to the losses. Ultimately the heat to be dissipated is more. To avoid this ‘Assembled stator and rotor ‘ are subjected to the impregnation with help of VPI (VACCUM PRESSURE IMPREGNATION) plant. This removes all the moisture present and insulates the required zone.
BHEL -PROFILE
BHEL is the largest engineering and manufacturing enterprise in India in the energy related in fracture sector to day. BHEL has built over the years , a robust domestic market position by becoming the largest supplier of power plant equipment in India, and by developing a strong market presence in select segments of the industries sector and the railways. BHEL was established more than 40 years ago ushering in the indigenous heavy electrical equipment industry in India, a dream which has been more than realized with a well-recognized track record of performance. Defying the scourge of worldwide recession, In 2008-09, BHEL saw a spectacular top line growth of 31% with a turnover of RS.28,033 Crore and net profit rising by 9.8% to Rs.3,138 crore over the previous year. Order inflow during 2008-09 was at a record high of Rs.59678 crore with total orders in hand in the 2nd quarter of 2009 at Rs. 1,25,800 crore. The cumulative capacity of BHEL’s projects installed worldwide stands at around 1,05,000 MW. BHEL’s manufacturing capacity expansion from 10000MW p.a to 15000MW p.a is proceeding apace and plans are afoot to hike this further to 20000MW p.a by 2011-12.
INTRODUCTION
An electrical generator is a machine which converts mechanical energy (or power) into electrical energy (or power). The energy conversion is based on the principle of the production of dynamically (or motionally) induced e.m.f. whenever a conductor cuts magnetic flux, dynamically induced e.m.f. is produced in it according to faraday’s laws of electromagnetic induction. This e.m.f. causes a current to flow if the conductor circuit is closed.
The Principal resource for power generation in our country is dominated by COAL. About 60% of power requirement is generated by thermal power plants in which steam is the working fluid, steam is produced in a boiler using coal as fuel and is used to drive the prime mover, usually the steam turbine. In the steam turbine heat, energy is converted into mechanical energy, which is used for generating electric power. The combination is known as STG (Steam turbine generator). The construction procedure for gas and steam turbo generator remains the same.
PRINCIPLE:
A Generator works on the principle of Faraday’s Law of Mutual Induction. According to Faraday’s when a conductor is moved in a magnetic field is moved across the stationary conductor an EMF is induced in the conductor, when the conductor cuts the flux produced by the magnetic field. A current flow through the load when the circuit is closed.
EXCITATION SYSTEM:
The excitation system consists of a small generator coupled to the main alternator through the excitation leads running through the shaft.
Conventional D.C Excitation Systems with a D.C. exciter enjoyed an unchallenged position till recently was adopted universally for all alternators. With the growth in unit size of large capacity D.C. exciters capacity became necessary. Due to problems in communication it became inevitable to design of large capacity D.C. exciters at low speeds leading to increase in the systems. Moreover, the D.C. excitation suffered from problems like – power cabling, problems associated with commutator and brush gear and maintenance.
VACCUM PRESSURE IMPREGNATION:
BHEL, Hyderabad had installed the state of the art technology of VACCUM PRESSURE IMPREGNATION SYSTEM for cage stators up to 125MW. Capacity, which is the largest of it’s kind in INDIA. This system conforms to the latest insulation system adopted by KWU-SIEMENS technology. The stator coils are taped with porous resin poor mica tape before inserting in the slots of cage stator, subsequently wounded stator is subjected to a special VPI process, in which first the stator is vacuum dried and then impregnation in a resin bath pressure of nitrogen gas. Then the stator is cured in an oven.