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The Turbo generator would be a multistage, impulse type, extraction condensing, having single reduction, parallel shaft gearbox. The alternator will be operating on 11.0 KV, A.C. 3 Phase, 50 Hz and having a power factor of 0.8 (lagging). The turbine alongwith alternator will be provided with a suitable gearbox assembly, exciter, Automatic Voltage Regulator (AVR), Neutral Grounding Panels (NGR) and Turbine Control Panel (TCP) alongwith protection relay etc. The superheated steam from the superheater consisting of thermal energy and pressure energy enters into the turbine through its inlet. The turbine consists of a set of rotating blades and stationary blades.
The rotating blades are mounted on the rotor drum and as the steam flows over these blades, pressure energy gets converted to kinetic energy. As a result of the same, the velocity of steam flow increases accompanied by a drop in its pressure. When this steam goes to the stator blades mounted on the turbine casing, these act as guide vanes and direct the steam flow to the next set of rotor blades. At the same time the temperature of steam drops, which causes a drop in the enthalphy of steam. It is this drop in enthalphy of steam, which is responsible for generation of mechanical energy from steam. To ensure uniform cooling of turbine rotor at slow speed during start up and during the time after tripping a motorized Barring Gear (turning device) has been provided. Digital Electronic Governor has been considered for load control and automatic loading controls alongwith control of condenser vacuum and for turbine safety following tripping and interlock arrangements have also been considered.
The turbine is coupled to the alternator by means of a gearbox. A speed reduction takes place in the gearbox between the turbine and the alternator. As a result of continuous motion in the turbine, alternator and gearbox, there will be heat dissipation from their moving surfaces, due to friction between the moving parts. It this is not controlled, then, this could lead to a drop in the efficiency of the equipment. The same could have serious repercussions in the overall scenario of power generation. In order to avoid this from happening, it has to be ensured that the fiction is kept to a minimum. This is achieved by pumping lube oil into the bearings of this equipment, so that frictional losses can be minimized.
| Parameters of Turbo Generator |
| Quantity Required |
One |
| Type |
Rated capacity of 6500 K.W. Multistage, horizontal, double extraction condensing impulse turbine |
Pressure of Steam at turbine
Inlet Kg/cm2(a) |
66.0 |
| Pressure of Steam at exhaust (ata) |
0.1 |
| Temperature of Steam at Turbine |
495 inlet (0C) |
| Temperature of saturated Steam |
45.6 inlet of condenser (0C) |
| Steam Flow (tph) |
33.0 |
| Drive |
Alternator |
| Gear Box Type |
Single reduction Parallel shaft (Helical) |
| Steam flow through first Extraction |
4.39/12 (TPH) / ata |
| Steam flow through second |
3.6 / 4.5 Extraction (TPH) / ata |
| Steam flow to condenser (TPH) |
25.01 |
| Power developed at alternator |
6500 KW, 8125 KVA terminals |
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