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Monday, 15 December 2014

Steam Turbine Control

Steam Turbine Control Points : Steam Turbine Control In definite process of steam turbine speed and output of turbine are to be continually monitored and controlled as seldom any turbine operates at stable load. This process of turbine at off-design conditions too deteriorates act of turbine. Thus, for safe and optimal operation of turbine it has definite control and monitor instruments. The number and size of these control and monitor instruments depends upon size of turbine and its function. A few of typical controls and instruments use are explain under:
  1. Eccentricity of shaft is too to be monitor for which an eccentricity recorder is give to show and record eccentricity of shaft at elevated pressure end of turbine. Eccentricity recorder has a detector coil at short pressure end of shaft, a move switch on turning gear, with a power unit and recorder mount on control panel. Eccentricity of shaft reason variation in air space among shaft and coil detector and thus change in current flowing during coil, which is being sense properly.
  2. Due to extreme temperature turbine casing can undergo axial expansion for which an expansion indicator is place. Expansion is monitor by respect to a few selected mark on foundation. Stable expansion of casing is allowable as unsteady expansion can be dangerous.
  3. Pressure amount is prepared for oil pressure to bearing, water/steam stress to gland seals, steam pressure at steam chest, stop valves, inlet and exit of every stage in turbine. Pressure gauges are mount at proper locations for every one of above.
  4. Vibrations at major bearings of turbine and generator are being monitor by vibration amplitude recorder. This kind of recorder has detector at every bearing and detector voltage is proportional to bearing vibrations. Voltage variation is sent for proper signal change and vibration amplitude is recorded.
  5. Control panel too has ammeters, wattmeters and voltmeters, for individual measurements. Control panel also has the digital control of different valves, governor control and so on.
  6. Speed measurement is necessary to know speed of turbine in rpm through starting and shutdown of turbine. Turbine speed is obtained as of the generator rate recorder.
  7. Flow speed of steam at every essential point in steam turbine is being precise employ flow meters and signals monitored on control panel.
  8. Noise of turbine process is being calculated using noise meter as some strange sound level may show option of failure.
  9. Temperature measurement is done at about every locations of pressure measurement.

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