What do you mean by Turbovisory or Turbine supervisory system?
Turbovisory or Turbine supervisory system is
the monitoring of a Turbine. It supervises the condition of turbine and informs
to an operating person. It also ensures the parameters do not exceed maximum allowable
the significance of Turbine supervisory system?
Turbines are heavy & high speed machines, failures
of machine lead into unrecoverable losses. So in case of any abnormality
turbine should stop automatically. This is taken care by Turbine supervisory
the equipments or systems used in Turbine supervisory system?
These probes are used
for sensing shaft or bearing casing vibrations. Generally two probes are fitted
at 900 apart at X & Y-directions to measure the shaft vibrations.
These vibrations are measured in microns, mills or mm/sec.
Speed probes: Speed sensors are generally Magnetic Pick up unit (MPU) type. These are fitted at teethed portion of turbine shaft for measurement. Generally 2 MPUs are used to measure the shaft speed, one for speed sensing & other for controlling.
shift probes: This probe is
fitted at the turbine front end to measure the axial displacement of shaft.
Axial displacement probe of the shaft is generally set between +/- 0.4 to +/-
temperature measuring sensors: These are used to sense the bearing metal temperature or bearing drain
oil temperature. For measuring bearing metal temperature, RTD is inserted into
drilled hole & touches the white metal & to measure the oil temperature
RTD sensor touches the drain oil only.
expansion probes: During abnormal
operation conditions like quick start up, wrong SOP & uninform temperature
distribution in casing & turbine rotor there could be the possibility of
rubbing among turbine internals. To measure & monitor these gaps
differential expansion probes are used & trips the turbine if these gaps
increase beyond set values.
measuring sensors: Generally
turbine casing thickness is very large around 150 mm &it depends on turbine
operating parameters. So it is very much necessary of uniform distribution of
temperature throughout the casing thickness.
And also the difference between top & bottom
casing temperature of turbine should be very less.
expansion measurement probes/sensors: These sensors are used to measure absolute
expansion of casing. During startup &subsequent loading conditions turbine
casing thermal expansion is must. Generally LVDTs are used for casing expansion
opening indication: This
is used to indicate the actual position of valves.
Eccentricity: This is very important supervision
system. This is used to measure the mechanical bow. This may happen due to
sudden trip of turbine & unavailability of barring device. Standstill
position of turbine rotor for long time
Why do vacuum breaker
valves are provided on steam condensers?
During tripping of turbine due to any of the above reasons like bearing
vibration, temperature, axial shift, differential expansion etc, the vacuum
breaker valve opens to bring down the turbine rotor speed to zero at the