Major causes for shut down of a thermal power plants are:
1)Boiler tube leaks is the major causes in a stable thermal power plant due to long run or due to entry of unwanted materials the boiler tubes will get holes and the water consumption if comes to uncontrollable level the unit will be shut down manually and is a planned shut down, which is a safe shut down.
2)PA fan failure which is due to cutoff oxygen to the boiler results in flame failure.
3)Improper handling during single ID fan or FD fan failure
4)Loss of all fuel condition due to negative pressure of fuel flow not sufficient or due to flame scanners fault
5)Due to lower drum level
6)Due to turbine temperatures
7)Due to cooling water temperature
8)Due to primary water temperature
9)Due to temperatures at turbine and generator areas
10)Due to electrical failure
11)Due to liquid in main leads
12)Improper response during BFP trip, as there will be turbine driven boiler feed pumps and motor driven boiler feed pumps and when the turbine driven pumps get tripped off the motor driven pumps will enter into service automatically during which the feed water control should be taken into manual mode if not acted properly during this condition the unit will get tripped out
13)Due to failure of hydraulic governor which is the heart of the operation of the turbine as the hydraulic governor supplies the oil to the control valves in the predefined fashion to operate as per the operator commands.
14)Due to control fluid pump failure
15)Due to improper control of main steam pressure.
16)Due to sudden opening of HPBypass either due to pressure or due to mal function
17)Due to LSR ( Load shedding relay) acted and plant not responded properly
18)Due to more turbine vibrations, in general the turbine vibrations are considered serious and if real can make shaft deform or misalign, but some times the vibrations may be faulty due to spike due to which careful study needs to be done before putting vibration trip into service
19)Due to axial shift crossing limits , if unit gets tripped due to axial shift condition, before starting the turbine there needs to be a thorough study regarding the case as turbine tripping under the axial shift condition is rare and is an indication of misalignment.
20)Due to flow in the bushing below defined value
21)Flame failure condition which occurs during the low load conditions, in the low load conditions even though the flame exists it will be unstable and the flame scanners will be unable to detect the flame due to which the flame failure condition arises and the boiler is tripped. During the low load condition proper maintenance of air flows and the fuel supplied in the elevations is most important.
1)Boiler tube leaks is the major causes in a stable thermal power plant due to long run or due to entry of unwanted materials the boiler tubes will get holes and the water consumption if comes to uncontrollable level the unit will be shut down manually and is a planned shut down, which is a safe shut down.
2)PA fan failure which is due to cutoff oxygen to the boiler results in flame failure.
3)Improper handling during single ID fan or FD fan failure
4)Loss of all fuel condition due to negative pressure of fuel flow not sufficient or due to flame scanners fault
5)Due to lower drum level
6)Due to turbine temperatures
7)Due to cooling water temperature
8)Due to primary water temperature
9)Due to temperatures at turbine and generator areas
10)Due to electrical failure
11)Due to liquid in main leads
12)Improper response during BFP trip, as there will be turbine driven boiler feed pumps and motor driven boiler feed pumps and when the turbine driven pumps get tripped off the motor driven pumps will enter into service automatically during which the feed water control should be taken into manual mode if not acted properly during this condition the unit will get tripped out
13)Due to failure of hydraulic governor which is the heart of the operation of the turbine as the hydraulic governor supplies the oil to the control valves in the predefined fashion to operate as per the operator commands.
14)Due to control fluid pump failure
15)Due to improper control of main steam pressure.
16)Due to sudden opening of HPBypass either due to pressure or due to mal function
17)Due to LSR ( Load shedding relay) acted and plant not responded properly
18)Due to more turbine vibrations, in general the turbine vibrations are considered serious and if real can make shaft deform or misalign, but some times the vibrations may be faulty due to spike due to which careful study needs to be done before putting vibration trip into service
19)Due to axial shift crossing limits , if unit gets tripped due to axial shift condition, before starting the turbine there needs to be a thorough study regarding the case as turbine tripping under the axial shift condition is rare and is an indication of misalignment.
20)Due to flow in the bushing below defined value
21)Flame failure condition which occurs during the low load conditions, in the low load conditions even though the flame exists it will be unstable and the flame scanners will be unable to detect the flame due to which the flame failure condition arises and the boiler is tripped. During the low load condition proper maintenance of air flows and the fuel supplied in the elevations is most important.
No comments :
Post a Comment