A method of detecting water induction in a steam turbine that may include the steps of: measuring the temperature of one of the steam lines of the steam turbine at regular intervals; recording the temperature measurements; and determining, from the recorded temperature measurements, whether there has been a sharp decrease followed by a gradual rise in the temperature of the steam line. The method further may include the steps of calculating the rate of change of the decrease in temperature of the steam line and the rate of change of the increase in temperature of the steam line. The sharp decrease followed by a gradual rise in the temperature of the steam line may include a decrease in temperature followed by an increase in temperature wherein the rate of change of the decrease in temperature exceeds the rate of change of the rise in temperature.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow diagram for an embodiment of an water induction detection algorithm according to the current invention.
FIG. 2 is a more detailed flow diagram for a component of the flow diagram shown in FIG. 1.
Claims
1. A method of detecting water induction in a steam turbine, comprising the steps of:
measuring the temperature of one of the steam lines of the steam turbine; anddetermining, from the measured temperatures, whether there has been a drop in temperature followed by a rise in temperature in the steam line.
2. The method of claim 1, further comprising the step of determining whether the rate of change of the drop in temperature exceeded the rate of change of the subsequent rise in temperature.
3. The method of claim 2, further comprising the step of determining that water induction is probable if there has been a drop in temperature followed by a rise in temperature in the steam lines wherein the rate of change of the drop in temperature exceeded the rate of change of the rise in temperature.
4. The method of claim 3, further comprising the steps of: determining if the steam turbine is operating at approximately 20% of its maximum power output; and
determining that water induction is not probable unless it is first determined that the steam turbine is operating at a minimum of approximately 20% of its maximum power output.
5. The method of claim 1, further comprising the steps of: determining the temperature of the steam seal system of the steam turbine; and determining that water induction is probable if the temperature of the steam seal system drops below a predetermined temperature and remains below the predetermined level for a predetermined amount of time.
6. The method of claim 5, wherein the determining the temperature of the steam system comprises measuring the temperature at an outlet of the steam seal system pipe of a steam turbine auxiliary system.
7. The method of claim 5, wherein the predetermined temperature is between approximately 200-300° F. (93 and 149° C.) and the predetermined amount of time is approximately 10 seconds.
8. The method of claim 4, wherein measuring the temperature of one of the steam lines comprises taking the temperature measurements at intervals between 0.5 and 2.5 seconds.
9. The method of claim 8, wherein the determination of whether there was a drop in temperature comprises determining whether the temperature has fallen at least a predetermined amount for each of a predetermined number of consecutive falling temperature measurement periods.
10. The method of claim 9, wherein the predetermined amount is approximately 3° F (1.7° C.) and the predetermined number of consecutive falling temperature measurement periods is 6.
11. The method of claim 8, wherein the determination of whether there is a drop in temperature comprises determining whether the temperature has fallen for at least a predetermined number of consecutive falling temperature measurement periods.
12. The method of claim 11, wherein the determination of whether there is a rise in temperature comprises determining whether the temperature has risen for at least a predetermined number of consecutive rising temperature measurement periods.
13. The method of claim 12, wherein the predetermined number of consecutive falling temperature measurement periods and the predetermined number of consecutive rising temperature measurement periods is 6.
14. The method of claim 12, wherein the determining whether the rate of change of the drop in temperature exceeded the rate of change of the subsequent rise in temperature comprises the steps of:
calculating the average rate of change for the predetermined number of consecutive falling temperature measurements;calculating the average rate of change for the predetermined number of consecutive rising temperature measurements; andcomparing the rate of change for the predetermined number of consecutive falling temperature measurements against the rate of change for the predetermined number of consecutive rising temperature measurements.
15. The method of claim 2, wherein the measuring the temperature of one of the steam lines occurs in the first stage bowl of the high pressure section, the exhaust bowl of the high pressure section, the first stage bowl of the intermediate pressure section, and/or the exhaust bowl of the intermediate pressure section.
16. A method of detecting water induction in a steam turbine, comprising the steps of:
measuring the temperature of one of the steam lines of the steam turbine at regular intervals;recording the temperature measurements; anddetermining, from the recorded temperature measurements, whether there has been a sharp decrease followed by a gradual rise in the temperature of the steam line.
17. The method of claim 16, further comprising the steps of calculating the rate of change of the decrease in temperature of the steam line and the rate of change of the increase in temperature of the steam line; wherein, the sharp decrease followed by a gradual rise in the temperature of the steam line comprises a decrease in temperature followed by an increase in temperature wherein the rate of change of the decrease in temperature exceeds the rate of change of the rise in temperature.
18. The method of claim 16, wherein measuring the temperature of one of the steam lines comprises taking the temperature measurements at intervals between 0.5 and 2.5 seconds;
determining whether there has been a sharp decrease in the temperature of the steam line comprises determining whether there has been a decrease in temperature for a predetermined number of consecutive decreasing temperature measurements; anddetermining whether there has been a gradual rise in the temperature of the steam line comprises determining whether there has been an increase in temperature for a predetermined number of consecutive rising temperature measurements.
19. The method of claim 18, wherein the sharp decrease in the temperature of the steam line comprises a decrease in temperature such that the average rate of change during the predetermined number of consecutive decreasing temperature measurements exceeds a predetermined rate.
20. The method of claim 18, wherein the gradual rise in the temperature of the steam line comprises a rise in temperature such that the average rate of change during the predetermined number of consecutive rising temperature measurements is less than a predetermined rate.
Patent Application
20070204452
