Analysis And Research On Cold Junction Compensation Of Thermocouple In Power Plant

Thermocouple is the most important sensor in power plant, its operation is able to directly affect the safe operation of generating units. In the thermal power industry,it is a very common problem that the thermocouple performance unstable and unreliable.As the performance of instability lead to false temperature signal has been troubled power plant operation and maintenance personnel,and when it Serious can cause power units shutdown,this will cause incalculable impact on power unit life and safety of the grid.By analyzing the principle of thermocouple temperature measurement, we know that only when the thermocouple cold junction temperature remains unchanged,the thermo emf is the single-valued function of the measured temperature.In the application of power plant, the Cold-side exposures to space, the cold junction temperature is easily affected by the fluctuation of the ambient temperature;the cold junction temperature is difficult to hold invariableness, so the thermocouple needs cold junction compensation. The existings exit a comparatively large error, so this paper proposes an improved based on the existing cold junction compensation method in order to improve the accuracy of measurements and completed the design of the hardware and software of computer compensation method.