A power plant can have hundreds of temperature measuring points. In the control room they appear as a row of values on a screen, but each one keeps part of the process within its safe limits. When one point gives the wrong data, the result can be a unit trip, equipment damage, or an unnoticed drop in efficiency.
In coal-fired and biomass plants, the heat journey begins with feedwater. Water from the deaerator is heated in stages through feedwater heaters before entering the boiler, and the temperature at each stage shows whether the heaters are performing as designed. A drop in feedwater temperature at the boiler inlet means the boiler has to burn more fuel to produce the same steam.
On the steam side, main steam and reheat steam temperatures are among the most important parameters in the plant. Steam that is too hot can shorten the life of superheater tubes and turbine blades, while steam that is not hot enough reduces efficiency. Measuring points on high-pressure, high-temperature steam lines usually use thermocouples mounted inside sturdy thermowells, so the sensor can be replaced without opening the pressurized system.
Flue gas from the furnace carries a lot of information about boiler condition. Gas temperature at the economizer and air preheater outlets shows how much heat has been absorbed. If stack temperature rises above normal, there may be scale or ash build-up on the heat transfer surfaces. On the other hand, a temperature that is too low can cause acid condensation that damages ducts and downstream equipment.
The cooling system matters just as much. The condenser needs a large flow of cooling water, and the difference between inlet and outlet temperature shows condenser performance. In gas-fired plants and hydropower plants, cooling water temperature for generators, transformers, and lubrication systems is also monitored continuously.
Because measuring points can be hundreds of meters from the control room in an environment full of high-voltage equipment, sensors are usually paired with temperature transmitters that output 4–20 mA. This signal is more resistant to interference and can be read directly by the DCS for alarms, control, and protection.
Sensor type follows the temperature range at each point. RTD Pt100 is better suited to water, oil, and cooling systems because of its high precision, while thermocouples are used for steam and flue gas, where temperatures are much higher.
CV. Rach Tekindo Makmur supplies Temperature Sensors & Temperature Transmitters for a wide range of industrial instrumentation needs. If you need sensors, transmitters, or consultation on configuration and installation for your temperature system, contact us on WhatsApp at 0877-8620-5656 to discuss your technical requirements and request a quotation tailored to your application.
