Issues regarding the number of settings for measuring the water level in boiler drums

In the design of power plant boilers, at least 3 transmitters are typically installed for measuring the drum water level. Of these 3 transmitters, usually 2 are used in the control system (for regulation), and 1 is used in the safety protection system (for protection). This distribution method is intended to ensure the proper operation and safety of the boiler. Regarding the handling of the MFT (Main Fuel Travel Switch), the signals from the three water level transmitters of the boiler are generally fed into the DCS system for processing. The control signals are used to regulate the water level in real time, while the protection signals are used to implement safety logic – for example, low water level protection helps prevent accidents such as dry burning of the boiler. It is also feasible to use a separate safety controller to handle the protection signals, which can increase the reliability and redundancy of the system. In short, the key is to ensure that there is at least one independent and reliable protection system in place to handle extreme or emergency situations, thereby safeguarding both the equipment and the personnel. At the same time, it is also very important to keep the system simple and easy to maintain. .

For the protection of the boiler drum water level, it is indeed recommended to use three transmitters to enhance the reliability and safety redundancy of the system. Typically, these protection transmitters are configured independently, separate from the control system, and they are primarily used to carry out safety-related functions, such as preventing equipment damage or operational failures caused by excessively low or high water levels. Three protection transmitters can be connected in parallel to an independent safety control system (such as SIS, Safety Instrumented System), thereby ensuring that the necessary protection functions are still available in the event of problems with the DCS system or the control controllers. Each transmitter can detect the water level independently, and the safety system evaluates whether an emergency shutdown or other safety measures need to be taken. In summary, three independent protection transmitters are a recommended approach to improving boiler safety, as this ensures that even if one or two of the sensors fail, there will still be sufficient inputs available for accurate safety assessments and responses. .