Fault Diagnosis Method for Ash Silo in Thermal Power Plant Based on Variable Weight Synthesizing Theory

Ash silos are an important part of thermal power plants. To ensure the safety of the thermal power plant, the failure following an extended period of operation should be monitored early. However, the traditional maintenance planning model suffers from the problem that the planned maintenance date is not synchronized with the equipment failure date, thus causing a waste of human and material resources. Real-time monitoring and diagnosing for ash silo equipment are thus desired to reduce losses. This paper aims to develop an effective method for ash silo fault diagnosis using failure mode and effects analysis (FMEA), fault tree analysis (FTA), and variable weight synthesis theory. The failure mode and effects analysis are used to identify the potential failures of the ash silo and the causes and probabilities of their occurrence. Based on this information, it further builds a fault tree of the ash silo. Finally, it establishes a variable-weight state evaluation system for ash silo based on the variable-weight synthesis theory. The degradation degree is also adopted to evaluate the health state of the ash silo. The experimental results demonstrate that this fault diagnosis method can evaluate the real-time health state of the equipment. Moreover, the developed variable-weight state evaluation model is more accurate than the constant-weight state evaluation model.