Design Of Essential Service Water Pump Condition Monitoring And Intelligent Diagnosis System In Nuclear Power Plants

The necessary service water pump is mainly used in the necessary service water system of large nuclear power plants,and its safety requirements are very high.The safety of nuclear power plant operation is related to many fields related to national development and security,such as clean energy,water conservancy and hydropower,nuclear hydrogen production,etc.The operating conditions of necessary service water pumps are complex,and the predictability of faults is weak,which can easily lead to the unit being out of repair or transitioning to maintenance.Therefore,designing an intelligent monitoring and fault diagnosis system for nuclear power is an urgent issue that needs to be addressed while vigorously developing nuclear power and increasing installed capacity.In response to this issue,the focus of this article is to analyze the signal characteristic theoretical laws of pump hydraulic,motor electrical,and bearing mechanical faults from the perspectives of theory and experiment.A database of hydraulic faults in necessary plant water pumps was constructed,and data acquisition,signal processing feature extraction,and fault classification algorithms were completed using LabVIEW.Finally,it was applied to the status monitoring and intelligent diagnosis system of necessary plant water pumps,providing technology and reference for the safe operation of main pumps in nuclear power plants.The main content is as follows:1.Modeling of necessary plant water pump systems;By using CFD simulation to calculate the external characteristic characteristics of different degrees of blade breakage and ring wear faults.The fault characteristics of rotor bar breakage,air gap eccentricity,and inter turn short circuit motor in the frequency domain of the current signal are calculated through magnetomotive force analysis.Using the relevant parameters of bearings used in necessary plant water pumps,the relative rotation frequency of the inner and outer rings,the frequency fault characteristics of the cage,inner ring,and rolling element are calculated through formulas,providing a basis for subsequent research.2.Build an necessary plant water pump test bench;This mainly includes the design of the test bench and the software and hardware equipment of the acquisition system.Starting from the perspective of multi-signal fusion,for different degrees of blade breakage and ring wear fault conditions,a collection program is built using the upper computer LabVIEW software.The pressure,flow,speed,and vibration signals are collected and analyzed through hardware devices such as flow meters,pressure transmitters,and acceleration sensors.3.Pre processing and feature extraction of vibration signals from necessary plant water pumps;A denoising method based on set empirical mode decomposition and wavelet packet threshold was adopted to solve the noise interference problem in the original signal of the wear fault of the necessary plant water pump mouth ring.This method can effectively extract fault information and improve the purity of the vibration signal.To improve the accuracy of fault diagnosis,common empirical indicators in the time and frequency domains were extracted based on signal preprocessing.The wavelet packet feature extraction method and CEEMD feature extraction method were proposed to reduce the feature dimension.4.Establish an intelligent diagnostic model for necessary plant water pumps;The main focus is to compare and analyze the four characteristics extracted from the above research results,and propose three classification models: BP neural network,GA genetic algorithm optimized support vector machine,and PSO genetic algorithm optimized support vector machine.By comparing the classification results with parameters such as learning rate,kernel function,and training samples,the accuracy of fault identification for necessary plant water pumps has been further improved.5.Establish an necessary plant water pump status monitoring and intelligent diagnosis system;Based on the above research methods,a good human-machine interaction interface is built using the upper computer software LabVIEW,and high-precision algorithms are implemented using MATLAB and Python.The system mainly includes status monitoring and intelligent diagnosis functions for necessary plant water pumps,which can achieve monitoring of multi frequency weak signals,comprehensive processing of fault features,hydraulic and mechanical fault diagnosis of common SEC pumps,and other functions.