Study On The Method Of Temperature Control In The Cavity Of Field Temperature Measuring Equipment

With the continuous improvement of living standards,people have higher and higher requirements for the stable and reliable performance of the power system,thus gradually increasing the management difficulty of national grid operation and maintenance monitoring.Field temperature measurement equipment can focus on solving the real problems such as inaccurate and untimely traditional detection technology,high cost of substation operation and maintenance,and low security.As the equipment works in the outdoor environment for a long time,it adopts an airtight structure for the purpose of rain,water and moisture protection,which causes the heat generated by the equipment after working for a long time cannot be dissipated in time and accumulates in the internal cavity of the equipment.The temperature of the device gradually rises,leading to jams in the measurement of the device,which affects the measurement accuracy of the device and the service life of the components.This paper is based on the air-cooled cooling method to cool it down,solving the problem of frequent fan work and high power consumption.Firstly,based on the theoretical basis of temperature rise the analysis of the heat generation source of the field temperature measurement equipment and the three heat transfer processes occurring in the equipment provides the theoretical basis for the design of the temperature control system and the temperature modeling of the equipment.Secondly,this paper designs a multi-channel temperature control system based on the aircooled heat dissipation method,with STM32F103C8T6 as the temperature control chip,DS18B20 and its own temperature sensor inside the chip to collect four channels of temperature in real time,and use AT8236 to drive and control multiple fans to run for heat dissipation purposes.The temperature data of the four parts of the device are collected and stored by simulating different ambient temperatures in the oven,and the data are pre-processed based on the criterion to reject abnormal data.Then,by analyzing the heat transfer process in the inner cavity of the equipment,based on the law of energy conservation and the principle of thermal equilibrium,the model of the temperature change of the inner cavity of the field temperature measurement equipment with time is determined,and the change law of temperature rise with time is consistent with the exponential function distribution,and the time when the inner cavity of the equipment starts to be in thermal equilibrium is constant when the material and structure of the equipment are known and constant.The overall structure of the field temperature measurement equipment and the internal heat transfer process are analyzed,and the temperature model is constructed based on the knowledge of thermoelectric similarity principle and heat transfer,using the circuit network containing capacitance and resistance to simulate the heat transfer system of the equipment.Based on the BP neural network,a model is built based on three factors,namely time,ambient temperature and wind speed,which affect the heat dissipation of the fan,and the cooling process of the equipment is analyzed.Using the three temperature models constructed,the correctness of the models is verified by comparing them with the actual temperature data.Finally,based on the temperature models built above,the temperature regulation method of the field temperature measurement equipment is studied.Based on the research and analysis of the temperature models,the relationship between the temperature rise ?T and the ambient temperature is obtained,and the fixed threshold and dynamic threshold are used in combination,when the ambient temperature is less than or equal to 30°C,the fixed threshold method is used;when the ambient temperature is higher than 30°C,the dynamic threshold is determined to drive the fan to work according to the relationship between the temperature rise and the ambient temperature.By dividing multiple fans into different combinations and calculating the working power consumption and heat dissipation of different combinations of fans respectively,the nonlinear regression model of fan power consumption and heat dissipation is constructed based on a multivariate nonlinear minimization algorithm with constrained objective function,with the minimum fan power consumption as the optimization objective and the number of fans running and rotational speed as constraints,and solved in Matlab’s optimal function fmincon to obtain The segmented control method of multiple fan cooling.Based on the above method,the intelligent regulation of the internal cavity temperature of the field temperature measurement equipment is realized,and the frequency of fan use is reduced to achieve the purpose of reducing the power consumption of fan operation.Based on the RBM and LCC,the temperature rise rate and relative value of the faulty equipment is compared with the normal equipment to develop an equipment maintenance strategy.