Research On The Law Of Outdoor Distribution Cabinet Condensation And Preventive Measures

As an important part of the power system,the distribution cabinet plays a vital role in power distribution,power control and protection.Outdoor power distribution cabinet often faces the problem of condensation in its working operation,which occurs when the surface temperature of its internal parts is lower than the dew point of air.Condensation can reduce the insulation performance of the equipment and cause short circuit of the equipment in serious cases,and even cause the burning of power distribution equipment.It can be seen that the prevention of condensation to ensure the safe operation of power distribution cabinet is of great significance.However,the existing distribution cabinet anti-condensation technology has poor effect and poor engineering practicality.Therefore,this paper carried out the analysis and research of distribution cabinet condensation law and preventive measures,the main work was as follows:First,this paper took a low-voltage distribution cabinet as an example,constructed a three-dimensional simulation model,and built a condensation experiment system in an artificial climate chamber to verify the model.The distribution of air temperature and relative humidity inside the distribution cabinet was simulated and analyzed to determine the parts of the cabinet that were prone to condensation,and the influence of material physical parameters on condensation was investigated.The results showed that the maximum difference in condensation time was only 0.4h when the bulk heat capacity varied between 500 and 5000k J/(m~3·K)for a motor with a density of 7000kg/m~3 and a thermal conductivity of 50W/(m·K);while the motor with a density of 7000kg/m~3 and a specific heat capacity of 420J/(kg·K),and the maximum difference in condensation time was only 0.27h when the thermal conductivity varied between 0.5 and 400W/(m·K),changing the physical parameters had less effect on the condensation time.Second,this paper analyzed the distribution of relative humidity in different regions of China to determine the areas where distribution cabinet condensation was likely to occur;and a simulation study was conducted on typical cities where the distribution cabinet condensation was prone in China,which quantitatively revealed the condensation duration of the distribution cabinet in the region and put forward the determination conditions of the distribution cabinet condensation.By fitting the correlation equation of ambient temperature and cabinet material temperature,the frequency of condensation of distribution cabinets in different regions was clarified,and the geographical areas in China were divided into Class Ⅰ and Ⅱ condensation risk areas accordingly,with the overall distribution characteristics showing a gradual decrease of condensation risk from southwest to northeast,and from south to north.Finally,the environmental parameters of condensation risk in Class Ⅰ condensation risk areas were explored.The results showed that when 89%≤RH≤100%,it was the high risk environment parameter of condensation for distribution cabinet;when 74%≤RH<89%,it was the low risk environment parameter of condensation;when RH<74%,no condensation occurred in distribution cabinet.Finally,for the phenomenon of time delay and temperature decay of the material temperature inside the distribution cabinet compared with the external ambient temperature,the method of measures to prevent condensation on the electric heating surface was proposed.Combined with the conditions for determining the condensation of distribution cabinets,the anti-condensation control system of distribution cabinets under different environmental parameters of condensation risk was designed.The anti-condensation effect of the system was verified in an artificial laboratory,which provided theoretical support and technical guidance to ensure the reliable operation of distribution cabinets in different regions.