Temperature Calculation And Experimental Study Of 10kV Three-core Cable And Accessories

With the accelerated development of the city, the city’s electricity consumption is increasing year by year, with the distribution of electricity load is more intensive. Because the city center area generally does not allow to set up the overhead line, this is because the overhead line compares the cable line to have the floor area to be big, the influence city is beautiful. Therefore, the central area of the city is often through the distribution network with the multi back cable to provide power for all walks of life. In order to ensure the safe operation of the distribution network cable, IEC developed a relatively conservative standard, it is difficult to meet the current demand for electricity in the city. Not only that, in a cable line, there are generally limited capacity to limit the flow of the bottleneck. For example, the cable intermediate joint, transformer substation outlet pipe laying cables and so on, and these are the bottleneck of the load flow and no standard to develop its carrying capacity. Therefore, accurate calculation of the load flow of cable and accessories, the maximum utilization of cable capacity, can avoid the waste of resources caused by blind increase line, and also can provide reliable scientific basis for power grid dispatching, ensure the safe operation of power network. And, by making full use of the transmission capacity of the existing cable lines, improving the transmission efficiency, the load of the city within the peak load to fill the valley.At present, a lot of researches have been carried out on the on-line temperature measurement system for cable environment temperature and cable surface temperature. The results have been applied to some urban power operation departments. Based on the different algorithm and the in situ temperature data acquisition of conductor temperature calculation calculation method are applied to the high-voltage cable, but according to the prediction of the distribution cable core has not spread, namely in the algorithm, 10 kV cable is still in the initial stage.The 10 kV three core cable as the research object, the two major factors of three core cable core temperature are analyzed, influence of thermal resistance and temperature of environment of three core cable temperature is analyzed by using the concept of partial sensitivity in biology. In order to ensure can rise temporarily buried under 10 kV distribution network three core cable ampacity, directly buried installation of 10 kV three core cable transient response time are calculated in the operation process. The transient thermal circuit model of cable is established, and the model is simplified to a first-order RC thermal path, and the relationship between the emergency time and the core temperature is deduced according to the established model. At the same time, the design of the buried cable laying loading different emergency load temperature rise experiment was measured. The experimental group emergency time. In addition, in order to study the distribution of temperature field in the middle of the joint, and determine the cause of limiting the flow in the middle of the joint, a method of combining the experimental and finite element analysis is presented. In the end, a new method is proposed to build the three core cable thermal path model and to find out the advantages and disadvantages of the model. According to the temperature distribution and structure characteristics of the three core cable, the steady and transient thermal circuit model of the three core cable is established by using the method of dividing. At the same time, the design of the 10 kV three core cable lift flow experiment, the use of automatic temperature measurement instrument to get the actual core temperature, compared with the experimental value of core temperature and the experimental value of the error, verify the correctness and accuracy of the proposed method.