Study On Forecasting System Of Current Carrying Capability For Power Cable In Duty

The purpose of this paper lies in studying on on-line forecasting system for power cable current carrying capability based on the electrical power engineering background. The steady heat characteristic of XLPE cable, the hardware circuit design of current carrying capability and system software design are studied. The paper focuses on researching the heat equation and equivalent circuit of power cable, deducing the function of current carrying capability and the outer sheathing of power cable and realizing current carrying capability forecasting. The research offers electric power attemper the nicety foundation and ensures safe operation of electric power system. Firstly, the structure of XLPE cable is studied to develop the formula of effective resistance, dielectric loss, metal sheathing loss, shield loss and the thermal resistance of cable main body, deduce the function of current carrying capability and the outer sheathing of power cable and analyse the influencing factors of current carrying capability. Secondly, extraction method of outer sheathing temperature signal is studied and the thirty two channels synchronous data acquisition system is designed. Finally, according to the results of theoretical study, a current carrying capability-forecasting software is developed and the simulative experiment is carried out. According to the requirement of the function of on-line forecasting system for power cable current carrying capability, the whole system design is divided into some function modules and modules are designed separately. Finally, each function module is integrated into the whole system design. It is discovered through forecasting that the percentage error of this device is less than 5% between the result of forecasting current carrying capability and the empericial value of current carrying capability and satisfied with the requirement of the common project.