Research On Temperature Rise Monitoring Device For Dry Type Transformer Based On DSP

Dry type transformer has developed rapidly, owe to its advantage of pollution-free, proof-burning, small size, light weight, easy Installation and maintaining, mainly applied to building, subway, airport and the other places. In operation, the transformers winding local temperature will be overheated, due to overload, insulation fault, high environmental temperature and inadequate cooling ventilation. If the temperature is higher than the winding insulation resistance's, it will damage insulation, cause transformer fault. Consequently, it is necessary to monitor transformer temperate online.Dry type transformer temperatures monitoring devices was developed according to actual demand, TMS320LF2407A and CPLD were chosen as core processor, platinum resistor pt100 as temperature sensor, and construct temperature signal acquisition and regulate circuit. And based on the success of the hardware circuit's structures, we carried out the system software's design and realization of the system, at last, we have test the system, and do contrast among the measured value and theoretical value in order to verify whether the system error is in permit or not.The main job was the acquisition and processing of temperature signal in DSP, and a linear interpolation method was used to eliminate the platinum resistance pt100 temperature and resistance of nonlinear. Secondly, the acquired temperature was compared to limit temperature, judge the working states of transformer, and then according to the state, the system may start or stop the fan or give temperature alarm. And modify the corresponding limit temperature according to the key value, finally the temperature data is transmitted to CPLD and PC. Logical circuit design was accomplished in CPLD, which including procedure of the system signal reset, outside enlarge memory signal chip selection, keyboard away shaking , data display processing, and reduce amount of DSP work.The communications between system and PC is realized by SCI interference in DSP, the system can monitor the temperature of the transformer real-timely, and a man-machine interface was designed using VC++.