Research Of The Oil-Immersed Transformer Windings Temperature Measurement On Line

Transformer is one of the important components in the power system. Transformer is widely used in the power system.The life of the transformer is decided by its windings.To make the transformer work safely and long lifely,it has very important significant to measure the transformer windings temperature.Based on the observation of normal winding thermo meter-hydraulic pressure and electro thermal winding thermometer,this article gives a full-electronic temperature measurement equipment.In this paper, a solution based on Atmega8 is introduced into the transformer windings temperature measurement and control system, according to the measuring principle of "thermal simulation" ,the Pt100 and the current transformer are used in signal acquisition circuit, and it also increases the accuracy of measurement.by the soft and the hardware,this system also increases the accuracy of measurement. The whole system makes full use of the hardware and the software of the ATmega8.It also has the communication interface of the 485 and the slave display meter. It controls the delay in starting the cooling system by soft programming.This system completed the transformer windings temperature measurement on line during the range from 0℃to 150°C, at the same time ,it can display the result of the measurement on line, the resolution is 0.1°C.To meet the require of the industry control,the 485 interface has been designed. It also has the integrator ,the system can supply (4～20)mA standard current.To make the transformer work safely, the relay has been designed to contrast the temperature alarm circuit. In order to guarantee the safe operation of the on-the-spot transformer, the system has been designed and formed the warning control circuit of temperature by the relay mainly. According to the actual condition of work of the transformer, setup different warning value of temperature. The continuous improvement of science and technology makes measurement and control requirements increase,mainly being incarnated in the precision,the response delay,the system reliability and so on. Simulation experiment was performed on the transformer model using this system inreliability in the Lab. The result shows that this system is of high accuracy and which can meet the theoretical design demand.