Winding Hot-spot Analysis And On-line Prediction Technology Of The Dry-type Phase-shifting Rectifier Transformer

With the increasing energy consumption and the deterioration of the natural environment,energy-saving technologies are becoming more and more valuable. National energy policy clearlystated that the use of the high-voltage inverter should be promoted. As an important part ofhigh-voltage inverter, the applications of the dry-type phase-shifting rectifier transformer have beengreatly developed. Compared with the conventional transformers, the heating problems of thedry-type phase-shifting rectifier transformer are more serious. With the heating problems, the dry-typephase-shifting rectifier transformer may fail to work and burn the nearly power units and controllers,and they can even influence the safety production of the mining industries and cause huge economiclosses. The hot-spot temperature of the transformer windings is the biggest factor limiting the loadcapacity of the transformer, and it is also a main factor affecting the life of insulating material.However, as the locations of hot-spot are different because of the structural differences, and thepositional deviation of the installation of the sensor, it is quite difficult to measure hot-spottemperature of the transformer winding directly. Therefore, it is important to get the on-line predictionof the hot-spot temperature of the dry-type phase-shifting rectifier transformer windings.As it is difficult to measure the hot-spot temperature of the transformer windings directly,winding hot-spot temperature on-line prediction system of transformer is designed.In this paper, a dry-type phase-shifting rectifier transformer is used for the study, and ANSYS isused to simulate the temperature field of the transformer under different conditions, so that therelationship between the temperature of the temperature sensor mounting point and the temperature ofthe winding hot-spot can be analyzed and generalized. By the temperature of mounting point of thetemperature sensor, the winding hot-spot temperature of transformer can be calculated. Pt100platinum resistance is used as a temperature sensor and STC89C51RC SCM is used as amicrocontroller in the temperature terminal. And after measured, the temperature data are sent to thehost computer in real time via GPRS. The upper computer software developed by VB6.0can recordtemperature data in real time, and complete the display and alarm actions, and modify the parametersof calculating temperature of windings hot-spot.