Transformer Temperature Detection System Based On ARM

Power transformer is the most important device of the electrical equipment in the electric power system, whether it can operate safety and stably will definitely influence on the reliability of power supply and will affect the normal operation of the electrical system. So there is great significance in the real-time or on-line monitoring running of the state of power transformer, and through the test we can discover the insulation fault of electrical equipment earlier and prevent accidence, at the same time, the monitoring work can also reduce unnecessary power overhaul, avoid the enormous losses in traditional test for electrical equipment due to "excessive overhaul", and prolong the service life of electrical equipment, so that we can optimize the configuration of equipment maintenance.It is very important of monitoring large power transformer winding temperature to ensure the safe operation of the equipment and prolong its life. Optical fiber Bragg grating temperature sensor boasts virtues of good insulation and high voltage, small volume, electromagnetic interference resistance etc, so that it provides good solution for the power system temperature detection. This paper using optical fiber Bragg grating temperature sensor and fix it to the hot position of power transformer windings to detect the temperature of the measure point, this method can greatly improve the instantaneity and accuracy of the monitoring system.Based on the analysis of domestic and international transformer temperature detection method, we draw up the method of internal power transformer winding detection and analyze the current way of fiber Bragg grating sensor demodulation. The advanced FBGA optical fiber analyzer is used in the system, so that a precise optical signal variation is provided for the system.The embedded temperature display system set in the temperature measurement field is the core of the whole work, it receives sensor data through a serial port and calculate temperature data using the sensor data then determine whether to set up the alarm signal, all the data and the signals are showed in the temperature measuring scene, at the same time, these data and signal are send to the principal computer in the control using the CDT communication agreement of the electric power system. This paper introduce the system realization method from both software and hardware aspects.The main chip of the embedded system is STM32microprocessor, the kernel of which is based on ARM cortex-m3architecture, we have designed the power, clock, communication, sound and light display and other peripheral circuit such as key for it in this paper, the main display interface of the system is3.2inch TFT touch panel, different with the previous monochrome LCD, this display interface is more beautiful and friendly, further more, the display part combined with an audible and visual alarm circuit so that when the system breakdown can be detected in the first time. In addition, RS-232communication interface for FBGA and RS-485communication interface for principal machine are designed in this system.The μcOS-ii operating system is transplanted in the embedded system, because of the operating system boasts no support of the graphical interfaces, μcGUI graphical interface system is added in the software structure, so as to give full play to the function of the touch panel. Except the start task, there are four memory-resident tasks running in the system, that is man-machine interactive task, computing task, CDT communication task and display task, all these four tasks will be scheduled in turn according to it’s priority and resources.The start-up mode of STM32is deeply analyzed in this paper, and the μcOS-ii operating system and μcGUI graphic interface are transplanted in this paper. Then each task established on the operating system are described in this paper, and the FBGA communication format and CDT statute format are briefly introdμced.At the end of this paper the test platform is established to test the accuracy of the temperature detection system, and the system interface with the parameters set mode are described.