【正文】 部故障油浸式變壓器指的是機 熱 ，加熱和電力，主要是后兩種?；跍囟葓鲂畔㈦娏ψ儔浩?，本研究由 國家自然科學基金支持 并 探索了一種新的狀態(tài)監(jiān)測和故障診斷方式。在目前，石油天然氣價值和局部放電信號通常選擇作為 電力變壓器監(jiān)測系統(tǒng)的 監(jiān)測對象 。對大型 油浸式變壓器 運行狀態(tài)的實時溫度檢測和故障診斷而言，具有較廣 闊的應用前景。 (e) Measuring range: 50 ~ + 200 。s temperature rising value, the infrared thermometer measures the temperature rising of box body, and the mercurial thermometer measures th e top oil temperature. The output wires of sensor are connected with the monitoring system, and the data can be shown on PC screen in the real time. The line connection and the experiment result are respectively showed as and . In the experiment, the thermometer, infrared thermometer, electric thermocouple and thermal resistance are all adopted, pared and verified. For example, a thermometer was made use of to test the top oil temperature, and electric thermocouple for the winding temperature rising, and thermal resistance and infrared radiation thermometer for the oil temperature at different locations. It can be seen from and that the highest temperature is always on the winding, the temperature of mild transformer oil and box body reflects grad change and has a stepbystep rise, and the temperature change of transformer bottom oil is paratively slow. The experiment result is basically agreed with the simulation calculation value in ANSYS. According to the experimental results, there are some characters for the designed temperature monitoring system of power transformers: (a) Realtime acquisition, real time transferring by USB bus. It can also transfer the data to PC by USB after data collecting。 (b) Main cycle part: this part is to be interrupted。4 channel, highspeed and 14 digit data collect chip [3]. USB interfaces chip choose PDIUSBD12 PDIUSBD12 hereinafter referred toD12 , supporting multiplexing, nonmultiplexing and DMA transfer, is one kind of parallel interface chip designed by Philips pany .It fully conforms to the USB specification Rev. (basic speed). It is also designed to be pliant with different types of transmission. The data collecting parts block diagrams of hardware system see . Block Diagram of hardware circuit system Cireuit block diagram of data acquisition B. Design of the Signal Conditioning Circuit The Signal Conditioning Circuit is posed of sensor, signal amplification and attenuation circuit, isolation circuit, wave filtering circuit, sample holding circuit, etc. Due to MAX125 AD chip with multiplexer and SampleHold Circuit itself, Signal Conditioning Circuit is made up with thermocouple, isolating amplifier circuit and antialiasing filter. The thermocouple produced by Anhui Tiankang incorporated pany, Model for the WRC, Indexing for T, is a special one for power station application. Its outputting voltage range is 161。s location, yet its realtime performance is weak. Based on the temperature field information of power transformers, this research supported by NSFC explores a new condition monitoring and fault diagnosis way for it. An online temperature monitoring system of oilimmersed power transformers based on MCU is designed in this paper. Its variation of temperature in power transformer often keeps a fixed orderliness when it is running normally. In most situations, its variation of temperature in power transformer has a close relationship with different fault types. The interior fault patterns of oilimmersed transformer are referring to mechanism, heating and electricity, and mainly the latter two. The machinery malfunction often is presented in the form of thermal or electricity. According to the investigation result presented in the table 1, the malfunction ways for the running oilimmersed transformers include mainly the overheating malfunction and discharging malfunction of high energy. The temperature rising will occur in some locations when overheat malfunction or high energy discharging malfunction occurs. Furthermore, an obviou emperature rising will occur for some power transformers before the malfunction are formed. Oncondition that the realtime monitoring to the correct areas can be realized, a preventive maintenance would alter the present maintenance and inspection mode, an d be able to reduce the Maintenance Cost. Therefore, it is very important to keep the power transformers in the best situation. There are several methods to measure the hotspot temperature. A simple method is that the temperature sensor can be used to convert temperature signal into the electric signal and then the sampling data can be collected by the instrument. In this paper, a realtime temperature monitoring system for oilimmersed power transformers is designed. The designed monitoring system can effectively monitor some key area39。s reliability. At designed monitoring system can effectively monitor present, the o il gas value and the signal