Research And Development On Transformer DGA Smart On-line Monitoring Instrument

Transformer is an important electric device in power system, and on-line real-time monitoring of its status is an effective measure to prevent severe accidents from happening. Based on "Research on Remote Monitoring and Diagnosis Methods of Large Transformer Based on Temperature Field Model and Feature Extracting" (National Natue Science Fund Project, No: 50574814), this paper put forwad the subject of "Research and Development on Transformer DGA Smart on-line Monitoring Instrument". From the viewpoint of smart instruments, we employ the thchnology of embedded system, data acquisition and processing, industrial Ethernet and GPRS wireless network communication to realize transformer DGA on-line monitoring instrument's basic functions, which include data acquisition of six transformer's fault-feature gases and communication between the instrument and upside monitoring center. Moreover, we studied and realized on-line diagnosis, on-line identification and on-line software upgrade these three instrument's intelligent functions.This paper's main contents are shown as follows:Chapter One: It introduced the developing state of transformer DGA on-line monitoring instruments at home and abroad, analyzed two typical products in detail which is in real use. Afterwards, it conluded the trend of transformer DGA on-line monitoring equipments. At last, the research contents and goal of this paper is put forward.Chapter Two: It analyzed the transformer's overall functions, and put forward the plan of building up embedded monitoring instument's lower platform. We also studied monitoring instrument's realization technology for data acquisition, data communication, intellectual functions and lower platform.Chapter Three: According to characteristics of monitoring instrument, we compared several kinds of embedded microprocessors and embedded operating systems, and chose ARM CPU S3C4510B as core of the hardware platform, μC/OS-II as core of software platform. After lower platform is built up, we analyzed the way of making it stable and reliable. Then we tested the lower platform.Chapter Four: We designed data acquisition hardware circuit of six fault-feature gases, developed data acquisition and linearization software. In order to solve the cross interference of none-measured gas and temperature to gas sensors, we studied the method of data fusion of multi-sensors.Chapter Five: According to different operating situations, we provided two ways to communicate with upper computer: industrial Ethernet and GPRS wireless network. We ported a embedded TCP/IP stack 1wIP, and developed GPRS dialing software. Using MODBUS/TCP application layer protocol, this chapter designed the format of data frame, and the communication between monitoring instrument and upper computer was realized.