Design For Temperature Measurement System And Power Supply Of The Transmission Line

As the electric power system develops to the direction of high voltage, large capacityand automation, higher requirements to the measurement of parameters have been putforward. For the joint temperature of the transmission line, the traditional methods formonitoring have many shortcomings, such as time-consuming, arduous, undetected,misreport, difficulties in wiring and large investment, which is hard to adapt to thedevelopment of electric power system. Therefore, research on new, reliable jointstemperature measuring system of the transmission line, represented by wireless automatictemperature measurement, becomes the general trend. At the same time, power supply ofthe high potential side circuit in the temperature measuring system is also one key of theresearch.Firstly, according to the characteristics of temperature monitoring in the workenvironment of transmission line, this paper analyses the performance requirement oftemperature monitoring system, and designs the overall system with modular thoughts.Performance of the modules, such as digital temperature sensor, RF transceiver chipnRF905, and micro controller in the system, is described in detail. Then the hardwarecircuit design of the master and slave of the system is provided, and its operating principleis introduced.Secondly, aiming at the current power supply requirements of the high potential sideof the joint temperature measuring system of the transmission line, this paper designs,develops and realizes the design scheme of power supply using tailor-made coil,based onwide investigation to the existing feasible power-supply scheme at home and abroad. Thisscheme uses a special iron core coil to get energy from high voltage bus, and ensures theiron core not to become saturated too early when the electricity is large. Then theproblems of temperature rise of the iron core coil and outputting narrow pulse voltage,which is caused by saturation, can be solved.At last, this paper designs back-end voltage processing circuit for tailor-made coil.The induced voltage on the rectifier bridge is reduced greatly by serieing a inductanceimpedance components and redundant energy inducted from high voltage bus isdischarged through the relay feedback loop, and protect the back-end DC-DC module.And the energy supply problems of the high voltage side circuit in the temperaturemeasurement system are solved successfully. Experiments show that, with the laboratory bus current in range of200~1000A, thepower part can provide energy no less than100mW for the high voltage side circuit of thetemperature measurement system.