| The transmission line plays an important role in conveying power to all sides.Once the fault happened,it will cause serious influence on the entire power grid.It is the guarantee for the safe operation of the transmission line to have the transmission line running status monitored on real-time by the online monitoring sensor devices.Because of the complexity of the sensor installation environment,the power supply has become the restricting factors on the development of transmission line online monitoring sensor equipment.In this paper,the existing power supply devices were analyzed and summarized,then take this as the foundation.According to researching our laboratory’s online monitoring sensor equipment about lightning location,conductor galloping,wind vibration etc,a power supply device is designed based on mutual inductance,which can obtain energy from the transmission line by using energy storage coil,then through the back-end processing get stable voltage output,finally supply power to the sensor device.Firstly,according to the magnetic saturation of the coil,the parameters and the structure can be taken to optimize,which greatly improve the magnetic saturation characteristics of the energy taking coil,and is verified by the simulation of Saber software.Secondly,according to the electric current of the line transmission wire is too small,which could lead to the problems of the small output power by adopting matching capacitance method of coil secondary side,which greatly improves the output power and is equipped with a lithium battery as a backup power to assist power supply,ensuring the stability of the entire power supply device.In addition,transmission line current is too large and can lead to control problems of secondary side voltage by applying PWM wave control switch tube’s closure time of adjustable duty ratio to leak energy,and guarantee the stability of the secondary side output;At last,through comparative analysis,choose the Fly-back topology as a DC-DC converter of supply device,when the transmission line current occurs fluctuates,DC-DC converter required duty ratio of output the maximum power almost do not need to change,which simplify the design of DC-DC converter;and designs the output over-voltage and over-current protection circuit,ensure the stability of the entire power supply device and the safety of sensor devices.The experiment platform is set up and verify the power supply device parameters and the whole performance.When the transmission line current is more than 50 A,the output power of the power supply device is higher than 8W,and the DC-DC converter efficiency is over 80%,which achieves targets of the designation parameters;When the transmission line current is higher than 50 A,the output voltage is stable at 12 V,which verify the effectiveness of bleeder circuit and over-voltage and over-current protection circuit.In a word,through the example analysis verifying the transmission line current can work between 0-1000 A,and designed power supply device can provide a stable power supply for the power transmission wire online monitoring sensor. |
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