Development Of Remote Wireless Calibration System For On-line Monitoring Device Of Capacitive Equipment

Capacitive equipment is an important transmission and transformation equipment in Substation.Dielectric loss is an important index reflecting the insulation performance of capacitive equipment.On-line monitoring and fault diagnosis of capacitive equipment is of great significance.At present,on-line monitoring device is used for real-time monitoring of capacitive equipment.After long-term operation,On-line monitoring device of capacitive equipment is vulnerable to complex environment of substation,which causes the accuracy and sensitivity of measurement problems.Aiming at the inconvenience of long-distance wire transmission of reference voltage in calibration process.A calibration method of on-line monitoring device for wireless transmission of reference voltage is presented in this paper.And it is compared with the calibration method of voltage wired transmission.It is verified that wireless verification system has better advantages.Specific research contents are as follows:(1)The main methods of on-line monitoring and verification of capacitive equipment at home and abroad are studied.The advantages and disadvantages of each method are analyzed.Accordingly,A new wireless calibration method with high efficiency and simple operation is proposed.(2)A method of wireless transmission of reference voltage is proposed.The theory of modem is deduced.The modem circuit is also designed.Laser is used to complete the wireless transmission process.The problem of long-distance repetitive wiring in calibration process is solved.(3)The overall and various parts of the instrument are described,including the transmission process of reference voltage and the output of exciting current.The main modules include frequency doubling phase-locked module,AC voltage generator module,AC voltage-to-current module and filter circuit module.(4)The software of each part of the instrument system is designed,mainly including signal communication and transmission software design,human-computer interaction interface software design,AC voltage generation software design and mobile data query software design.(5)Complete the hardware design and software programming of the excitation current generator.Human-machine interface displays the parameters of the calibration process.After completion of the test machine,Testing each part of the circuit.Finally,a comparative experiment of wired and wireless calibration is carried out in the laboratory of Zhejiang Electric Power Research Institute of State Grid.And through the audit and evaluation of Zhejiang Institute of Metrology.The results show that the maximum relative error of resistive current is 3.44%.The maximum relative error of the total current is 2.41%,all within the allowable range of error.It is hopeful that wireless calibration will replace wired calibration.Data of verification can be obtained on cloud query system.The research of this subject adds wireless transmission and cloud query function on the basis of the existing capacitive device online monitoring and verification device.FM demodulation technology is used in wireless transmission,which greatly improves the convenience of verification device,reduces the cost of operation and maintenance,and enhances security.Cloud query function greatly liberates human resources,and enables staff to query and verify the number at anytime and anywhere.according to.It is of great value to research on calibration of on-line monitoring device for capacitive equipment.At the same time,it has a far-reaching impact on the application of FM demodulation technology.Finally,a large number of experiments verify that wireless calibration can achieve the effect of wired calibration.Wireless verification will become a new trend of verification in the future.