| Radio interference (RI) measurement in time domain instead of the traditional methods in frequency domain have the advantages in excavating inner mechanism of RI generated by corona of high-voltage transmission lines. So the chief purpose of the research is to develop new technology and system to measure RI signals in time domain.Firstly, a new compensation technique has been developed by introducing new definition of antenna factor called complex antenna factor. With establishing parallel-plate transmission line experiment platform and magnetic field experiment platform, the complex factor of loop antenna was obtained. And the results of two kinds of experiment platform were consistent.Secondly, based on the loop antenna equivalent circuit and designing methods, the loop antenna for RI measurement in time-domain was designed and fabricated under the simulation of HFSS software. Furthermore, the complex factor of designed antenna has been obtained which meet the design requirements.Thirdly, the RI measurement system in time-domain was completed, which included loop antenna, post-compensation part, data acquisition card and upper computer. The post-compensation part is to compensate the complex factor inversely based on the FIR digital filter principles.In the end, using magnetic field experiment platform, the performance of RI measurement in time-domain system has been tested. Corona current typical curve was injected into platform as the signal source. The results showed that the system satisfied design requirements and can be used for measuring radio interference in time-domain. Furthermore, measured the RI of ±1100kV UHVDC test transmission line with the RI measurement system in time-domain. The results verified the effectiveness of the system and the measurement method further. |
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