| DC power transmission has many advantages compared to AC power transmission, especially in the large capacity, long distance power transmission. HVDC has been playing an increasing role in power system in China. However, HVDC transmission lines have some impact on the surrounding environment, such as total electric field, ionic current and so on.The total electric field on the ground level should be measured in the electromagnetic environment study of HVDC transmission lines in order to testify the validity of calculation or to evaluate the environment generated by HVDC transmission lines. Because of high cost of the traditional measuring instruments, the author designs a set of low-cost measurement system based on virtual instrument technique. In the design of the probe, the total electric field on the ground level is converted to alternating current signal. An integrated operational amplifier which is more suitable for micro-current amplification to process the weak signal form the probe is used to design and develop the signal amplification and filtering circuit. The analysis and processing of the measurement data is based on the software LabVIEW. The measurement system is validated by experiment results after the calibration, and it can be applied to measure the total electric field on the ground level under the HVDC transmission lines.This paper introduces the hardware design, software development, system debugging and experiment results from the perspective of the overall design. |
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