Research on High-Frequency Signal Monitoring Scheme and Key Technology for Near HVDC Converter Station

This paper presents a comprehensive system architecture and device specifically designed for high-frequency signal monitoring for near HVDC converter station. The system is meticulously organized into two core modules: the master station and the substation. The master station is responsible for efficient data reception and panoramic monitoring analysis, and the substation includes a high-frequency signal synchronized measurement unit with a dedicated data processing unit. A novel spectrum correction method is proposed, which employs the mixed base FFT + ratio correction techniques and takes into account the filter compensation coefficient, leading to higher accuracy and precision. Through prolonged measurements on-site, it is confirmed that stable propagation of the 37th high-order harmonic exists at UHVDC near-field stations, and the dynamic trends of its amplitude and phase characteristics are revealed. In conjunction with power grid topology analysis, an in-depth exploration is conducted on the propagation characteristics of high-frequency signals and source localization strategies. The experimental results verify the prototype system's exceptional performance in terms of measurement stability and real-time capability, enabling wide-area synchronized monitoring of harmonics on-site and meeting the requirements of engineering applications.