Protection design technology of measurement and acquisition unit of primary and secondary fusion distribution switch

The measurement and acquisition unit is based on the digital primary and secondary deep integration technology. At the switch side, the analog small signal output by the voltage/current sensor and the switch remote signaling quantity are locally converted into digital quantities and output to the distribution terminal. Based on the primary and secondary integrated experiment, this paper obtains the coupling characteristics of high-frequency conducted disturbance, and proposes a protection design method for the measurement and acquisition unit, including filtering protection module, secondary signal analog quantity AD sampling module, frequency measurement module, etc., and develops a prototype to realize disturbance blocking and signal isolation. Experiments show that the measurement error is low. Experiments show that the measurement error of the measurement and acquisition unit is no more than $\pm 0.17 \%$, which helps to promote the development of primary and secondary deep integration distribution switchgear in multi-functional integration, IoT design, high reliability and miniaturized design.