In this paper

the test method of equivalent series inductance (ESL) with nH-level for DC-link capacitor is proposed on the basis of the development experience of DC-link capacitor for flexible DC transmission

its correctness is verified and the difficult problem of testing method for nH-level inductance is solved. The calculation method of nH-level inductance based on DC support capacitor lead line is verified in accordance with the test method

which provides a new design idea for reducing the nH-level inductance of DC-link capacitor. Moreover

the AC partial discharge of pole to enclosure-the perennial problem for the DC-link capacitor

is developed

analyzed and summaried

which provides reference for solving the AC partial discharge to the enclosure of the DC-link capacitor. Some suggestions for the study of DC partial discharge between poles are propsoed. Based on the test and operation experience

the contact resistance test

temperature rise test

small inrush current test and large inrush current test are carried out on the current outgoing terminals of DC-link capacitor. The test verification results show that only the thickened round nut can pass the large inrush current test

which is of great reference value for improving safe operation of DC-link capacitor.