The application of the unbalance current protection for capacitor of AC filter used in the HVDC system of CSG

Based on the familiar configuration and the typical fault characteristics of the capacitor used in AC filters,the principle of the unbalance current protection for AC filter is introduced.The unbalance current protection for capacitor of AC filter used in the HVDC system of CSG is discussed.The influence on the unbalance current protection caused by the inrush current at the moment of putting into operation of the AC filters and the improving measurements such as adopting POW equipment and setting protection coordination reasonably have been analyzed combined with the actual examples.All of these are valuable to the design of the protection and the maintenance and operation.