Back-up Protection to Enhance Operation of HVDC System

Abstract

the most important part of HVDC transmission project is DC control and protection system which decides DC system operation and equipment safety directly. If DC control and protection system modules fail, system safety will be threatened heavily. DC line short circuit is different from AC short circuit, because once DC fault starts it will not be extinguished by itself until the current is reduced to zero and the arc is deionised. Thus, there has to be some control function that brings the current down to zero when a fault occurs on a DC line. This paper presents a detailed analysis and simulation of HVDC line protection under the single pole to ground fault of CIGRE HVDC benchmark model. In order to prevent the fall of the operation reliability due to DC protection system failure, back-up protection is adopted.