DC line current in a compact MTDC system for DC short-circuit fault analysis

In the search for alternatives to solve the challenges that protection philosophy entails in MTDC systems due to their low resistance, it is desirable to have a base system where it is possible to analyze the various types of short-circuit faults, the contribution of fault current from other transmission lines and the contribution of fault current from the AC system through the stations. Currently, most MTDC systems available through transient analysis tools include complex voltage, power, and frequency controls, to name a few. Since these controls do not have a significant influence on the amplitude and behavior of a short-circuit fault current, they can be eliminated to reduce the computational load. In this way, the fidelity of the behavior of the fault current increases and leads to a precise analysis of the short-circuit phenomenon that opens up new proposals for fault detection and mitigation schemes. In order to clearly analyze the different types of faults, a compact CIGRE four station MTDC system is proposed through the PSCAD/EMTP transient analysis tool.