Feasibility of HVDC for Very Weak AC Systems with SCR below 1.5

This paper exposes the feasibility to connect high voltage dc transmission (HVDC) systems to very weak ac networks leading to short circuit ratios (SCR) lower than 1.5. The existing literature does not provide solutions for such a low SCR systems and often the HVDC expansions cannot grow enough as expected. The studies developed are for the short-term voltage stability phenomena, where a solution using the PSCAD/EMTDC program for a very weak ac network with SCR = 1.0 is presented. The reactive power characteristics are shown since they are important to judge the behavior of solutions for ac/dc interactions.