Effect of Link Failure on the Stability of dc Microgrid

In the dc microgrid, the network configurations used for supplying power generated by sources to the loads are radial, ring or generic of the two. The failure of interconnecting lines or cables due to the opening of Circuit Breaker (CB) contacts and network reconfiguration, may lead to the modification of the existing configuration. The variation in parameters of the dc microgrid due to modification in network configuration may affect the small signal stability. The papers discussed in the literature deal with small signal stability analysis of dc microgrid having fixed topology and do not consider the effect of transition in configurations on the stability of dc microgrid. At the same time, during fault conditions, the nonlinear variation in parameters of the Metal Oxide Varistor (MOV) used in Hybrid Circuit Breaker (HCB) may also affect the system stability. The effect of variation in the parameters of MOV on system stability is not discussed in the literature. To fill this gap, a small signal model is derived to study the effect of modification in configuration on the stability of dc microgrid. The viability of the analysis is carried out with simulation studies using Matlab.