Protection, transient stability and fault ride-through issues in distribution networks with dispersed generation

This paper describes the transient stability analysis of a 10 kV distribution network with wind generators, microturbines and CHP plants. The network being modeled in Matlab/Simulink takes into account detailed dynamic models of the generators. Fault simulations at various locations are investigated. For the studied cases, the critical clearing times are calculated. Some network parameters which influence transient stability are also observed. The compliance of DG protection to stability criteria requirements is further studied. The ride-through capability of the DG units is also investigated through transient stability analysis and the equivalent CCT-voltage dip curves are derived. It is concluded that during fault DG unit availability can be increased through modification of undervoltage protection requirements.