Analysis of operation of transformer differential protection under current transformer saturation: Software simulations and relay testing

In the paper the analyses of the current transformer saturation influence to operation of differential protection are presented. Analyses are performed using a simulation tool and a relay model, as well as using the physical relay by injecting test currents from test equipment on relay inputs. The comparison of relay behavior in these two analyses has been performed and discussed. Network modeling has been performed in DIgSILENT PowerFactory and physical relay testing using DOBLE test equipment.