Testing methodology of modern digital power system protections

In the paper power system digital relay test types are presented. Different types of analysis to which relay communication systems should be submitted are described. Among them the following can be enumerated: communication control board, communication interface between the device and the local monitoring PC, communication monitoring systems between protective devices. Also a particular attention was paid to the description of tests which should be performed on network-based communication systems (i.e. protection devices using the UCA protocol) both on site and in laboratory conditions. Moreover test procedure of UCA-based devices and the laboratory bench destined for network-based device testing are described. Finally some test examples and their results are presented with the appropriate comments.