Problems found during testing of PDH devices used for transmitting data between power systems line differential protections

The paper presents the testing methods, laboratory stand and equipment applied for the tests of exchanging data from protection devices by the PDH equipment. The paper has been developed as a result of cooperation between the Power Engineering Institute of Warsaw University of Technology and PSE Operator S.A. (PPGC Operator). A number of tests had been made under this cooperation, including functional tests of protections and PDH equipment performed with regard to determining the possibilities, conditions and problems that may arise or occur during their interoperability.