Analysing protection of lines with numerical distance relays against short circuit and power swing in electrical power systems and implementing its dynamic simulation

As a consequence of changing world policies and developing technology, electric enery has been an indispensable requirement and development mark for all countries.In recent years, major investments have been made and continued for energy sector in our country.Because of countries' increasing capacity of electric,electrical power system quality has become more important.Hence, improvement works for main demands such as continuity, safety, selectivity, being simple-structured and being economic increasingly continue.So, the power-system protection has become more important topic in engineering branch. Especially, launching digital protection relays in last 30 years have increased protection engineering works.Basic protection functions such as distance,differential, overcurrent protection,have become more effective and continue to develop with these works.In this thesis study, main distance protection functions which are very important for protecting transmission lines, had been studied practically and theoretically.Then, event reports which was gotten from relay after dynamic testing according to calculated values or settings, were analyzed.In the same way, out-of-step blocking and tripping functions were analyzed.Thus, it was seen that relay dynamic responses for different fault conditions. In typical distance protection tests, five stepped protection was applied by considering protection criteria.With correct calculations and relay settings,it was seen that the relay can send tripping signals with suitable time delays. Also,it was shown that existing symmetric components and calculated fault location zones in proportion to impedance are matched up with theory.In out-of-step blocking and tripping applications,calculation and simulation were made for impedance-based concentric scheme.It was seen that,in spite of easily applying concentric scheme with correct stability studies,because of the load encroachment, it is not applicable for long and heavy loaded lines. In this thesis study,Eplan software was used for protection system secondary design,Artes 460 relay test system and its software were used for testing the relay and fault simulation , also Sel-421 distance protection relay was used for setting the relay and getting the event reports. Keywords: Numerical distance relay, out-of-step tripping, out-of-step blocking, stability, selectivity