Modeliranje nihanja moči in odziv distančne zaščite v okolju OpenModelica

BRATKOVIČ, SHAM (author), Pantoš, Miloš (mentor), Bogovič, Jerneja (comentor)

Magistrsko delo obravnava delovanje in zanesljivost distančne zaščite prenosnega voda med dinamičnimi pojavi v elektroenergetskem sistemu s poudarkom na blokadi zaščite med nihanjem moči. Analizirana je problematika napačnih izklopov distančnih relejev med stabilnimi nihanji in potreba po zanesljivem izklopu ob izgubi sinhronizma. Namen naloge je v odprtokodnem okolju razviti simulacijski model, ki bo dokazal prisotnost nihanja moči na visokonapetostnih daljnovodih ob pojavu in odpravi kratkega stika na srednjenapetostnem omrežju. Za dosego zastavljenih ciljev je bil uporabljen poenostavljen model elektroenergetskega sistema SMIB (Single Machine Infinite Bus), ki predstavlja sinhronski generator, povezan na togo mrežo. Tak model je pogosto uporabljen v raziskavah, saj na enostaven način omogoča vpogled v osnovne pojave stabilnosti in nihanja sistema. Najprej smo natančno razložili osnove delovanja distančne zaščite, blokado distančne zaščite med nihanjem moči in izklop ob izgubi sinhronizma, nato pa v okolju OpenModelica z odprtokodno knjižnico OpenIPSL zgradili simulacijski model, ki je vseboval vse ključne elemente. Za preveritev zanesljivosti odprtokodnega pristopa je bil vzporedno izdelan referenčni model v okolju MATLAB/Simulink, kar je omogočilo primerjavo odzivov sistema. V nalogi smo izvedli več simulacij, s katerimi smo pokazali, da se po odpravi kratkega stika v sistemu pojavijo nihanja moči. Z analizo potovanja impedančne točke smo nato izpostavili primere, kjer bi distančna zaščita brez dodatnih funkcij lahko napačno izklopila vod. Rezultati potrjujejo, da je z odprtokodnimi orodji mogoče zanesljivo modelirati in proučevati tudi naprednejše zaščitne funkcije v elektroenergetskih sistemih. Predstavljeni pristop prinaša preglednost, prilagodljivost in dostopnost, kar ga dela privlačnega tako za raziskovalno kot tudi pedagoško okolje. Uporabljena metodologija uspešno povezuje področje stabilnosti sistema z algoritmi zaščitnih relejev v odprtem simulacijskem okolju, rezultati pa ponujajo dragocene vpoglede v delovanje distančne zaščite med nihanji moči in so lahko v pomoč pri nadaljnjem izboljševanju varnosti ter zanesljivosti elektroenergetskih omrežij.

• Language: Slovenian
• Keywords: Stabilnost elektroenergetskega sistema, nihanja moči, distančna zaščita, blokada distančne zaščite med nihanjem moči (PSB), OpenModelica, OpenIPSL
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: FE - Faculty of Electrical Engineering
• Year: 2025
• PID: 20.500.12556/RUL-172860
• COBISS.SI-ID: 256948995
• Publication date in RUL: 11.09.2025

Secondary language

• Language: English
• Title: Power Swing Modeling and Distance Protection Analysis in OpenModelica

Abstract

The master's thesis addresses the performance and reliability of distance protection of transmission lines under dynamic conditions in a power system, with a particular focus on power swing blocking (PSB). The study analyzes the issue of unwanted tripping of distance relays during stable power swings and the need for reliable tripping in the case of loss of synchronism. The objective of the thesis is to develop an open-source simulation model that demonstrates the occurrence of power swings on high voltage transmission lines following the initiation and clearing of a fault in the medium voltage network. To achieve the stated objectives, a simplified Single Machine Infinite Bus (SMIB) model was employed, representing a synchronous generator connected to an infinite bus. This reference model is widely used in research, as it provides a straightforward framework for studying fundamental aspects of system stability and power swings. The work first presents the principles of distance protection, including power swing blocking (PSB) and out-of-step tripping (OST), and then develops a simulation model in OpenModelica using the open source OpenIPSL library, incorporating all key system components. To validate the reliability of the open source approach, a reference model was also implemented in MATLAB/Simulink, enabling a direct comparison of system responses. Several simulations were carried out to demonstrate that power swings occur in the system after fault clearing. By analyzing the trajectory of the impedance locus, scenarios were identified where distance protection, without additional functions, could result in undesired tripping. The results confirm that open-source tools can be reliably used to model and study advanced protection functions in power systems. The proposed approach offers transparency, flexibility, and accessibility, making it valuable for both research and educational purposes. The applied methodology successfully bridges the field of power system stability with relay protection algorithms in an open simulation environment, while the results provide useful insights into the operation of distance protection during power swings and can support further improvements in the security and reliability of the power system.

• Keywords: Power system stability, power swings, distance protection, power swing blocking (PSB), OpenModelica, OpenIPSL