Spänningsstyrd underfrekvenslastfrånkoppling i elektriska kraftsystem
This report is a Master?s Thesis performed by Andreas Adolfsson and David Jacobsson atChalmers University of Technology. The purpose of this master?s thesis is to evaluate anew method for load-shedding, the voltage controlled underfrequency load-sheddingdeveloped by ABB. This report presents a comparison between conventionalunderfrequency load-shedding and this new method for load-shedding. This master?sthesis also aims to present a detailed description of how the frequency regulation isperformed in the Nordic power system.The simulations are performed using the analysis program Power System Simulator forEngineering (PSS/E). The Nordic32 power system is used for the simulations, this is asystem with 32 buses based on the Nordic power system and developed by CIGRÉ.A PSS/E user model for the voltage controlled underfrequency load-shedding has beendeveloped in this master?s thesis which is used for the simulations on this new method ofload-shedding.A study of the voltage controlled underfrequency load-shedding shows that this methodhas important advantages compared to the conventional load-shedding when used in apower system with evenly distributed production and load. This method is not suitable forpower systems where load and production is not evenly distributed, in a case like this theconventional load-shedding performs better.The results show that the use of voltage controlled underfrequency load-sheddingachieves less constraint on transmission lines in the power system after a production loss.The voltage in vicinity of the production loss is improved when the voltage controlledunderfrequency load-shedding is used.