تحلیل پایداری یک ماشین سنکرون مجازی
Abstract
1- Introduction
2- Modelling of PMSG
3- Stability analysis and dynamic performance of the proposed VSM
4- Simulation and discussion
5- Conclusion
Acknowledgements
Appendix A.
References
Abstract
This paper proposes a Virtual Synchronous Machine (VSM) strategy for Permanent Magnet Synchronous Generator based wind turbines which enables seamless operation in all operating modes. It guarantees Maximum Power Point Tracking in grid-connected operation, Load Following Power Generation in islanded operation and Low Voltage Ride Through capability during faults. To achieve optimal performance in all operating modes, the stability of the VSM is investigated in the event of small and large perturbations. The small-signal stability analysis of the VSM is conducted using a linearized state space model and the impact of the controllers on the dominant modes are derived using participation factor analysis. The transient stability and dynamic performance of the VSM are analyzed using a non-linear model. Based on this analysis, design guidelines and operational limits of the VSM are established. The results of this analysis are validated using time-domain simulations in MATLAB/SIMULINK.
Introduction
Driven by environmental, technical and economical factors, the grid topology is evolving, from centralized fossil-based power generation to distributed generation from renewable energy sources (RES) [1]. Irrespective of the power generation source, substantial system inertia is required to maintain stability and suppress oscillations due to disturbances on the network. According to National Grid [2], 70% of the British power system inertia is currently provided by large synchronous generators (SG). However, with the commitment of the UK to reduce 80% of its greenhouse emission by 2050, RES must generate at least 60% of power demand. This results in a massive reduction in the system inertia, which must be compensated by implementing ancillary infrastructures or integrating RES with control paradigms which offer similar robustness as the SG [3,4]. In terms of infrastructures, Nguyen et al. [5], studied the impact of synchronous condensers (SC) in maintaining the stability of the future grid. A model of the western Danish power system was utilized for the test scenario and results confirmed that, the application of SC at strategic locations, adequately damps power system oscillations and improves the frequency stability. Several research works [6–8], have corroborated this findings and it has been applied in some HVDC projects [4,9], to improve grid strength. Despite the benefits that the SC offers, it may not be economically viable for scenarios with 100% RES. Hence, several research works have been focused on augmenting the control paradigm of RES rather than adding expensive infrastructures to support the grid.