Simple and Efficient Method for Steady-State Voltage Stability Analysis of Islanded Microgrids with Considering Wind Turbine Generation and Frequency Deviation

چکیده مقاله

Distribution grids are being transformed from passive to active networks. The active distribution systems are constructed through the implementation of microgrids (MGs) which are characterised as ‘the building blocks of smart grids’. This type of network eases the integration of distributed generation into power networks and makes it possible to define a new index for voltage stability. The penetration of renewable power sources such as wind turbines can create new challenges in this system that will affect voltage stability index (VSI). In this study, an improved indicator is proposed to estimate the voltage stability margin of a two-bus system based on both saddle node and limited induced bifurcations considering different types of load model. The catastrophe theory is used to define this new VSI of an islanded MG (IMG), called as cat_VSI_IMG. A new concept, named reduced IMG network, is also used to generalise the proposed index to n-bus IMGs by splitting these networks. The cat_VSI_IMG, which is validated by a verified continuation power flow method for IMGs is called the maximum loadability margin of IMG. The performance and effectiveness of the proposed method are demonstrated on 33-bus and 69-bus test systems for different types of load model.