International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-9 Issue-2, December, 2019 2768 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number: B2271129219/2019©BEIESP DOI: 10.35940/ijeat.B2277.129219 Abstract: Low voltage ride through capability is an ability of the wind farm to stay connected with grid at the time of disturbance in the power system. The penetration of wind based renewable energy resources is increasing and the low voltage ride through consideration is vital for systems studies. The literature available demonstrates the improvement in low voltage ride through either by using fault current limiters or by implementing a control strategy for induction generator based wind farms. In this paper the low voltage ride through capability enhancement of the fixed speed induction generator is presented with various fault current limiters. The authors have presented the effects of fault current limiters in the aggregated hybrid wind farm consisting the combination of fixed speed induction generators and doubly fed induction generators which is not available in literature so far. A transient fault is simulated using PSCAD/EMTDC software in both the cases and the results are presented and discussed. Keyword: Doubly Fed Induction Generator (DFIG), Fault Current Limiters (FCLs), Fixed Speed Induction Generators (FSIG), Low Voltage Ride Through (LVRT) I. INTRODUCTION The penetration of renewable energy sources in power generation have increased due to technological developments and affordability in recent times due to environmental concerns. The bulk renewable power generation is mainly achieved through solar and wind farms. As the penetration of renewable energy generation is increased the transmission system operators (TSOs) have specified grid code requirements for integration of wind energy based power plants (WPP) in the grid. Low voltage ride through (LVRT) is one of the grid code requirements for the integration of WPPs. According to this requirement, WPPs should stay connected to the grid and inject reactive power to support the voltage at point of common coupling (PCC) during the fault [1][2]. Induction generator based technologies are used in wind energy based power generation, which includes fixed speed induction generators (FSIG) and doubly fed induction generators (DFIG). In past few decades, doubly fed induction generator has dominated the world's market in wind energy Revised Manuscript Received on December 08, 2019 * Correspondence Author Chintan R. Mehta*, Assistant Professor, Electrical Engineering Department, Institute of Technology, Nirma University, Ahmedabad, India. Bhavik D. Nathani, Electrical Engineering Department, Institute of Technology, Nirma University, Ahmedabad, India. Prasad D. Deshpande, Electrical Engineering Department, Institute of Technology, Nirma University, Ahmedabad, India. Santosh C. Vora, HOD, Electrical Engineering Department, Institute of Technology, Nirma University, Ahmedabad, India. generation [3]. However, there are many WPPs installed with FSIG based WPPs. Although the FSIGs exhibit simple and robust construction features, it suffers from poor performance with respect to LVRT requirements as it behaves differently during voltage sag. For SCIGs to stay connected to the grid, its speed and voltage should be controlled during and post fault events [4][5]. On the other side the DFIG-based wind turbines are very sensitive to voltage dips during grid faults. This is due to the partially-rated back to back power converter. If WPPs are directly connected to grid, it causes the short circuit current surpassing beyond capacities of existing equipment in the grid at some point, resulting into instability from WPPs point of view [6] [7].To satisfy the LVRT requirement of the wind farms, both series and shunt types of devices have been used. Static synchronous compensator (STATCOM) [8], thyristor switched capacitor [9], static VAR compensator [10] have been used as shunt options while Dynamic voltage restorer [11], series dynamic braking resistor (SDBR) [12], unified inter‐phase power controller [13], gate controlled series capacitor [14] are the series options. These devices have the capability of improving the transient stability but they are costlier and required huge capital investments. The other options for improving the transient stability and LVRT are fault current limiters (FCLs) as proposed in [15] - [23]. The application of FCLs allows WTs to remain in service, even if fault current exceeds its rated peak value. Moreover, as the magnitude of voltage sag during short circuit event depends upon the magnitude of fault current, an effective FCL connected to the WPP not only limits the large short circuit current but also reduces the voltage sag at Point of Common Coupling (PCC) during fault. II. GRID CODE REQUIREMENT OF INDIA The grid code requirement of India is shown in Fig.1 [24]. In this case, as seen from Table I, the voltage at fault V f should not go below 15% of nominal system voltage. V pf is the voltage after the clearance of fault. T is the minimum time for which the wind farm should remain connected to the grid under the system disturbances. The fault clearing time depends on the voltage level of the system. Table-I shows the voltage level and fault clearing time as per grid code requirement Effects of Fault Current Limiters in Transient Stability Performance of Hybrid Wind Farm Chintan R. Mehta, Bhavik D. Nathani, Prasad D. Deshpande, Santosh C. Vora