2021 3rd International Conference on Sustainable Technologies for Industry 4.0 (STI), 18-19 December, Dhaka 978-1-6654-0009-1/21/$31.00 ©2021 IEEE Impact of wind power plant in Bangladesh power system stability Pollen Barua 1 , M.G Rabbani 2 , Muhammad Quamruzzaman 3 Dept. of Electrical and Electronic Engineering, Chittagong University of Engineering and Technology 1,3 Dept. of Electrical and Electronic Engineering, Eastern University, Dhaka 2 pollen.eee@gmail.com 1 Abstract—Government of Bangladesh has recently approved the maiden private wind power project of 55 MW in Bagerhat region. In this case the stability of Bangladesh Power System (BPS) is of prime concern as the behavior of renewable energy sources are different from non-renewable sources. Wind power based non-conventional source of energy integration may change the stability. Hence, this paper investigates the steady state, small signal and transient state stability replacing the conventional sources of generation with equivalent size in step by step for different penetration levels. Eigenvalue analysis technique is used to find out the oscillatory modes basically the critical modes and Hopf Bifurcation (HB) point. Doubly Fed Induction Generator (DFIG) is considered to model the Wind Turbine Generator (WTG) in Bagerhat. NEPLAN software is used to carry out all the simulations. Keywords—BPS, wind power, small signal stability, Eigen value analysis, DFIG, NEPLAN I. INTRODUCTION Wind energy is getting incremental preference throughout the world. As the conventional sources have limitations, every country has a plan towards renewables, among which wind has a great potential. Country like Denmark, Germany, Spain and Ireland are in leading role to utilize the wind energy for their power generation. Location of Bangladesh is between 20.3-26.38 degree north latitude and 88.04-92.44 degree east. It has a 574 k.m long coast line and many small island in the Bay of Bengal [1]. BPS is going to integrate WTG at Bagerhat grid due to suitability of location for wind. As WTG behaves differently from synchronous machine [2], the integration of WTG can alter the behavior of whole BPS. In [3,4,5] , the steady and dynamic response of some systems were studied with the injection of renewable sources. BPS was studied thoroughly in [6,7] by dividing the whole power system in two regions called eastern and western. These regions are connected by East-West Interconnector System (EWIS). The planned WTG of BPS is at western region. Stability is a very vital factor to ensure proper operation of power system. A system is desired to exploit thermal limit of its capacity but voltage regulation limit and stability limit always put a limitation. Saddle Node Bifurcation (SNB) and HB are used to find out these limitations [6]. Basically Eigenvalue analysis plays the key role to study the stability [8]. Eigenvalues of the critical mode of oscillation before and after the integration of WTG will find out the influences of it on BPS.There is a plan to set 55 MW WTG at Bagerhat grid. As the plan will be expanded later, present study inserts up to 83 MW and each unit having 5.2 MW of WTG. DFIG is used to model WTG. It can operate in variable speed of wind whether it is sub synchronous or super synchronous [9]. It is called doubly fed as both the stator and rotor of the generator is connected to electrical source [2]. It can exploit maximum power from the wind and ratings of associated electronic devices are reduced [9]. A. Contributions In this paper BPS is modelled with WTG incorporation in Bagerhat grid. WTG is penetrated gradually to observe the response in term of stability. SNB and HB is determined at around 20% penetration of wind power in BPS. The load is increasing to examine the response with the penetration of WTG. Small signal stability of BPS is also observed at different penetration level. Transient state stability is also analyzed before and after the WTG incorporation in the system. B. Paper Organisation This paper is oriented as section II highlights the methodology where the steps of work are described, section III comes with mathematical modelling of BPS and DFIG. Next, in section IV the results of simulations are carried out. Finally, section V outlines the conclusion. II. METHODOLOGY A. Scenerio Description BPS is already having Bagerhat grid of 132 K.V. There is no generating stations. When the WTG is penetrated in this grid, equivalent amount of conventional generation is replaced from the nearest Khulna grid which is having 160 MVA generating station. Fig. 1 shows the EWIS of BPS system. Bagerhat grid is equipped with sixteen units of 5.2 MW WTG at different penetration level gradually as stated in table I. The penetration level is the ratio of total renewable power generated ∑PRG to the total load ∑PL as shown in equation (1) Penetration Level (%) = ∑  ∑  (1) TABLE I: DIFFERENT PENETRATION LEVELS OF WIND POWER Case Wind (MW) Penetration Level (%) Wind connected Bus Replacing Bus 01. 0 0 -------- ------- 02. 26 6.5 Bagerhat Khulna 03. 52 13 Bagerhat Khulna 04. 74.2 18.55 Bagerhat Khulna 05. 83.2 20.8 Bagerhat Khulna NEPLAN simulation software is used to model the system and Eigenvalue analysis [10]. At first the base case is considered and the steady state limit and dynamic stability limit point is determined. Then with case 05, new steady state stability limit