2021 IEEE PES/IAS PowerAfrica 978-1-6654-0311-5/21/$31.00 ©2021 IEEE The Impact of Wind Generation on Low Frequency Oscillation in Power Systems Mohammad M. Almomani Elec. Engineering Department Mutah University Karak, Jordan monqedmohammad@gmail.com Abdullah Odienat Elec. Engineering Department Al-Ahliya Amman University Amman,Jordan a.odienat@ammanu.edu.jo Seba F. Al-Gharaibeh Elec. Engineering Department Mutah University Karak, Jordan 620180441015@mutah.edu.jo Khaled Alawasa Elec. Engineering Department Mutah University Karak, Jordan Kmalawasa@gmail.com Abstract—Integration the renewable energy resources (RES) with the modern power system is increased in the last decays due to its environmental and economic benefits. In contrast these technologies impact on the dynamic behavior of the power system. In this paper, the effect of wind turbine penetration level on the low frequency oscillations is investigated. Both local and interarea oscillation modes are covered in the study. Two types of wind turbine are selected here; fixed speed wind turbine (FSWT) and double-fed induction generator (DFIG). The impact of the existence of the FSWT and the penetration level of the DFIG on the electromechanical oscillations are conducted. The results show that the penetration level of the wind turbine is highly impact on the low frequency oscillations. Some local modes are highly affected by these types of generation. Index Terms—RES, Fixed speed wind turbine, DFIG, LFO, WAMPAC, PMU, local area oscillation, interarea oscillation. I. INTRODUCTION Any power system has two networks: a power flow network and a data flow network. In the traditional power system, the power flow and data flow networks have only one direction, so the power is transmitted from the huge generation area via a high voltage transmission system to multi-distribution areas, and the data is transmitted from the loads (customers) to the control center (server). When the smart grid takes a position in the power grid, these networks are dramatically changed. The smart grids have multi-type of the generation with multi-size at different locations (in generation and distribution areas [1]); also, they introduce new concepts (new devices and algorithms) for the monitoring, control, and protection systems; therefore, WAMS based on PMUs is presented for real-time monitoring, control and protection systems (WAMPAC) for the transmission level (mainly) [2]. The power and data networks in a smart grid are bi- directional transferred due to distribution generators and WAMPAC. Using the WAMPAC, the real-time data is collected by PMUs and transmitted via communication channels to the control center (real-time monitoring), then to the high-level energy management systems include real-time optimal power flow, contingency analysis, real-time economic dispatch and other real-time applications to identify the optimal situation to the system. After that, the feedback signals are sent from the control center to the actuators (wide-area control systems), relays (wide-area protection [3-4]) and generators (automatic generation control). These technologies can help to increase the safe penetration level of the renewable energy in the system. Once the renewable energy penetration level exceeds the safe limit, the inertia of the system decreases to a dangerous level. To make a clear view on the impact of these energy on the system dynamic performance, each type of generation has to be considered alone. For example, the modelling of the PV [5] may mainly impact on the inertia of the system. In this research, model-based small-signal (Eigen value analysis) analyzer for the low-frequency oscillations is generated for a three-area test system. The selected test system has three local area modes (one for each area) and two interarea modes. Thenceforward, two types of wind generations are added to the three-area test system to study their effect on the eigenvalue analyses; fixed speed wind turbine (FSWT) and double fed induction generator (DFIG). These generators cover types 1 and 3 of the wind generation types, whereas the dynamic response of type 2 is similar to the dynamic response of type 1 and type 4 wind turbine is handled in [6]. The two wind generators are added to different system topologies and operation point to show the relation between the penetration level and the system topology and operation points. In the next section in this paper, section II, the model of synchronous generators and wind turbines for low frequency oscillation application are discussed. The impacts of FSWT on the low frequency oscillation are presented in section IV, then, the results of adding DFIG to the three-area test system is shown in section V. II. SYSTM UNDER STUDY A. System Modeling Three-area test system [7] is used here to present the impact of the wind turbine on the low frequency oscillation. This test system has three similar areas with two synchronous generators and a load in each area. To show the impact of wind generation on the interarea oscillation modes for strong and weak tie-lines connection, two configurations are considered; string configuration and ring configuration. Where the three areas are connected in the string configuration stronger than that in ring configuration. The single line diagrams of these configurations are shown in Figures 1-2. On the other hand, three different operation points are considered. In each operation point, there is one area heavy loaded and one area lightly loaded, where the first area is heavy loaded in the first operation point and lightly loaded in the second operation point, the second area is heavy loaded in second operation point and lightly loaded in the third and the third area is heavy loaded in the third operation point and lightly loaded in the first. In each case, 400MW is transmitted from lightly loaded area to heavy loaded area. These operation points are applied to the two configurations;