Influence of Distributed Generations and Renewable Energy Resources Power Plant on Power System Transient Stability Mohd Zamri Che Wanik and IstvÆn Erlich Department of Electrical Power System University of Duisburg Essen Duisburg, Germany Azah Mohamed and Azuki Abdul Salam Dept. of Electrical, Electronic and System Eng Universiti Kebangsaan Malaysia Bangi, Malaysia Abstract This paper analyzing influence of distributed generation (DG) on transient stability of power system network operating parallel with large renewable energy resources (RES) power plant. The study is performed in hypothetical power system network envision in the future which contains a large number of DG. Network behavior when subjected to disturbance is compared with different level of DG penetration. The results are compared with the performance of the network without DG and RES power plant as a reference case. It can be concluded that addition of DG and RES power plant makes power system network more transiently stable. This integration enhances the power system network capability in handling more larger disturbances. Keywords ü Transient Stability; Distributed Generation; Renewable Energy Resources; Fault Ride Through I. INTRODUCTION The need for unconventional generation units for supplying electricity is clearly due to various reasons such as responding to current climate change; depleting sources of fossil fuel; and to overcome the threat on security, reliability, and quality of supplies due to ageing infrastructures. It is anticipated that future generation of electricity will be shared between central power plants, small scale distributed generation (DG) units and large renewable energy sources (RES) power plant. In this electricity network as illustrated in Fig. 1, DG and large RES power plant will replace a proportion of electricity presently generated by conventional power plants [1-2]. DG technologies mostly anticipated in future network is microturbine generation system (MTGS), fuel cell generation system (FCGS) and photovoltaic generation system (PVGS). The sharing of generation among conventional power plant, large RES power plant and DG is in fact already realized in many European countries. In Germany for example, by the end of 2007, 22.2 GW of wind turbines and 3.8 GWp of Photovoltaic systems had been installed. Combining with other energy sources including hydropower and biomass plant a total of 34 GW RES has been installed [3]. This magnitude of penetration is considered significant comparing to the Germany load demand of 40-80 GW. This DG and RES can constitute more than 50% of the total power generation when the weather condition is optimum. With this large number penetration, some conventional power plant is dismantled and the supplied power is replaced by DG and RES which are mostly coupled to grid through power electronic converter (PEC). Different characteristic posses by these nonconventional generation creates a lot of concern on power system network stability which led to transient stabilities studies [4-5,13]. In [4-5] the stability of a power system network with the penetration of DG is analyzed. In [13] the influence of windfarm on transient stability is investigated in. It is demonstrated these nontradional generation units improves the stability of power system if they are properly sized, located and controlled. In [4-5] however DG units are disconnected if the voltage at the point of connection goes bellow 80 % [4] or 85% [5]. This disconnection however creating another disturbance to the network after already went through a critical situation. If DG penetration is large as expected in future power system which is termed smart grid, there is substantial loss of active power supply inside the network and this strategy is feared will brings the power system network to instability. In [13] the influence of different control strategy in wind farm and the influence on power system stability is compared. In this studies even voltage at the point of connection reaching zero, fault ride through is necessary if the disturbance is less than 150 ms. With appropriate control, addition of wind farm to power system is shown enhances power system transient stability. Figure 1. Future power system network. Active Distribution Network Conventional Power plant Wind Farm PVGS MTGS MTGS FCGS MTGS 2010 IEEE International Conference on Power and Energy (PECon2010)., Nov 29 - Dec 1, 2010, Kuala Lumpur, Malaysia 978-1-4244-8945-9/10/$26.00 ©2010 IEEE 420