Fault Detection in IEEE 14-Bus Power System with DG Penetration Using Wavelet Transform

Wavelet transform is proposed in this paper for detection of islanding and fault disturbances distributed generation (DG) based power system. An IEEE 14-bus system with DG penetration is considered for the detection of disturbances under different operating conditions. The power system is a hybrid combination of photovoltaic, and wind energy system connected to different buses with different level of penetration. The voltage signal is retrieved at the point of common coupling (PCC) and processed through wavelet transform to detect the disturbances. Further, energy and standard deviation (STD) as performance indices are evaluated and compared with a suitable threshold in order to analyze a disturbance condition. Again, a comparative analysis between the existing and proposed detection is studied to prove the better performance of wavelet transform. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by the authors or by the respective copyright holders. The original citation of this paper is:Prakash K. Ray, B. K. Panigrahi, P. K. Rout, Asit Mohanty, Harishchandra Dubey, "Fault Detection in IEEE 14-Bus Power System with DG Penetration Using Wavelet Transform", In the Proceedings of First International Conference on Advancement of Computer Communication & Electrical Technology, Oct. 2016, Murshidabad, India. DOI: 10.13140/RG.2.2.32899.09763 IEEE 14-bus system is described in Section 2, WT as signal processing based detection tool is presented in Section 3. Then, the MATLAB based simulation results with descriptions are given in Section 4. Finally, concluding remarks are presented in Section 5. 2 IEEE 14-BUS POWER SYSTEM The penetration level of different renewable power is increasing with time, thereby; the hybrid power system becomes more complex. Hence, the design, operation and control of power system are becoming more challenging. Suitable methods are to be adopted to identify the normal as well as abnormal operating conditions. While operating in grid-connected mode, the grid may be disconnected due to some abnormal conditions leading to islanding condition where the DG still continues to supply power the local loads. Similarly, there may arise fault disturbances due some type of faulty conditions between the phases and ground. Figure 1. IEEE 14-bus power system with interconnection of DGs. Fig. 1 shows the IEEE 14-bus power system with interconnection of DGs to some of its distribution buses. This model is developed in MATLAB/Simulink. 2.1 Wind energy conversion system (WECS) Wind turbines are a non-linear, dynamic system that converts the wind kinetic energy into mechanical energy which is then processed to produce electrical energy by using wind generators. The characteristics of wind turbines are highly uncertain, non-linear and complex to design and study. Different models of wind turbines are proposed with many degrees of freedom (DOFs) to ensure the energy conversion. The mechanical power output from wind turbine in terms of wind speed is expressed as (Ackermann 2005). 3 ( , ) 2 mech wind wind wind P A C V     (1) where is the mechanical power output from the wind in watts; ρ is the air density (kg/m3); is the power coefficient; is the tip-speed ratio ( / ), (m/s) is blade tip speed, and (m/s) is wind speed; is the area covered by rotor of wind turbine (m); and β is the pitch angle (in degrees). The tip-speed ratio  is given as