International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, Volume 2, Issue 3, March 2012) 468 Identification of Power Electronics Controlled Loads in Distribution Power System Using 10 Complex MUSIC Technique Jai Shree Gupta 1 , K. P. Singh 2 , Dr. A. N. Tiwari 3 1 M.Tech. Student, Department of Electrical Engineering 2,3 Professor, Department of Electrical Engineering 1,2,3 M.M.M Engineering College Gorakhpur (U.P.)-India. 1 jaishree.ideal@gmail.com 2 kp1960@rediffmail.com 3 amarndee@rediffmail.com Abstract— In this paper, we propose a model of distributed power system with power electronic controlled loads. Distribution networks transport the electrical energy from the transmission substations to the various loads. There are so many power electronics controlled loads that are connected in the distribution power system. Due to intensive use of power electronics controlled loads in an industry and other consumers in general, the harmonics produces a distortion in distribution network. Therefore, to protect the power system from the power electronics controlled loads, it is very important to identify the types and number of all the working power electronics controlled loads. The result of this paper shows that the method of calculating the number and also the types of all working power electronics controlled loads in any distribution system. A Multiple Signal Classification (MUSIC) Spectrum technique is used to identify the power electronics controlled loads in distribution power system. Here a case study for all types of power electronics controlled loads has been made which are taken in the power system using MUSIC algorithm. Keywords—Digital signal processing, MUSIC algorithm, nonlinear loads, power electronics controlled loads, power quality problems I. INTRODUCTION In large power stations, ideal assumption is that, an electricity supply should have invariably a perfectly sinusoidal voltage signal at every customer location. But because of the number of reasons, utilities generally it becomes difficult to preserve such desirable conditions. The intensive use of non-linear loads in industry and by consumers in general, is keeping harmonic distortion in distribution network on the rise. The most used nonlinear device is perhaps the AC regulators, adjustable speed drives, electrical transportation system, PWM inverters and electrodomestic appliances. Therefore, to save or protect the distribution system from the additional power losses, it is necessary to identify that in any distributed power system which types of nonlinear loads are used and how many loads work at a time. The existing nonlinear loads identification techniques in electric power system are unsuitable, inefficient and very complex. Therefore, to find out easy solution for Multiple Signal Classification Spectrum (MUSIC) technique to identify the nonlinear loads in distribution power system has been worked out. This identification technique is much reliable, efficient and more easy to understand [1]. II. SYSTEM DESIGN With an increasing amount of measurement data, automating power quality characterization and classification of disturbances is desirable. This will require combined effort and knowledge from both electrical power systems and signal processing. A digital signal processor is a specialized microprocessor designed specifically for digital signal processing, generally used in real-time computing. DSP algorithms require a large number of mathematical operations to be performed quickly on a set of data. The digital signal processor can be programmed to perform a variety of signal processing operations, such as filtering, spectrum estimation, and other DSP algorithms [3]. There are so many techniques to perform the DSP operation. Here the MUSIC technique to identify the loads has been considered. The MUSIC method employs a harmonic model and estimates the frequencies and powers of the harmonics in the signal. The MUSIC algorithm is a noise subspace based method. MUSIC detects signal frequencies by performing an eigen decomposition on the data vector covariance matrix from received signal samples. III. SIMULATION RESULTS Overall system voltage is set as 600V & frequency is set on 60 Hz. The simulation block diagram of distribution power system with power electronic loads is shown in fig.1. Power electronic loads are the part of nonlinear loads and also it is the main cause of power losses and power quality problem in distribution power system. To achieve the output consider only four types of power electronic loads in distribution power system & simulated on MATLAB/SIMULINK.