The rapid increase of the sensitive loads in the electrical grid and the high cost of power quality pollution, the focus of researchers on protecting the sensitive loads and decreasing the damages of power quality pollution have increased. On the other hand, with the technology expansion, new switching loads are added to electrical grid that adding pollution to electrical grid. Lighting loads such as LEDs, CFLs and fluorescent lamps, monitors, air conditionings, rectifiers, inverters and in larger loads such as arc furnaces are the loads that affects the quality of electrical grid. Therefore, it is important to examine these loads to understand the effects of their single and integrated power quality, as well as to reduce these pollutions. Also, due to the fact that the polluting loads are used collectively and mixed in the all systems, it is necessary to examine their collective effect, in order to obtain an accurate picture of the pollution caused by such loads. In this thesis, first we investigate the polluting loads such as lighting loads, rectifiers, inverters, displays, etc., using the equations and mathematical models expressed in references, as well as measurements conducted in the laboratory environment by the power quality analyzers. The case studies are based on harmonics of current and voltage. In the next step, the impact of these loads are examind in a collective state. At this stage, the loads are identical with each other and the volume of harmonics or voltages is calculated by simulation or measurement, so that a model can be extracted based on the size and percent of current or voltage and phase of the collective loads. The model used in this dissertation for individual and collective loads is based on normal distribution function for the amplitude and phase of currents or voltage harmonics. In the next step, the simulation of a large load consisting of loads with the collective effect of mixed loads will be addressed. an algorithm is used to identify the polluting loads within a load center based on the measured power quality information on the bus. It should be noted that the voltage and current of the network in this dissertation are considered sinusoidal so that using the power quality information can be used to predict the polluting load inside the bus. To implement the algorithm, data Keywords: 1-Harmonic 2-Power Quality 3-Polluting Load 4-Clustering 5-Filtering 6-Normal Distribution Factor 7-Non-Linear Loads
