Power swing conditions in power systems make distance relays take the wrong breaker action in some cases. In this context, power swing blocking and power swing deblocking are two important functions in distance relays so as to distinguish power swing from a fault, which maintains stability of system and continuity of the power supply. In this paper, a sample estimation and error calculation method based on Taylor Series expansion is proposed for improving power swing detection performance of the relay. Performance of the method is compared with four conventional methods and a novel method in literature. Analyses are carried out in two systems: single machine-infinite bus system with parallel lines and 68-bus New England test-New York power system for fault, power swing, and fault during power swing scenarios. Simulations and performance analyses are carried out by using EMTDC/PSCAD and MATLAB, respectively. According to the results, when performances in correct operation, algorithm response times, clarity of outputs, and time passed for program execution on processor are considered, the proposed method has the best performance overall. It is found that by using the proposed method, distance relay performance in correct operation and speed for taking power swing blocking and deblocking actions are improved.

With increasing number of electric vehicles and electric vehicle charge stations, the question that if existing infrastructure of distribution system will meet new requirements has gained great importance. Mutable load profiles of distribution system and charge stations makes engineering analyses more sophisticated. In this study, some probabilistic analyses are carried out in a local distribution system in order to demonstrate effects of electric vehicle loads on the system parameters. Analysis studies have been carried out on the model which is based on real data. Conventional and electric vehicle loads are forecasted in order to determine the effects of electric vehicle charge stations on voltage profile changes and transformer loading. Results are presented as comparative figures for different years studied.

Conventional light sources are less efficient as compared to the light emitting diode and compact fluorescent lamps. Conventional incandescent filament lamps are resistive and therefore do not depend on power quality parameters. In the electric power system, nonlinear loads are increasing rapidly and the high content of harmonic due to the nonlinear loads cannot be neglected. Harmonic generation from the light emitting diode and the compact fluorescent lamp is one of the main problems for power quality. In this study, the light efficiency and electrical characteristics of the light emitting diode lamps and compact fluorescent lamps are evaluated under various voltage harmonic levels. The results show that light emitting diode, produces more harmonics as compared to the compact fluorescent lamps, with the increase of the voltage harmonic distortion from 0.7% to 3.52% in the light emitting diode, current harmonic increased from 140% to 192%. The results also show that increase in voltage harmonic distortion just not only increase current harmonics distortion but also affect the light wavelength of the lamp.