javad modarresi

Resonance in transmission lines can cause unusual over-voltages and put the equipment at risk. One of conditions that can lead to resonance in transmission lines is the asymmetrical connection (single-phase and two-phase) of transmission lines compensated by shunt reactor. The asymmetrical connection of the line can be caused by the failure of the circuit breaker, activation of the single-phase recloser, or the presence of switchsync relay. In this paper, the feasibility of resonance in the 400 kV Abu Talib-Torbat Jam transmission line is investigated using EMTP-RV software. According to the results, in the case of asymmetrical connection (single-phase and two-phase) of the Abu Talib-Torbat Jam transmission line, resonance does not occur in the power frequency. But this line has a resonant frequency in the range of harmonics. In order to investigate the effect of harmonics, harmonic studies have been conducted and it is shown that harmonics cannot cause unusual over-voltages in this line.

Desirable lighting is one of the most important factors for optimization of the educational environments. The goal of this paper is to evaluate the lighting of educational environments according to the world standards and make smart lighting for classrooms. For this purpose, classrooms of building A at the Quchan University of Technology is simulated by DIALux software and they examined for glare, energy consumption and uniformity of light on the students workplace. The simulation results and practical measurements show that the glare, uniformity and energy consumption of these classes are not good. To address these problems, an innovative approach is presented for lighting the classrooms by considering the proper lighting on the student’s workplace and whiteboard, glare and lighting uniformity. In addition, an intelligent lighting system is designed for classrooms using motion sensors. This system turn the lamps off and save energy if students are not present in the classroom. Simulation results and practical implementation confirm the effectiveness of the proposed method.

Several factors can affect the received power of solar collectors which among them, the solar collector angle can be determined by the users. So in this paper, general models for optimum tilt angles are proposed for Solar Hejri (SH) months that which are applicable for all of iranian cities. Obtained models are a function of SH day number and latitude and the optimum tilt angles can be calculated only by SH day number and latitude in each point of iran. In order to examine the validity of proposed model, the obtained results are compared with other literatures.

Nowadays since the speed of reaching to response is getting more important، the random searching algorithms are mostly used instead of the overall search of the problem space. This paper presents the application and the performance comparison of HBMO and PSO optimization techniques for designing an output feedback damping controller for STATCOM in order to enhance the damping of power system. The problem of the damping controller design is considered as an optimization problem with a multi-purpose criterion function and it is solved by HBMO and PSO algorithms. This controller is designed in order to transmit unstable electromechanical modes to the specific area of the complex plane. The proposed controller performance is confirmed by the analysis of the eigenvalue and nonlinear time-domain simulation under various disturbances with both control parameters of STATCOM (capacitor voltage control and terminal voltage control). Simulation results illustrate that the designed controller by HBMO performs better than PSO in finding the solution. Moreover، the design of the controller based on the capacitor voltage control in comparison with terminal voltage control has better low frequency oscillation damping and it increases the dynamical stability of the power system.

The essay is based on a new reading of Kamal-ed-Din Behzad’s painting regarding the construction of Khavarnaq Palace. Behzad painted the picture to be used in a manuscript copy of Nezami’s Khamse. The writer believes that Behzad has not merely illustrated Nezami’s story, but referring to his thought and understanding has manipulated it. Behzad’s Khavarnaq palace despite Nezami’s is not a decorated and luxurious one; rather it is a simple building made of soil. Behzad’s reading is the narration of labour, hand, and manipulation of soil and material. It is the narration of those who manipulate the material to make it appropriate for their living, but unaware of the fact that they are raising their own death construction.