The presence of the actuator saturation in a three-loop autopilot of a flying vehicle arising from the windup phenomena leads to the performance degradation. In this paper, a dynamic anti-windup and a static anti-windup COMPENSATORS are proposed. The dynamic compensator, available in some references for systems with output feedback is designed to make the controller states of the saturated system arbitrarily close to the controller states of the unsaturated system. In this paper, this compensator is developed for controllers similar to three-loop autopilot of a flying vehicle, in which, the controller is a feedback of both plant output and plant states. In order to compare with the dynamic compensator, a static compensator is also designed with a new approach in such a way that the controller output tracks the output of saturation function. With this requirement, it is expected that no windup will occur. These two COMPENSATORS have been applied on the autopilot of an aerodynamic tail-controlled flying vehicle in two stable and unstable conditions and their performances have been compared to each other in terms of control performance. The results show the better performance of the static compensator compared to the dynamic compensator in tracking the desired command in both operating conditions. Moreover, through simulation of flying vehicle guidance system, it is shown that using anti-windup leads to the less miss distances. Especially, using the static compensator leads to reduction of the miss distance by about 50% in unstable conditions compared to the use of the dynamic compensator.

The paper presents a simple yet powerful fuzzy logic based static VAR compensator (FLSVC) applied to an industrial power network consisting of three phase synchronous, asynchronous and DC motor loads. In the proposed fuzzy logic controller (FLC), the speed and acceleration variations of a specific machine are taken as the inputs. To demonstrate the effectiveness and capabilities of the employed FLSVC, several nonlinear time domain are performed. The results how that over a wide range of operating conditions and disturbances, the FLSVC improves remarkably the voltage profile and the overall dynamic performance.

In order to solve the problem of voltage drop and voltage imbalance in the distribution systems, the injection of reactive power by multiple static COMPENSATORS is used. The distributed generation such as photovoltaic systems could play a role of the static COMPENSATORS by producing reactive power. In this paper, the integral to droop line algorithm is used to control the reactive power in busbars. The droop coefficient and integral gain are important parameters in this algorithm. The determination process of these coefficients is modeled as a nonlinear and multi-objective optimization problem. The objective function in this problem is defined to establish a tradeoff between the voltage deviation and voltage unbalanced factor considering stability condition, in which the salp swarm optimization algorithm is used to solve the problem. The above problem is solved by three other optimization algorithms, which the salp algorithm has a better performance than the three algorithms. Applying the obtained optimal gain coefficients to the COMPENSATORS, not only the voltage profile is improved but also the voltage unbalanced factor is reduced. The proposed method is simulated on the IEEE-34 Node test feeder. To evaluate the stability of the system, the eigenvalue analysis is used. The results show the validity of the proposed method on the system stability.

Electric arc furnaces (EAFs) are unbalanced, nonlinear and time varying loads, which can cause many problems in the power system quality. In steel industries, the two arc furnaces often perform in parallel and stand on a single bus, which surely deteriorate the power quality. In this paper, in order to study and analyze the harmful effects of parallel operation of EAFs, first, a three phase arc furnace model, which can simulate all the operational conditions of EAFs are simulated based on Hyperbolic- Exponential Model. In this process, in order to perform exact analysis of EAFs, effects of arc furnace transformer and the mutual inductance of the flexible cables are also considered. In the next step, in order to improve the power quality indices, the TSC and TCR/FC COMPENSATORS are designed optimally and then simulated. Finally, the simulation results that are accomplished by PSCAD/EMTDC software show the validity of the proposed method in the entire power systems.

Fault location in transmission lines compensated by flexible alternating current transmission system (FACTS) devices and series capacitor (SC) COMPENSATORS is much more complicated than simple lines due to the presence of time-variant voltage and current sources in the topology of transmission lines. In recent years, due to the increasing presence of reactive power COMPENSATORS in power systems and the researchers’ desire to study the presence of such equipment in the network, many articles have been published in the field of fault location in transmission lines equipped with reactive power COMPENSATORS. Thus, the fault location problem in electrical power transmission lines equipped with reactive power COMPENSATORS, including FACTS and SC devices, is comprehensively discussed and analyzed in this paper. For the first time, all the basic indices and factors that have always been very effective in analyzing the fault location problem in transmission lines equipped with reactive power COMPENSATORS in various papers are classified thoroughly. Then, based on the types of reactive power COMPENSATORS, all the literature published in the field of fault location in compensated transmission lines are categorized. Finally, a comparison table is presented to examine the fundamental indices of the literature in this field.

One of the intensity modulated radiation therapy (IMRT) methods is based on using COMPENSATORS. The most important factor in designing a compensator is the accurate calculation of its thickness to achieve the intensity modulation of interest. To achieve that, the exact attenuation coefficient of compensator materials must be calculated. Using Map CHECK 2 model 1177 and phantom (SP34). We studied the effect of compensator thickness and field size on the calculation of the effective attenuation coefficient (EAC) of the brass compensator for 6-MV photon beams. Experimental measurements were carried out at 100 cm source-to-surface distance and 5 cm depth for the 6-MV photon beams of an Elekta linac using various field size and compensator thickness. The field sizes investigated ranged from 1×1 cm2 to 20×20 cm2 and the brass compensator thickness from 0.5-6 cm. Our results indicated that the compensator thickness and field size have the most significant effect on the calculation of the compensator EAC for the 6-MV photon beam and also these parameters can reduce the error due to delivered dose to target volume and organs at risk.

This paper presents a new intelligent algorithm, named binary real genetic algorithm (BRGA) to design parameters of PSS and STATCOM controller simultaneously. The proposed algorithm has a strong search capability and high speed convergence to find the global optimum points. The objective function used in this paper to be minimized is the time integral absolute error (ITAE). The objective will be minimizing the deviations of rotor speed (Dw) and the voltage of the bus in which STATCOM has been installed. The simulations are carried out on a two-area four-machine power system to show the superior performance of the proposed method, when compared with GA and PSO algorithms.