Phase shifting transformers are used to control the power transmitted through the lines by changing the amplitude and phase angle of the voltage. In the first group, mechanical switches and moving parts are used in PST types, and in the second group, semiconductor switc More
Phase shifting transformers are used to control the power transmitted through the lines by changing the amplitude and phase angle of the voltage. In the first group, mechanical switches and moving parts are used in PST types, and in the second group, semiconductor switches and electronic power converters have replaced mechanical switches. In this article, the analysis of internal structure and performance of Class A, D and E phase shift transformers is expressed and using a program, power distribution in the power grid in two modes of use of phase shift transformers and without these transformers in soft The MATLAB software is simulated and the numerical results of the effect of phase shift transformers on current and power distribution between two 110KV parallel lines are investigated. It turns out that phase shifting transformers are used to control the distribution of active power between lines, and in Class A phase shifting transformers, the upper and lower limits of the thyristor fire angle are a function of the operating conditions of the power system and the limiting determinant. The performance of these transformers is the high harmonic content of the output voltage. In Class D, GTO switches are used and their switching on and off is forced by switching method, and one of their outstanding features is that the converters do not depend on the operating conditions of the system, whose output can be controlled continuously and in all conditions.
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In this paper, we have designed and implemented low voltage drop regulators and very small output changes using new solutions. In the regulator circuit structure, for the first time, two solutions of body power supply and variable voltage reference have been used. The p More
In this paper, we have designed and implemented low voltage drop regulators and very small output changes using new solutions. In the regulator circuit structure, for the first time, two solutions of body power supply and variable voltage reference have been used. The power supply of the body, with the aim of increasing the gain of the regulation loop and using the variable voltage reference, has been done with the aim of further stabilizing the output voltage and increasing the power supply removal ratio (PSRR). Another important point in this paper is the implementation of the error amplifier with the help of three single-headed operational amplifiers with PMOS input, which significantly increases the accuracy of the regulation loop. The obtained PSRR value is equal to 46dB at a frequency of 1KHz. The input voltage can vary between 1.8V to 2.5V and the stabilized output voltage is 1.6V. The maximum output voltage ripple is equal to 1mV, which is equivalent to 0.03%. The output ohmic load is equal to 20 and the average capacitive load is equal to 100pF. The maximum output current for the desired output impedance and voltage drop of 0.2V is equal to 80mA.
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This paper presents a multi-objective optimization model for optimal placement of fixed capacitors and voltage regulators to manage the voltage profile of radial distribution networks, in which the realities of the distribution network of Ahvaz city (as representing the More
This paper presents a multi-objective optimization model for optimal placement of fixed capacitors and voltage regulators to manage the voltage profile of radial distribution networks, in which the realities of the distribution network of Ahvaz city (as representing the tropical regions of southern Iran) are considered. The objective functions include minimizing the investment cost, minimizing the sum of absolute value of the node’s voltage deviations from 1 p.u., and minimizing the cost of energy losses on the planning horizon. The optimization model is formulated by considering two different load patterns according to the warm and temperate periods of the year in Ahvaz city. The loads are modeled as a combination of constant power and constant impedance components and the share of each component in the warm and temperate periods of the year is considered in accordance with the actual conditions of the Ahwaz power distribution network. The cost of energy losses as well as the final profit of the project is calculated based on the current rules of Iranian power market for active and reactive powers. The optimization problem is solved using multi-objective non-dominated-sorting genetic algorithm-II (NSGA_II), and in order to choose the best answer among none-dominated Pareto front, a selection index is introduced. The proposed model is implemented on two 33 kV test feeders (i.e., a 33-bus test feeder and a real 123-bus feeder from Ahvaz distribution company) and the results are analyzed.
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