Non-characteristic harmonics and DC side capacitor calculation in VSC connected to a distribution system with unbalanced voltage

Author(s):  
Claudionor F. Nascimento ◽  
Edson H. Watanabe ◽  
Alvaro B. Dietrich ◽  
Robson F. S. Dias ◽  
Oumar Diene
Author(s):  
Darmawansyah Darmawansyah ◽  
M Khairul Amri Rosa ◽  
Ika Novia Anggraini

ABSTRACTIn the current era of globalization, various human jobs depend on electrical equipment such as three-phase induction motors. Three-phase induction motors are very important to use according to their roles and functions. The occurrence of voltage variations in the electric power system is due to the magnitude of the voltages between the three phases which are not the same so that there are differences in the angle of the R, S and T phases, which causes an uneven load overload in the electrical distribution system. Among the disturbances that can occur are overvoltage, under voltage, unbalance voltage between phases, overload, and overheating. Based on these problems, a three-phase induction motor protection system was designed, the system uses current, voltage, temperature sensors, which functions to measure the value when a disturbance occurs, a magnetic contactor as a breaker and a liaison when the disturbance is given in accordance with the set point value given to the microcontroller. The results of the research for unbalanced voltage of V1 112 V, V2 114 V, V3 108 V, overvoltage of V1 228 V, V2 207 V, V3 264 V, over current of A1 104 A, A2 107 A, A3 0.77 A , the overload on the resistance source is 333 ?, 250 ?, 200 ?, 167 ?, and the overheating is 40.75 ºC at 6.5 minutes with tripping conditions in each test. The final results of this study indicate that the protection system which is designed is better used for three-phase induction motors.Keywords: unbalaced, disturbances, protection systems, sensors, magnetic contactor, microcontroller.


2019 ◽  
Vol 22 (3) ◽  
Author(s):  
Ivo Benitez Cattani

In this paper two reconfiguration methodologies for three-phase electric power distribution systems based on multi-objective optimization algorithms are developed in order to simultaneously optimize two objective functions, (1) power losses and (2) three-phase unbalanced voltage minimization. The proposed optimization involves only radial topology configurations which is the most common configuration in electric distribution systems. The formulation of the problem considers the radiality as a constraint, increasing the computational complexity. The Prim and Kruskal algorithms are tested to fix infeasible configurations. In distribution systems, the three-phase unbalanced voltage and power losses limit the power supply to the loads and may even cause overheating in distribution lines, transformers and other equipment. An alternative to solve this problem is through a reconfiguration process, by opening and/or closing switches altering the distribution system configuration under operation. Hence, in this work the three-phase unbalanced voltage and power losses in radial distribution systems are addressed as a multi-objective optimization problem, firstly, using a method based on weighted sum; and, secondly, implementing NSGA-II algorithm. An example of distribution system is presented to prove the effectiveness of the proposed method.


Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4623 ◽  
Author(s):  
Ryuto Shigenobu ◽  
Akito Nakadomari ◽  
Ying-Yi Hong ◽  
Paras Mandal ◽  
Hiroshi Takahashi ◽  
...  

This paper presents a compensation method for unbalanced voltage through active and reactive power control by utilizing a smart inverter that improves the voltage unbalance index and detects an unbalanced state of voltage magnitude and phase, and thus enhances power quality by minimizing the voltage imbalance. First of all, this paper presents an analysis of a mathematical approach, which demonstrates that the conventional voltage unbalanced factor (VUF) using the symmetrical component cannot correctly detect the imbalanced state from index equations; and by only minimizing the VUF value, it cannot establish a balanced condition for an unbalanced state of the voltage profile. This paper further discusses that intermittent photovoltaic (PV) output power and diversified load demand lead to an unexpected voltage imbalance. Therefore, considering the complexity of unbalanced voltage conditions, a specific load and an PV profile were extracted from big data and applied to the distribution system model. The effectiveness of the proposed scheme was verified by comparing VUF indices and controlling the active and reactive power of a smart inverter through a numerical simulation.


2018 ◽  
Vol 138 (2) ◽  
pp. 131-139
Author(s):  
Yukimasa Ikai ◽  
Mutsumi Aoki ◽  
Yu Fujita ◽  
Hiroshi Kobayashi ◽  
Mika Oguri ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document