Unbalanced Power Flow in Distribution Systems With Embedded Transformers Using the Complex Theory in <formula formulatype="inline"> <tex Notation="TeX">$\alpha \beta 0\;$</tex></formula> Stationary Reference Frame

Heuristic methods by first order sensitivity analysis are often used to determine location of capacitors of distribution power system. The selected nodes by first order sensitivity analysis often have virtual high by first order sensitivities, which could not obtain the optimal results. This paper presents an effective method to optimally determine the location and capacities of capacitors of distribution systems, based on an innovative approach by the second order sensitivity analysis and hierarchical clustering. The approach determines the location by the second order sensitivity analysis. Comparing with the traditional method, the new method considers the nonlinear factor of power flow equation and the impact of the latter selected compensation nodes on the previously selected compensation location. This method is tested on a 28-bus distribution system. Digital simulation results show that the reactive power optimization plan with the proposed method is more economic while maintaining the same level of effectiveness.

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Efficient three-phase power-flow method for unbalanced radial distribution systems

Melecon 2010 - 2010 15th IEEE Mediterranean Electrotechnical Conference ◽

10.1109/melcon.2010.5476323 ◽

2010 ◽

Cited By ~ 9

Author(s):

Karar Mahmoud ◽

Mamdouh Abdel-Akher

Keyword(s):

Radial Distribution ◽

Power Flow ◽

Distribution Systems ◽

Flow Method ◽

Three Phase ◽

Power Flow Method

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Control Strategy Based on Arm-Level Control for Output and Circulating Current of MMC in Stationary Reference Frame

Energies ◽

10.3390/en14144160 ◽

2021 ◽

Vol 14 (14) ◽

pp. 4160

Author(s):

Waqar Uddin ◽

Tiago D. C. Busarello ◽

Kamran Zeb ◽

Muhammad Adil Khan ◽

Anil Kumar Yedluri ◽

...

Keyword(s):

Reference Frame ◽

Control Method ◽

Second Harmonic ◽

Harmonic Component ◽

Effective Control ◽

Level Control ◽

Circulating Current ◽

Stationary Reference Frame ◽

Pr Controller ◽

Dc Component

This paper proposed a control method for output and circulating currents of modular multilevel converter (MMC). The output and circulating current are controlled with the help of arm currents, which contain DC, fundamental frequency, and double frequency components. The arm current is transformed into a stationary reference frame (SRF) to isolate the DC and AC components. The AC component is controlled with a conventional proportional resonant (PR) controller, while the DC component is controlled by a proportional controller. The effective control of the upper arm and lower arm ultimately controls the output current so that it delivers the required power to the grid and circulating current in such a way that the second harmonic component is completely vanished leaving behind only the DC component. Comparative results of leg-level control based on PR controller are included in the paper to show the effectiveness of the proposed control scheme. A three-phase, five-level MMC is developed in MATLAB/Simulink to verify the effectiveness of the proposed control method.

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Meshing Efficiency Analysis of Two Degree-of-Freedom Epicyclic Gear Trains

Journal of Mechanical Design ◽

10.1115/1.4033693 ◽

2016 ◽

Vol 138 (8) ◽

Cited By ~ 6

Author(s):

Essam Lauibi Esmail

Keyword(s):

Reference Frame ◽

Power Efficiency ◽

Power Flow ◽

Flow Direction ◽

Efficiency Analysis ◽

Degree Of Freedom ◽

Gear Train ◽

Epicyclic Gear ◽

Gear Trains ◽

Two Degree Of Freedom

The concept of potential power efficiency is introduced as the efficiency of an epicyclic gear train (EGT) measured in any moving reference frame. The conventional efficiency can be computed in a carrier-moving reference frame in which the gear carrier appears relatively fixed. In principle, by attaching the reference frame to an appropriate link, torques can be calculated with respect to each input, output, or (relatively) fixed link in the EGT. Once the power flow direction is obtained from the potential power ratio, the torque ratios are obtained from the potential power efficiencies, the particular expression of the efficiency of the EGT is found in a simple manner. A systematic methodology for the efficiency analysis of one and two degree-of-freedom (DOF) EGTs is described, and 14 ready-to-use efficiency formulas are derived for 2DOF gear pair entities (GPEs). This paper includes also a discussion on the redundancy of the efficiency formulas used for 1DOF GPEs. An incomplete in the efficiency formulas in previous literature, which make them susceptible to wrong application, is brought to light.

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