Flexible Non-Sinusoidal Zero Sequence Voltage Injection Method to Extend Negative Sequence Current Compensation Range for Star-Connected CHB STATCOM

In this paper, two new methods for locating single-phase to ground faults in isolated neutral distribution networks are proposed. The methods are based on the analysis of symmetrical sequence currents. They are solely based on currents, not requiring voltage measurement. The first method employs only the zero sequence current and the second one utilizes the negative sequence current in combination with the zero sequence current. It is revealed why using only zero sequence current with a simple threshold is insufficient and may lead to false results. Using the proposed methods, earth faults with high resistances can be located in isolated neutral distribution networks with overhead lines or cables.

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YN/VD connected balance transformer‐based electrical railway negative sequence current compensation system with passive control scheme

IET Power Electronics ◽

10.1049/iet-pel.2015.0874 ◽

2016 ◽

Vol 9 (10) ◽

pp. 2044-2051 ◽

Cited By ~ 12

Author(s):

Bin Xie ◽

Zhiwen Zhang ◽

Sijia Hu ◽

Yong Li ◽

Longfu Luo ◽

...

Keyword(s):

Passive Control ◽

Compensation System ◽

Current Compensation ◽

Negative Sequence ◽

Control Scheme ◽

Negative Sequence Current

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Research on Electrical Characteristics of a Novel Balance Transformer with Asymmetrical Winding

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.536-537.1523 ◽

2014 ◽

Vol 536-537 ◽

pp. 1523-1526 ◽

Cited By ~ 1

Author(s):

Yong Sheng Li ◽

Yi Fa Sheng ◽

Kai Yi Zhang ◽

Bo Fan

Keyword(s):

Magnetic Force ◽

Short Circuit ◽

Neutral Current ◽

Force Balance ◽

Analysis Method ◽

Systematic Analysis ◽

Negative Sequence ◽

Transfer Equations ◽

Zero Sequence ◽

Negative Sequence Current

For problems of zero sequence current and negative sequence current of traction transformer in Electrified Railway, a novel balance transformer with asymmetrical windings was presented. By a systematic analysis method based on the magnetic force balance equations, winding connection equations, output-port equations and voltage transfer equations, the current relationships of the primary windings and secondary windings, the balance condition and the short circuit impedances (when the neutral current in the primary side is zero) were deduced, and the electric characteristics of the balance transformer was analyzed. Through the experimental model of balance transformer in simulation platform based on Matlab/Simulink, the electric characteristics of balance transformer and change law of zero sequence current and negative sequence current in different mode were researched. Correctness and feasibility of the theoretical analysis are verified through the simulation experiment.

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A Novel STATCOM Based on Flying Capacitor Modular Multilevel Converter

International Journal of Emerging Research in Management and Technology ◽

10.23956/ijermt.v6i11.51 ◽

2018 ◽

Vol 6 (11) ◽

pp. 86

Author(s):

T. Sanjeeva Rao ◽

T. Sowjanya

Keyword(s):

Control Method ◽

Modular Multilevel Converter ◽

Multilevel Converter ◽

Static Synchronous Compensator ◽

Current Compensation ◽

Negative Sequence ◽

Capacitor Voltage ◽

Voltage Balance ◽

Capacitor Voltage Balance ◽

Negative Sequence Current

A new static synchronous compensator (STATCOM) based on Flying Capacitor modular multilevel converter (DCM2C) is proposed in this thesis. In this converter topology the capacitor voltage is clamped by using a low power rating diode in each sub-module (SM). The quantity of voltage sensors is significantly reduced and is free from the number of voltage levels. Furthermore the voltage balancing control method becomes very simple and the capacitor voltage balance speed is fast. Based on the structure of MMC the DCM2C-STATCOM has the capability of Var compensation and negative sequence current compensation. The topology characteristics and compensation control method of DCM2C-STATCOM are investigated in this thesis. That the capacitor voltage of the proposed DCM2C-STATCOM can be well balanced and the Var and negative-sequence current compensation are effective.

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