Zero-sequence voltage compensation of a distribution network through a four-wire modular multilevel static synchronous compensator

2019 ◽  
Vol 109 ◽  
pp. 57-72 ◽  
Author(s):  
Samuel N. Duarte ◽  
Frederico T. Ghetti ◽  
Pedro M. de Almeida ◽  
Pedro G. Barbosa
Keyword(s):  
Distribution Network ◽  
Static Synchronous Compensator ◽  
Voltage Compensation ◽  
Zero Sequence ◽  
Zero Sequence Voltage

scholarly journals Zero-Sequence Voltage Injection Method for DC Capacitor Voltage Balancing of Wye-Connected CHB Converter under Unbalanced Grid and Load Conditions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1019
Author(s):  
Jae-Myeong Kim ◽  
Geum-Seop Song ◽  
Jae-Jung Jung
Keyword(s):  
Calculation Method ◽  
Stable Operation ◽  
Energy Balancing ◽  
Static Synchronous Compensator ◽  
Unbalanced Load ◽  
Zero Sequence ◽  
Zero Sequence Voltage ◽  
Balancing Control ◽  
Unbalanced Grid ◽  
Load Conditions

Leg capacitor energy balancing control is one of the crucial issues for stable operation of a cascaded H-bridge (CHB) converter. Because this topology inherently consists of numerous submodule cells with DC capacitors, the cell voltages and leg capacitor energy instantaneously fluctuate depending on operation sequence of the CHB converter. In general, a wye-connected CHB-converter-based static synchronous compensator (STATCOM) utilizes a zero-sequence voltage component for leg capacitor energy balancing. In this paper, to improve the dynamics of leg energy balancing control, a feedforward calculation method of the zero-sequence voltage injection is proposed. The feedforward term can be instantaneously calculated by using the information from the measured leg voltages and leg currents, and the method ensures successful regulation of the leg energy balance even under unbalanced grid and load conditions. Moreover, the verification of the proposed method is supported by the mathematical vector theorems. A 50MVA full-scale wye-connected CHB–STATCOM system simulation was performed to verify the proposed feedforward calculation method considering unbalanced grid as well as unbalanced load conditions.

Optimization of zero-sequence voltage compensation for zero-sequence directional elements

2021 ◽  
Vol 197 ◽  
pp. 107300
Author(s):  
Hao Xu ◽  
Chaoyong YIN ◽  
Guoqin DONG ◽  
Shannuo WANG ◽  
Liqiang XU ◽  
...  
Keyword(s):  
Voltage Compensation ◽  
Zero Sequence ◽  
Zero Sequence Voltage

scholarly journals Analysis of the influence of three-phase asynchronization recording on fault location of distribution network

2021 ◽  
Vol 2087 (1) ◽  
pp. 012070
Author(s):  
Kai Zhang ◽  
Mingming Xu ◽  
Xinhui Zhang ◽  
Supeng Wang ◽  
Wenhao Wu
Keyword(s):  
Fault Location ◽  
Measurement Accuracy ◽  
Single Phase ◽  
Distribution Network ◽  
Start Up ◽  
Fault Indicator ◽  
Three Phase ◽  
Zero Sequence ◽  
Practical Effect ◽  
Zero Sequence Voltage

Abstract In order to improve the practical effect of the fault location technology, it is necessary to analyze the error caused by the three-phase asynchronization of the fault indicator recording. The influence of the three-phase recording asynchronization on the fault location of the distribution network is analyzed from the aspects of the start-up criterion, the error level of the zero-sequence current and the zero-sequence voltage. The simulation results show that fault location devices of different principles are affected differently by the asynchronization recording. In order to avoid mistake start-up of the fault location device, the change value should be used to construct the fault location start-up criterion. Meanwhile, the measurement accuracy of transient fault characteristics will be affected to a certain extent by the asynchronization of the fault indicator recording, but it has little effect on the reliability of fault location, and it can even make the fault characteristics more obvious after the single- phase fault occurs.

scholarly journals A novel fault section locating method based on distance matching degree in distribution network

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zhenxing Li ◽  
Jialing Wan ◽  
Pengfei Wang ◽  
Hanli Weng ◽  
Zhenhua Li
Keyword(s):  
Single Phase ◽  
Distribution Network ◽  
Matlab Simulink ◽  
Grounding Resistance ◽  
Blind Zone ◽  
System Transition ◽  
Transition Resistance ◽  
Zero Sequence ◽  
Matching Degree ◽  
Amplitude Characteristics

AbstractFault section location of a single-phase grounding fault is affected by the neutral grounding mode of the system, transition resistance, and the blind zone. A fault section locating method based on an amplitude feature and an intelligent distance algorithm is proposed to eliminate the influence of the above factors. By analyzing and comparing the amplitude characteristics of the zero-sequence current transient components at both ends of the healthy section and the faulty section, a distance algorithm with strong abnormal data immune capability is introduced in this paper. The matching degree of the amplitude characteristics at both ends of the feeder section are used as the criterion and by comparing with the set threshold, the faulty section is effectively determined. Finally, simulations using Matlab/Simulink and PSCAD/EMTDC show that the proposed section locating method can locate the faulty section accurately, and is not affected by grounding mode, grounding resistance, or the blind zone.

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