Voltage balancing in low‐voltage radial feeders using Scott transformers

To reveal the penetration characteristics of high-frequency harmonics of the traction network to the three-phase 380 V power system in the traction substation (TSS), the harmonic equivalent circuit model and harmonic penetration mathematical model of the two-phase to three-phase Scott-T transformer are established. Through the power quality measurement and harmonic analysis, the results indicate that the high-frequency harmonics in the traction network will severely penetrate the three-phase 380 V power system, which will cause almost the same degree of harmonic distortion, verifying the correctness of the harmonic penetration model. To filter high-frequency harmonics in TSS, a novel structure of high-pass filter (HPF) is proposed that features with high-pass characteristic at high frequencies while highimpedance at fundamental frequency. Furthermore, a set of three-phase experimental device is developed, and a long-term filtering experiment in the TSS is performed. The experimental results show that the novel HPF experimental device can effectively filter out high-frequency harmonics of the three-phase 380 V power system, and have almost no loss and reactive power. The feasibility and effectiveness of the suppression scheme based on the novel HPF are verified.

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“…Fig. 2 shows the specific structure of the Scott-T transformer to achieve this conversion [29]. In Fig.…”

Section: B Hramonic Permeability Model Beased On Scott-t Transformermentioning

confidence: 99%

Research on the Harmonics Penetration Characteristics of the Traction Network to Three-Phase 380 V Power System of the Traction Substation and Suppression Scheme

et al. 2020

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“…Thus, it has the characteristics of small individual capacity, but a massive number of nodes. Owing to the LV level, installation and development of LV feeders require lower finance compared with higher‐voltage feeders such as MV and HV [21]. However, the massive number of LV feeders requires a significant amount of work that might consume most of a utility's capital [22].…”

Section: LV Distribution Networkmentioning

confidence: 99%

“…However, the LV level (120 V) at the secondary side of the single‐phase transformer is about half of the European single‐phase secondary voltage (240 V), which leads to some technical issues and barriers. For instance, it is limited to the extension of the single‐phase feeder which only has the ability to carry the power efficiently up to 60 m from the substation [23] In addition, the level of power losses and voltage drop‐in single‐phase LV feeder is much higher than that in the three‐phase LV feeders [21].…”

Section: LV Distribution Networkmentioning

confidence: 99%

Planning and operation of LV distribution networks: a comprehensive review

Al-Ja’Afreh

Mokryani

2019

IET Energy Systems Integration

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The low‐voltage (LV) distribution network is the last stage of the power network, which is connected directly to the end‐user customers and supplies many dispersed small‐scale loads. To achieve environmental targets and to address the energy shortage issue, governments worldwide increase the renewable energy sources (RESs) into the electricity grid. In addition, different types of low carbon technologies (LCTs) such as electric vehicles are becoming widely used. A significant portion of RES and LCTs is penetrated into the LV distribution network, which poses a wide range of challenges. To address these challenges, there is a persistent need to develop traditional planning and operation frameworks to cope with these new technologies. In this context, this study provides a comprehensive review of planning, operation, and management of LV distribution networks. The characteristics, types, and topologies of LV distribution networks plus different aspects of operation and planning are investigated. An insightful investigation of the reasons impacts and mitigation of voltage and current unbalanced in LV networks is provided. Moreover, the main three‐phase power flow techniques used to analyse the LV networks are analysed.

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“…Due to the increased magnitude of single-phase loads and unbalanced three-phase loads, voltage unbalance in the power system is actually increasing [1]. For example, in a 10 kV distribution system in China, the ratio of three-phase unbalanced loads in this system accounted for 6.94% [2].…”

Section: Introductionmentioning

confidence: 99%

Contribution Determination for Multiple Unbalanced Sources at the Point of Common Coupling

Sun

et al. 2017

Energies

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Three-phase unbalance is an important power quality issue that can cause many negative effects to the power system. Effective mitigation and management of voltage unbalance will benefit from the knowledge of how the unbalanced sources contribute to the voltage asymmetry at the point of evaluation (POE). In this paper, a method is proposed to assess the overall unbalance contribution of the multiple unbalanced sources at the point of common coupling (PCC). Firstly, the equivalent circuit for analysis is established and the unbalance contribution indices are proposed. Then a method is proposed to determine whether the dominant unbalanced polluter is at the upstream or downstream of POE. If the main unbalanced source is identified to be downstream of POE, a procedure is further proposed to determine the individual contribution of the multiple unbalanced sources. Moreover, for the multiple unbalanced source condition, the current flowing in each feeder is proposed to be used for the contribution estimation instead of the current actually emitted by the unbalanced source. Finally, a method is proposed to estimate the equivalent negative sequence impedance of the aggregate loads. Simulation and field analysis results validate the effectiveness and accuracy of the method.

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Voltage balancing in low‐voltage radial feeders using Scott transformers

Cited by 21 publications

References 21 publications

Research on the Harmonics Penetration Characteristics of the Traction Network to Three-Phase 380 V Power System of the Traction Substation and Suppression Scheme

Research on the Harmonics Penetration Characteristics of the Traction Network to Three-Phase 380 V Power System of the Traction Substation and Suppression Scheme

Planning and operation of LV distribution networks: a comprehensive review

Contribution Determination for Multiple Unbalanced Sources at the Point of Common Coupling

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