Modelling and analysis of asymmetrical three-phase distribution transformer banks with mid-tap connected to the secondary neutral conductor

Chen, T.-H; Yang, Wen-Lung; Guo, Tzong‐Yih; Pu, Guan‐Chih

doi:10.1016/s0378-7796(99)00075-9

Cited by 24 publications

(13 citation statements)

References 7 publications

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“…The open loop impedance matrix (Thevenin equivalent impedance matrix) is used to deal with PV node [13][14]23] …”

Section: Compensation For Pv Nodesmentioning

confidence: 99%

A Three-phase Hybrid Power Flow Algorithm for Meshed Distribution System with Transformer Branches and PV Nodes

Li¹,

Wu²,

Jiang³

et al. 2016

Journal of Electrical Engineering and Technology

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-Aiming at analyzing the power flow of the distribution systems with distribution transformer (DT) branches and PV nodes, a hybrid three-phase power flow methodology is presented in this paper. The incidence formulas among node voltages, loop currents and node current injections have been developed based on node-branch incidence matrix of the distribution network. The method can solve the power flow directly and has higher efficiency. Moreover, the paper provides a modified method to model DT branches by considering winding connections, phase shifting and off-nominal tap ratio, and then DT branches could be seen like one transmission line with the proposed power flow method. To deal with the PV nodes, an improved approach to calculate reactive power increment at each PV node was deduced based on the assumption that the positive-sequence voltage magnitude of PV node is fixed at a given value. Then during calculating the power flow at each iteration, it only needs to update current injection at each PV node with the proposed algorithm. The process is very simple and clear. The results of IEEE 4 nodes and the modified IEEE 34 nodes test feeders verified the correctness and efficiency of the proposed hybrid power flow algorithm.

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“…The open loop impedance matrix (Thevenin equivalent impedance matrix) is used to deal with PV node [13][14]23] …”

Section: Compensation For Pv Nodesmentioning

confidence: 99%

A Three-phase Hybrid Power Flow Algorithm for Meshed Distribution System with Transformer Branches and PV Nodes

Li¹,

Wu²,

Jiang³

et al. 2016

Journal of Electrical Engineering and Technology

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show abstract

“…A pesar de la existencia de sofisticados métodos para el flujo de potencia en circuitos de distribución [7][8] [9], para reducir el tiempo de cálculo en la evaluación de la función de aptitud, se ha programado un flujo de potencia trifásico simplificado, que determina las corrientes de los tramos de línea en cada hora del día, considerando tensión nominal en todos los nodos de la red. Esto reduce considerablemente el esfuerzo de cálculo al evaluar la aptitud de decenas de miles de variantes diferentes de conexión.…”

Section: B Función De Aptitudunclassified

Genetic Algorithm for the Load Balance on Primary Distribution Circuits

Abril

2010

IEEE Latin Am. Trans.

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The measurements registered in eight of the 50 primary distribution circuits of Santa Clara city (Cuba), shown the presence of a 29.8% of phase currents unbalance and a 51.5% of neutral current as average. The phase current unbalance increases the energy losses in primary circuit and contributes to voltages unbalance on the different buses. On the other hand, the presence of a high neutral current on normal operation make it difficult the detection of earth faults by neutral over current relays. The main purpose of this work is to develop a method that determines the minimal reconnection operations needed for the two-phase three-wire and the single-phase twowire circuit laterals, as well as for the three-phase transformers banks and the single-phase distribution transformers, to minimize the energy losses on the primary distribution circuit and reduce the neutral current to an accepted level. A successful application example of the presented methodology is achieved in a distribution circuit of the Santa Clara city. The results show the energy saving benefits as well as the neutral current reduction on the circuit.

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“…The authors of [14] present the nodal admittance matrices for nine common connections of three-phase transformers (i.e., [18]. The authors of [21] presents the phase coordinate models for five asymmetrical three-phase distribution transformer banks (i.e., GY-D, Y-D, D-D, U-V and V-V) with mid-tap connected to the secondary neutral conductor; the models in [20] are proposed for the single-phase, V-, and Scott connections of transformers; the phase-coordinate transformer models in [24] can take into account the effects of inter-phase coupling, particularly the lowered impedance of three-phase units to zero-sequence magnetizing currents. If necessary, the nodal admittance matrices for other particular types of transformers can also be developed using the methods in [16], [20] or [24].…”

Section: A Nodal Admittance Matrix Model Of Transformersmentioning

confidence: 99%

Implementing Transformer Nodal Admittance Matrices Into Backward/Forward Sweep-Based Power Flow Analysis for Unbalanced Radial Distribution Systems

Wang

Fen²,

Li³

2004

IEEE Trans. Power Syst.

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This paper proposes a new method to handle distribution transformers of various winding connections in the backward/forward sweep-based power flow analysis for unbalanced radial distribution systems. The method takes advantage of available nodal admittance matrices of distribution transformers, and can automatically solve the problem of conductively isolated subnetworks to obtain their equivalent phase-to-reference voltages. In addition, this paper presents a limitation of backward/forward sweeps, and an extension of the power summation method for distribution power flow analysis from single-phase to unbalanced three-phase. The validity and effectiveness of the proposed method can be demonstrated by numerous examples and real systems. Index Terms-Backward/forward sweep, distribution transformer model, nodal admittance matrix, radial distribution system, unbalanced power flow. Zhuding Wang (SM'03) received the Ph.D. degree in electrical engineering from University of Wisconsin, Milwaukee.He was previously with SKM Systems Analysis, Inc., Manhattan Beach, CA. Currently, he is a Professor of Power

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Modelling and analysis of asymmetrical three-phase distribution transformer banks with mid-tap connected to the secondary neutral conductor

Cited by 24 publications

References 7 publications

A Three-phase Hybrid Power Flow Algorithm for Meshed Distribution System with Transformer Branches and PV Nodes

A Three-phase Hybrid Power Flow Algorithm for Meshed Distribution System with Transformer Branches and PV Nodes

Genetic Algorithm for the Load Balance on Primary Distribution Circuits

Implementing Transformer Nodal Admittance Matrices Into Backward/Forward Sweep-Based Power Flow Analysis for Unbalanced Radial Distribution Systems

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