Analysis of unbalanced distribution lines with mutual coupling across different voltage levels and the corresponding impact on network voltage

Abstract

In many countries, it is common for medium voltage (MV) and low voltage (LV) to share the same pole and power line corridor, and this has been a general practice for decades. The MV line and the LV line separation distance may be short under some situations; therefore the mutual coupling may become substantial, which can have a significant impact on network voltages. In the literature, such coupling effect is generally ignored, and there is a lack of a detailed model of the coupled MV and LV lines for incorporation into load flow programs. This study develops a model for unbalanced distribution lines considering the mutual coupling between different voltage levels. Then the established model is utilised in a current injection load flow program to analyse the MV/LV coupling impacts on distribution system voltage.

Self‐consumption and storage as a way to facilitate the integration of renewable energy in low voltage distribution networks

“…The subject of three‐phase unbalanced load flow in distribution grids has been intensely approached in the literature, in recent years. The mutual coupling effect between medium voltage and low voltage distribution lines, which share the same poles and power line corridor, is assessed in [35]. In [36], a complex vector‐based model in stationary reference frame αβ 0 is developed with the aim of representing the power flow equations using a compact matrix.…”

Modeling and Analysis of Open-Delta Step Voltage Regulators for Unbalanced Distribution Network With Photovoltaic Power Generation

“…The basic voltage-current relationship of the two regulators can be summarized in (2), and it should be noted that the shunt admittance is negligible [7]. The leakage impedance of the regulator is normally referred to the series winding side, which is very small in value due to the square term of the low turns ratio ( _ 2 ) and the small low-voltage winding impedance ( _ 2 ) in (3).…”

“…ITH a rapid increase of distributed generation (especially Photovoltaic -PV) in low-voltage (LV) systems, distribution network analysis becomes substantially more active in recent years. Especially, there is a tendency of utilizing more accurate models for representing network unbalance [1][2][3] and applying long-term evaluation methods (e.g. probabilistic load flow [4] and Quasi-Static Time-Series [5]) for acquiring statistical significance.…”

Investigation of the interaction between step voltage regulators and large‐scale photovoltaic systems regarding voltage regulation and unbalance

“…The model for delta-to-wye-ground transformer has been adopted and modified from [32,33] and expressed in (4), where represents the admittance matrix of a three-phase four-wire delta to wye-ground transformer and is the transformer…”