# Applicability of True Voltage Unbalance Approximation Formula for Unbalance Monitoring in LV Networks with Single-phase Distributed Generation

### Ognjen Gagrica, Tadeusz Uhl, Phuong H. Nguyen, J. F. G. Cobben

#### Abstract

In the hierarchy of power transmission and distribution systems, the three-phase LV distribution networks are most susceptible to voltage unbalance (VU). The main causes are large presence of randomly distributed single-phase loads and, following the latest trends, the increasing presence of single-phase distributed generators. Most widely accepted VU calculation is based on percentile ratio of negative and positive sequence voltage (voltage unbalance factor, VUF). Obtaining sequence voltages is a complex domain calculation and requires simultaneous sampling of three-phase voltages and angles. This is why the existing VU monitoring and mitigation solutions are dominantly three-phase. Without an additional three-phase aggregation device, there is an inherent gap in VU monitoring for single-phase loads and generators. In this paper, the data concentrators for a growing PV micro-inverter niche are identified as an infrastructure that could be exploited to somewhat close this gap. Due to potential technical limitations of PV data concentrators, a non-complex VUF approximation formula is tested as a "light" calculation alternative, by comparing it against conventional VUF. The comparison results are obtained from Monte Carlo load flow simulation for an unbalanced LV network.

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#### Paper Citation

#### in Harvard Style

Gagrica O., Uhl T., Nguyen P. and Cobben J. (2016). **Applicability of True Voltage Unbalance Approximation Formula for Unbalance Monitoring in LV Networks with Single-phase Distributed Generation** . In *Proceedings of the 5th International Conference on Smart Cities and Green ICT Systems - Volume 1: SMARTGREENS,* ISBN 978-989-758-184-7, pages 286-292. DOI: 10.5220/0005783202860292

#### in Bibtex Style

@conference{smartgreens16,

author={Ognjen Gagrica and Tadeusz Uhl and Phuong H. Nguyen and J. F. G. Cobben},

title={Applicability of True Voltage Unbalance Approximation Formula for Unbalance Monitoring in LV Networks with Single-phase Distributed Generation},

booktitle={Proceedings of the 5th International Conference on Smart Cities and Green ICT Systems - Volume 1: SMARTGREENS,},

year={2016},

pages={286-292},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0005783202860292},

isbn={978-989-758-184-7},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the 5th International Conference on Smart Cities and Green ICT Systems - Volume 1: SMARTGREENS,

TI - Applicability of True Voltage Unbalance Approximation Formula for Unbalance Monitoring in LV Networks with Single-phase Distributed Generation

SN - 978-989-758-184-7

AU - Gagrica O.

AU - Uhl T.

AU - Nguyen P.

AU - Cobben J.

PY - 2016

SP - 286

EP - 292

DO - 10.5220/0005783202860292