Analyzing Cross-Phase Effects of Reactive Power Intervention on Distribution Voltage Control

TL;DR

This paper addresses cross-phase voltage effects arising from reactive power interventions by PV inverters in unbalanced distribution networks. It develops a voltage–reactive power sensitivity framework (VQ-SM) and analyzes both simple and complex feeder scenarios to reveal how Q injections in one phase can cause beneficial or adverse changes in other phases. The work identifies key drivers of cross-phase effects, demonstrates their impact on voltage control strategies, and proposes a cross-phase aware, iterative optimization approach that improves hosting capacity and reliably mitigates voltage violations. The findings highlight the necessity of incorporating cross-phase coupling into practical voltage control algorithms for PV-rich distribution systems, enabling more robust and scalable operation.

Abstract

Increasing photovoltaic (PV) penetration in the distribution system can often lead to voltage violations. Mitigation of these violations requires reactive power intervention from PV inverters. However, the unbalanced nature of the distribution system leads to mixed effects on the voltages of nearby nodes for each inverter injecting or absorbing reactive power. In particular, reactive power absorption to reduce over-voltage in one phase can exacerbate over-voltage in a different phase. In this paper, the factors impacting the incremental and decremental voltage effects of reactive power intervention are analyzed in detail. The result of these effects on the distribution system performance is presented to highlight their significance and the need to factor them in for any coordinated voltage control algorithm.

Figures (5)

• Figure 1: Simple 4-wire, 2-bus system
• Figure 2: Phasor diagrams showing effects of Q perturbation
• Figure 3: Sensitivity of a single SVR node to all PVs
• Figure 4: Cross-phase sensitivity effects using Algorithm \ref{['Alg_1']}
• Figure 5: Cross-phase sensitivity effects with high PV penetration