Assessment for Voltage Violations considering Reactive Power Compensation Provided by Smart Inverters in Distribution Network

Jindi Hu,Yi Ding,Weidong Bao,Weibin Yin,Jiajia Wu,Chengjin Ye

doi:10.3389/fenrg.2021.713510

Abstract

Due to the high proportion of renewable energies, traditional voltage regulation methods such as on-load tap changers (OLTCs) and switching capacitors (SCs) are currently facing the challenge of providing fast, step-less, and low-cost reactive power to reduce the increasing risks of voltage violations in distribution networks (DNs). To meet such increasing demand for voltage regulation, smart inverters, including photovoltaics (PVs) and electric vehicle (EV) chargers, stand out as a feasible approach for reactive power compensation. This paper aims to assess the voltage violation risks in DNs considering the reactive power response of smart inverters. Firstly, reactive power compensation models of PVs and EV chargers are investigated and voltage deviation indexes of the regulation results are proposed. Moreover, kernel density estimation (KDE) and slice sampling are adopted to provide the PV output and EV charging demand samples. Then, the risk assessment is carried out with a voltage regulation model utilizing OLTCs, SCs, and available smart inverters. Numerical studies demonstrate that the reactive power support from smart inverters can significantly mitigate the voltage violation risks and reduce the switching and cost of OLTCs and capacitors in DNs.

Highlights

The development of power electronics in distribution networks (DNs) brings prosperity for distributed photovoltaics (PVs), electric vehicle (EV) chargers, and other devices with AC-DC inverters
The results demonstrate that smart inverters have better voltage regulation effects and are able to reduce the operation cost of on-load tap changers (OLTCs) and switching capacitors (SCs)
This paper establishes a voltage violation assessment model considering the support provided by smart inverters

Summary

Introduction

The development of power electronics in distribution networks (DNs) brings prosperity for distributed photovoltaics (PVs), electric vehicle (EV) chargers, and other devices with AC-DC inverters. Traditional reactive power compensation facilities such as on-load tap changers (OLTCs) and switching capacitors (SCs) are only able to provide step-wise and high-delay reactive power at the feeder head, which limits the regulation effect (Kekatos et al, 2015), while the high cost of Distribution Static Synchronous Compensators (D-STATCOMs) restricts its application in DNs (Chen et al, 2018). The two-way reactive power ability of smart inverters (i.e., PVs and EV chargers in this paper) enables these terminal end power electronics in DNs to participate in voltage regulation. There have already been some investigations to achieve reactive power delivery from smart inverters

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Conclusion