Overvoltage Prevention and Curtailment Reduction Using Adaptive Droop-Based Supplementary Control in Smart Inverters

Manisha Maharjan,Bishnu Bhattarai,Reinaldo Tonkoski,Zhen Ni,Ujjwol Tamrakar

doi:10.3390/app11177900

Abstract

Recent developments in the renewable energy sector have seen an unprecedented growth in residential photovoltaic (PV) installations. However, high PV penetration levels often lead to overvoltage problems in low-voltage (LV) distribution feeders. Smart inverter control such as active power curtailment (APC)-based overvoltage control can be implemented to overcome these challenges. The APC technique utilizes a constant droop-based approach which curtails power rigidly, which can lead to significant energy curtailment in the LV distribution feeders. In this paper, different variations of the APC technique with linear, quadratic, and exponential droops have been analyzed from the point-of-view of energy curtailment for a LV distribution network in North America. Further, a combinatorial approach using various droop-based APC methods in conjunction with adaptive dynamic programming (ADP) as a supplementary control scheme has also been proposed. The proposed approach minimizes energy curtailment in the LV distribution network by adjusting the droop gains. Simulation results depict that ADP in conjunction with exponential droop reduces the energy curtailment to approximately 50% compared to using the standard linear droop.

Highlights

Renewable energy sources (RES) have extended the capability of the grid to fulfill an ever-increasing load demand
The main contributions of the paper are twofold: First, we aim to study the impacts of different droop functions in active power curtailment (APC)-based inverter control for low voltage (LV) distribution networks with
This section consists of results from the benchmark model with two case scenarios: a droop-based APC method with linear, quadratic, and exponential droop functions, and APC with the supplementary adaptive dynamic programming (ADP) controller added to each of the three different droop functions

Summary

Introduction

Renewable energy sources (RES) have extended the capability of the grid to fulfill an ever-increasing load demand. The benefits of RES are reduced cost of energy production, increased generation capacity, reduction in energy curtailment, and improved voltage profile across the feeder [1]. Inconsistency of photovoltaics (PV) generation accounts for numerous challenges in low voltage (LV) distribution networks [2]. Some of these challenges are sustained power interruptions, voltage regulation, harmonics, and voltage sags [3]. Smart inverters with appropriate control strategies can tackle these challenges to increase the profitability from RES like PV in LV grids. Voltage regulation describes the ability of a system to maintain constant voltage under different load conditions.

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Results

Conclusion