An Enhanced Emulated Inertia Control for Grid-Connected PV Systems with HESS in a Weak Grid

Ratnam Kamala Sarojini,Hamid Reza Baghaee,Palanisamy Kaliannan,Yuvaraja Teekaraman,Srete Nikolovski

doi:10.3390/en14061721

Abstract

The role of renewable energy sources in the power grid is increasing tremendously. However, power electronic converters are used to incorporate RES into the grid without inertia. This article recommends an improved emulated inertia control approach focused on the frequency deviation and rate of change of frequency to enhance the inertia of a power system. The required inertial power calculated from emulated inertia control is delivered through hybrid energy storage systems equipped with a proper hybrid energy storage system control. The fast-varying power calculated from emulated inertia control is linked to super-capacitor. Simultaneously, the battery handles the slow varying power by regulating the DC bus voltage proportionate to the frequency variations. Further, the stability of the emulated inertia control and hybrid energy storage system controller is validated by Bode plots. The simulation results verified the correctness of the proposed emulated inertia control and hybrid energy storage system control. The real-time simulation results with the help of OPAL-RT are presented to validate the proposed method’s feasibility.

Highlights

Electricity generation from renewable energy sources (RES) is growing due to environmental protection rules and to improve energy conservation [1]
This paper explores the grid frequency support support offered by grid-connected PV-hybrid energy storage systems (HESS) system with the emulated inertia control (EIC) technique’s help
The inertial support provided by the grid-connected PV-HESS system was investigated in this paper

Summary

Introduction

Electricity generation from renewable energy sources (RES) is growing due to environmental protection rules and to improve energy conservation [1]. The rise in the electricity generation from power electronic converter-based RES does not possess inertia without a proper control technique. In a conventional power system, kinetic energy stored in the synchronous generator (SG) plays an important role in the inertial response. When a frequency event occurs, the SG adjusts the rotational speed depending on its inertia [2,3]. The phenomenon of low inertia in a weak grid results in two significant challenges under frequency events. The first challenge refers to a high rate of change of frequency (ROCOF), that may result in protective relay tripping, and the same has been identified by the Irish grid operators [4]. The second challenge is that large frequency deviations may cause load shedding and cascading failure [5]

Methods

Results

Conclusion