Real-Time Load and Ancillary Support for a Remote Island Power System Using Electric Boats

Abstract

Powering small islands with reliable, affordable and green electricity is a big challenge due to their dispersed geographical location with limited number of consumers and the heavy dependence on fossil fuels. This paper aims to address this challenge of reducing dependency on fossil fuel generators by providing an easy and feasible solution using available and accessible energy resources. The proposed method utilizes the bidirectional energy transfer mechanism available in electric boats to support the consumers' power demand. It proposes a new realtime load-support (RTLS) system with a coordinated control using electric boats (EBs), community generators and battery energystorage systems. It analyzes the management of the intermittent sources-dependent small-scale grid in real time, under various weather, load, and battery state-of-charge conditions. The RTLS system coordinates the customers' load demand with the available EBs, photovoltaics (PVs) and battery storage to provide efficient load support and to regulate the bus voltage and frequency. The efficacy of the proposed system is validated both computationally in a real network and in a laboratory setup. It is found that this novel system can substantially reduce the grid load demand and maintain the power quality under various load/source uncertainties and fault conditions. The system robustness is also evaluated considering undesirable conditions, such as severe threephase faults and sudden EB disconnections. The performance of the proposed method is compared with that of the day-ahead loadmanagement approach to validate its effectiveness under various scenarios. Index Terms--Ancillary support, electric boat, forecasting, island energy management, island power systems, load support. NOMENCLATURE single PV module capacity efficiency of PV module , , , efficiency of converter 1, 2, 3, 4 current from PV , current from EB and battery respectively amount of power supplied from PV to AC bus amount of power supplied from PV to fixed battery EB battery capacity fixed battery capacity , max. charging limit of the EB and battery respectively , min. discharging limit of the EB and battery respectively , SOC of the EB and battery at a particular ( ) time

Rebound behaviour of uncoordinated EMS and their impact minimisation

“…Since the rebound effect occurs at the same time due to load-curve Fig. 4 Charging-discharging management of EV and battery storage [5,25] (a) EV and battery charging-discharging constraints, (b) EV battery SOC segmentation and management α t = λ ev r e (1/( − λ ev similarity, the summation of rebound effect by individual EMS creates big spikes of power demand at the substation.…”

“… Charging‐discharging management of EV and battery storage [5, 25] (a) EV and battery charging–discharging constraints, (b) EV battery SOC segmentation and management…”

“…However, a holistic impact by different types of load patterns and their behaviours to the EMS are needed to be further investigated. Another common method to tackle the load demand of a grid‐connected or islanded microgrid is to shift the controllable loads [23] and minimise the peaks [24] either in real‐time [25] or day‐ahead operation [26]. In some investigations [27], AC/DC hybrid microgrid considering various intermittent renewable energy sources are discussed.…”

A Linear Parameter Varying Control Approach for DC/DC Converters in All‐Electric Boats

“…For instance, low voltage battery packages need step-up converters to provide the required voltage for the DC-link of these vehicles [5]. For this reason, while the conventional boost converters are used as an interface circuit in the structure of the EVs and EBs propulsion system, a suitable robust controller is required to guarantee the correct operation of the converters [6][7][8][9][10][11]. e mathematical and black-box analyses of a power converter are two different approaches to design the controllers of the power converters.…”

A comparison between central- and self-dispatch storage management principles in island systems

“…The main finding was that annual renewable penetration levels could reach up to 100% in the presence of suitably sized storage. Topics related to frequency regulation, including provision of inertial and fast response reserves for low-or no-inertia microgrids and isolated systems are the subject of [31][32][33].…”