State of Charge Control Integrated with Load Frequency Control for BESS in Islanded Microgrid

Abstract

The dependence of distributed generations (DGs) on climate conditions and fluctuating load demands are the challenges for the implementation of battery energy storage systems (BESSs) in islanded microgrids. BESS participation in system frequency regulation becomes one of the solutions to those challenges. Frequency regulation by BESS can be realized by applying the load-frequency control (LFC) in BESS. However, this participation clearly poses problems for the battery state of charge (SOC), as the battery is often overcharged or undercharged. In this paper, a control that maintains SOC at a certain level is introduced. This control strategy focuses on the battery operation function, which is determined from five control scenarios. All scenarios are achieved by applying the droop reference shifting method in the LFC to allow battery operation change. Control verification is carried out on an islanded microgrid system that experiences load demand changes and photovoltaic (PV) output power changes. The test results show that the SOC is maintained at 45–75% by applying load and PV power variations. The results correspond to the predetermined criteria control.

Disruption Potential Assessment of the Power-to-Methane Technology

“…Regarding the identified mainstream needs of potential P2M adopters (producing and utilizing more renewable energy) and the recent literature about the identified alternative technologies, mainly BGU and BESS could be considered as sustaining technologies. In the case of BGU and BESS, frequent use and relatively high TRL can be seen [81,82] for renewable energy production and utilization, but there are also novel ways for BGU (TRL3-7) [83] and there are also efforts to optimize and develop the efficiency of batteries [84], which may indicate incremental developments. In contrast, P2H, CC, and P2L are rather in the demonstration phase or less frequently used.…”

Integration of Small Productive Processes Into an Energy Management System for Microgrids

“…The electrical part of the DGU is represented by a sixth-order state-space model [73]. The excitation system and the governor of the DGU are based on the IEEE type DC1A excitation system model [74], and the governor block diagram presented in [75], respectively. The transformers are represented by a three-phase two-winding transformer with DY connection [54], [76].…”

Impact of Advanced Load-Frequency Control on Optimal Size of Battery Energy Storage in Islanded Microgrid System

“…Region 1 represents linear operation, where the BES power is proportional to the droop curve. Region 2 and Region 3 represent frequency saturation regions, where f max and f min point out the saturated frequency [37]. Figure 4 shows the BES power and frequency relation according to the droop ch acteristics.…”