This paper designs a unified management framework in zero-energy building (ZEB) integrated with renewable resources, energy storage, AC/DC loads, and critical/non-critical loads. The developed model ...controls solar-cell and fuel-cell operation, battery charging-discharging, load energy, and voltage of buses. The faults, outages and cyber-attacks are detected, separated and dealt with. The AC loads with different voltage levels and frequencies are integrated and successfully supplied. The loads are considered as critical and non-critical and the system is forced to supply the critical loads under any circumstances. The fault detection units on both AC and DC buses are designed to control the AC and DC voltages under steady-state and fault conditions. The outage detection unit is also designed to compensate lack of disconnected resources. The cyber-attack detection unit is implemented to detect the attacks on solar-cell power, fuel-cell power, AC voltage and DC voltage. With the operation of control system, the DC bus voltage is stabilized on 100 V and under outage conditions, the solar-cell is supported by fuel-cell and the battery is operated as backup for fuel-cell. The fault conditions in AC and DC buses are improved by battery performance. Furthermore, a variety of individual and concurrent cyber-attacks are detected. The simulations validate that the proposed method conveniently realizes all the objectives, including feeding DC/AC loads, managing battery/ resources and identifying/dealing with outages/faults/attacks.
•Zero-energy building is designed with DC/AC and critical/non-critical loads.•AC loads with different voltage levels and frequencies are integrated and supplied.•Fault detection unit is designed on both AC and DC buses.•Multi-layer control is implemented to deal with outage of resources.•Cyber-attack detection unit is designed to detect attacks on powers and voltages.
This paper presents a control scheme including resources and load management in the residential DC microgrid. The DC microgrid is supported by fuel-cell, solar-cell and battery. The DC, AC ...single-phase and AC three-phase loads with 50 Hz frequency are integrated. The DC microgrid is connected to the external 60 Hz AC three-phase network. An efficient multi-bus topology is proposed for the microgrid and it is formed by various AC/DC buses to supply the loads and managing the resources. The main bus of system is a 470 V DC bus and it is connected to the external 440 V/60 Hz AC grid. The main DC bus supplies three LV, MV and HV DC buses with 100, 220, and 110–380 V, respectively. The HV DC bus produces a variable output DC voltage between 110 and 380 V in order to regulate the load power (i.e., motor speed). The MV DC bus is connected to 220 V/50 Hz AC single-phase loads. The connections between DC microgrid with AC loads and AC external gird are made by single-phase or three-phase inverters. The interface inverters between DC bus and AC loads are operated to control power, torque, speed, frequency and voltage of loads. The unbalanced AC loads are appropriately balanced by proper control of interface inverters. The resources and inverters are efficiently controlled to enable operation of residential building under both off-grid or grid-tied conditions. The coordination of fuel-cell, solar-cell and battery can supply a fixed 8 kW power to external grid and supply the internal loads under all outages and off-grid conditions. The simulations demonstrate that the proposed control realizes all the objectives including AC/DC load management, unbalanced load amendment, frequency adaptation, and off-grid operation.
•Designing residential DC microgrid with several voltage levels and frequencies.•Implementing multiple generation/load managements under off-grid and grid-tied.•Multi-bus topology for building including low, medium and high-voltage buses.•Balancing the unbalanced loads from the external network standpoint.•Implementing load shedding strategy in off-grid under critical situations.
Abstract A comprehensive model is developed for coordinated control of voltage‐frequency‐inertia and identifying multiple cyberattacks simultaneously in two microgrids (MGs). The MGs are integrated ...with solar units, Wind turbine (WT), hybrid supercapacitor‐battery, and fuelcell. The MGs are modelled and controlled for operation under both an island and connected states. In the proposed method, a data centre is designed in which all the electrical and control signals related to the solar, wind, hybrid supercapacitor‐battery, and Fuel cell (FC) are collected, evaluated, and matched. The data centre comprises the following blocks: voltage‐frequency control, inertia control of WT, and identification of false data injection (FDI) cyberattacks on frequency, power, power/frequency, and voltage. The technique used in this article to identify FDI attacks is based on the real‐time method coupled with logical comparisons conducted in the time domain. This methodology provides prompt and precise detection, allowing for timely preventive measures and strategic responses. After FDI attacks occur, the implemented control system effectively manages and regulates the voltage and frequency at the desired levels, efficiently differentiating between ordinary functioning, faulty states, and potential cyber‐attacks. The unhealthy MG can transfer its load to the healthy MG for safety reasons. The healthy MG is then connected to the external grid and the synchronisation conditions are checked by the proposed control system. The results of the non‐linear simulation performed in MATLAB‐Simulink software confirm that the proposed model successfully operates and controls all resources (i.e. solar/wind/battery/FC), regulates the voltage/frequency under various loading conditions, and identifies FDI cyberattacks.
In this paper, a DC microgrid (DCMG) integrated with a set of nano-grids (NG) is studied. DCMG exchanges predetermined active and reactive power with the upstream network. DCMG and NGs are ...coordinately controlled and managed in such a way the exchanged P-Q power with external grid are kept on scheduled level following all events and operating conditions. The proposed control system, in addition to the ability of mutual support between DCMG and NGs, makes NGs support each other in critical situations. On the other hand, in all operating conditions, DCMG not only feeds three-phase loads with time-varying active and reactive power on the grid side but also injects constant active power into the grid. During events, NGs support each other, NGs support DCMG, and DCMG supports NGs. Such control strategies are realized by the proposed control method to increase resilience of the system. For these purposes, all resources and loads in DCMG and NGs are equipped with individual controllers. Then, a central control unit analyzes, monitors, and regularizes performance of individual controllers in DCMG and NGs. Nonlinear simulations show the proposed model can effectively control DCMG and NGs under normal and critical conditions.
In this article, a comprehensive control scheme is designed on multimicrogrid system. The system is formed by several submicrogrids. In each submicrogrid, the dc and ac buses are linked via three ...single-phase converters. The hybrid wind/solar system based on Maximum power point tracking (MPPT) is utilized in the submicrogrids. The proposed control system balances the unbalanced loads, compensates the harmonics of nonlinear loads and supplies time-varying loads. The submicrogrids are designed to operate under both the islanded and grid-tied modes. In the islanded condition, the proposed model enables the submicrogrids to support each other for resilience improvement. Such model increases the load restoration following faults on both the dc and ac buses. The proposed model is tested on a typical multimicrogrid including five submicrogrids. The simulations are performed in MATLAB software. The results demonstrate that the developed scheme achieves all the purposes at the same time.
