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Trabajo presentado en la 20th IEEE International Conference on Industrial Technology, celebrada en Melbourne (Australia) del 13 al 15 de febrero de 2019 ; Uncertain generation by renewable sources and load variations have resulted in adding energy storage systems in the grid to maintain grid parameters (voltage, frequency) within prescribed limits. The disturbances being non-deterministic in nature, the voltage regulation control by the storage systems relies mostly on dual loop architecture with an outer voltage and inner current loop. Improvement in controller dynamics can be achieved through feed forward of disturbance profile but at expense of additional sensors and communication in the grid. This work explores the application of an adaptive disturbance rejection control scheme for disturbance estimation (without using additional sensors) employing an extended state and proportional integral observer (PI+ESO). The proposed observer aim to achieve robust disturbance estimation under grid parameter uncertainty. The effectiveness of the proposed scheme over the conventional one will be put forward through H¿ and H2 norm analysis of the system. The design and simulation results of the proposed scheme will be presented in this work. ; This work is done as part of project which has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska Curie grant agreement No 675318 (INCITE). This work has been partially funded by the MINECO/FEDER project DPI2015-69286-C3-2-R. This work is supported by the Spanish State Research Agency through the Mara de Maeztu Seal of Excellence to IRI (MDM-2016-0656). This work is partially funded by AGAUR of Generalitat de Catalunya through the Advanced Control Systems (SAC) group grant (2017 SGR 482)

Publisher Copyright: Author ; Recently, renewable energy sources (RESs) have increasingly being integrated into the power grids as a result of environmental and governmental perspectives. In this regard, the installation of RESs as potential power sources in active distribution systems would benefit the grid by decreasing the power losses, as well as addressing the fossil fuel shortages, and their environmental aspects. Nevertheless, the high-level integration of RESs as well as the development of distributed formations in local systems could challenge the reliable operation of the grid. In this context, conventional approaches could not optimally mitigate the regulation-voltage issue; therefore, utilities have to exploit the scheduling of local responsive sources to address the regulation-voltage issue in systems with high-level penetration of RESs. Consequently, the offered scheme in this paper enables the system operator to activate flexibility service from local responsive sources with the aim of addressing the regulation-voltage issue in the grid. Respectively, the system operator as the leader provides incentive control signals to ensure collaboration of the independent agents in voltage regulating procedure. Finally, the developed framework is applied on the 37-bus IEEE test network to investigate its application in mitigating the regulation-voltage issue in the active distribution systems with multi-agent formations. ; Peer reviewed

Integrating renewable energy sources and distributed energy resources (DERs) in the Malaysian low voltage distribution network has introduced voltage stability challenges, particularly voltage rises, leading to detrimental impacts on network performance. This paper presents a novel reactive power control strategy for addressing these challenges. Unlike conventional methods with fixed reactive power references, the proposed technique dynamically adjusts the reactive power reference in real time, considering voltage and active power injection. It calculates the rate of change in reactive power reference (ΔQ) per second by analyzing Volt-VAR and Watt-VAR components and updates the reference accordingly. Simulations conducted on a low voltage distribution network in Taman Impian Putra, Malaysia, showcase the adverse effects of high photovoltaic (PV) penetration on voltage stability and highlight the success of the proposed strategy in mitigating voltage rise. The technique effectively reduces average voltage, maintains voltage regulation during high sun irradiance and low load demand periods, and surpasses the adaptability of existing methods dependent on PV active injection or network voltage alone. The proposed strategy ensures accurate control and efficiently addresses dynamic network changes by accounting for both PV active power injection and network voltage. This approach offers enhanced voltage regulation, adaptability to varying network conditions, and reduced losses, making it a promising solution for mitigating voltage rise in the Malaysian low voltage distribution network. The simulations, validated using MATLAB Simulation and OpenDSS, confirm the strategy's efficacy and potential for real-world implementation.

The proportion of renewable energies in power generation has increased significantly in recent years according to the political aims. In low-voltage grids, these are mostly distributed intermittent generation systems such as photovoltaic systems that are connected through inverters to the grid. Thus, the distribution networks have to meet hitherto unfamiliar technical challenges. A temporary reversal of the power flow can cause overvoltage problems. Traditional voltage regulation strategies cannot solve this problem. Consequently, regenerative sources need to be turned off temporarily or on the long term the grid infrastructure has to be extended by the network operator. Therefore, the distributed generation has to take part in the voltage regulation. With the help of reactive power, which is generated by the solar inverters, power capability and voltage quality of the networks can be increased. Thus, grid extension can be delayed or even avoided in many times. This paper presents a new approach to the evaluation of reactive power control strategies. Different reactive power control concepts are simulated and evaluated concerning their efficiency, effectiveness and stability.

This paper proposes an adaptive droop control strategy for simultaneous regulation of voltage and frequency in isolated microgrids to meet the relevant legislation (NBR 5410 and IEEE 1547). The technique is based on the traditional structure of the Droop control (P-f) and (Q-V), aided by recursive least squares methods to estimate the line parameters. The control law is adaptive because the controller gains are self-adjusting to the operating conditions imposed by the loads and the legal restrictions for fluctuations in voltage and frequency in the microgrid. The controller was validated in different microgrids (1-bus, 3-bus, and IEEE 14-bus) and different types of loads. The simulation results show the effectiveness of the controller: rapid response in the accommodation of variations in loads; active power-sharing between the inverters and; stable and safe operation of the microgrid.