Biblio
This paper proposes a distributed fixed-time based secondary controller for the DC microgrids (MGs) to overcome the drawbacks of conventional droop control. The controller, based on a distributed fixed-time control approach, can remove the DC voltage deviation and provide proportional current sharing simultaneously within a fixed-time. Comparing with the conventional centralized secondary controller, the controller, using the dynamic consensus, on each converter communicates only with its neighbors on a communication graph which increases the convergence speed and gets an improved performance. The proposed control strategy is simulated in PLECS to test the controller performance, link-failure resiliency, plug and play capability and the feasibility under different time delays.
The massive integration of Renewable Energy Sources (RES) into power systems is a major challenge but it also provides new opportunities for network operation. For example, with a large amount of RES available at HV subtransmission level, it is possible to exploit them as controlling resources in islanding conditions. Thus, a procedure for off-line evaluation of islanded operation feasibility in the presence of RES is proposed. The method finds which generators and loads remain connected after islanding to balance the island's real power maximizing the amount of supplied load and assuring the network's long-term security. For each possible islanding event, the set of optimal control actions (load/generation shedding) to apply in case of actual islanding, is found. The procedure is formulated as a Mixed Integer Non-Linear Problem (MINLP) and is solved using Genetic Algorithms (GAs). Results, including dynamic simulations, are shown for a representative HV subtransmission grid.
The goal of this document is to provide knowledge of Security for Industrial Control Systems (ICS,) such as supervisory control and data acquisition (SCADA) which is implemented in power transmission network, power stations, power distribution grids and other big infrastructures that affect large number of persons and security of nations. A distinction between IT and ICS security is given to make a difference between the two disciplines. In order to avoid intrusion and destruction of industrials plants, some recommendations are given to preserve their security.
With the rapid development of the smart grid, a large number of intelligent sensors and meters have been introduced in distribution network, which will inevitably increase the integration of physical networks and cyber networks, and bring potential security threats to the operating system. In this paper, the functions of the information system on distribution network are described when cyber attacks appear at the intelligent electronic devices (lED) or at the distribution main station. The effect analysis of the distribution network under normal operating condition or in the fault recovery process is carried out, and the reliability assessment model of the distribution network considering cyber attacks is constructed. Finally, the IEEE-33-bus distribution system is taken as a test system to presented the evaluation process based on the proposed model.
One of the various features expected for a smart power distribution system - a smart grid in the power distribution level - is the possibility of the fully automated operation for certain control actions. Although this is very expected, it requires various logic, sensor and actuator technologies in a system which, historically, has a low level of automation. One of the most analyzed problems for the distribution system is the topology reconfiguration. The reconfiguration has been applied to various objectives: minimization of power losses, voltage regulation, load balancing, to name a few. The solution method in most cases is centralized and its application is not in real-time. From the new perspectives of advanced distribution systems, fast and adaptive response of the control actions are required, specially in the presence of alternative generation sources and electrical vehicles. In this context, the multi-agent system, which embeds the necessary control actions and decision making is proposed for the topology reconfiguration aiming the loss reduction. The concept of multi-agent system for distribution system is proposed and two case studies with 11-Bus and 16-Bus system are presented.
Today's more reliable communication technology, together with the availability of higher computational power, have paved the way for introduction of more advanced automation systems based on distributed intelligence and multi-agent technology. However, abundance of data, while making these systems more powerful, can at the same time act as their biggest vulnerability. In a web of interconnected devices and components functioning within an automation framework, potential impact of malfunction in a single device, either through internal failure or external damage/intrusion, may lead to detrimental side-effects spread across the whole underlying system. The potentially large number of devices, along with their inherent interrelations and interdependencies, may hinder the ability of human operators to interpret events, identify their scope of impact and take remedial actions if necessary. Through utilization of the concepts of graph-theoretic fuzzy cognitive maps (FCM) and expert systems, this paper puts forth a solution that is able to reveal weak links and vulnerabilities of an automation system, should it become exposed to partial internal failure or external damage. A case study has been performed on the IEEE 34-bus test distribution system to show the efficiency of the proposed scheme.