The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, a preventive control method against transient instabilities due to a set of critical contingencies that could occur in a large power system is proposed. The generation rescheduling, adopted as the preventive control, is based on the coherency between the generators. The rescheduling is done by attempting to bring the generators’ rotor speeds equal after a three phase fault that might...
Increasing consumer choices and market options in the power market necessitate a more resilient grid operation. Security level indication based on the desired risk index and thus a risk-based security constrained optimal power flow is described and simulated in this paper. It highlights the possibility of giving a choice of security level to a consumer area and also presents the computation of risk...
Security Constrained Optimal Power Flow (SCOPF) is becoming more important in the electrical power system especially in the present deregulated environment. This paper focuses on completely linearizing the complex non-linear SCOPF problem. The objective function is linearized using Piecewise linearization technique and the constraints are framed using linear sensitivity factors. DC power flow analysis...
The cryptographic substitution boxes are the substantive constituent of most modern day block cryptosystems. Here, we proposed a novel method to generate cryptographically potent S-boxes by exploring the blended strength of chaos and neural network in its design. The designed chaos-based neural network, engaged to yield S-boxes, consists of four layers each of which have eight, four, two and one neuron(s),...
The goal of this paper is to construct an dynamic secure combinatorial keying approach. We focus on heterogeneous mobile wireless sensor network environments. The proposed approach is called dynamic secure combinatorial keying approach (DSCKAD). Most of the previous work on WSN security focuses on homogeneous motes. In homogeneous WSN, sensors have the same resource specifications such as battery...
Security assessment is an important means to prevent large-scale blackouts. This paper proposes an overall evaluation indicator from a macro perspective of the grid security. The indicator is proposed from the view of the main task of the grid operation. It takes the reserve level as the carrier and sets various security and stability constraints on power outputs to get the total maximum output of...
Special operating conditions arise in deregulated systems. Generators pump scheduled powers as determined by the market into the grid. System operator has to assume responsibility for secure operation. For commercial reasons generator bids are generally pinned at maximum capacities. Q-capabilities are severely curtailed. Specifying PV bus voltages which generator owners are not obliged to adhere to,...
This article presents a method of steganographic keys generation for case of embedding many secrets in single container. The most important requirements of proposed algorithm are as follows. The generated keys cannot overlap what means that the positions they indicate in the cover have to be different. An authorized user with known key should be able to easily retrieve any secret from carrier file...
The security of cryptographic functions such as pseudo random number generators (PRNGs) can usually not be mathematically proven. Instead, statistical properties of the generator are commonly evaluated using standardized test batteries on a limited number of output values. This paper demonstrates that valuable additional information about the properties of the algorithm can be gathered by analyzing...
A standard operational requirement in power systems is that the voltage magnitudes must lie within pre-specified bounds. Conventional wisdom suggests that such a tightly regulated voltage profile should also guarantee a secure system, operating far from static bifurcation instabilities such as voltage collapse. Here we demonstrate that this conclusion is generally false, and that the distance from...
The main goal of this work is to determine the optimum operating conditions of the control variables within the constraints of control variables and minimization of transmission losses at normal operating condition of the system. The upper and lower values of voltages at load bus, the lower and upper values of generator reactive powers and normal operating values of transformer tap settings and generator...
The massive integration of wind power brings more challenges to the safe operation of power system. In this paper, risk assessment methods of power system with wind power integration are studied by using DSR (dynamic security region) and risk assessment theory. The basic construction method of DSR boundary is introduced. The risk index calculation and comprehensive analysis method of wind power integration...
This article presents a new method of steganographic keys generation for secret key visual steganography, when there is a need of embedding many secret messages in one container. The main assumptions which such algorithm has to meet are such that there should be no conflicts in generated keys, in other words keys cannot indicate the same positions (determining the way of secret image distribution...
While cyber-physical systems are widely deployed and known to be difficult to analyze due to their increasing complexity, the number of sophisticated attacks against them have been constantly growing. This necessitates semi-automated intrusion response and recovery capabilities for timely termination of ongoing attacks and effective recovery of the infrastructural normal and safe operations. In this...
Among the power system corrective controls, defensive islanding is considered as the last resort to secure the system from severe cascading contingencies. The primary motive of defensive islanding is to limit the affected areas as soon as possible to maintain the stability of the resulting subsystems and to reduce the total loss of load in the system. The design of the defensive islanding must address...
In this paper, we investigate two decomposition methods for their convergence rate which are used to solve security constrained economic dispatch (SCED): 1) Lagrangian Relaxation (LR), and 2) Augmented Lagrangian Relaxation (ALR). First, the centralized SCED problem is posed for a 6-bus test network and then it is decomposed into subproblems using both of the methods. In order to model the tie-line...
Inter-area Oscillations pose serious threats to the stability of power transmission grids. Failure to notice or to handle inter-area oscillations may lead to widespread catastrophic blackouts. It is, therefore, critically important to monitor the oscillation conditions such that timely mitigation controls can be applied at the early stage. Recent research shows that it is an effective approach to...
True Random Numbers represents a sensitive research area for cryptographic algorithms and applications. They are mostly used in generating non-reproducible and non-deterministic patterns used in different cryptographic protocols. A True Random Number Generator basically consists of three main components: a noise generator, that is based on a physical incontrollable phenomenon, a randomness extractor...
In a restructured power system, one of the key objectives of transmission network expansion is to provide nondiscriminatory access to cheaper generation for all consumers. However, the robustness of the transmission network against all uncertainties such as credible contingencies should equally be maintained. Thus the development of effective methodologies and strategies to satisfy this objective...
The paper deals with the cryptographic design and experimental implementation of a scheme for (but not limited to) vehicular ad-hoc networks (VANETs). In contrast to existing solutions, our scheme does not need any complex infrastructure (like costly road-side units or special on-board devices) and is based just on users' smart-phones and Internet connection. We call this simplified concept SVANETs...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.