Branch-and-bound algorithms

With the increase in use of information technology in advanced demand side management and given the growth in power consumption in the computation and communications sectors, a new class of cyberintrusion plans is emerging that aims to alter the load through the Internet and by means of automatic and distributed software intruding agents. These attacks work by compromising direct load control command signals, demand side management price signals, or cloud computation load distribution algorithms to affect the load at the most crucial locations in the grid in order to cause circuit overflow or other malfunctions and damage the power system equipment. To gain insights into these less-examined yet important intrusion strategies, in this paper, we identify a variety of practical loads that can be volnurable to Internet-based load altering attacks. In addition, we overview a collection of defense mechanisms that can help in blocking these attacks or minimizing the damage caused by them. Our simulation results based on the standard setting in the IEEE 24-bus Reliability Test System show that our proposed cost-efficent load protection strategy can significantly reduce the cost of load protection while it guarantees that no Internet-based load altering attack may overload the power distribution system.

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Distributed Internet-Based Load Altering Attacks Against Smart Power Grids

With the integration of advanced computing and communication technologies, smart grid is considered as the next-generation power system, which promises self healing, resilience, sustainability, and efficiency to the energy critical infrastructure. The smart grid innovation brings enormous challenges and initiatives across both industry and academia, in which the security issue emerges to be a critical concern. In this paper, we present a survey of recent security advances in smart grid, by a data driven approach. Compared with existing related works, our survey is centered around the security vulnerabilities and solutions within the entire lifecycle of smart grid data, which are systematically decomposed into four sequential stages: 1) data generation; 2) data acquisition; 3) data storage; and 4) data processing. Moreover, we further review the security analytics in smart grid, which employs data analytics to ensure smart grid security. Finally, an effort to shed light on potential future research concludes this paper.

Survey of Security Advances in Smart Grid: A Data Driven Approach

Tuning of PID load frequency controller for power systems

In this paper, the optimal probabilistic neural network (PNN) is proposed as the core classifier to discriminate between the magnetizing inrush and the internal fault of a power transformer. The particle swarm optimization is used to obtain an optimal smoothing factor of PNN which is a crucial parameter for PNN. An algorithm has been developed around the theme of the conventional differential protection of the transformer. It makes use of the ratio of voltage-to-frequency and amplitude of differential current for the determination of operating condition of the transformer. The performance of the proposed heteroscedastic-type PNN is investigated with the conventional homoscedastic-type PNN, feedforward back propagation (FFBP) neural network, and the conventional harmonic restraint method. To evaluate the developed algorithm, relaying signals for various operating condition of the transformer, including internal and external faults, are obtained by modeling the transformer in PSCAD/EMTDC. The protection algorithm is implemented by using MATLAB.

Power Transformer Differential Protection Based On Optimal Probabilistic Neural Network

Power transformer protective relay should block the tripping during magnetizing inrush and rapidly operate the tripping during internal faults. The frequency environment of power system has been made more complicated and the quantity of 2nd frequency component in inrush state has been decreased because of the improvement of core steel. Then, traditional approaches will likely be maloperated in the case of magnetizing inrush with low second harmonic component and internal faults with high second harmonic component. This paper proposes a new relaying algorithm to enhance the fault detection sensitivities of conventional techniques by using a fuzzy logic approach. The proposed fuzzy-based relaying algorithm consists of flux-differential current derivative curve, harmonic restraint, and percentage differential characteristic curve. The proposed relaying was tested with relaying signals obtained from Salford EMTP simulation package and showed a fast and accurate trip operation.

Fuzzy logic-based relaying for large power transformer protection

Extended integral control for load frequency control with the consideration of generation-rate constraints

Novel technique for fault location estimation on parallel transmission lines using wavelet

A CORDIC-based digital protective relay and its architecture

In AC feeding system, the fault location is calculated by using ratio of current absorbed in the neutral point of AT(Automatic Transformer) or by measuring reactance. In this way, however, an estimation error can be happened due to the many reasons. In addition, for measuring currents in the neutral point of AT, other measuring devices and communication equipments are additionally required. In order to solve the disadvantages, this paper suggests a novel technique using the distribution ratio of catenary current. The proposed technique uses existing protective relays and measures catenary current. With the measured data, we can calculate the distribution ratio of catenary current and determine fault location. Through the simulated results, we derived the correlation between current ratio and fault location. Using this technique, additional equipments and expenses can be reduced. Besides, fault location can be determined more correctly.

Myong-Chul Shin

Papers

Fuzzy logic-based relaying for large power transformer protection

Extended integral control for load frequency control with the consideration of generation-rate constraints

Novel technique for fault location estimation on parallel transmission lines using wavelet

A CORDIC-based digital protective relay and its architecture

A Study on Fault Location Estimation Technique Using the distribution Ratio of Catenary Current in AC Feeding System