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The rapid introduction of electric vehicles (EVs) in the transportation market has initiated the concept of vehicle-to-grid (V2G) technology in smart grids. However, where V2G technology is intended to facilitate the power grid ancillary services, it could also have an adverse effect on the aging of battery packs in EVs. This is due to the instant depletion of power during the charge and discharge cycles, which could eventually impact the structural complexity and electrochemical operations in the battery pack. To address this situation, a median expectation-based regression approach is proposed for parameter estimation of vehicle batteries in V2G systems. The proposed method is built on the property of uncertainty prediction of Gaussian processes for parameter estimation while considering the cell variations as an exogenous function. First, a median expectation-based Gaussian process model is derived to predict the fused and individual cell variations of a battery pack. Second, a magnitude-squared coherence model is developed by the error matrix to detect and isolate each variation. This is obtained by extracting the cross-spectral densities for the measurements. The proposed regression-based approach is evaluated using experimental measurements collected from lithium-ion battery pack in EVs. The parametric analysis of the battery pack has been verified using D-SAT Chroma 8000ATS hardware platform. Performance evaluation shows an accurate estimation of these dynamics even in the presence of injected faults. [ABSTRACT FROM AUTHOR]

The complexity of an interconnected power system has grown exponentially with the increased load demands. These demands and stress conditions are the potential nodes in coupled system to challenge the control and stability of a multi-operational power system. Once these potential nodes are exploited, this could lead to developing stringent conditions and generation of power system oscillations which are required by the grid codes to be damped and controlled adequately. A poorly damped set of power oscillations may lead to system-wide breakups or considerably reduce the power transfer over critical channels and corridors. In recent years, a compelling need has arisen to understand the oscillation damping in the conventional and modern power grids for better performance management, control, and stability in power transfer. In this paper, a bibliographic review on the damping of power system oscillations is provided. The study identifies various control design techniques, technologies, and characteristics used in power systems. Moreover, it discusses various devices and tools to minimize damping during the era of conventional grids and renewable energy integration. The methodology of different approaches and their likely combination are discussed for different types of control design. This study also represents useful information for readers on the complete life-cycle and development phase of technology to minimize the instability variations in generating units, transmission lines, transformers, loads, and HVDC lines. A comprehensive list of publications to date in the open literature is compiled to portray a complete visual of different developments in this area. • Unstable power oscillations result in blackouts and reduced interarea power transfers. • Compel the need to understand oscillation dynamics and damping control in renewable rich grids. • Overview of analysis and control techniques, infrastructure and systems characteristics hitherto. • Classification of past and emerging oscillation frameworks from the perspective of smart grids. • Highlighting technology life cycle and development/deployment phases to minimize instability risk. • Comprehensive list of publications for a visual scenery of hitherto developments in this field. [ABSTRACT FROM AUTHOR]

The generation of the mix-based expansion of modern power grids has urged the utilization of digital infrastructures. The introduction of Substation Automation Systems (SAS), advanced networks and communication technologies have drastically increased the complexity of the power system, which could prone the entire power network to hackers. The exploitation of the cyber security vulnerabilities by an attacker may result in devastating consequences and can leave millions of people in severe power outage. To resolve this issue, this paper presents a network model developed in OPNET that has been subjected to various Denial of Service (DoS) attacks to demonstrate cyber security aspect of an international electrotechnical commission (IEC) 61850 based digital substations. The attack scenarios have exhibited significant increases in the system delay and the prevention of messages, i.e., Generic Object-Oriented Substation Events (GOOSE) and Sampled Measured Values (SMV), from being transmitted within an acceptable time frame. In addition to that, it may cause malfunction of the devices such as unresponsiveness of Intelligent Electronic Devices (IEDs), which could eventually lead to catastrophic scenarios, especially under different fault conditions. The simulation results of this work focus on the DoS attack made on SAS. A detailed set of rigorous case studies have been conducted to demonstrate the effects of these attacks. [ABSTRACT FROM AUTHOR]