Articles
Electric Power Systems Research (03787796)
Today, the expansion utilization of telecommunication systems results in the power systems having a physical-cyber structure. Despite the advantages of this structure, one of the main challenges is the impact of cyber on physical and vice versa. This study focuses on False Data Injection (FDI) attacks, where the attacker's aim is to overload a transmission line, leading to load shedding. It is proven that the attacker can bypass Bad Data Detection (BDD) module in DC state estimation (DC-SE) by considering both voltage phase angle and magnitude, even when they only know network parameters and can only inject false data in local area. The proposed method is formulated as a bi-level max-min optimization problem where the load shedding is maximized and minimized from the attacker's and operator's perspectives, respectively. To demonstrate the effectiveness of the proposed method, simulations are carried out on IEEE 39 Bus New England System using DIgSILENT PowerFactory 2021 SP2. © 2024 Elsevier B.V.
Haghighat, M.,
Tafti, H.D.,
Gholipour shahraki, M.,
Niroomand, M.,
Townsend, C.D.,
Barajas, N.V.,
Liang, G.,
Konstantinou, G.,
Pou, J. IEEE Access (21693536)12pp. 168568-168580
Grid-connected photovoltaic (PV) systems enhance grid stability during frequency fluctuations by adopting power reserve control (PRC) and contributing to frequency regulation. The cascaded H-bridge (CHB) converter is a suitable choice for large-scale photovoltaic systems. This paper introduces a distributed PRC strategy designed for CHB-based PV systems, necessitating minimal inter-module communication and thus simplifying implementation. Each submodule (SM) within the CHB converter periodically engages in maximum power point tracking to assess the system’s total accessible PV power. Through coordinated control, the strategy evenly allocates the necessary power across sub-modules based on their PV power availability, offering a balanced power distribution while acknowledging operational constraints on power disparity among SMs. Simulation and experimental results confirm the efficiency of the proposed approach under various conditions, showcasing accurate PV power estimation, seamless transition between operating modes, fast dynamic response, and regulation of the dc-link voltages. © 2013 IEEE.
IET Generation, Transmission and Distribution (17518687)18(19)pp. 3097-3107
The increasing penetration of the distributed energy resources (DER) in the power grid, which, while having significant advantages, also pose significant challenges. The behaviors of DERs differ from those of synchronous generators, particularly in abnormal conditions. For this reason, the power grid enforces grid codes to ensure that DERs perform properly in different conditions. For instance, short circuit faults and unbalanced grid voltage are severe transient events that inverters need to be able to pass through without disconnecting from the grid. Furthermore, the inverters are required to support the grid voltage by regulating the active and reactive power injections. This article proposes a voltage support control scheme to support grid voltage during asymmetrical voltage drop by utilizing an optimization problem. In this optimization problem, the active and reactive powers injected into the grid will be obtained optimally by considering constraints such as instantaneous active and reactive power oscillation magnitudes and peak current limitation. To aid in this purpose, the corresponding mathematical formulations such as instantaneous active and reactive power oscillation magnitudes will be obtained by using the currents and voltages in stationary reference frame. The proposed scheme will be verified by simulating it in MATLAB/Simulink under three different scenarios and tested on a real-time experimental Opal-RT platform. © 2024 The Author(s). IET Generation, Transmission & Distribution published by John Wiley & Sons Ltd on behalf of The Institution of Engineering and Technology.
Electric Power Systems Research (03787796)
This paper proposes a new unsynchronized parameter-free fault location scheme for transmission lines (an overhead line (OHL) combined with an underground cable (UGC)). Utilizing unsynchronized measurements at both ends, the proposed method accurately locates faults without requiring OHL and UGC parameters. Therefore, the variation of OHL and UGC parameters values do not affect its accuracy. In this method, first using distributed line model for UGC and OHL, the fault location problem is converted into a system of nonlinear equations problem according to both pre-fault and fault measurements. Then, using a novel algorithm, the system of nonlinear equations is solved. This algorithm consists of two stages which in the first one, the system of nonlinear equations is converted into an optimization problem and in the next stage, using the first stage results, the problem is solved by a modified Newton method. Simulation results performed by MATLAB, verify the high accuracy of the proposed method in determining the fault location (whether in UGC or in OHL). In these simulations, it is shown that the proposed method is independent of the fault resistance, synchronization angle, and fault type and consequently, is superior to the existing methods. Moreover, the simulation results confirm the ability and efficiency of the proposed model in estimating OHL and UGC parameters. © 2020 Elsevier B.V.
