arXiv subjects

Ashu Verma

Publications and source records attributed to Ashu Verma.

10 recordsLinked to original sources

arXiv2023

DeeBBAA: A benchmark Deep Black Box Adversarial Attack against Cyber-Physical Power Systems

An increased energy demand, and environmental pressure to accommodate higher levels of renewable energy and flexible loads like electric vehicles have led to numerous smart transformations in the modern power systems. These transformations make the cyber-physical power system highly susceptible to cyber-adversaries targeting its numerous operations. In this work, a novel black box adversarial attack strategy is proposed targeting the AC state estimation operation of an unknown power system using historical data. Specifically, false data is injected into the measurements obtained from a small subset of the power system components which leads to significant deviations in the state estimates. Experiments carried out on the IEEE 39 bus and 118 bus test systems make it evident that the proposed strategy, called DeeBBAA, can evade numerous conventional and state-of-the-art attack detection mechanisms with very high probability.

cs.CR↗

arXiv2022

DOBC-Based Frequency & Voltage Regulation Strategy for PV-Diesel Hybrid Microgrid During Islanding Conditions

This paper proposes a disturbance observer-based control (DOBC) method for frequency and voltage regulation of a solar photovoltaic (PV)-diesel generator(DG) based hybrid microgrid during islanding conditions. The DOBC is integrated as a feed-forward control to the synchronous generator based DG, which handles real-time power mismatches and regulates the microgrid frequency and voltage under islanding. To substantiate the operational robustness of the developed controller under real-time uncertainties arising due to variability in PV output and load, the controller has been tested under worstcase uncertainty conditions. The proposed controller has been developed as a MATLAB/Simulink model and the results are validated on the real-time simulator OPAL-RT. The effectiveness of the proposed control scheme has further been validated in the presence of communication delays and noisy load conditions. Results verify the dynamic performance of the controller in regulating the system frequency and voltage for low-inertia microgrids. Finally, the proposed control strategy has been implemented on laboratory scale microgrid setup in which synchronous generator based diesel generator regulates system frequency fast and efficiently under worst case uncertainty scenario.

eess.SY↗

arXiv2022

Disturbance Observer Based Frequency & Voltage Regulation for RES Integrated Uncertain Power Systems

This paper proposes a disturbance-observer-based control (DOBC) scheme for frequency and voltage regulation for a renewable energy sources (RES) integrated power systems. The proposed approach acts a feed-forward control which improves the dynamic performance of the conventional proportional-integral-derivative (PID) controller. Robustness of the proposed control scheme has been validated through simulations under worst-case and stochastic uncertainties to mitigate real-time variability in RES output and load. The performance of the proposed control technique is compared to well established technique in presence of communication delay and white noise.

eess.SY↗

arXiv2022

A Multi-Head Convolutional Neural Network Based Non-Intrusive Load Monitoring Algorithm Under Dynamic Grid Voltage Conditions

In recent times, non-intrusive load monitoring (NILM) has emerged as an important tool for distribution-level energy management systems owing to its potential for energy conservation and management. However, load monitoring in smart building environments is challenging due to high variability of real-time load and varied load composition. Furthermore, as the volume and dimensionality of smart meters data increases, accuracy and computational time are key concerning factors. In view of these challenges, this paper proposes an improved NILM technique using multi-head (Mh-Net) convolutional neural network (CNN) under dynamic grid voltage conditions. An attention layer is introduced into the proposed CNN model, which helps in improving estimation accuracy of appliance power consumption. The performance of the developed model has been verified on an experimental laboratory setup for multiple appliance sets with varied power consumption levels, under dynamic grid voltages. Moreover, the effectiveness of the proposed model has been verified on widely used UK-DALE data, and its performance has been compared with existing NILM techniques. Results depict that the proposed model accurately identifies appliances, power consumptions and their time-of-use even during practical dynamic grid voltage conditions.

eess.SY↗

arXiv2021

Estimating State of Charge for xEV batteries using 1D Convolutional Neural Networks and Transfer Learning

In this paper we propose a one-dimensional convolutional neural network (CNN)-based state of charge estimation algorithm for electric vehicles. The CNN is trained using two publicly available battery datasets. The influence of different types of noises on the estimation capabilities of the CNN model has been studied. Moreover, a transfer learning mechanism is proposed in order to make the developed algorithm generalize better and estimate with an acceptable accuracy when a battery with different chemical characteristics than the one used for training the model, is used. It has been observed that using transfer learning, the model can learn sufficiently well with significantly less amount of battery data. The proposed method fares well in terms of estimation accuracy, learning speed and generalization capability.

eess.SP↗

arXiv2019

Efficient Multi-Year Security Constrained AC Transmission Network Expansion Planning

Solution of multi-year, dynamic AC Transmission network expansion planning (TNEP) problem is gradually taking center stage of planning research owing to its potential accuracy. However, computational burden for a security constrained AC TNEP is huge compared to that with DC TNEP. For a dynamic, security constrained AC TNEP problem, the computational burden becomes so very excessive that solution for even moderately sized systems becomes almost impossible. Hence, this paper presents an efficient, four-stage solution methodology for multi-year, network N-1 contingency and voltage stability constrained, dynamic ACTNEP problems. Several intelligent logical strategies are developed and applied to reduce the computational burden of optimization algorithms. The proposed methodology is applied to Garver 6, IEEE 24 and 118 bus systems to demonstrate its efficiency and ability to solve TNEP for varying system sizes.

eess.SY↗

arXiv2019

A New Efficient Methodology for AC Transmission Network Expansion Planning in The Presence of Uncertainties

Consideration of generation, load and network uncertainties in modern transmission network expansion planning (TNEP) is gaining interest due to large-scale integration of renewable energy sources with the existing grid. However, it is a formidable task when iterative AC formulation is used. Computational burden for solving the usual ACTNEP with these uncertainties is such that, it is almost impossible to obtain a solution even for a medium-sized system within a viable time frame. In this work, a two-stage solution methodology is proposed to obtain quick, good-quality, sub-optimal solutions with reasonable computational burden. Probabilistic formulation is used to account for the different uncertainties. Probabilistic TNEP is solved by 2m+1-point estimate method along with a modified artificial bee colony (MABC) algorithm, for Garver 6 bus and IEEE 24 bus systems. In both the systems, rated wind generation is considered to be more than one-tenth of the total generation capacity. When compared with the conventional single stage and existing solution methods, the proposed methodology is able to obtain almost identical solutions with extremely low computational burdens. Therefore, the proposed method provides a tool for efficient solution of future probabilistic ACTNEP problems with greater level of complexity.

math.OC↗

arXiv2018

Security Constrained AC Transmission Network Expansion Planning

Modern transmission network expansion planning (TNEP) is carried out with AC network model, which is able to handle voltage and voltage stability constraints. However, such a model requires optimization with iterative AC power flow model, which is computationally so demanding that most of the researchers have ignored the vital (N-1) security constraints. Therefore, the objective of this research work is to develop an efficient, two stage optimization strategy for solving this problem. In the first stage, a DC expansion planning problem is solved which provides an initial guess as well as some very good heuristics to reduce the number of power flow solutions for the second stage of AC transmission and reactive expansion planning. A modified artificial bee colony (MABC) algorithm is used to solve the resulting optimization problem. Static AC TNEP results for Garver 6 bus, IEEE 24 bus and IEEE 118 bus test systems have been obtained with the proposed and rigorous approaches and wherever possible, compared with similar results reported in literature to demonstrate the benefits of the proposed method. Also, multi-stage dynamic AC TNEP for the Garver 6 bus system is solved to show the applicability of the methodology to such problems.

math.OC↗

arXiv2018

Computationally Efficient Day-Ahead OPF using Post-Optimal Analysis with Renewable and Load Uncertainties

This paper presents a method to handle renewable source and load uncertainties in Dynamic Day-ahead Optimal Power Flow (DA-OPF) using post-optimal analysis of linear programming problem. The method does not require the uncertainty distribution information to handle it. A new Participation Factor (PF) to distribute changes caused by uncertainty has been developed based on the current optimal basis. The proposed PF takes care of all the constraints and ensures optimality with uncertain renewable generation and load using Sensitivity Analysis (SA) and Individual Tolerance Ranges (ITR) for individual and multiple simultaneous changes respectively. For quantification of confidence level, standard density distribution of solar power output and load is used. The test results on IEEE 30-Bus establishes the applicability of the proposed method for handling single and multiple bus uncertainties.

math.OC↗

arXiv2018

Piecewise Linearization of Quadratic Branch Flow Limits by Irregular Polygon

This letter addresses the issue of linearization of quadratic thermal limits of transmission lines for linear OPF formulation. A new irregular polygon based linearization is proposed. The approach is purely based on geometrical concepts and does not introduce any optimization problem. Comparison of the number of constraints is given with different errors for different branch capabilities and systems. Test case analysis is also presented to validate the irregular polygon linearization strategy with optimal value and computational time results.

math.OC↗