Better reliability of power supply is assured with the inculcation of distributed generators (DGs) in a distribution network. Smart sensors and latest grid communication protocols have played a ...crucial role in the development of intelligent microgrids (MGs). Conventional protection schemes do not provide reliable performance when implemented in MGs. This article proposes an approach which requires root mean square value of one cycle three -phase voltage and current measurements during fault. These data are treated as inputs for developing a fault isolation and locator module. This module is supposed to be available at central protection system, and is designed using machine learning (ML) based techniques viz. Gaussian process regression for fault location prediction and support vector machine for fault identification. Effectiveness of the proposed methodology is evaluated by considering practical grid scenarios with load variation and different DG penetration level. Furthermore, the robustness of the proposed model is assessed by performing sensitivity analysis with consideration of variation in line parameters and load as well as effect of DG correlation. A 7-bus meshed ac MG test system consisting of three DGs and two grid sources is modeled in SIMULINK platform, and is used to demonstrate the proposed module. Data analytics tools of MATLAB 2020a has been explored to develop an ML-based fault isolation and location module for MGs. The proposed scheme has also been validated with real-time MG data obtained from OPAL Real time (OPAL-RT) real-time simulator OP-4510. The accuracy in predicted results proves that the proposed scheme is pertinent for real-time practical applications.
•The summation of the accumulated difference of residual voltage is used for discriminating HIF from any other no-fault events.•DWT analysis is used to compute the wavelet features.•The wavelet ...features are fed to the decision tree to classify the fault event and the faulty zone.•The proposed method is also validated for unbalanced loading, varying the DG parameter and distribution line length, and the addition of noise.•The performance indicators such as accuracy, precision, recall, F-measure of the method are compared with other classifiers like SVM, KNN, and ensemble classifiers.
Conventional overcurrent protective relay is unable to detect high impedance faults (HIFs) in the micro-grid system owing to the reduced levels of fault magnitude. In this paper, numerous fault detection methods are discussed for developing a technique to identify HIFs, and also three steps approach of summation of accumulated difference of residual voltage, discrete wavelet transform (DWT), and decision tree(DT) approach has been used to detect and classify the fault. It also differentiates the faulty events from the various non-faulty ones such as switching of generators, capacitors, loads, etc. The residual voltage is used for the extraction of wavelet coefficients by DWT and fed to a DT classifier for fault event classification and confusion matrix created to view the accuracy. After classification, the predicted fault and the actual fault are obtained subsequently by training the data is 99.5% true positive rate and 0.5% false-negative rate. Similarly, this approach is also applied for faulty zone and non-faulty zone classification. The accuracy of the technique is analyzed with other classifiers like support vector machine(SVM), k-nearest neighbor(KNN), and ensemble classifiers. The DT classifier yields more accurate results compared to other classifiers. The proposed method performance is further evaluated by taking different performance indicators such as precision, recall, and F-measure. The proposed technique gives an overall accuracy of 99.95%, precision index of 100%, recall index of 99.9%, and F-measure index of 99.94% as compared to other classifiers under normal operation. The proposed method is also validated with unbalanced loading, varying DG parameters, varying distribution line length, and the addition of noise in the signal. To implement and demonstrate this method, a 5 bus micro-grid system integrated with a wind turbine-based system(WTS) generator is simulated using Power System Computer-Aided Design (PSCAD) software.
This letter presents a novel non-iterative impedance based two-terminal fault location algorithm with unsynchronized terminals. The novelty of this method lies in the fact that it is non-iterative, ...does not require signal alignment, are independent of fault classification, suitable for both transposed and untransposed lines with distributed line model. Several results of simulations on standard and practical data of Power Grid Corporation of India Limited (PGCIL) are presented. The test results verifies the validity and accuracy of the developed fault location algorithm.
Damping of low-frequency oscillations (LFOs) has become a critical challenge in modern power system. Since interarea LFO modes are associated with power oscillation, therefore, proper modulation of ...power through energy capacitor system (ECS) can be a competent way to conserve system stability. In this article, modeling of grid-connected ECS unit is explained thoroughly. Further to provide adequate damping to critical LFO modes, a linear quadratic Gaussian (LQG) based optimal <inline-formula><tex-math notation="LaTeX"> H_{2}</tex-math></inline-formula> wide-area damping controller (WADC) is proposed for ECS integrated power grid. The parameters of the proposed WADC are tuned by accelerated particle swarm optimization (APSO) technique. Furthermore, to select the proper wide-area signals for controller design, geometric approach is adopted. The efficacy of proposed methodology has been tested on large power systems containing multiple interarea modes viz. 10-machine, 39-bus system and 16-machine, 68-bus system. Simulation studies demonstrated the capability of proposed WADC to adequately damp the multiple interarea modes simultaneously. Moreover, it also provides robust performance for operating point uncertainties (load variation, permanent outage of transmission lines, etc.) and variable time delays in feedback signals.
This article presents the impact of demand response (DR) on an identical restructured two-area power system considering communication latency. DR is emerging as a leading approachforthe future ...electric power system, ameliorating thesystem reliability and frequency stability. Each test area comprises a solar photovoltaic, wind turbine, bio-gas unit, traditional thermal power plant, and an asset of electric vehicles. In this article, a hybrid hierarchical DR control mechanism is developed by incorporating the inherent communication latency in the loop. The stability of the investigated system with and without DR is compared in terms of stability margin to illustrate the significance of DR on system stability. The quasi-oppositional Harris Hawks optimization technique is used to optimize the coefficients of the proposed hybrid two degree of freedom (proportional-integral-derivative) linear active disturbance rejection control (TDOF-LADRC). The proposed controller's efficacy in terms of system dynamics is contrasted with LADRC in order to examine its adequacy for the studied power system. Moreover, the practical feasibility of the proposed technique is demonstrated through experimental validation utilizing OPAL-RT-based real-time simulation followed with analysis.
Wide area monitoring, protection, and control has now become an essential infrastructure to run an interconnected power system. To accomplish this by using synchrophasor technology, a wide range of ...phasor measurement unit (PMU) designs are available in the literature, but most of them are very costly because of the requirement of a high-speed processor to run complex algorithms. In this article, an algorithm for the synchrophasor and frequency estimation is proposed for processing platforms with low computational resources and is delineated extensively in respect of both accuracy and processing time. The proposed solution harnesses the main advantages of two well-known algorithms, viz. the zero-crossing detection and nonlinear least-squares method. Both algorithms are incorporated in a computationally efficient manner to reduce the processing time up to a lower extent while maintaining a good accuracy as per the standard IEEE testing conditions. The performance of the proposed algorithm has been evaluated through simulations as well as experimentally on the Raspberry Pi board. The consistency of the test results and minimum processing time provides clear evidence that the implemented design is suitable for PMU prototyping and is compliant with the mandatory IEEE standard C37.118.1-2011 and its amendment IEEE C37.118.1a-2014.
This letter presents a parameter-free fault location algorithm on a two-terminal double-circuit transposed line with unsynchronized terminals. The presented algorithm is formulated using ...positive-sequence components of measurands at both terminals. The salient features of the proposed method are that it is non-iterative and does not require pre-fault data. Also, it considers distributed parameter model of a line unlike existing techniques, which adopt lumped model of a line. Simulation results using EMTP-RV platform alongside the results with field data of Power Grid Corporation of India Limited (PGCIL) are presented. The test results established the validity and accuracy of the proposed algorithm.
This letter presents a novel fault location algorithm for single circuit untransposed line, which is independent of transmission line parameters and unsynchronized measurement. The novelty of ...proposed algorithm is that it considers asymmetry in untransposed line while considering unequal angles of synchronism mismatch in pre-fault and fault conditions. Thus, in contrast to existing techniques the proposed algorithm can be applied to conductor configuration other than delta/flat configuration of untransposed line. Simulation results using EMTP-RV platform along with those obtained using field data are presented. The test results verify the accuracy and validity of the proposed method.
This paper presents an impedance-based non-iterative fault location algorithm for a two-terminal line considering unsynchronized measurements to account for the loss of Global Positioning System ...(GPS) signal. Based on the availability of pre-fault signals two algorithms are proposed, one using pre-fault data and the other without using pre-fault data. The algorithms are formulated by using fundamental frequency phasor based decoupled modal components of the measured signals at both ends of the line while considering distributed line model. Application of decoupled modal components with distributed model enhances the accuracy of the presented algorithms in both transposed and untransposed configuration of the line. The proposed algorithms have been tested and analyzed with different fault conditions simulated in EMTP-RV platform. Comparative analysis with existing methods is also presented to establish prominent features of the proposed methods. The algorithms have also been tested with practical data of Power Grid Corporation of India Limited (PGCIL) and the test result validates the accuracy of the developed fault location algorithms.
