Real Time Hardware-in-the-Loop (RT-HIL) performance assessment of three different passive islanding detection methods for both local and wide-area synchrophasor measurements is carried out in this ...article. Islanding detection algorithms are deployed within the Phasor Measurement Unit (PMU) using logic equations. Tripping decisions are based on local and wide-area synchrophasors as computed by the PMU and trips are generated using IEC 61850-8-1 Generic Object Oriented Substation Event (GOOSE) messages. The performance assessment compares these islanding detection schemes for Non Detection Zone and operation speed under different operating conditions. The test-bench demonstrated is useful for a myriad of applications in which simulation exercises in power system CAD software provides no realistic insight into the practical design and implementation challenges. Finally different communication latencies introduced due to the utilization of synchrophasors and IEC 61850-8-1 GOOSE messages are determined.
This paper presents the software implementation of a Phasor Measurement Unit (PMU) data-based mode estimation application in a decentralized mode estimation architecture. This work builds from ...previous efforts in the development of a mode estimator implemented using a centralized architecture, meaning a set of modes were estimated for the whole system in a single processing location. One drawback of mode estimators that use centralized mode architecture is that the observability and therefore estimation of important low-damped local electromechanical modes can be affected by the higher observability of other dominant modes of the systems (e.g inter-area modes). This work proposes, implements and tests a decentralized architecture in order to increase the observation capability to provide better estimates of local low damped oscillations. In this architecture, the data from a single PMU or a group of local PMUs could be processed by a processor to estimate the modal parameters observed at a specific part of the grid or observed by specific group of PMUs. The decentralized architecture and results of tests are presented in this paper together with comparison with a centralized architecture.
Wide-area early warning systems are dependent on synchrophasor data-based applications for providing timely information to operators so that preventive actions can be taken. This article proposes the ...use of voltage sensitivities computed from syncrhophasor data for voltage stability monitoring, and a visualization approach that can be implemented in wide-area early warning systems. In order to provide reliable information, synchrophasor data must be pre-processed to extract only the useful features embedded in measurements and correct for errors. Hence, this article also addresses the issue of data filtering and correction, and proposes a filtering methodology for robust voltage sensitivity computation. The methodology is developed considering both positive-sequence simulations for methodology development purposes, and real phasor measurement data from a real-time (RT) hardware-in-the-loop (HIL) laboratory for testing the robustness of the developed approach for use in the control room. The results from both approaches are contrasted against each other, the limitations of the positive-sequence simulation approach for developing PMU-data applications are highlighted and the challenges of working with the RT HIL lab are recognized.
This article presents a software development toolkit for Wide Area Monitoring Systems. By using this development toolkit, a researcher is able to manipulate synchrophasor data in the LabView ...environment, which enables fast software prototyping and testing. This toolkit makes full scale testing in real-time easier for researchers, liberating them of complex and time consuming synchrophasor data handling. The toolkit exploits the IEEE C37.118.2-2011 protocol making it independent of any specific equipment and their manufacturers. An application of the development kit is demonstrated in a laboratory environment with a specially designed experimental setup composed of a real-time digital simulator and four phasor measurement units (PMUs).
This article provides an overview of a monitoring application, its testing and validation process. The application was developed for the detection of sub-synchronous oscillations in power systems, ...utilizing real-time measurements from phasor measurement units (PMUs). It uses two algorithms simultaneously to both detect the frequency at which the oscillatory event occurs and the level of energy in the oscillations. The application has been developed and tested in the framework of SmarTS Lab, an environment capable of hardware-in-the-loop (HIL) simulation. The necessary components of the real-time chain of data acquisition are presented in this paper, as well as testing and validation results, to demonstrate the accuracy of the monitoring tool and the feasibility of fast prototyping for real-time PMU measurements based applications using the SmarTS Lab environment.
Real-time hardware-in-the-loop performance assessment of three different passive islanding detection methods for local and wide-area synchrophasor measurements is carried out in this paper. Islanding ...detection algorithms are deployed within the phasor measurement unit (PMU) using logic equations. Tripping decisions are based on local and wide-area synchrophasors as computed by the PMU, and trips are generated using IEC 61850-8-1 generic object-oriented substation event messages. The performance assessment compares these islanding detection schemes for the nondetection zone and operation speed under different operating conditions. The testbench that is demonstrated is useful for a myriad of applications where simulation exercises in power system computer-aided design software provide no realistic insight into the practical design and implementation challenges. Finally, different communication latencies introduced due to the utilization of synchrophasors and IEC 61850-8-1 GOOSE messages are determined.
This paper experimentally assesses the impact of time synchronization spoofing attacks (TSSA) on synchrophasor-based wide-area monitoring, protection and control (WAMPAC) applications. Phase angle ...monitoring, anti-islanding protection, and power oscillation damping applications are investigated. TSSA are created using a real-time (RT) IRIG-B signal generator and power system models are executed using an RT simulator with commercial phasor measurement units (PMUs) coupled to them as hardware-in-the-loop. Because PMUs utilize time synchronization signals to compute synchrophasors, an error in the PMUs' time input introduces a proportional phase error in the voltage or current phase measurements provided by the PMU. The experiments conclude that a phase angle monitoring application will show erroneous power transfers, whereas the anti-islanding protection mal-operates and the damping controller introduces negative damping in the system as a result of the time synchronization error incurred in the PMUs due to TSSA. The proposed test-bench and TSSA approach can be used to investigate the impact of TSSA on any WAMPAC application and to determine the time synchronization error threshold that can be tolerated by these WAMPAC applications.
Wide-area damping controller (WADC) utilizing synchrophasor measurements to generate damping signals which are fed directly to the commercial Excitation Control System (ECS) to provide oscillation ...damping.
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•Wide-area damping controller (WADC) prototype and its interface with commercial Excitation Control System.•Synchrophasor communication latency compensation.•Remote tuning of damping parameters.•Modular and scalable architecture.
A supplementary function of Excitation Control Systems (ECSs) for synchronous generators is that of a Power System Stabilizer (PSS). The PSS implementation in these ECSs only allows the use of a limited type of pre-defined local input measurements and built-in PSS algorithms. To adapt existing ECSs to take advantage of synchrophasors technology, this paper proposes and implements a prototype wide-area damping controller (WADC) that provides synchrophasor-based damping input signals to existing ECSs. The developed WADC comprise (i) a real-time mode estimation module, (ii) synchrophasor’s communication latency computation module, and (iii) phasor-based oscillation damping algorithm executing in a real-time hardware prototype controller.
Through Real-Time Hardware-in-the-Loop (RT-HIL) simulations, it is demonstrated that synchrophasor-based damping signals from the WADC can be utilized together with a commercial ECS, thus providing new options for selection of the best feedback signal for oscillation damping.
Phytochemical studies on the root of Abrus precatorius Linn. (Fabaceae), leads towards the identification of four undescribed (abruquinones M, N, O, and P), and seven known abruquinones, ...(abruquinones A, E, B, F, I, D, and G). Spectroscopic analyses (1D, and 2D NMR, HRESI-MS) were used in elucidating structures of the all compounds. Evaluation of anticancer activities of the isolated isoflavanquinones revealed that abruquinones M, and N showed cytotoxicity against oral CAL-27 (IC50 values 6.48 and 5.26 μM, respectively), and colon (Caco-2) cell lines (IC50 values 15.79 and 10.33 μM, respectively). Abruquinone M also inhibited the growth of lung cancer cells (NCI–H460) with IC50 of 31.33 μM. The isolated isoflavanquiones also showed potent anti-inflammatory potential through phagocyte oxidative burst and pro-inflammatory cytokine TNF-α inhibition in vitro. These findings suggest isoflavanquinones from A. precatorius roots as candidates for further research in cancer treatment.
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•Four unreported isoflavanquinones (1–4) were isolated from the roots of Abrus precatorius.•Compounds 1, 2, 5, and 7 exhibited cytotoxicity against CAL-27, CaCO2, NCI-H460 cancer cells.•The compounds displayed potent TNF- α inhibition and other anti-inflammatory activities.
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