Faculty Publications

Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736

Publications by NITK Faculty

Browse

Has files: NoSubject: search.filters.subject.DVR

Search Results

Now showing 1 - 6 of 6
  • No Thumbnail Available
    Item
    DSC filter based unit vector estimator for reference generation and control of dynamic voltage restorer
    (Institute of Electrical and Electronics Engineers Inc., 2017) Kasyap, M.S.; Karthikeyan, A.; Venkatesa Perumal, B.V.; Nagamani, C.
    DVR control requires a robust algorithm for computing grid voltage magnitude and phase angle. Conventional SRF-PLL performs poorly as it cannot filter out negative sequence voltages and harmonics that could occur in the grid voltage. In this paper a Positive and Negative Sequence Extractor (PNSE) is formed by a Delayed Signal Cancellation (DSC) filter, which filters harmonics and extracts Instantaneous Symmetrical Components (ISC) of the source voltage in stationary reference frame. The phase angle information of the grid voltage is derived by computing the unit vectors of the ISC in stationary frame. This eliminates the need for a conventional PLL and thus simplifies the reference generation algorithm. A PI controller tracks the capacitor reference voltage in synchronous reference frame to restore the fundamental load voltage while resonant controllers are tuned to mitigate the lower order odd harmonics in the load voltage. Simulation studies carried out in PSCAD/EMTDC for a Medium Voltage DVR model shows that the presented control works effectively for all the test cases considered such as voltage sags and harmonics. © 2016 IEEE.
  • No Thumbnail Available
    Item
    Phase advance compensation of voltage sags using full bridge inverter based DVR
    (Institute of Electrical and Electronics Engineers Inc., 2018) Remya, V.K.; Parthiban, P.; Nandakumar, A.
    Voltage sag is considered as the most expensive power quality problem. With the advent of power electronics, custom power devices are introduced to mitigate the sag issues. Among the custom power devices, Dynamic Voltage Restorer (DVR) is the most cost-effective one. The voltage injected in series by the DVR compensates the load profile during sag events. The compensation techniques such as in-phase, energy minimized and phase advance methods determine the way in which the DVR voltage is injected into the grid. By providing a phase advance to the DVR voltage with respect to the supply voltage gives the merit of reduced active power injection and thereby reduces the rating of energy storage. The disadvantages such as increased DVR voltage magnitude, phase shift, load swings and discontinuity of wave shape are associated with this compensation technique. This method is suitable for magnitude sensitive loads. This paper presents simulation results showing the compensation of both sag and swell using phase advance compensation. © 2017 IEEE.
  • No Thumbnail Available
    Item
    Design and Analysis of Multi-Loop Feed Forward Control Schemes for DVR under Distorted Grid Conditions
    (Institute of Electrical and Electronics Engineers Inc., 2018) Karthikeyan, A.; Abhilash Krishna, D.G.A.; Kumar, S.; Nagamani, C.
    Voltage sags are considered as important power quality problems and the Dynamic Voltage Restorer(DVR) is an effective solution to mitigate the sags and other power quality problems related to voltage. The DVR involves two major aspects: (i) reference generation and (ii) control algorithm. Under unbalanced grid conditions the presence of negative sequence components in the grid voltage causes sustained oscillations in the estimated dq- voltages, which makes sag detection difficult with conventional SRF-PLL and there by chances of controller malfunctioning. In this paper, a Delayed Signal Cancellation (DSC) pre-filter based Positive and Negative Sequence Extractor (PNSE) is employed to extract the Instantaneous Symmetrical Components (ISC) of the grid voltage and filter out the harmonic voltages from the estimated dq-voltages. As the response of the DVR mainly depends on the controller action this paper presents an multiloop PI feed forward controller for enhancing the operation of DVR under distorted grid conditions. The efficacy of the proposed controller is illustrated by comparative study with multiloop feed forward P controller using time response and relative stability analysis. Simulation studies are performed in PSCAD/EMTDC for a 10kV medium voltage DVR under various voltage disturbances such as symmetric and asymmetric voltage sags. © 2017 IEEE.
  • No Thumbnail Available
    Item
    A comparative study of full-bridge inverter based DVR and SEMI-Z-source inverter based DVR
    (Institute of Electrical and Electronics Engineers Inc., 2018) Remya, V.K.; Parthiban, P.; Nandakumar, A.
    There is always a necessity to protect the voltage sensitive industrial systems from Power Quality (PQ) issues to prevent the loss of product quality and revenue. Generally, custom power devices take the responsibility to mitigate these PQ problems, restore the voltage and thus maintain the PQ standards. Dynamic Voltage Restorer (DVR) is one among the custom power devices which offers an economical compensation of load voltage under abnormal supply voltage conditions. The voltage injected in series by the DVR compensates the load profile during PQ events; appropriate voltage injected by the DVR in series with supply protects the load and restores the voltage to pre-defined values. The required injected voltage is generated by the inverter circuit in the DVR system. The most commonly used DVR inverter is the full-bridge inverter which consists of four switches. The Semi-Z-Source (SZS) inverter based DVR which offers same injection capability with only two-switches is compared with the full-bridge inverter. The in-phase compensation technique is employed in both the DVRs for injecting required voltage into the grid. The efficiency, quality of the injected voltage and load voltage are studied. This paper presents simulation results in MATLAB/Simulink environment to validate thecomparison. © 2018 IEEE.
  • No Thumbnail Available
    Item
    Dynamic voltage restorer (DVR) –areview
    (River Publishers editor@jgenng.com, 2018) Remya, V.K.; Parthiban, P.; Ansal, V.; Babu, B.
    Power quality (PQ) is gaining a great deal of importance as more sensitive loads are introduced into the utility grid. The degradation of product quality, damage of equipment and temporary shutdowns are the general issues associated with PQ problems in industries. Any mal-operation or damage of the industrial sensitive loads results in monetary losses disproportionately higher than the severity of the PQ issues. The evolution of power electronics technology replaced the traditional power quality mitigation methods with the introduction of Custom Power System devices (CUPS). The major power electronic controller based CUPS are DSTATCOM, DVR and UPQC. DVR is a pertinent solution for the economic losses caused by the PQ issues in the industries. Among the CUPS, DVR is the most cost-effective one. In the published literature, only a few papers correspond to the review of DVR technology. In this paper, a systematic review of published literature is conducted and a description is given on the design, standards and challenges in the DVR technology. A detailed survey is conducted on the published literature to address the various aspects and issues in the DVR system. This paper arrangement gives the working principle, structure, various topologies, compensation techniques, voltage sag detection methods and control methods of the DVR under different sections. The section “Challenges faced by the DVR” included in the manuscript can be useful for the researchers beginning their work in the domain of DVR. The simulation results using the sim power system tool of MATLAB/Simulink software are provided for analysis and comparison. © 2018 the Author(s). All rights reserved.
  • No Thumbnail Available
    Item
    Single-Phase DVR with Semi-Z-Source Inverter for Power Distribution Network
    (Springer Verlag, 2018) Remya, V.K.; Parthiban, P.; Ansal, V.; Nandakumar, A.
    A novel topology of single-phase dynamic voltage restorer (DVR) is proposed to compensate the load voltage during voltage sag and voltage swell events. The semi-Z-source converter is utilised in its inverter operating mode for this proposed topology. The reduction in the number of active switches in the inverter and also in the current conduction path without compromising the output voltage range is the merit of the semi-Z-source inverter-based DVR against the commonly used full-bridge inverter-based DVR. The load voltage contains harmonics within the permissible limits when the compensation is performed by the semi-Z-source inverter-based DVR. The need for the filter circuit is eliminated; hence, the magnitude difference and the phase shift in the inverter output voltage due to the filter circuit are not present in the semi-Z-source inverter-based DVR. The proposed topology is cheap compared to the full-bridge inverter-based DVR topology. The simulations performed in MATLAB/Simulink environment are presented to validate the performance of the proposed topology. A comparison between the semi-Z-source inverter-based DVR and full-bridge inverter-based DVR is presented in this paper. The novel topology of DVR using semi-Z-source inverter is proved to be a better solution to the full-bridge inverter-based DVR. © 2017, King Fahd University of Petroleum & Minerals.