Real Time Digital Simulator Hardware Research Articles

Исследование точности определения места повреждения воздушных линий по данным от устройств синхронизированных векторных измерений различных классов и производителей

The technology of synchronized phasor measurements has been widely used in the Russian power system to analyze the parameters of steady-state electrical power modes and to record electro-mechanical transient processes. Issues on fault location based on synchronized phasor measurements have mainly been discussed in foreign publications. A significant drawback of most research papers on this issue is simplified modeling of both overhead lines and current and voltage measurement channel as well as digital filters of phasor measurement units (PMUs). The goal of this research is to develop a fault location algorithm based on synchrophasor measurements and to study its accuracy by using specialized equipment including a real-time digital simulator (RTDS), PONOVO current and voltage amplifiers and production-grade PMUs. A PMU-based double-ended fault location algorithm is developed using long-line equations and well-known electromagnetic transient theory concepts. Currents and voltage oscillograms of both overhead transmission line ends are modelled in the MATLAB/Simulink software package. These oscillograms are saved as COMTRADE files and played back using the RTDS hardware and all-in-one software package RSCAD. In addition, the study uses two production-grade PMUs, the first one is TPA-02, and the second one is a merging unit ENMU acting as a PMU, thus imitating PMUs at the line terminals. To time-align all the measurements and to aggregate PMU data frames, various auxiliary software such as PMU Connection Tester, and hardware is used. A double-ended fault location (FL) method utilizing synchrophasors under a fault has been developed. The method is based on an overdetermined system of nonlinear equations that describes physical processes in an overhead power line and can be applied under various fault types. An integrated study of the efficiency of the developed FL method has been conducted. FL errors have been computed using production-grade PMUs ENMU and TPA-02, along with the RTDS and other equipment. The authors have considered the case of configuring PMUs of different classes at the overhead line terminals, and different phasor reporting rates as well. The conducted experiments make it possible to reveal that the fault location errors do not exceed the thresholds imposed by the standard STO 56947007-29.120.70.241-2017 in 88 % of all the analyzed fault scenarios. The developed FL method makes it possible to achieve the accuracy required by regulatory guide in calculating the distance to the short circuit point in most of the cases examined. Based on the results of numerical experiments for various types of fault cases, it can be concluded that the PMU class and phasor reporting rate do not have a significant impact on the FL accuracy, provided that the fault duration is enough for the PMU filter to approach a steady output.

Multi-Terminal DC Grid with Wind Power Injection

With the development of offshore wind generation, the interest in cross-country connections is also increasing, which requires models to study their complex static and dynamic behaviors. This paper presents the mathematical modeling of an offshore wind farm integrated into a cross-country HVDC network forming a multi-terminal high-voltage DC (MTDC) network. The voltage source converter models were added with the control of active power, reactive power, frequency, and DC link voltages at appropriate nodes in the MTDC, resembling a typical cross-country multi-terminal type of HVDC scenario. The mathematical model for the network together with the controllers were simulated in MATLABTM and experimentally verified using a real-time digital simulator hardware setup. The resulting static and dynamic responses from the hardware setup agreed well with those from simulations of the developed models.

PI and Fuzzy-Controlled 3-Phase 4-Wire Interleaved Buck Active Power Filter with Shoot-Through Elimination for Power Quality Improvement using RTDS Hardware

Abstract In this paper, shoot-through current elimination DC–AC converter circuit has been presented with the application of active power filter (APF). The intuitive analysis of the shoot-through in the conventional DC–AC converter has been reported first. Interleaved buck (IB) converter is adopted to eliminate the shoot-through current, thereby increasing the reliability of the interleaved buck–based active power filter (IB-APF). The 3-phase 4-wire IB-APF eliminates the current harmonics produced by the load just as a conventional one does and are innately immune to “shoot-through” phenomenon, with the elimination of special protection features required in conventional inverter circuits. A comparison has been made about the compensation capabilities of the IB-APF with the PI and fuzzy logic controller (FLC) used by id–iq control strategy under different supply voltage conditions. The id–iq control strategy used for extracting the three-phase reference current for IB-APF, evaluating their performance here in MATLAB/Simulink environment and also implemented using real-time digital simulator hardware (OPAL-RT hardware). The RTDS result verifies that the total harmonic distortion percentage of the source current can be reduced below 5% according to IEEE-519 standard recommendations on harmonic limits.

Real time implementation of PI and fuzzy logic controller based 3-phase 4-wire interleaved buck active power filter for mitigation of harmonics with id–iq control strategy

The “shoot-through” failure, one of the most hazardous failure modes encountered in conventional inverter circuit which is used as the main circuit of the active power filter (APF). Shoot-through phenomenon has few distinct disadvantages like; it introduces typical ringing, increases temperature rise in power switches, causes higher Electromagnetic Interference (EMI) and reduces the efficiency of the circuit. To avert the “shoot-through”, dead time control could be added but it deteriorates the harmonic compensation level. A novel 3-phase 4-wire active power filter (APF) based on interleaved buck (IB) DC-to-AC converter with the instantaneous active and reactive current component (id–iq) control strategy is proposed here to mitigate the harmonics having PI and fuzzy logic (FLC) controllers. This interleaved buck (IB) DC-to-AC converter is an augmented version of the conventional phase leg configuration and is innately immune to “shoot-through” phenomenon, with the elimination of special protection features required in conventional inverter circuits. Here in this paper, a comparison has been made between the compensation capabilities of the 3-phase IB-APF with the PI and fuzzy logic controller (FLC) used by id–iq control strategy under different supply voltage conditions. The performance of the control strategies have been evaluated in terms of harmonic mitigation and DC link voltage regulation. Extensive simulations have been carried out in the MATLAB / SIMULINK environment and also implemented using Real-Time Digital Simulator Hardware (RTDS-Hardware).

Simulation and real-time implementation of shunt active filter i d – i q control strategy for mitigation of harmonics with different fuzzy membership functions

In this research study, the shunt active filter (SHAF) is used to improve the power quality of the electrical network by mitigating the harmonics with the help of different fuzzy membership functions (M.Fs) (trapezoidal, triangular and Gaussian). It is quite difficult to optimise the performance of power system networks using conventional methods, because of the complex nature of the systems that are highly non-linear and non-stationary. Three-phase reference current waveforms generated by the proposed scheme are tracked by the three-phase voltage source converter in a hysteresis band control scheme. The performance of the proposed control strategy has been evaluated in terms of harmonic mitigation and dc-link voltage regulation under various source conditions. The proposed SHAF with different fuzzy M.Fs is able to eliminate the uncertainty in the system and SHAF gains outstanding compensation abilities. The detailed simulation results using Matlab/Simulink software are presented to support the feasibility of the proposed control strategy. To validate the proposed approach, the system is also implemented on a real-time digital simulator hardware and adequate results are reported for its verification.

Real-time implementation of PI and fuzzy logic controllers based shunt active filter control strategies for power quality improvement

Instantaneous active and reactive power (p–q) and current (Id–Iq) control strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source voltage conditions with PI and fuzzy logic controllers in MATLAB/Simulink environment and also implemented using Real-Time Digital Simulator Hardware (RTDS Hardware). When the supply voltages are balanced and sinusoidal, then all control strategies with both controllers converge to the same compensation characteristics. However, when the supply voltages are distorted and/or un-balanced sinusoidal, these control strategies result in different degrees of compensation in harmonics. The p–q control strategy unable to yield an adequate solution when source voltages are not ideal. Extensive simulations are carried out with PI as well as fuzzy logic controller for both p–q and Id–Iq control strategies by considering different voltage conditions and adequate results were presented. On owing Id–Iq method with fuzzy logic controller gives away an out-standing performance under balanced, un-balanced and non-sinusoidal supply conditions. The detailed simulation and RTDS Hardware results are included.

RTDS Hardware Implementation and Simulation of 3-ph 4-wire SHAF for Mitigation of Current Harmonics with p-q and Id-Iq Control Strategies using Fuzzy Logic Controller

Control strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source voltage conditions in MATLAB/Simulink environment and also with Real Time Digital Simulator (RTDS) Hardware. When the supply voltages are balanced and sinusoidal, then all control strategies converge to the same compensation characteristics. However, when the supply voltages are distorted and/or un-balanced sinusoidal, these control strategies result in different degrees of compensation in harmonics. The p-q control strategy unable to yield an adequate solution when source voltages are not ideal. Extensive Simulations are carried out with Fuzzy Controller for both p-q and Id-Iq control strategies for different voltage conditions and adequate results were presented. The 3-ph 4-wire SHAF system is also implemented on a RTDS Hardware to further verify its effectiveness. The detailed simulation and RTDS Hardware results are included.

Simulation and RTDS Hardware Implementation of SHAF for Mitigation of Current Harmonics with p-q and Id-Iq Control Strategies Using PI Controller

Control strategies for extracting the three-phase reference currents for shunt active power filters are compared, evaluating their performance under different source conditions in MATLAB/Simulink environment and also with Real Time Digital Simulator (RTDS) Hardware. When the supply voltages are balanced and sinusoidal, the two control strategies are converging to the same compensation characteristics but when the supply voltages are distorted and/or un-balanced sinusoidal, these control strategies result in different degrees of compensation in harmonics. The p-q control strategy is unable to yield an adequate solution when source voltages are not ideal. Extensive Simulations are carried out with PI controller for both p-q and Id-Iq control strategies for different voltage conditions and adequate results were presented. The 3-ph 4-wire SHAF system is also implemented on RTDS Hardware to further verify its effectiveness. The detailed simulation and RTDS Hardware results are included.

Design and implementation of a real-time training environment for protective relay

This paper presents our work involving the development of a real-time operator training system using a protective relay implemented by the user defined component (UDC) model of a Real-Time Digital Simulator (RTDS). Operator training, within a real-time environment for the principles and behavior of protective relaying with respect to power system stability and protection, can provide a very strong benefit in facilitating operators’ understanding of the basic concepts of a protective relay as well as handing undesirable operations. The operator training system includes (a) RTDS hardware, (b) a mimic board that has detailed state information of a simple two-area system with an electronically display, (c) a control panel so that the user can apply a disturbance to the system (i.e., fault, load shedding, etc.), and (d) a generator protective relay model. The relay model using a UDC, which is designed to facilitate the investigation and evaluation of the protective relay, is based on integrating six functions into a single model. The testing of the relay model described in this paper is summarized into three steps: static, dynamic and advanced testing methods. The simulation results of these tests show that the developed relay model using the UDC operates correctly for the various events. We also discuss the utilization of an operator training system via simple application examples.