Anti-Jamming Modification of Exciting System in 600MW Generating Unit

2013 ◽  
Vol 303-306 ◽  
pp. 1291-1296
Author(s):  
Zeng Ji Chen ◽  
Wei Min Fang ◽  
Cong Rong Guan
Keyword(s):  
Electromagnetic Interference ◽  
Transient Stability ◽  
Reactive Power ◽  
Current Control ◽  
Full Duplex ◽  
Control Mode ◽  
Control Voltage ◽  
Stable Operation ◽  
Operation Condition ◽  
Excitation System

In order to reduce excitation system swing and resultant reactive power swing, namely, reduce external electromagnetic interference to stable operation of 600MW generating unit, the paper analyses unit excitation control mode and designs hardware and software of excitation system. First, digital microcomputer control system organization was designed based on nonlinear control theory, which had an increase of control mode such as PID control mode, nonlinear optimum electronic control (NOEC) mode besides original voltage difference and current control mode. Second, full duplex collocation configuration mode of excitation system was designed, namely two controllers were master-slave concurrent, and each controller could meet excitation requirement of various operation condition including constrained excitation. Finally, in electric network disturbance test, measured excitation system parameters recovered stably in 1020 ms such as stator voltage Ut, rotor voltage Uf, comprehensive amplified control voltage Uc, active power P and reactive power Q. It is verified that transient stability and unit operating condition are improved.

Study on Reactive Power Compensation Control of STATCOM Based on MMC

2014 ◽  
Vol 530-531 ◽  
pp. 1022-1025
Author(s):  
Yan Xie ◽  
Ya Ne Liao ◽  
Hong Xie
Keyword(s):  
Reactive Power ◽  
Power Level ◽  
Response Speed ◽  
Reactive Power Compensation ◽  
Current Control ◽  
Control Mode ◽  
Compensation Control ◽  
Control Response ◽  
In Series ◽  
Level Converter

This paper introduced a new modular multi-level converter (MMC), which could enhance the voltage and power level by sub-converter modules in series and was easy to extend to any level of output. Its structure and working mechanism were described. By analyzing the performance of STATCOM based on MMC working conditions in the reactive power compensation, this paper studied compensation control theory in reactive changing conditions. To obtain compensation control response speed faster and better compensation effect, a compensation control strategy was proposed based on direct current control mode. The simulation results show the strategy has a better tracking precision and response speed for the reactive power compensation.

scholarly journals Fault Ride through Capability Augmentation of a DFIG-Based Wind Integrated VSC-HVDC System with Non-Superconducting Fault Current Limiter

2019 ◽  
Vol 11 (5) ◽  
pp. 1232 ◽  
Author(s):  
Md Alam ◽  
Mohammad Abido ◽  
Alaa Hussein ◽  
Ibrahim El-Amin
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Fault Current ◽  
Fault Current Limiter ◽  
Hvdc System ◽  
Fault Ride Through ◽  
Current Limiter

This paper proposes a non-superconducting bridge-type fault current limiter (BFCL) as a potential solution to the fault problems of doubly fed induction generator (DFIG) integrated voltage source converter high-voltage DC (VSC-HVDC) transmission systems. As the VSC-HVDC and DFIG systems are vulnerable to AC/DC faults, a BFCL controller is developed to insert sizeable impedance during the inception of system disturbances. In the proposed control scheme, constant capacitor voltage is maintained by the stator VSC (SVSC) controller, while current extraction or injection is achieved by rotor VSC (RVSC) controller. Current control mode-based active and reactive power controllers for an HVDC system are developed. Balanced and different unbalanced faults are applied in the system to show the effectiveness of the proposed BFCL solution. A DFIG wind-based VSC-HVDC system, BFCL, and their controllers are implemented in a real time digital simulator (RTDS). The performance of the proposed BFCL control strategy in DFIG-based VSC-HVDC system is compared with a series dynamic braking resistor (SDBR). Comparative RTDS implementation results show that the proposed BFCL control strategy is very efficient in improving system fault ride through (FRT) capability and outperforms SDBR in all cases considered.

scholarly journals Control of MMC-Based STATCOM as an Effective Interface between Energy Sources and the Power Grid

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1264 ◽  
Author(s):  
Fatemeh Shahnazian ◽  
Ebrahim Adabi ◽  
Jafar Adabi ◽  
Edris Pouresmaeil ◽  
Kumars Rouzbehi ◽  
...  
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Second Harmonic ◽  
Power Grid ◽  
Harmonic Component ◽  
Current Control ◽  
Energy Sources ◽  
Stable Operation ◽  
Multilevel Converters ◽  
Steady State Operation

This paper presents a dynamic model of modular multilevel converters (MMCs), which are considered as an effective interface between energy sources and the power grid. By improving the converter performance, appropriate reactive power compensation is guaranteed. Modulation indices are calculated based on detailed harmonic evaluations of both dynamic and steady-state operation modes, which is considered as the main contribution of this paper in comparison with other methods. As another novelty of this paper, circulating current control is accomplished by embedding an additional second harmonic component in the modulation process. The proposed control method leads to an effective reduction in capacitor voltage fluctuation and losses. Finally, converter’s maximum stable operation range is modified, which provides efficiency enhancements and also stability assurance. The proficiency and functionality of the proposed controller are demonstrated through detailed theoretical analysis and simulations with MATLAB/Simulink.

scholarly journals FACTS Providing Grid Services: Applications and Testing

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2554 ◽  
Author(s):  
Panos Kotsampopoulos ◽  
Pavlos Georgilakis ◽  
Dimitris T. Lagos ◽  
Vasilis Kleftakis ◽  
Nikos Hatziargyriou
Keyword(s):  
Power Flow ◽  
Transient Stability ◽  
Reactive Power ◽  
Renewable Energy Sources ◽  
Field Testing ◽  
Control Voltage ◽  
Hardware In The Loop ◽  
Grid Services ◽  
Testing Environments ◽  
Comparison Of The Results

The role of flexible alternating current transmission systems (FACTSs) in the provision of grid services is becoming increasingly important, due to the massive integration of intermittent renewable energy sources, energy storage systems, and the decommissioning of thermal plants. A comprehensive literature review of grid services offered by FACTS is performed, focusing on the different grid services that they can provide, such as power flow control, reactive power control, voltage control, power quality improvement, harmonic mitigation, improvement of transient stability, and damping of inter-area and intra-area oscillations. These grid services need to be realistically and economically validated in suitable testing environments. A review of relevant standards, guides, and the literature is performed, which covers the entire range from functional specification and factory testing up to the field testing of FACTS. Advanced industry practices, such as controller hardware in the loop (CHIL) testing of FACTS controllers by the manufacturer, and recent trends, such as CHIL testing of replica controllers by the owner, are underlined. Limitations of conventional testing and CHIL testing are explained and the use of power hardware in the loop (PHIL) simulation for FACTS testing is discussed. CHIL and scaled-down PHIL tests on a transmission static synchronous compensator (STATCOM) are performed and a comparison of the results is presented.

scholarly journals Control Method of Parallel Inverters with Self-Synchronizing Characteristics in Distributed Microgrid

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3871 ◽  
Author(s):  
Yan ◽  
Cui ◽  
Cui
Keyword(s):  
Reactive Power ◽  
Control Method ◽  
Dynamic Performance ◽  
Synchronous Generator ◽  
Power Sharing ◽  
Control Mode ◽  
Stable Operation ◽  
Centralized Control ◽  
Local Data ◽  
Precise Control

The centralized control mode is no longer applicable for microgrid operation due to the high penetration rate of distributed energy, which is responsible for the widespread interest in the use of the distributed microgrid. Focusing on the issues of power coupling and uncontrollable droop coefficient at the terminal of the connecting line between the micro-source and AC bus, which is rarely considered, this paper proposes an improved virtual synchronous generator (VSG) control strategy based on local data considering precise control of the droop coefficient and realizing the power decoupling and the expected droop characteristics. Then, combined with the virtual rotor characteristic matching method, the reasonable active and reactive power sharing of the parallel microgrid inverters are realized in terms of static and dynamic performance without additional improvement of reactive power control. Finally, the effectiveness and feasibility of the proposed method are verified based on the MATLAB/Simulink simulation platform. The combination of the proved strategy and matching principle endows inverters with self-synchronization characteristics, forming the self-synchronizing voltage sources, which gives the distributed microgrid a higher self-stability, autonomy and robustness to ensure the stable operation of the microgrid.

Study on Direct Current Controlled Distribution Static Synchronous Compensator with Mechanical Properties Used for Improvement of Voltage Quality

2013 ◽  
Vol 387 ◽  
pp. 254-257
Author(s):  
Qun Feng Zhu ◽  
Lei Huang ◽  
Deng Xiang Yang ◽  
Guang Yao Zhu
Keyword(s):  
Direct Current ◽  
Reactive Power ◽  
Current Control ◽  
Control Mode ◽  
Voltage Source ◽  
Voltage Sag ◽  
Static Synchronous Compensator ◽  
Synchronous Reference Frame ◽  
Voltage Quality ◽  
Voltage Control Mode

A type of direct current controlled static reactive power compensator (DSTATCOM) used for improvement of voltage quality in low-medium distribution network is introduced. The main circuit of DSTATCOM consists of VSI-SPWM voltage source inverter. The extraction of reference current and the tracking control of compensator current are realized in synchronous reference frame. The function of DSTATCOM to mitigate voltage sag and flicker is presented in this paper and the control mode of DSTATCOM is discussed in detail. The function of DSTATCOM to mitigate voltage sag and flicker under different control mode is simulated with MATLAB. The simulation results shows that the current control mode is suitable for mitigating voltage flicker and the voltage control mode is suitable for mitigating voltage sag.

scholarly journals Grid Connected Inverter for Current Control by Using Anti-Islanding Technique

2018 ◽  
Vol 9 (2) ◽  
pp. 926
Author(s):  
B V Rajanna ◽  
K S Srikanth
Keyword(s):  
Critical Loads ◽  
Reactive Power ◽  
Detection Method ◽  
Current Control ◽  
Control Mode ◽  
Islanding Detection ◽  
Voltage Variation ◽  
Clearing Time ◽  
Indirect Current Control ◽  
Grid Connected Inverter

The inverter with critical loads should be able to provide critical loads with a stable and seamless voltage during control mode change as well as clearing time. The indirect current control has been proposed for providing stable voltage with critical load during clearing time and seamless control mode transfer of inverters. However, the islanding detection is difficult since with the indirect current control the magnitude and frequency of voltage do not change when the islanding occurs. The conventional anti-islanding method based on the magnitude and frequency of voltage variation cannot apply to the indirect current control. This paper proposes an islanding detection method for the indirect current control. The proposed islanding detection method can detect the islanding using reactive power perturbation and observation when the frequency and magnitude of voltage don’t vary during clearing time. In order to verify the proposed anti-islanding method, the experimental results of a 600W three-phase inverter are provided.

Power system stability with parallel active filter ensuring compensation of capacitive reactive power of a resonant LC circuit

2012 ◽  
Vol 60 (2) ◽  
pp. 353-361 ◽  
Author(s):  
T. Platek
Keyword(s):  
Reactive Power ◽  
Experimental Studies ◽  
Input Voltage ◽  
Active Filter ◽  
Current Control ◽  
System Stability ◽  
Stable Operation ◽  
Additional Measurement ◽  
Lc Circuit

Abstract. This paper presents an analysis allowing for the determination of the differential equation describing the circuit of the active filter inverter output current control with an additional measurement of input voltage. The resulting equation allows to determine the conditions that ensure stable operation of the filter with the load in form of a resonant LC circuit. Analysis results were confirmed by computer simulation and experimental studies of commercial active filter.

scholarly journals Generalized Proportional Model of Relay Protection Based on Adaptive Homotopy Algorithm Transient Stability

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 899 ◽  
Author(s):  
Feng Zheng ◽  
Jiahao Lin ◽  
Jie Huang ◽  
Yanzhen Lin
Keyword(s):  
Power Systems ◽  
Transient Stability ◽  
Relay Protection ◽  
Information Value ◽  
Normal Operation ◽  
Stable Operation ◽  
Operation Condition ◽  
Homotopy Algorithm ◽  
Newton Homotopy ◽  
Monitoring Information

Relay protection equipment is important to ensure the safe and stable operation of power systems. The risks should be evaluated, which are caused by the failure of relay protection. At present, the fault data and the fault status monitoring information are used to evaluate the failure risks of relay protection. However, there is a lack of attention to the information value of monitoring information in the normal operation condition. In order to comprehensively improve monitoring information accuracy and reduce, a generalized proportional hazard model (GPHM) is established to fully exploit the whole monitoring condition information during the whole operation process, not just the monitoring fault condition data, with the maximum likelihood estimation (MLE) used to estimate the parameters of the GPHM. For solving the nonlinear equation in the process of parameter estimations, the adaptive homotopy algorithm is adopted, which could ensure the reversibility of the Jacobi matrix. Three testing cases have been reviewed, to demonstrate that the adaptive homotopy algorithm is better than traditional algorithms, such as the Newton homotopy algorithm, regarding the calculation speed and convergence. Therefore, GPHM could not only reflect the real time state of the equipment, but also provide a sound theoretical basis for the selection of equipment maintenance types.

scholarly journals Simulation and Analysis of DFIG System with Wind Turbine Implementing Fuzzy Logic Control

2019 ◽  
Vol 8 (6) ◽  
pp. 2764-2771
Keyword(s):  
Fuzzy Logic ◽  
Wind Turbine ◽  
Fuzzy Logic Controller ◽  
Reactive Power ◽  
Current Control ◽  
Control Voltage ◽  
Active And Reactive Power ◽  
Grid Side ◽  
Rotor Side Converter ◽  
Grid Side Converter

A doubly-fed induction generator (DFIG) applied to wind power generation driven by wind turbine is under study for low voltage ride-through application during system unbalance. Use of DFIG in wind turbine is widely spreading due to its control over DC voltage and active and reactive power. Conventional dq axis current control using voltage source converters for both the grid side and the rotor side of the DFIG are analyzed and simulated. An improved control and operation of DFIG system under unbalanced grid voltage conditions by coordinating the control of both the rotor side converter (RSC) and the grid side converter (GSC) is done in this thesis. Simulation and analysis of DFIG system with wind turbine using Fuzzy logic controller for RSC and GSC under unbalanced condition is presented in the positive synchronous reference frame. The common DC-link voltage is controlled by grid side converter and control of DFIG’s stator output active and reactive power is controlled by rotor side converter. The steady-state operation of the DFIG and its dynamic response to voltage sag resulting from a remote fault on the 120-kV system is shown in this thesis using controllers. Modeling of DFIG system under Fuzzy logic controller to control voltage and active-reactive powers is done using MATLAB/SIMULINK.

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