Dynamic grid support in low voltage grids — fault ride-through and reactive power/voltage support during grid disturbances

2014 ◽  
Author(s):  
Gustav Lammert ◽  
Tobias Hess ◽  
Maximilian Schmidt ◽  
Peter Schegner ◽  
Martin Braun
Keyword(s):  
Reactive Power ◽  
Low Voltage ◽  
Fault Ride Through ◽  
Dynamic Grid Support ◽  
Voltage Support

scholarly journals Development of HVRT and LVRT Control Strategy for PMSG-Based Wind Turbine Generators

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5442
Author(s):  
Liang Yuan ◽  
Ke Meng ◽  
Jingjie Huang ◽  
Zhao Yang Dong ◽  
Wang Zhang ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Synchronous Generator ◽  
Vital Role ◽  
Turbine Generators ◽  
Wind Turbine Generators ◽  
Fault Ride Through ◽  
Control Scheme

Various challenges are acknowledged in practical cases with high wind power penetration. Fault ride-through (FRT) capability has become the most dominant grid integration requirements for the wind energy conversion system worldwide. The high voltage ride-through (HVRT) and low voltage ride-through (LVRT) performance play a vital role in the grid-friendly integration into the system. In this paper, a coordinated HVRT and LVRT control strategy is proposed to enhance the FRT capability of the permanent magnet synchronous generator (PMSG)-based wind turbine generators (WTG). A dual-mode chopper protection is developed to avoid DC-link overvoltage, and a deadband protection is proposed to prevent oscillations under edge voltage conditions. The proposed strategy can ride through different levels of voltage sags or swells and provide auxiliary dynamic reactive power support simultaneously. The performance of the proposed control scheme is validated through various comparison case tests in PSCAD/EMTDC.

Fault Ride through of Doubly Fed Induction Generator Wind Turbine Based on Supercapacitors Energy Storage

2011 ◽  
Vol 130-134 ◽  
pp. 2851-2854
Author(s):  
He Ping Zou ◽  
Peng Yu ◽  
Hui Sun ◽  
Ji Yan Zou ◽  
Jian Liu ◽  
...  
Keyword(s):  
Energy Storage ◽  
Reactive Power ◽  
Low Voltage ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Low Voltage Ride Through ◽  
Fault Ride Through ◽  
Doubly Fed ◽  
Grid Side ◽  
Grid Side Converter

This paper proposes a low voltage ride through (LVRT) scheme of doubly fed induction generator (DFIG) based on the supercapacitors energy storage. The novel control strategy of the bi-directional converter and the grid side converter is established. Simulation model of the DFIG system is developed. Simulation results show that the presented scheme can efficiently reduce the DC-link overvoltage, supply reactive power to the power system through grid side converter, and help grid recovery under system fault, improving the LVRT capability of the system.

scholarly journals Voltage Support under Grid Faults with Inherent Current Limitation for Three-Phase Droop-Controlled Inverters

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 997 ◽  
Author(s):  
Alexandros Paspatis ◽  
George Konstantopoulos
Keyword(s):  
Reactive Power ◽  
Digital Simulation ◽  
Negative Sequence ◽  
Grid Current ◽  
Voltage Drops ◽  
Fault Ride Through ◽  
Three Phase ◽  
Control Concept ◽  
Point Of Common Coupling ◽  
Voltage Support

A novel nonlinear current-limiting controller for three-phase grid-tied droop-controlled inverters that is capable of offering voltage support during balanced and unbalanced grid voltage drops is proposed in this paper. The proposed controller introduces a unified structure under both normal and abnormal grid conditions operating as a droop controller or following the recent fault-ride-through requirement to provide voltage support. In the case of unbalanced faults, the inverter can further inject or absorb the required negative sequence real and reactive power to eliminate the negative sequence voltage at the point of common coupling (PCC) whilst ensuring at all times boundedness for the grid current. To accomplish this task, a novel and easily implementable method for dividing the available current into the two sequences (positive and negative) is proposed, suitably adapting the proposed controller parameters. Furthermore, nonlinear input-to-state stability theory is used to guarantee that the total grid current remains limited below its given maximum value under both normal and abnormal grid conditions. Asymptotic stability for any equilibrium point of the closed-loop system in the bounded operating range is also analytically proven for first time using interconnected-systems stability analysis irrespective of the system parameters. The proposed control concept is verified using an OPAL-RT real-time digital simulation system for a three-phase inverter connected to the grid.

scholarly journals Reactive power control of DFIG-based wind turbines for voltage support during faults

2020 ◽  
Author(s):  
João Paulo Man Kit Sio ◽  
Romeu Reginatto
Keyword(s):  
Power Control ◽  
Wind Turbines ◽  
Reactive Power ◽  
Low Voltage ◽  
Current Injection ◽  
System Level ◽  
Reactive Power Control ◽  
Injection Strategy ◽  
Reactive Current ◽  
Voltage Support

The wind power penetration in the power system has already reached a considerate proportion. An important step in that path was the requirement of wind farms to provide Low Voltage Ride Through (LVRT) capacity, remaining connected to the grid during faults. More recently, grid codes are also requiring wind turbines to inject reactive power during the fault event so as to contribute to grid voltage support. The purpose of this work is to analyze a reactive current injection strategy for DFIG-based wind turbines that acts on the reactive power control loop during faults. The results of the simulations show, the behavior of the voltage, active power, and the total current injected in the system for different connection characteristics. The reactive current injection strategy helps in the voltage level during the fault, and the effectiveness is better for connections to the transmission system level.

scholarly journals An Improved Dynamic Voltage Restorer Model for Ensuring Fault Ride-Through Capability of DFIG-based Wind Turbine Systems

2020 ◽  
Vol 19 (1) ◽  
pp. 9-16
Author(s):  
Musayyibi Shuaibu ◽  
Adamu Saidu Abubakar
Keyword(s):  
Electricity Market ◽  
Energy Demand ◽  
Reactive Power ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Test System ◽  
Dynamic Voltage Restorer ◽  
Fault Ride Through ◽  
Voltage Restorer ◽  
Dynamic Voltage

Renewable energy sources (RES) are being integrated to electrical grid to complement the conventional sources in meeting up with global electrical energy demand. Among the RES, Wind Energy Conversion Systems (WECS) have gained global electricity market competitiveness especially the Doubly Fed Induction Generator (DFIG)-based Wind Turbines (WTs) because of flexible regulation of active and reactive power, higher power quality, variable speed operation, four quadrant converter operation and better dynamic performance. Grid connected DFIG-based WTs are prone to disturbances due to faults in the network which made the utilization of the power generated a major concern. The grid code requirement for integrating the DFIGs to grid specified that they must remain connected and support the grid stability during grid disturbances of up to 1500milliseconds. The ability of the DFIG WT system to uphold to the grid codes requirement is termed the Fault Ride – Through (FRT). This paper presented a 1.5MW grid connected DFIG-based WT model with a Dynamic Voltage Restorer (DVR) for FRT capability enhancement. The design and simulation were performed in MATLAB/Simulink software. The test system was subjected to disturbances leading to Low Voltage Ride – Through (LVRT), Zero Voltage Ride – Through (ZVRT) and High Voltage Ride – Through (HVRT) considering three – phase balanced fault and single line to ground fault. The performance of improved model of DVR shows enhancement over conventional DVR in terms of voltage compensation and fault current mitigation.

scholarly journals A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3222
Author(s):  
Duc Nguyen Huu
Keyword(s):  
Adaptive Control ◽  
Voltage Stability ◽  
Reactive Power ◽  
Control Method ◽  
Offshore Wind ◽  
Voltage Source ◽  
Long Distance ◽  
Control Approach ◽  
Hvdc System ◽  
Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

scholarly journals Using Energy Storage Inverters of Prosumer Installations for Voltage Control in Low-Voltage Distribution Networks

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1121
Author(s):  
Rozmysław Mieński ◽  
Przemysław Urbanek ◽  
Irena Wasiak
Keyword(s):  
Energy Storage ◽  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Storage System ◽  
Distribution Networks ◽  
Energy Storage System ◽  
Voltage Regulation ◽  
Active Power ◽  
Total Power

The paper includes the analysis of the operation of low-voltage prosumer installation consisting of receivers and electricity sources and equipped with a 3-phase energy storage system. The aim of the storage application is the management of active power within the installation to decrease the total power exchanged with the supplying network and thus reduce energy costs borne by the prosumer. A solution for the effective implementation of the storage system is presented. Apart from the active power management performed according to the prosumer’s needs, the storage inverter provides the ancillary service of voltage regulation in the network according to the requirements of the network operator. A control strategy involving algorithms for voltage regulation without prejudice to the prosumer’s interest is described in the paper. Reactive power is used first as a control signal and if the required voltage effect cannot be reached, then the active power in the controlled phase is additionally changed and the Energy Storage System (ESS) loading is redistributed in phases in such a way that the total active power set by the prosumer program remains unchanged. The efficiency of the control strategy was tested by means of a simulation model in the PSCAD/EMTDC program. The results of the simulations are presented.

The reactive power voltage control strategy of PV systems in low-voltage string lines

2017 ◽  
Author(s):  
Feng Zhang ◽  
Xiaolong Guo ◽  
Xiqiang Chang ◽  
Guowei Fan ◽  
Lianger Chen ◽  
...  
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Low Voltage ◽  
Voltage Control ◽  
Voltage Control Strategy ◽  
Pv Systems

scholarly journals A Novel Hierarchical Control Strategy for Low-Voltage Islanded Microgrids Based on the Concept of Cyber Physical System

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1835 ◽  
Author(s):  
Qiuxia Yang ◽  
Dongmei Yuan ◽  
Xiaoqiang Guo ◽  
Bo Zhang ◽  
Cheng Zhi
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Reactive Power ◽  
Low Voltage ◽  
Hierarchical Control ◽  
Physical Layer ◽  
Cyber Physical System ◽  
Droop Control ◽  
Control Effect ◽  
Consensus Control

Based on the concept of cyber physical system (CPS), a novel hierarchical control strategy for islanded microgrids is proposed in this paper. The control structure consists of physical and cyber layers. It’s used to improve the control effect on the output voltages and frequency by droop control of distributed energy resources (DERs), share the reactive power among DERs more reasonably and solve the problem of circumfluence in microgrids. The specific designs are as follows: to improve the control effect on voltages and frequency of DERs, an event-trigger mechanism is designed in the physical layer. When the trigger conditions in the mechanism aren’t met, only the droop control (i.e., primary control) is used in the controlled system. Otherwise, a virtual leader-following consensus control method is used in the cyber layer to accomplish the secondary control on DERs; to share the reactive power reasonably, a method of double virtual impedance is designed in the physical layer to adjust the output reactive power of DERs; to suppress circumfluence, a method combined with consensus control without leader and sliding mode control (SMC) is used in the cyber layer. Finally, the effectiveness of the proposed hierarchical control strategy is confirmed by simulation results.

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