scholarly journals Modeling and Analyzing the Effect of Frequency Variation on Weak Grid-Connected VSC System Stability in DC Voltage Control Timescale

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4458 ◽  
Author(s):  
Yang ◽  
Yuan
Keyword(s):  
Voltage Control ◽  
System Stability ◽  
Voltage Source ◽  
Frequency Variation ◽  
Voltage Source Converter ◽  
Small Signal ◽  
Small Signal Stability ◽  
Dc Voltage ◽  
Weak Grid ◽  
Dc Voltage Control

The effect of frequency variation on system stability becomes crucial when a voltage source converter (VSC) is connected to a weak grid. However, previous studies lack enough mechanism cognitions of this effect, especially on the stability issues in DC voltage control (DVC) timescale (around 100 ms). Hence, this paper presented a thorough analysis of the effect mechanism of frequency variation on the weak grid-connected VSC system stability in a DVC timescale. Firstly, based on instantaneous power theory, a novel method in which the active/reactive powers are calculated with the time-varying frequency of voltage vectors was proposed. This method could intuitively reflect the effect of frequency variation on the active/reactive powers and could also help reduce the system order to a certain extent. Then, a small-signal model was established based on the motion equation concept, to depict the effect of frequency variation on the weak grid-connected VSC system dynamics. Furthermore, an analytical method was utilized to quantify the effect of frequency variation on the system’s small-signal stability. The quantitative analysis considered the interactions between the DC voltage control, the terminal voltage control, phase-locked loop, and the power network. Finally, case studies were conducted, and simulation results supported the analytical analyses.

scholarly journals Modelling of multi-VSCs in DC voltage control timescale for small-signal stability analysis

2017 ◽  
Vol 2017 (13) ◽  
pp. 2057-2061 ◽  
Author(s):  
Yunhui Huang ◽  
Aihong Tang ◽  
Binyu Xiong ◽  
Yong Huang ◽  
Haiyan Tang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Voltage Control ◽  
Small Signal ◽  
Small Signal Stability ◽  
Dc Voltage ◽  
Signal Stability ◽  
Dc Voltage Control ◽  
Small Signal Stability Analysis

Multi Point Voltage Control for DFIG wind farms in VSC-MTDC Network

2017 ◽  
Vol 18 (2) ◽  
Author(s):  
Yang Gao ◽  
Qian Ai
Keyword(s):  
Voltage Control ◽  
Wind Farms ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Stable Operation ◽  
Dc Voltage ◽  
Induction Generators ◽  
Dc Voltage Control ◽  
Doubly Fed ◽  
The Stability

Abstract The development of voltage source converter (VSC) based multi-terminal HVDC network (VSC-MTDC) is emerging as the most adaptive approach to managing high penetration of wind energy in long distance.However, MTDC networks depend on highly controllable devices, which may permit not only transporting power, but also assuring secure and stable operation for AC grids. This paper first presents an overview of different control schemes for VSCs in VSC-MTDC network, then proposes a modification scheme of multi-point DC voltage control for wind farms equipped with doubly fed induction generators (DFIG). Finally, the proposed strategy is verified on PSCAD/EMTDC software, and simulation results show that the state of constant power control and constant DC voltage control can be automatically conversed, thus guarantee the stability of DC voltage and the transmission reliability after the power variation in DFIG wind farms and the operation fault at converter stations.

scholarly journals Application of Multipoint DC Voltage Control in VSC-MTDC System

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yang Xi ◽  
Ai Qian ◽  
Huang Jiantao ◽  
An Yiran
Keyword(s):  
Control Strategy ◽  
Wind Farm ◽  
Power Transmission ◽  
Voltage Control ◽  
Stability Control ◽  
Control Mode ◽  
Voltage Source ◽  
Voltage Control Strategy ◽  
Dc Voltage ◽  
Dc Voltage Control

The voltage-source-converter- (VSC-) based multiterminal VSC-HVDC power transmission system (VSC-MTDC) is an ideal approach to connect wind farm with power grid. Analyzing the characteristics of doubly fed induction generators as well as the basic principle and the control strategy of VSC-MTDC, a multiterminal DC voltage control strategy suitable for wind farm connected with VSC-MTDC is proposed. By use of PSCAD/EMTDC, the proposed control strategy is simulated, and simulation results show that using the proposed control strategy the conversion between constant power control mode and constant DC voltage control mode can be automatically implemented; thus the DC voltage stability control and reliable power output of wind farm can be ensured after the fault-caused outage of converter station controlled by constant DC voltage and under other faults. The simulation result shows that the model can fulfill multiterminal power transmission and fast response control.

scholarly journals Small Signal Model for VSC-HVDC Connected DFIG-Based Offshore Wind Farms

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Kai Liao ◽  
Zheng-you He ◽  
Bin Sun
Keyword(s):  
Wind Farms ◽  
Offshore Wind ◽  
Voltage Source ◽  
Voltage Source Converter ◽  
Small Signal ◽  
Small Signal Stability ◽  
Offshore Wind Farms ◽  
Signal Stability ◽  
The Impact ◽  
Small Signal Stability Analysis

Large-scale offshore wind farms are integrated with onshore ac grids through the voltage source converter based high voltage direct current (VSC-HVDC) transmission system. The impact on the stability of the ac grids will be significant. The small signal model of a wind farm connected with voltage source converter based dc transmission system is studied in this paper. A suitable model for small signal stability analysis is presented. The control system of wind generator and the HVDC system has also been modeled in this model for small signal stability analysis. The impact of the control parameters on the network stability is investigated.

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