scholarly journals A Self-Regulation Strategy for the Power Fluctuation of the Islanded Voltage Source Converter (VSC) Station Delivering Large-Scale Wind Power

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 560
Author(s):  
Juanjuan Sun ◽  
Hui Wang ◽  
Xiaomin Zhu ◽  
Qian Pu

When the power source of a voltage source converter (VSC) station at the sending end solely depends on wind power generation, the station is operating in an islanding mode. In this case, the power fluctuation of the wind power will be entirely transmitted to the receiving-end grid. A self-regulation scheme of power fluctuation is proposed in this paper to solve this problem. Firstly, we investigated the short-time variability characteristic of the wind power in a multi-terminal direct-current (MTDC) project in China. Then we designed a virtual frequency (VF) control strategy at the VSC station based on the common constant voltage constant frequency (CVCF) control of VSC station. By cooperating with the primary frequency regulation (PFR) control at the wind farms, the self-regulation of active power pooling at the VSC station was realized. The control parameters of VF and PFR control were carefully settled through the steady-state analysis of the MTDC grid. The self-regulation effect had been demonstrated by a twenty-four-hour simulation. The results showed that the proposed scheme could effectively smoothen the power fluctuation.

2016 ◽  
Vol 10 (1) ◽  
pp. 156-165
Author(s):  
Wu Jiahui ◽  
Wang Haiyun ◽  
Wang Weiqing ◽  
Zhang Qiang

This paper evaluates application feasibility of a Hybrid Multi-terminal HVDC system and wind-thermal-bundled plants simulated in DIgSLIENT PowerFactory environment. The proposed hybrid MTDC system consists of two line-communicated converters (LCC), which are connected to both wind farms and thermal power plants, and one voltage source converter (VSC) at the grid side. Control strategies for each converter are designed to handle this system under different disturbance conditions. Simulation results show that the wind power fluctuation can be compensated by the thermal-generated power. Results demonstrate the effectiveness of the proposed control strategies of the hybrid MTDC system compared to a conventional MTDC system. The proposed scheme combines advantages of both LCC and VSC HVDC systems and provides a new way to transmit wind power over long distances to the main grid.


Theoretical review of various topologies of high voltage DC links in application to off shore wind forms has been studied and analysed. In addition to that, various types of high voltage DC links such as back to back, two terminal, multi-terminal systems has been covered under this study. The Line-Commutated Converters, Voltage Source Converter, Modular Multi-Level Converter as well as some of advanced hybrid high voltage DC topologies in application to off shore wind forms has been reviewed. This study covers complication arising from large-scale wind power generation. The review paper also points out the scope of future research in high voltage DC converters.


2013 ◽  
Vol 291-294 ◽  
pp. 407-414 ◽  
Author(s):  
Guo Peng Zhou ◽  
Fu Feng Miao ◽  
Xi Sheng Tang ◽  
Tao Wu ◽  
Shan Ying Li ◽  
...  

The output power of wind farms has significant randomness and variability, which results in adverse impacts on power system frequency stability. This paper extracts wind power fluctuation feature with the HHT (Hilbert-Huang Transform) method. Firstly, the original wind power data was decomposed into several IMFs (Intrinsic Mode Functions) and a tendency component by using the EMD (Empirical Mode Decomposition) method. Secondly, the instantaneous frequency of each IMF was calculated. On this basis, taking a WSCC 9-bus power system as benchmark, the impact on power system frequency caused by wind power fluctuation was simulated in a real-time simulation platform, and the key component which results in the frequency deviation was found. The simulation results validate the wind power fluctuation impacts on frequency deviation, underlying the following study on power system frequency stability under the situation of large-scale intermittent generation access into the grid.


2012 ◽  
Vol 546-547 ◽  
pp. 295-300
Author(s):  
Hui Fang Liu

Applying non-grid-connected wind power to high energy consuming industry has broad development prospects. This paper presents a compound DC power transmission net to realize high efficiency and reduce the loss. This net consists of current source converter (CSC) based on naturally commutated thyristor and voltage source converter (VSC) based on IGBT. Super capacitor connected to the load side stabilizes the wind power fluctuation. The coordinated control strategy of wind power, energy storage device and load is provided. Simulation results based on real wind power shows the validity of the system.


2013 ◽  
Vol 860-863 ◽  
pp. 267-270
Author(s):  
Xiao Yan Bian ◽  
Li Jun Hong ◽  
Yang Fu

Reactive and active power variation of large scale wind farms always lead to the instability of voltage and frequency. To solve this problem, this paper proposed a method of joining with frequency and voltage control loop of Voltage Source Converter HVDC (VSC-HVDC). Control loop of VSC-HVDC converter WFVSC (Wind Farm Side VSC) and GSVSC (Grid Side VSC) were detailed designed. By the frequency loop of WFSVSC, transient stability is greatly improved. Finally, based on the DIgSILENT/Power Factory simulation, the results show its validity and effectiveness.


Author(s):  
Sarika D. Patil

Recently the wind power generation has attracted special interest and many wind power stations are being in service in the world. In the wind turbine that mostly uses induction generators, tend to drain large amounts of Vars from the grid, potentially causing low voltage and may be voltage stability problems for the utility owner, especially in the case of large load variation on distribution feeder. Voltage-source converter based various FACTS devices have been used for flexible power flow control, secure loading and damping of power system oscillations. Some of those are used also to improve transient and dynamic stability of the wind power generation (WPGS).


Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5220
Author(s):  
Facai Xing ◽  
Zheng Xu ◽  
Zheren Zhang ◽  
Yangqing Dan ◽  
Yanwei Zhu

To guarantee the reliable and efficient development of wind power generation, oscillation problems in large-scale wind power bases with Type-IV generators are investigated from the view of resonance stability in this paper. Firstly, the transfer characteristics of disturbances in Type-IV wind generators are analyzed to establish their impedance model, based on the balance principle of frequency components. Subsequently, considering the dynamic characteristics of the transmission network and the interaction among several wind farms, the resonance structure of a practical wind power base is analyzed based on the s-domain nodal admittance matrix method. Furthermore, the unstable mechanism of the resonance mode is further illustrated by the negative-resistance effect theory. Finally, the established impedance model of the Type-IV wind generator and the resonance structure analysis results of the wind power bases are verified through the time-domain electro-magnetic transient simulation in PSCAD/EMTDC. Case studies indicate that there is a certain resonance instability risk in large-scale wind power bases in a frequency range of 1–100 Hz, and the unstable resonance mode is strongly related to the negative-resistance effect and the capacitive effect of Type-IV wind generators.


2014 ◽  
Vol 521 ◽  
pp. 151-156
Author(s):  
Sheng Wei Tang ◽  
Yi Tan ◽  
Juan Liu ◽  
Jian Wei Sun

The fluctuation is an important factor that limits large-scale integration of wind power into power grid. In order to improve penetration level of wind power, the EVs based on V2G are considered to participate in regulating wind power while considering charge-discharge characteristics of EV battery. Thus, in this paper, an optimized EV charge-discharge control model is proposed to reduce output fluctuation of wind power. The Monte-Carlo method is used to simulate the stochastic wind speed based on Weibull probability density function. Finally, Genetic Algorithm (GA) is adopted to solve the problem. Results indicate that the EVs based on V2G can reduce the wind power fluctuation level to some extent, absorbing the wind power surplus and compensating the of wind power shortage.


2013 ◽  
Vol 724-725 ◽  
pp. 463-468
Author(s):  
Jian Bo Wang ◽  
Wen Ying Liu ◽  
Wei Zheng ◽  
Chen Liang

Due to the fluctuations and intermittency of wind power, large-scale wind farms integration will cause adverse impact on the safety and stability of the system,such as harmonic pollution, bad power quality, system stability destruction.On the basis of multiple constraints, including hydropower’s and thermal power’s operating characteristics, determination of reserve capacity considering wind power forecasting bias, climbing speed constraints, and maximum output constraints, this paper proposed a control strategy of joint coordination of wind, hydropower and thermal power, which suppressed the fluctuations of wind power effectively. At last, the article give a simulation to verify the feasibility of the control strategy to stabilize system frequency.


2014 ◽  
Vol 1070-1072 ◽  
pp. 200-203
Author(s):  
Ze Tian Wei ◽  
Wen Ying Liu ◽  
Fu Chao Liu ◽  
Jian Zong Zhuo

This paper firstly analyzes the mechanism of transmission line and transformer loss and illustrates the equivalent model and calculating method. Then creates a simple three-node model and discusses the main factors which affect the grid loss with adequate formula. At last, we draw a concise conclusion that there are several factors affecting grid loss. The main factors are the location of wind power access, the active power flow of transmission lines, the active power output of wind farms and the voltage level of wind power access.


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