scholarly journals Coordinated Control in VSC-HVDC Multi-Terminal Systems to Improve Transient Stability: The Impact of Communication Latency

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3638 ◽  
Author(s):  
Javier Renedo ◽  
Aurelio García-Cerrada ◽  
Luis Rouco ◽  
Lukas Sigrist

Power transmission is the main purpose of high voltage direct current systems based on voltage source converters (VSC-HVDC). Nevertheless, this type of system can also help to improve transient stability by implementing suitable supplementary controllers. Previous work proposed active- (P) and reactive-power (Q) control strategies in VSC-HVDC multi-terminal systems (VSC-MTDC, for short) to improve transient stability, producing significant improvements. In those strategies, each VSC station of the MTDC system compares its frequency measurement with the average of the frequencies measured by all converter stations of the MTDC system (weighted-average frequency, WAF) in order to modulate its own P and Q injections. Hence, a communication system is required. This paper presents a detailed analysis of the impact of communication latency on the performance of those control strategies. The communication delays have been modelled using a Padé’s approximation and their impact on the performance of the control strategies have been assessed by means of time-domain simulation in PSS/E. The effect of the control strategies on transient stability has been quantified with the critical clearing time (CCT) of a set of faults. Results show that the control strategies analysed present good results for realistic values of communication delays.

2018 ◽  
Vol 7 (3.27) ◽  
pp. 500
Author(s):  
R Vasudevan ◽  
S Ramalakshmi

A new management approach for the reactive-power injections of Voltage supply Converters in High Voltage DC (VSC-HVDC) multi-terminal Systems to enhance grid transient stability. A reactive-power supplementary signal is provided for each convertor. Its worth is proportional to the frequency deviation of its consequent AC bus with admiration to the weighed-average frequency of the multiterminal system stations. The hope is to extend (decrease) the magnetism torsion of generators close to those terminals during which the frequency is superior to (below) the weighed-average frequency used. The AC frequency for all VSC stations is ever more accessible regionally for synchronization functions and will be utilized by a central controller. Simulations are allotted victimization PSS/E and therefore the outcome have revealed that transient stability is enlarged victimization this approach. Since this approach uses world capability of all VSC stations, the collision of the communication delays has been analyzed, concluding that the depressing consequence is modest, for realistic latency values. 


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2260
Author(s):  
Fan Cheng ◽  
Lijun Xie ◽  
Zhibing Wang

This paper investigated the characteristics of a novel type of hybrid high voltage direct current (HVdc) converter, which is composed by line commutated converter series with voltage source converter. The system and valve level control strategies are introduced, which can provide ac system voltage support. A novel filter design scheme composed by resonant filers for hybrid HVdc are also proposed, which can decrease the capacity of reactive power compensation equipment without deteriorate harmonic characteristics. The ac voltage of HVdc fluctuation level caused by transmitted power variation will be effectively reduced, with the coordination between filter design scheme and converter control. In addition, the influence of ac grid strength is also analyzed by equivalent source internal impedance represented by short circuit ratio (SCR). Finally, the +800 kV/1600 MW hybrid HVdc system connecting two ac grids under different SCR cases are studied, and the PSCAD/EMTDC simulation results have validated the effectiveness for proposed strategy.


2020 ◽  
Vol 10 (19) ◽  
pp. 6792 ◽  
Author(s):  
Soumya Ranjan Das ◽  
Prakash K. Ray ◽  
Arun Kumar Sahoo ◽  
Somula Ramasubbareddy ◽  
Thanikanti Sudhakar Babu ◽  
...  

Nowadays, the application of distributed energy sources (DES) has been extensively employed to serve the power system by supplying the power into the grid and improving the power quality (PQ). Therefore, DES is one solution that can efficiently overcome the energy crisis and climate change problems. The DES, such as solar photovoltaic (PV), wind turbine (WT), and battery energy storage systems (BESS), are incorporated to form the microgrid (MG), which are interfaced with the power system. However, interfacing MG to the power system is undoubtedly a big challenge. Therefore, more focus is required on the control strategy to control the MG with the power system. To address the PQ problems, a controlled MG integrated with a hybrid shunt active power filter (HSAPF) is provided in this work. For controlling the MG integrated HSAPF, different control strategies are applied. In this work, a learning-based incremental conductance (LINC) technique is used as a maximum power point tracking (MPPT) for tracking the maximum power in PV and WT. The voltage source inverter (VSI) of HSAPF is controlled using a wavelet-based technique with a synchronous reference frame (SRF). The main focus is to improve the PQ by compensating the harmonics and regulating the reactive power in both grid-interactive and islanded condition and also supply continuous and adequate power to the non-linear load. The power system model has been developed with MATLAB/Simulink tool, which shows the efficiency of the proposed method. The results obtained have been satisfactorily under various operating conditions and can be validated further using the real-time dSPACE.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Sandeep Gupta ◽  
Ramesh Kumar Tripathi

A current source converter (CSC) based static synchronous compensator (STATCOM) is a shunt flexible AC transmission system (FACTS) device, which has a vital role as a stability support for small and large transient instability in an interconnected power network. This paper investigates the impact of a novel and robust pole-shifting controller for CSC-STATCOM to improve the transient stability of the multimachine power system. The proposed algorithm utilizes CSC based STATCOM to supply reactive power to the test system to maintain the transient stability in the event of severe contingency. Firstly, modeling and pole-shifting controller design for CSC based STATCOM are stated. After that, we show the impact of the proposed method in the multimachine power system with different disturbances. Here, applicability of the proposed scheme is demonstrated through simulation in MATLAB and the simulation results show an improvement in the transient stability of multimachine power system with CSC-STATCOM. Also clearly shown, the robustness and effectiveness of CSC-STATCOM are better rather than other shunt FACTS devices (SVC and VSC-STATCOM) by comparing the results in this paper.


2014 ◽  
Vol 543-547 ◽  
pp. 878-883
Author(s):  
Jun Dong ◽  
Jian Guo Xu ◽  
Hao Zhang ◽  
Yu Jie Pei ◽  
Xian Feng Li

The cause serious deterioration in power quality problems for the growing impact and nonlinear load capacity, introduced SVC device in the role of modern power systems and applications. According to the lack of adequate regional dynamic reactive power regulation means to cause voltage fluctuations, harmonics exceeded the actual situation, through analysis and simulation of the existing 66kV grid power quality conditions, refers to the necessity of application of SVC, the compensation capacity for SVC, filter capacitor system parameters and control strategies were designed, the results show improved 220kV SVC reactive power flow distribution system, reducing the system once or twice a net loss, reducing the impact and harmonic interference voltage caused by nonlinear loads, system security, economic operation of great significance.


2018 ◽  
Vol 7 (4.5) ◽  
pp. 121 ◽  
Author(s):  
Harnek Singh ◽  
Maneet Kour ◽  
Dip Vinod Thanki ◽  
Prakash Kumar

Shunt active power filter (SAPF) has now become a well-known sophisticated technology to overcome current harmonics and reactive power compensation issues. In this paper a technical review of various control strategies for operation of SAPF has been presented. Control strategies such as reference current generation by time domain, frequency domain and soft computing approaches; voltage control for dc link voltage regulation and current control for generating switching patterns for voltage source inverter has been discussed. This paper aims to provide a broad understanding on SAPFs for various research and engineering applications.  


2013 ◽  
Vol 860-863 ◽  
pp. 2062-2067
Author(s):  
Ben Feng Gao ◽  
Jin Liu ◽  
Shu Qiang Zhao ◽  
Kun Xu

The study on the HVDC based on voltage-source converter focuses mainly on the control strategy while less on the impact of electrical damping on the adjacent units by VSC-HVDC. The mechanism of VSC-HVDC on inhibiting sub-synchronous oscillation is analyzed theoretically in the respect of its operation principle. Then the complex torque coefficient method realized by time domain simulation-the test signal method, is adopted to investigate the impact of the unit interaction factor, control mode, active power level and reactive power level on the electrical damping on the adjacent units.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1061
Author(s):  
Iván Andrade ◽  
Rubén Pena ◽  
Ramón Blasco-Gimenez ◽  
Javier Riedemann ◽  
Werner Jara ◽  
...  

The development of distributed generation, mainly based on renewable energies, requires the design of control strategies to allow the regulation of electrical variables, such as power, voltage (V), and frequency (f), and the coordination of multiple generation units in microgrids or islanded systems. This paper presents a strategy to control the active and reactive power flow in the Point of Common Connection (PCC) of a renewable generation system operating in islanded mode. Voltage Source Converters (VSCs) are connected between individual generation units and the PCC to control the voltage and frequency. The voltage and frequency reference values are obtained from the P–V and Q–f droop characteristics curves, where P and Q are the active and reactive power supplied to the load, respectively. Proportional–Integral (PI) controllers process the voltage and frequency errors and set the reference currents (in the dq frame) to be imposed by each VSC. Simulation results considering high-power solar and wind generation systems are presented to validate the proposed control strategy.


2019 ◽  
Vol 8 (2S11) ◽  
pp. 3994-4000

This paper proposes the brushless direct current (BLDC) motor with high power density and high efficiency characteristics may be used to propulsion framework for electric vehicle. The progressive model for BLDC motor under rotor flux linkage route reference frame might have been providing. Here we analyzed the chart of ann vector and principal of ann control strategies and proposing the ann based reactive power with BLDC motor. To make ann based framework on active power, torque ripple, dc voltage, power factors can be used BLDC motor was designed. After designed simulation results was test the validity of field weakening based on reactive power with BLDC for electric vehicle application. In this research work will introduced artificial neural network (ANN) for non electrical input used. To control the BLDC motor speed it can using pulse width modulated control of the voltage source inverter (VLSI) using DC link voltage (Vdc) controller. To perform electronic commutation by hall signal sensing they are using PWM signal, to generate PWM signal inbuilt encoder can be used in this circuit. Analyze the BLDC motor performance driving propulsion framework is carried out under the MATLAB/Simulink software’s and efficiency of whole frame work is calculated under various source conditions


Author(s):  
Niraj Kumar Choudhary ◽  
Soumya Ranjan Mohanty ◽  
Ravindra Kumar Singh

This paper presents an investigation about the impact of integrating renewable energy based generation sources on the existing distribution system in terms of load sharing. The study of load sharing among various distributed generators (DGs) and utility grid has been performed for two cases: (a) when equivalent source based DG is connected and (b) when real PV/Fuel cell based DG is properly integrated to the distribution system. The real photovoltaic and fuel cell based DG do not behave as stiff current/voltage source due to disturbances happening either internally in system known as parametric uncertainties or due to external disturbances like weather conditions, load change etc. Further it has been observed with extensive analysis using simulation result, that even though all DGs are of equal capacity in their generation but when the load is either increased or decreased this doesn’t essentially guarantee that all DGs will equally share the active and reactive power demand


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