scholarly journals Dynamic Stability Improvement of Power System with VSC-HVDC Transmission

2018 ◽  
Vol 7 (3.27) ◽  
pp. 500
Author(s):  
R Vasudevan ◽  
S Ramalakshmi
Keyword(s):  
Power System ◽  
Dynamic Stability ◽  
High Voltage ◽  
Transient Stability ◽  
Reactive Power ◽  
Average Frequency ◽  
Management Approach ◽  
Communication Delays ◽  
Hvdc Transmission ◽  
Central Controller

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. 

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
Keyword(s):  
Transient Stability ◽  
Reactive Power ◽  
Control Strategies ◽  
Weighted Average ◽  
Frequency Measurement ◽  
Average Frequency ◽  
Voltage Source ◽  
Communication Delays ◽  
Communication Latency ◽  
The Impact

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.

scholarly journals A Three-Stage Procedure for Controlled Islanding to Prevent Wide-Area Blackouts

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3066 ◽  
Author(s):  
Hongbo Shao ◽  
Yubin Mao ◽  
Yongmin Liu ◽  
Wanxun Liu ◽  
Sipei Sun ◽  
...  
Keyword(s):  
Power System ◽  
Dynamic Stability ◽  
Power Flow ◽  
Transient Stability ◽  
Load Shedding ◽  
Area Measurement ◽  
Wide Area ◽  
Measurement Systems ◽  
Controlled Islanding ◽  
Three Stages

Controlled islanding has been proposed as a last resort action to stop blackouts from happening when all standard methods have failed. Successful controlled islanding has to deal with three important issues: when, and where to island, and the evaluation of the dynamic stability in each island after islanding. This paper provides a framework for preventing wide-area blackouts using wide area measurement systems (WAMS), which consists of three stages to execute a successful islanding strategy. Normally, power system collapses and blackouts occur shortly after a cascading outage stage. Using such circumstances, an adapted single machine equivalent (SIME) method was used online to determine transient stability before blackout was imminent, and was then employed to determine when to island based on transient instability. In addition, SIME was adopted to assess the dynamic stability in each island after islanding, and to confirm that the chosen candidate island cutsets were stable before controlled islanding was undertaken. To decide where to island, all possible islanding cutsets were provided using the power flow (PF) tracing method. SIME helped to find the best candidate islanding cutset with the minimal PF imbalance, which is also a transiently stable islanding strategy. In case no possible island cutset existed, corresponding corrective actions such as load shedding and critical generator tripping, were performed in each formed island. Finally, an IEEE 39-bus power system with 10 units was employed to test this framework for a three-stage controlled islanding strategy to prevent imminent blackouts.

scholarly journals Investigating the impacts of the SVCs and the SCs affecting to the transient stability in multi-machine power system

2016 ◽  
Vol 19 (2) ◽  
pp. 16-24
Author(s):  
Quang Huu Vinh Luu
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Reactive Power ◽  
Voltage Regulation ◽  
State Variables ◽  
Static Var Compensators ◽  
Transient Energy ◽  
Voltage Frequency ◽  
Power Outputs ◽  
Synchronous Condensers

A new algorithm simulating the impacts of the VAR supporting devices such as the static var compensators (SVCs) and the synchronous condensers (SCs) under condition of symmetrical disturbances in multi-machine power system is mentioned. Some typical numerical examples are presented in this article. The comparisons of variation of the state parameters, such as the voltage, frequency, reactive power outputs and asynchronous torques…are simulated under condition of the action of the automatic voltage regulation systems of generators and of the VAR supporting devices. The transient energy margins are calculated and compared to assess the transient stability in multi-machine power system. Basing on this algorithm, the PC program uses the elements of the eigen-image matrix to bring the specific advantages for the simulation of the transient features of state variables.

scholarly journals Transient Stability Enhancement of Multimachine Power System Using Robust and Novel Controller Based CSC-STATCOM

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Sandeep Gupta ◽  
Ramesh Kumar Tripathi
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Reactive Power ◽  
Controller Design ◽  
Current Source ◽  
Test System ◽  
Vital Role ◽  
Static Synchronous Compensator ◽  
Ac Transmission ◽  
The Impact

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.

scholarly journals Power Flow and Transient Stability Enhancement using Thyristor Controlled Series Compensation

2018 ◽  
Vol 37 (4) ◽  
pp. 685-700 ◽  
Author(s):  
Zaira Anwar ◽  
Tahir Nadeem Malik ◽  
Tahir Abbas
Keyword(s):  
Power System ◽  
Transmission Line ◽  
Dynamic Stability ◽  
Power Flow ◽  
Transient Stability ◽  
Dynamic Models ◽  
Efficient Solutions ◽  
Simulation Software ◽  
Series Compensation ◽  
Thyristor Controlled Series Compensation

TL (Transmission Line) congestion is a key factor that affects the power system operational cost. In addition of renewable generation in National Grid of Pakistan, transmission line congestion are frequent. Consequently, the network in this particular region faces severe congestion and dynamic stability problems. It has been planned that renewable plants shaved to curtail some available generation to minimize this inevitable congestion. However, one of the cost-efficient solutions to this problem is series compensation of lines using TCSC (Thyristor Controlled Series Compensation). It significantly increases the transfer capability of existing power transmission and enhances the dynamic stability of system at a lower cost, and has shorter installation time as compared to the construction of new TLs. This paper deals with the dynamic modeling of a TCSC in the NTDC (National Transmission and Dispatch Company) network with its applications to alleviate congestion during fault conditions. This study has been carried out using simulation software PSS/E (Power System Simulator for Engineers) which does not have a predefined dynamic model for TCSC, this leads to the necessity of creating a user defined model. The model of TCSC has been programmed in FORTRAN and compiled along with existing dynamic models of network components. The results indicate that power flow and dynamic stability of network is enhanced

scholarly journals Enhancement Stability of the Power System Using Static Synchronous compensators Connected in Different Formats

2021 ◽  
Vol 28 (1) ◽  
pp. 1-12
Author(s):  
Maha Al-Flaiyeh ◽  
Nagham Aziz
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Reactive Power ◽  
Research Strategy ◽  
Static Synchronous Compensator ◽  
Clearing Time ◽  
Better Than

The research strategy focuses on the effect of connecting a STATCOM to mend critical-clearing-time (CCT) for the studied system and its transient stability. This paper targets to connect STATCOM in two situations, grouped and distributed. The first situation connects STATCOM at one placement with 100 MVAR reactive power while the second situation connects two STATCOMs at two different placements with the value 50 MVAR for each one and 60 MVAR,40 MVAR in another case. It has been found through this research that when distributing the necessary compensation capacity to more than one static synchronous compensator better than from combined them in one compensator in improving the CCT. It used MATLAB / ver.2017 for simulation of our studied system (IEEE-9 nodes).

scholarly journals A Mathematical Framework for Modelling of Current Source Converter Based High Voltage DC Transmission Systems

2019 ◽  
Vol 9 (1) ◽  
pp. 4497-4505
Keyword(s):  
High Voltage ◽  
Reactive Power ◽  
Electrical Power ◽  
Current Source ◽  
Current Control ◽  
Mathematical Framework ◽  
Transmission Systems ◽  
Pass Filter ◽  
Hvdc Transmission ◽  
Current Source Converter

Transmission of electrical power through High Voltage Direct Current (HVDC) has attracted the attention of several researchers in the recent years. To investigate the performance of HVDC transmission systems, a complete linear mathematical model is required. In this paper, a well-developed linear continuous model of current source converter based twelve pulse HVDC transmission systems is presented. In which, the converter AC system is represented by damped LLR equivalents at fundamental frequency and at the third harmonic. Also, they are equipped with double tuned harmonic filter and second order high pass filter to suppress the AC harmonics and a capacitor for reactive power compensation. The DC system is secured with rectifier current control, inverter current control, inverter voltage control and inverter extinction angle control. The HVDC transmission system model is implemented in the MATLAB/Simulink environment and the performance of the system has been investigated by observing the rectifier side AC quantities, rectifier DC quantities, inverter side AC quantities and inverter DC quantities

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