Suppression of Low-Frequency Oscillation in Traction Network of High-Speed Railway Based on Auto-Disturbance Rejection Control

2016 ◽  
Vol 2 (2) ◽  
pp. 244-255 ◽  
Author(s):  
Guinan Zhang ◽  
Zhigang Liu ◽  
Shulong Yao ◽  
Yicheng Liao ◽  
Chuan Xiang
Keyword(s):  
Disturbance Rejection ◽  
High Speed ◽  
Low Frequency ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
High Speed Railway ◽  
Disturbance Rejection Control ◽  
Traction Network

scholarly journals THE ANALYSIS OF LOCAL OSCILLATION IN THE GAS TURBINE GENERATOR CONNECTTO POWER GRID SYSTEMS USE LINEAR OBSERVER

2020 ◽  
Vol 5 (2) ◽  
pp. 159-169
Author(s):  
Nguyen Hoang Mai ◽  
Tran van Dung
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Power Plants ◽  
Power Grid ◽  
Low Frequency ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Turbine Generator ◽  
Local Oscillation ◽  
Linear Observer

The low frequency oscillation in the electrical generator connect to power grid is an important problem to control systems, especially in the gas turbine generators with high speed. The oscillation makes affect to life time, finance of operating and effect of energy process. There are many cause of the oscillation in governor speed control of power plants. They use PSS to do damping low frequency oscillation in recently [11], [12], [13], [14], [22], [23]. So PSS usually does process with delay cycle time, therefore it makes effect isn’t good result. This paper presents a method using linear in the gas turbine generator, which connects to power grid. By observe affect action of local oscillation of the power, study finds key point of oscillation time. From that, we take out decision to do prediction of damping in system and supply signal in to PSS to reduce damaging of this oscillation. Simulation results explain difference action of the system with linear observer and system without linear observer.

scholarly journals Suppression Research Regarding Low-Frequency Oscillation in the Vehicle-Grid Coupling System Using Model-Based Predictive Current Control

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1803 ◽  
Author(s):  
Yaqi Wang ◽  
Zhigang Liu
Keyword(s):  
High Speed ◽  
Low Frequency ◽  
Current Control ◽  
Control Voltage ◽  
Continuous Control ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Model Based ◽  
Coupling System ◽  
The Impact

Recently, low-frequency oscillation (LFO) has occurred many times in high-speed railways and has led to traction blockades. Some of the literature has found that the stability of the vehicle-grid coupling system could be improved by optimizing the control strategy of the traction line-side converter (LSC) to some extent. In this paper, a model-based predictive current control (MBPCC) approach based on continuous control set in the dq reference frame for the traction LSC for electric multiple units (EMUs) is proposed. First, the mathematical predictive model of one traction LSC is deduced by discretizing the state equation on the alternating current (AC) side. Then, the optimal control variables are calculated by solving the performance function, which involves the difference between the predicted and reference value of the current, as well as the variations of the control voltage. Finally, combined with bipolar sinusoidal pulse width modulation (SPWM), the whole control algorithm based on MBPCC is formed. The simulation models of EMUs’ dual traction LSCs are built in MATLAB/SIMULINK to verify the superior dynamic and static performance, by comparing them with traditional transient direct current control (TDCC). A whole dSPACE semi-physical platform is established to demonstrate the feasibility and effectiveness of MBPCC in real applications. In addition, the simulations of multi-EMUs accessed in the vehicle-grid coupling system are carried out to verify the suppressing effect on LFO. Finally, to find the impact of external parameters (the equivalent leakage inductance of vehicle transformer, the distance to the power supply, and load resistance) on MBPCC’s performance, the sensitivity analysis of these parameters is performed. Results indicate that these three parameters have a tiny impact on the proposed method but a significant influence on the performance of TDCC. Both oscillation pattern and oscillation peak under TDCC can be easily influenced when these parameters change.

scholarly journals Nonlinear Second-Order Model and Equilibrium Point Characteristic Analysis of DC Traction Power Supply System

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Y. H. Li ◽  
X. J. Tian ◽  
X. Q. Li
Keyword(s):  
Power Supply System ◽  
Short Circuit ◽  
Low Frequency ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Traction Power Supply System ◽  
Traction Network ◽  
Traction Power Supply ◽  
Short Circuit Fault ◽  
Traction Power

According to the different features of the DC traction network transient current in the Metro, the electromagnetic transient process of traction power supply system that should be divided into the two forms of short-circuit fault and the low-frequency oscillation was proposed. While traction network short-circuit fault happens, the system model is a weakly nonlinear first-order differential equation, which feeder current is increasing exponentially and eventually stabilized. While the load current becomes low-frequency oscillation current, the system model is a nonlinear second-order differential equation. After linear processing in unique equilibrium point neighborhood, the state space equation of linear system is built, and the structural reason of low-frequency oscillation is revealed by eigenvalue analysis method. The simulation result shows that the simulation current waveforms are consistent with the recorded current waveforms and the division of transient process is reasonable.

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