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 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.

The Impact of Wind Generation on Low Frequency Oscillation in Power Systems

2021 ◽  
Author(s):  
Mohammad M. Almomani ◽  
Abdullah Odienat ◽  
Seba F. Al-Gharaibeh ◽  
Khaled Alawasa
Keyword(s):  
Power Systems ◽  
Low Frequency ◽  
Wind Generation ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
The Impact

The Impact of Hydro-Turbine and its Governor System on Power System Low Frequency Oscillation

2012 ◽  
Vol 614-615 ◽  
pp. 875-879
Author(s):  
Jian Guo Zhu
Keyword(s):  
Power System ◽  
Transient Stability ◽  
Mechanical Load ◽  
Low Frequency ◽  
Hydraulic Turbine ◽  
Small Signal Stability ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
Hydro Turbine ◽  
The Impact

This paper studies the effect of the soft feedback in hydro-turbine and its governor system on power system transient stability. Low frequency oscillation phenomenon in which the hydraulic turbine sets participate occurred on power system many times this year, which with no mechanism discovered. In this paper, we first study the effect of mechanical load moment output of the prime mover system on the mechanism of low frequency oscillations, then by analysis of small-signal stability on hydro-turbine and its governor system and simulation experiments on an two-generator power system using PSASP, we come to the conclusion that: If the soft feedback output values of hydro-turbine governor systems are set small in the power system, it will come to the unstable oscillation condition.

scholarly journals Inertia Control Strategy of DFIG-Based Wind Turbines Considering Low-Frequency Oscillation Suppression

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 29
Author(s):  
Haoming Liu ◽  
Suxiang Yang ◽  
Xiaoling Yuan
Keyword(s):  
Wind Turbines ◽  
Control Strategy ◽  
Low Frequency ◽  
Frequency Regulation ◽  
Analysis Method ◽  
Frequency Oscillation ◽  
Low Frequency Oscillation ◽  
The Difference ◽  
Inertia Control ◽  
The Impact

It has become a basic requirement for wind turbines (WTs) to provide frequency regulation and inertia support. The influence of WTs on the low-frequency oscillation (LFO) of the system will change after adopting inertia control methods. This paper intends to investigate and compare in detail the IC effects on LFO characteristics in two systems with different structures. First, the mechanism of inertia control of doubly fed induction generator (DFIG)-based WTs is analyzed. Then, the small-signal analysis method and modal analysis method are used to study the influence of the inertia control on the LFO characteristics based on the two-machine infinite-bus system and the four-machine two-area system, respectively. The difference in impact rules of IC on LFO is compared in detail. Finally, considering that the inertia control might worsen the LFO in some systems, an improved inertia control strategy of DFIG-based WTs is proposed to suppress the LFO. The simulation results demonstrate that, in systems with different structures, the impact rules of the inertia control parameters on LFO are different. With the improved inertia control strategy, DFIG-based WTs can suppress the LFO of the system and provide inertia support for the system.

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