Impact Analysis of Excitation System Reactive Current Compensation on the Stability of Sichuan Power Grid

2013 ◽  
Vol 805-806 ◽  
pp. 735-740
Author(s):  
Fan Tang ◽  
Li Jie Ding ◽  
Hua Zhang ◽  
Biao Wang
Keyword(s):  
Transient Stability ◽  
Impact Analysis ◽  
Reactive Power ◽  
Simulation Analysis ◽  
Power Grid ◽  
Heavy Load ◽  
Current Compensation ◽  
Reactive Current ◽  
The Stability ◽  
Damping Torque

Heffron-Philips model including excitation reactive current compensation (RCC) is set up, impact analysis of RCC on the stability of power system is carried out by theoretical analysis and time domain simulation. Analysis results show that positive RCC increases damping torque while reduces synchronous torque; negative compensation increases synchronizing torque while reduces damping torque, and this phenomenon is more obvious in heavy load. Combined with the actual situation in Sichuan power grid, the role of negative RCC to increase transient stability and provide dynamic reactive power for emergency HVDC power support is analyzed, also negative RCC's influence on the damping characteristics in Sichuan power grid is evaluated.

Reliable Analysis on Fast Valving of Ultra-Supercritical Unit Under Transient Fault Conditions

2017 ◽  
Author(s):  
Yu Cai ◽  
Wei Li ◽  
Bao Zhang ◽  
Wenjian Wu ◽  
Deren Sheng ◽  
...  
Keyword(s):  
Power System ◽  
Steam Turbine ◽  
Dynamic Model ◽  
Transient Stability ◽  
Power Grid ◽  
Load Shedding ◽  
Control Mode ◽  
Normal Operation ◽  
Transient Fault ◽  
The Stability

Fast valving of ultra-supercritical unit has great effects on over-speed prevention, load-shedding control, transient stability analysis of electrical system and other security problems. The purpose of fast valving is to maintain the stability of power system once fault or load shedding of unit occurs in the electric power system. Therefore, it is of great significance to study the reliability of fast valving for ultra-supercritical unit. In this paper, the KU ( short shedding) logic condition of SIEMENS T3000 system is analyzed as the research object of fast valving. The unit can be avoided over speed by monitoring the unit load and fast valving under faulty grid conditions based on the KU control. A series of measures will be taken after KU is triggered, for instance the governing valving will be closed quickly and the DEH (digital electro-hydraulic) control of the steam turbine will be switched to speeding control mode. On the other hand, the unit will return to normal operation if the transient fault of power grid disappears. The key contributions of this thesis include three parts: Firstly, based on the analysis of control characteristics of ultra-supercritical unit and protective logic and triggered conditions of KU function, a novel dynamic model by coupling the fast valving of steam turbine and the transient stability of generator is established by applying the PSCAD software. Then, the dynamic response process of ultra-supercritical unit is simulated and calculated by adopting the coupling dynamic model when KU function is triggered. Also the influence factors and reliability of fast valving are analyzed under transient fault conditions. Finally, two optimized measures by increasing the time delay and the speed of quantitative judgment are put forward to reduce risks and avoid the misoperation of signal distortion which may be caused by the power transmitter under transient fault conditions. The results of this study can not only help to evaluate the reliability of fast valving function scientifically in power grid transient fault, but also guide the technicians to analyze the stability of the power grid.

Study of Influence on Power System Voltage Stability of Wind Farm Power Output Fluctuation

2013 ◽  
Vol 694-697 ◽  
pp. 846-849
Author(s):  
Jian Yuan Xu ◽  
Wei Fu Qi ◽  
Yun Teng
Keyword(s):  
Power System ◽  
Wind Power ◽  
Power Output ◽  
Voltage Stability ◽  
Wind Farm ◽  
Reactive Power ◽  
Simulation Analysis ◽  
Power Grid ◽  
Reactive Power Compensation ◽  
Grid Integration

This paper mainly studies wind power fluctuations how to affect voltage stability after the wind power grid integration, and reactive power compensation equipment on improving effect. In certain parts of the wind farm, for example, firstly, analyzing the wind farm reactive power problems. Then introduce the reactive power compensation equipment that used in the wind farm. Finally, with PSCAD software, making a simulation analysis about the influence on the power grid voltage according to adopting the different reactive power compensation devices or not.

The Study of Chopper in the LVRT of Direct-Drive Wind Energy Generation System

2014 ◽  
Vol 950 ◽  
pp. 314-320 ◽  
Author(s):  
Jun Jia ◽  
Xin Xin Hu ◽  
Ping Ping Han ◽  
Yan Ping Hu
Keyword(s):  
Power System ◽  
Wind Power ◽  
Wind Turbines ◽  
Reactive Power ◽  
Power Grid ◽  
Synchronous Generator ◽  
Direct Drive ◽  
Fault Ride Through ◽  
Wind Power System ◽  
The Stability

With the scale of wind farm continuously increasing, when grid fault, the influences of the wind turbines connected to the grid on the stability of the power grid can never be ignored. Therefore, there are higher standards of the wind turbines’ abilities of fault ride-through (FRT) and producing reactive power. This paper studies the direct-drive wind power system, and the main point is the fault ride-through (FRT) of the permanent magnetic synchronous generator (PMSG) with Chopper. By establishing the dynamic model of PMSG under the environment of DigSILENT, this paper simulates the fault ride-through (FRT) of the direct-drive wind power system connecting into power grid. During the research, we focus on the stability of voltage about the Chopper to the DC bus under faults. What’s more, in this paper, we analysis the data about how the Chopper help the DC bus to improve its stability. The simulation results show that: when there is a fault on the point of common coupling, the permanent magnetic synchronous generator has the capability of fault ride-through (FRT). Especially when there is a voltage dip on the grid side, the permanent magnetic synchronous generator could produce reactive power for power grid, effectively preventing the system voltage from declining seriously, so as to improve the system stability under faults.

Experimental Voltage Stabilization of a Variable Speed Wind Turbine Driving Synchronous Generator using STATCOM based on Genetic Algorithm

2016 ◽  
Vol 17 (5) ◽  
pp. 541-546 ◽  
Author(s):  
Helmy M. El-Zoghby ◽  
Ahmed F. Bendary
Keyword(s):  
Genetic Algorithm ◽  
Power System ◽  
Wind Turbine ◽  
Reactive Power ◽  
Power Grid ◽  
Synchronous Generator ◽  
Voltage Regulation ◽  
Operating Conditions ◽  
Static Synchronous Compensator ◽  
The Stability

Abstract In this paper Static Synchronous Compensator (STATCOM) is used for improving the performance of the power grid with wind turbine that drives synchronous generator. The main feature of the STATCOM is that it has the ability to absorb or inject rapidly reactive power to grid. Therefore the voltage regulation of the power grid with STATCOM device is achieved. STATCOM also improves the stability of the power system after occurring severe disturbance such as faults, or suddenly step change in wind speed. The proposed STATCOM controller is a Proportional-Integral (PI) controller tuned by Genetic Algorithm (GA). An experimental model was built in Helwan University to the proposed system. The system is tested at different operating conditions. The experimental results prove the effectiveness of the proposed STATCOM controller in damping the power system oscillations and restoring the power system voltage and stability.

Research on Stability of Power System with Distributed Generation Synthesis Load Model

2013 ◽  
Vol 341-342 ◽  
pp. 1374-1379
Author(s):  
Yang Liu ◽  
Zhen An Zhang ◽  
Wei Liu ◽  
Ya Nan Wang
Keyword(s):  
Power System ◽  
Distributed Generation ◽  
Transient Stability ◽  
Power Grid ◽  
Stable Operation ◽  
Power Network ◽  
Small Hydropower ◽  
Large Power ◽  
Load Model ◽  
The Stability

With different element models and parameters in power system, the transient stability analysis results are also different, especially the model of generator and load. Based on the actual parameters of Hunan power grid, this paper builds the synthesis load model of the distribution network with small hydropower considered, and then the Hunan simulation network can also be got. Using PSASP, analyses the transient stability of Hunan power system with distributed small hydropower under different operation modes systematically and comprehensively. Through an overall check of the stability level in each Hunan area, and then compared with the analysis results of Hunan power grid based on the currently used load model , the influences of the distributed small hydropower on the safe and stable operation of the large power network are summarized.

scholarly journals Transient Stability Improvement of IEEE 9-Bus System Using Static Var Compensator

2021 ◽  
Vol 4 (4) ◽  
pp. 98-102
Author(s):  
Manish Shrivastava ◽  
Vinay Prakash ◽  
Vishal Kaushik ◽  
Vivek Kumar Upadhyay
Keyword(s):  
Power Systems ◽  
Transient Stability ◽  
Reactive Power ◽  
Test System ◽  
Limiting Factor ◽  
Static Var Compensator ◽  
Voltage Profile ◽  
Matlab Simulation ◽  
The Stability ◽  
Stability Limits

With increase in power demand over the last few decades, there has been a great expansion in power generation & transmission. But due to various disturbances, improper loading and environmental conditions the power systems are working near their stability limits which have become a power-transfer limiting factor. This in turn poses a threat to the stability of the system. Transient stability has been considered as one of the most important stability for a power system. In this paper Static VAR Compensator (SVC) has been discussed for reactive power control and hence improvement of transient stability and voltage profile. This paper incorporates IEEE-9 BUS test system with SVC controller using MATLAB Simulation.

Nonlinear Time Transient Stability Analysis of Multilobe Bearings

2005 ◽  
Author(s):  
S. K. Kakoty ◽  
M. Kalita ◽  
T. Thivagar
Keyword(s):  
High Speed ◽  
Transient Stability ◽  
Mass Parameter ◽  
Critical Mass ◽  
Heavy Load ◽  
Aspect Ratios ◽  
Nonlinear Transient ◽  
Precision Machine Tools ◽  
The Stability ◽  
Insight Into

In some specialized applications, plain circular bearing is mostly replaced by some other bearings, as plain bearing does not suit the stability requirements of high-speed machines and precision machine tools. Grooved circular bearings and multi-lobe bearings with two lobes, three lobes and four lobes are commonly used. The present work gives insight into nonlinear transient analysis of multi lobe journal bearing systems. An attempt has been made to evaluate the critical mass parameter (a measure of stability) for various values of aspect ratios besides finding out the steady state characteristics of multilobe journal bearings (two grooved, two lobe, three lobe and four lobe) such as load bearing capacity, Sommerfeld number and attitude angle At moderate and heavy load conditions (Sommerfeld number from 0.1 to 0.3), four-lobe bearing is most stable. Three-lobe bearing is the best in the range of Sommerfeld number from 0.3 to 0.8. Two-lobe bearing is found to be more stable than other bearings beyond this range.

scholarly journals Penalty Based Control Mechanism for Strategic Prosumers in a Distribution Network

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 452
Author(s):  
Arnob Ghosh ◽  
Vaneet Aggarwal
Keyword(s):  
Power Flow ◽  
Reactive Power ◽  
Control Mechanism ◽  
Power Grid ◽  
Power Network ◽  
Flow Equations ◽  
Active And Reactive Power ◽  
Theoretic Problem ◽  
Game Theoretic ◽  
The Stability

The distribution side of the traditional power grid is changing as the users (known as prosumers) can inject power to the grid. However, uncontrollable injection of power can destabilize the grid. Thus, the stability of the grid must be maintained. Since the prosumers are self-interested entities, they will take their actions to maximize their own pay-offs. We formulate the problem as a non-cooperative game theoretic problem where the magnitude of the voltage must be within an acceptable limit at each node of the power network. Since the power-flow equations must be satisfied at each node, it becomes a coupled constrained game where the constraints are the same across the prosumers. We propose a distributed penalty based algorithm which converges to an equilibrium. In this mechanism, the prosumers are quoted a price based on the active and reactive power drawn or injected to the power grid. The algorithm is easy to implement and it converges to an efficient solution which maximizes the sum of the utilities of the prosumers while maintaining the grid’s stability.

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