The Coordinated Immersion and Variance Control of Power Systems With Excitation and Steam-Valve

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Shengtao Li ◽  
Xiaomei Liu ◽  
Xiaoping Liu
Keyword(s):  
Power Systems ◽  
Energy Function ◽  
Transient Stability ◽  
Lyapunov Method ◽  
Control Performance ◽  
Immersion And Invariance ◽  
Angle Stability ◽  
Simulation Results ◽  
Lyapunov Energy Function ◽  
Large Disturbance

Transient stability is the key problem for reliable and secure planning under the new deregulated market conditions. By using immersion and invariance (I&I) method, a nonlinear coordinated generator excitation and steam-valve controller is designed to improve transient stability of power systems. The proposed coordinated I&I controller can assure power angle stability, voltage, and frequency regulations, when a large disturbance occurs on the transmission line or a small perturbation to mechanical power. Compared with the Lyapunov method, the proposed method does not need to construct a Lyapunov energy function. Some numerical simulations are used to validate the proposed controller. Simulation results show that the nonlinear coordinated I&I controller has better control performance than the existing coordinated passivation controller (CPC).

scholarly journals A New Indicator of Transient Stability for Controlled Islanding of Power Systems: Critical Islanding Time

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2975 ◽  
Author(s):  
Zhenzhi Lin ◽  
Yuxuan Zhao ◽  
Shengyuan Liu ◽  
Fushuan Wen ◽  
Yi Ding ◽  
...  
Keyword(s):  
New York ◽  
Power Systems ◽  
New England ◽  
Transient Stability ◽  
Time Frame ◽  
Test System ◽  
Crucial Importance ◽  
Interconnected System ◽  
Controlled Islanding ◽  
Simulation Results

Transient stability after islanding is of crucial importance because a controlled islanding strategy is not feasible if transient stability cannot be maintained in the islands created. A new indicator of transient stability for controlled islanding strategies, defined as the critical islanding time (CIT), is presented for slow coherency-based controlled islanding strategies to determine whether all the islands created are transiently stable. Then, the stable islanding interval (SII) is also defined to determine the appropriate time frame for stable islanding. Simulations were conducted on the New England test system–New York interconnected system to demonstrate the characteristics of the critical islanding time and stable islanding interval. Simulation results showed that the answer for when to island could be easily reflected by the proposed CIT and SII indicators. These two indicators are beneficial to power dispatchers to keep the power systems transiently stable and prevent widespread blackouts.

Transient stability analysis and control of power systems with considering flux decay by energy function approach

2012 ◽  
Vol 60 (1) ◽  
pp. 3-8
Author(s):  
D. Lu ◽  
X. Zhang
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Energy Function ◽  
Transient Stability ◽  
Stability Boundary ◽  
Function Approach ◽  
Fault System ◽  
Rotor Angle ◽  
And Control ◽  
Transient Stability Analysis

Transient stability analysis and control of power systems with considering flux decay by energy function approach In this paper, transient stability of power systems with structure preserving models is considered. A Hamiltonian function which can be regarded as a Lyapunov function for the system is proposed. Based on this, the influence of flux decay dynamics, especially during a fault, on transient stability is analyzed. With the increase of load power, the variation of stability boundary in the rotor angle/E'q plane is shown. The Energy-based excitation control, aiming at injecting additional damping into the post-fault system may reduce the critical clearing time (CCT). This can be demonstrated by the comparison of different flux decay dynamics in the fault-on condition, and the reason is illustrated by the relationship between rotor angle/E'q and the stability boundary. An improved control strategy is proposed and applied to increase the CCT. Simulation results verify that improvement is obtained both in transient stability and dynamic performance.

Transient stability analysis of stressed power systems using the energy function method

1988 ◽  
Vol 3 (1) ◽  
pp. 239-244 ◽  
Author(s):  
V. Vittal ◽  
S. Rajagopal ◽  
A.A. Fouad ◽  
M.A. El-Kady ◽  
E. Vaahedi ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Power Systems ◽  
Energy Function ◽  
Function Method ◽  
Transient Stability ◽  
Transient Stability Analysis

scholarly journals Immersion and Invariance-Based Coordinated Generator Excitation and SVC Control for Power Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Adirak Kanchanaharuthai
Keyword(s):  
Power Systems ◽  
Small Perturbation ◽  
Feedback Linearization ◽  
Transient Stability ◽  
Dynamic Properties ◽  
Voltage Regulation ◽  
Nonlinear Controller ◽  
Electrical Power System ◽  
Immersion And Invariance ◽  
Large Perturbation

A nonlinear coordinated control of excitation and SVC of an electrical power system is proposed for transient stability, and voltage regulation enhancement after the occurrence of a large disturbance and a small perturbation. Using the concept of Immersion and Invariance (I&I) design methodology, the proposed nonlinear controller is used to not only achieve power angle stability, frequency and voltage regulation but also ensure that the closed-loop system is transiently and asymptotically stable. In order to show the effectiveness of the proposed controller design, the simulation results illustrate that, in spite of the case where a large perturbation occurs on the transmission line or there is a small perturbation to mechanical power inputs, the proposed controller can not only keep the system transiently stable but also simultaneously accomplish better dynamic properties of the system as compared to operation with the existing controllers designed through a coordinated passivation technique controller and a feedback linearization scheme, respectively.

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