Online Detection of Loss of Synchronism Using Energy Function Criterion

Padiyar, К.R.; Krishna, S.

doi:10.1109/tpwrd.2005.848652

Cited by 81 publications

(31 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Most of the methods reported in the literature focus on the stability criterion based on the system dynamic response that can decide the transient stability without the need for results obtained from the time-domain simulation. These methods include energy function analysis [8], phase-plane trajectories [9,10], timedomain equal-area criterion [7,11] and Lyapunov's method [12]. However, in multi-machine power systems, the generator groups must be identified before the online stability assessment.…”

Section: Introductionmentioning

confidence: 99%

Augmentation of transient stability margin based on rapid assessment of rate of change of kinetic energy

Al-Taee

Al-Nuaimy

2016

Electric Power Systems Research

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Augmentation of transient stability margin based on rapid assessment of rate of change of kinetic energy

Al-Taee

Al-Nuaimy

2016

Electric Power Systems Research

View full text Add to dashboard Cite

“…The most popular and well-known out-of-step detection technique in China is the three-impedance element model based on the variation of apparent impedance locus at machine terminal. When applied to multi-machine systems, it can distinguish whether the oscillation center is internal or external of the generator-transformers [4]. This method can also adjust setting valves of allowable tripping current and the number of sliding pole.…”

Section: Introductionmentioning

confidence: 99%

Out-of-step Protection combining Three-impedance Element Model with the Equal Area Criterion

Yuan¹,

Zhang²,

Chen³

2016

Proceedings of the 2015 2nd International Forum on Electrical Engineering and Automation (IFEEA 2015)

View full text Add to dashboard Cite

This paper proposes a new procedure for out-of-step protection through the combination of a three-impedance element model with equal area criterion. The P   curve of the system is transferred into P t  curve and then P t  curve is applied to forecast whether the oscillation between the generator and the power system is out-of-step or stable. The forecasting results determine the operation of the out-of-step protection: If the oscillation is unstable, the signals will be sent during the first period of unstable oscillation, and then the number of sliding pole will be counted to achieve a delay action. Otherwise, no response will be made. A three-machine infinite bus system has been used to test the proposed method by simulation with PSCAD software. The simulations test the protection in a variety of faults within the system, including unstable and stable oscillation, loss of excitation and short-circuit faults. Simulation results confirm that this method can work effectively as a backup protection when faults such as loss of excitation and short-circuit fault are not promptly removed. Moreover, the simulations provide a reliable basis for the scheme and design of out-of-step protection in the power plant. IntroductionElectromechanical oscillation in power systems occurs due to an imbalance between input and output powers. Whether the power system will return to a stable state depends on the level of the disturbance. The oscillations will not damp out after a severe disturbance and consequently lead to an unstable operating condition called an out-of-step condition. In order to lead the rest of the system back into a new stable condition, the out-of-step relays are equipped to detect such conditions in the power system and disconnect part of the system at preselected locations [1].Currents and voltages oscillate in amplitude and phase during power system swings. At certain locations of the power system, the calculated impedances will be so small during a disturbance that they enter the protection dead zones of distance relays [2]. In many cases where the disturbance is not severe, the systems should be allowed to settle down to a stable state. In other cases, the systems should be disconnected from one another as they are likely to become unstable. After disconnection, the individual systems should be allowed to settle down to stable states. In order to maintain generation load balance, it at times become necessary to shed load or generation, which depends on the situation of the disturbance. Conventional power swing relays use distance relays and delay timers to distinguish power swings that are likely to result in system instability from those which are likely to settle into stable states [3].There are various techniques available in literature and in practice to detect out-of-step conditions. The most popular and well-known out-of-step detection technique in China is the three-impedance element model based on the variation of apparent impedance locus at machine terminal. When applied to multi-machi...

show abstract

“…To realise fast online transient stability assessment, other researches reported in the literature concentrate on the stability criterion based on the system dynamic response, including energy function analysis [13], phase-plane trajectories [14][15][16] and equal area criterion [17][18][19]. These methods can decide the transient stability without pre-existing results obtained from the time-domain simulation.…”

Section: Introductionmentioning

confidence: 99%

Criterion to evaluate power system online transient stability based on adjoint system energy function

Zhao

Jia

Fang

et al. 2015

IET Generation, Transmission & Distribution

View full text Add to dashboard Cite

In this paper, a new criterion to quickly evaluate the system transient stability based on wide area measurement system (WAMS) information, energy function method and adjoint power system (APS) model is proposed. APS is a two-dimensionalfirst-order differential equation model, which can be considered as a virtual representation to the real power system. Meaning of APS is first explained by using the one machine infinite bus system. Then, a new criterion based on projection kinetic energy of APS is proposed to determine the transient stability of the original power system with multiple generators. Trajectory prediction method based on curve fitting technique is adopted to accelerate the evaluation process. The proposed method is sufficiently rapid since it does not rely on the network structure, system model, system parameters and the identification of the coherent generator groups. Therefore, it can be utilised for online transient stability assessment based on WAMS. Simulation results on the New England system and one of North China Power System validate the correctness and effectiveness of the proposed method. Nomenclature Minertia constant of OMIB system M i inertia constant of ith generator P mi mechanical power output of ith generator P ei electrical power output of ith generator P e1 electrical power output of the generator in pre-fault P e2 electrical power output of the generator in fault P e3 electrical power output of the generator in post-fault t system time t cl fault clearing time Δt sampling time interval of WAMS α rotor acceleration of OMIB system α i ith rotor acceleration in COI reference δ rotor angle of OMIB system δ re maximum rotor angle of OMIB system in a stable swing δ cr critical rotor angle of OMIB system θ i ith rotor angle in centre of inertia (COI) reference ω rotor speed of OMIB system v i ith rotor speed in COI reference

show abstract

Online Detection of Loss of Synchronism Using Energy Function Criterion

Cited by 81 publications

References 10 publications

Augmentation of transient stability margin based on rapid assessment of rate of change of kinetic energy

Augmentation of transient stability margin based on rapid assessment of rate of change of kinetic energy

Out-of-step Protection combining Three-impedance Element Model with the Equal Area Criterion

Criterion to evaluate power system online transient stability based on adjoint system energy function

Contact Info

Product

Resources

About