A review of pole slipping protection

Redfern, M.A.; Checksfield, Matt

doi:10.1049/ic:19961407

Cited by 5 publications

(4 citation statements)

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“…Out-of-Step (OOS) event are ideally an unstable power swing condition, which cannot be tolerable for a prolonged period of time due to its negative impact on power system equipment and integrity. OOS and pole slipping are similar designations for the condition where impedance trajectory as seen by protection relay, lies across generator impedance characteristics during a fault (Redfem & Checksfield, 1996). If the impedance trajectory goes through the characteristics of transmission line, then that is identified as an unstable power swing condition in the network (Apostolov et al, 1997).…”

Section: March 2021mentioning

confidence: 99%

“…Number of OOS events had taken place in past decades, leading to total or partial blackouts all around the world. In 1965In , 1994In , 1996In and 2003, different parts of the United States power system suffered severe power outages lead by OOS conditions with uncontrolled separation of the system (Allen et al, 2007). Power systems of Italy in 2003, Malaysia in 2005, Colombia in 2007 and India in 2012 had faced similar crises where formations of unstable islands were observed (Allen et al, 2007).…”

Section: Background Studymentioning

confidence: 99%

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Identification of coherent groups of generators for out-of-step protection using online measurements

Muthugala¹,

Wadduwage

Wijayapala

et al. 2021

J. Natn. Sci. Foundation Sri Lanka

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Power swings are translations of oscillations in generator rotors, when the power system is subjected to severe disturbances. They can be categorised as stable swings, for which, the system itself can recover and the unstable swings, where system cannot recover itself but need some remedial action to gain the stability. An unstable power swing condition or out-of-step (OOS) event cannot be tolerable for a prolonged period of time due to its negative impact on the power system equipment and integrity. These oscillations might trigger protection relays, removing key transmission elements leading to widespread outages and even blackouts. Controlled islanding of the system is one of the solutions to isolate the systems operating asynchronously during OOS events. Therefore, identification of generator coherency would come in handy in the process of controlled islanding, where the generators with similar rotor dynamic characteristics swing together forming separate clusters in transmission network. Also, it is important that the coherency identification to become online based, as coherent groups may differ in response to various events and operating conditions. This paper proposes a generalized methodology to identify coherent groups of generators as an online decision-making approach based on real-time data. The accuracy of the proposed methodology is demonstrated using Sri Lanka power system as a case study.

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Section: March 2021mentioning

confidence: 99%

Section: Background Studymentioning

confidence: 99%

Identification of coherent groups of generators for out-of-step protection using online measurements

Muthugala¹,

Wadduwage

Wijayapala

et al. 2021

J. Natn. Sci. Foundation Sri Lanka

View full text Add to dashboard Cite

show abstract

“…In (8), 9 is the maximum stable rotor angle that is known as Unstable Equilibrium Point (UEP) [21][22]. In post-fault condition, the generator is stable if it has the ability to return the excess absorbed kinetic energy during the acceleration area, A 1 to the power system, before the rotor angle reaches the UEP.…”

Section: Concept Of Impedance-based Oos Relaymentioning

confidence: 99%

Out-of-Step Protection Based on Equal Area Criterion

Alinezhad

Karegar

2016

IEEE Trans. Power Syst.

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This paper proposes a novel self-tuning and response-based method for estimation of a single generator instability after large disturbances in multi-machine power systems. The proposed method takes advantage of the Equal-Area Criterion (EAC) and least-squares method. The instability is determined by monitoring the cumulative acceleration and deceleration areas in the power-angle plane. These areas are continuously computed in order to determine whether or not the rotor angle reaches the Unstable Equilibrium Point (UEP). A realtime curve-fitting algorithm based on the least-squares method is suggested to estimate the UEP. The generator rotor angle is calculated readily using three-phase voltages and currents taken at the generator terminal, and no further information such as fault clearing instant is required. The algorithm is independent upon changes in network parameters and only needs locally measured quantities. Self-tuning and response-based operation are the main advantages of the proposed algorithm over the other existing algorithms. The performance of the proposed algorithm and its independence from the network configuration are successfully validated and compared with that of impedance-based out-of-step protection relays.

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“…The OOS of a generator not only is a threat for its mechanical components but also may affect the stability of the other generators in the network. Thus, early disconnection of an unstable generator can prevent other generators from instability and helps to save the rest of the system from total instability …”

Section: Introductionmentioning

confidence: 99%

Predictive out-of-step relay based on equal area criterion and PMU data

Alinezhad

Karegar

2017

Int. Trans. Electr. Energ. Syst.

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This paper proposes a novel-predictive and setting-free out-of-step protection technique based on synchronized phasor measurements and equal area criterion. Generator instability is predicted by comparing the acceleration and deceleration areas corresponding to the fault and postfault conditions, respectively. For each generator, the acceleration area during fault condition is calculated directly using the generator output power and rotor angle in real time. As soon as the fault is cleared, the deceleration area is predicted based on estimating the postfault Thévenin equivalent of the power network. The proposed technique is verified on the New England 39-bus test network. The effect of the proposed technique on improvement of the power network stability is compared with that of the well-known impedancebased out-of-step relay. KEYWORDS equal area criterion, impedance-based OOS relay, out-of-step, phasor measurement unit, Thévenin equivalent

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A review of pole slipping protection

Cited by 5 publications

References 0 publications

Identification of coherent groups of generators for out-of-step protection using online measurements

Identification of coherent groups of generators for out-of-step protection using online measurements

Out-of-Step Protection Based on Equal Area Criterion

Predictive out-of-step relay based on equal area criterion and PMU data

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