Multi-generator transient-stability performance under fault conditions

Scott, E.C.; Casson, W.; Chorlton, Alan E. L.; Banks, J.H.

doi:10.1049/piee.1963.0147

Cited by 6 publications

(3 citation statements)

References 4 publications

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“…4a), the swing current following fault clearance will fall to approximately one-third of the fault current, and this may be seen from the results of system tests. 2 In Section 4, backup-overcurrent relay settings are derived using fault-current/time curves which neglect rotor swing on the basis that curves of this kind give adequate margins. Fig.…”

Section: Postfault Recoverymentioning

confidence: 99%

“…Fig. 4 Generator stator currents during and following fault clearance a Single-phase-to-earth fault 2 b 3-phase fault 3 -computed c 3-phase fault followed by sustained pole slipping 2 Fault applied at t = 0, and cleared at I -f Average values of current are used to illustrate the principle rather than an integration of relay current with time to determine incremental disc travel. This is permissible in this case because the fault-current variation in Fig.…”

Section: Postfault Recoverymentioning

confidence: 99%

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Some aspects of generator backup protection in relation to synchronous-machine performance during h.v.-system faults

Cook

Rushton

1972

Proc. Inst. Electr. Eng. UK

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The fault performance of large generator units is considered in relation to the selection of generatorbackup-protection settings, and a method of determining protection performance is presented, based on a simplified analysis of generator fault currents and neglecting rotor-angle swings. The validity of this approach is demonstrated and the method is used to determine the fault performance of negative-phase-sequence current and overcurrent protection. Alternative methods of overcurrent protection are examined which appear to provide improved backup protection for internal and external faults.

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Section: Postfault Recoverymentioning

confidence: 99%

Section: Postfault Recoverymentioning

confidence: 99%

Some aspects of generator backup protection in relation to synchronous-machine performance during h.v.-system faults

Cook

Rushton

1972

Proc. Inst. Electr. Eng. UK

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“…This has been confirmed by practical tests. 5 The stator-resistance losses due to this direct current and the interaction of the d.c. flux with the rotor windings produce a braking torque in the synchronous machine, which has been represented by the equation 8 This relation can be used to correct the net accelerating power of the synchronous machine. PROC.…”

Section: DC Brakingmentioning

confidence: 99%

Transient damping torques in synchronous machines during disturbances

Akhtar

1969

Proc. Inst. Electr. Eng. UK

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During power-system disturbances, the relative speed between the resultant flux and the rotor causes eddy currents to be induced in the rotor iron structure and an induction-motor or induction-generator torque to be developed owing to the amortisseur winding; both these effects damp out the synchronousmachine oscillations. Damping has been considered previously as directly proportional to the slip of the rotor with respect to synchronous speed for a single-machine study, and with respect to instantaneous frequency of Thevenin's equivalent e.m.f. for a multimachine study; this is erroneous and can lead to a substantially different assessment of power-system transient stability, as is shown by illustrative examples. It is indicated that the conclusions drawn from a single-machine study for damping purposes (as is sometimes done in the literature) are not really applicable to a multimachine study; and, moreover, it cannot be said with certainty that the damping will be positive or negative. The damping torque depends on the instantaneous slip between the rotor and the resultant flux, and requires knowledge of synchronous-machine torque/slip characteristics. V e v' d , X' q T" 9 ~1 D H K D eu, /o 80 8 1 List of symbols = damping power = braking power due to negative-phase-sequence current = braking power due to rapidly decaying d.c. component = negative-phase-sequence current component = d.c. component = negative-phase-sequence resistance = positive-phase-sequence resistance = infinite bus voltage = external reactance = direct-axis saturated reactance = quadrature-axis saturated reactance = Potier reactance = direct-axis transient reactance = quadrature-axis transient reactance = direct-axis subtransient reactance = quadrature-axis subtransient reactance direct-axis open-circuit transient time constant direct-axis open-circuit subtransient time constant : quadrature-axis open-circuit subtransient time constant • damping torque coefficient inertia constant slope of asynchronous characteristics expressed as p.u.-torque/p.u.-slip for synchronous machine synchronous angular velocity system nominal frequency phase angle of O at the beginning of time interval At phase angle of 0 at the end of time interval A/ phase angle of E q at the beginning of time interval Af phase angle of E q at the end of time interval A/ IntroductionIn power-system planning, various studies are normally carried out to ascertain the ability of a power system to overcome disturbances. Owing to the generally long and tedious calculations necessary, the following assumptions have been made in the past for treating synchronous machines, to achieve simplification: (a) constant flux linkages (b) transient salience neglected (c) damping torques neglected (d) voltage-regulator and -governor effects neglected (e) saturation neglected Moreover, stability has been determined by the first swing of the machine. Many of the above assumptions are self-com-

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Integrated control of a nonlinear turboalternator model under fault conditions

Nicholson

1967

Proc. Inst. Electr. Eng. UK

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Multi-generator transient-stability performance under fault conditions

Cited by 6 publications

References 4 publications

Some aspects of generator backup protection in relation to synchronous-machine performance during h.v.-system faults

Some aspects of generator backup protection in relation to synchronous-machine performance during h.v.-system faults

Transient damping torques in synchronous machines during disturbances

Integrated control of a nonlinear turboalternator model under fault conditions

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