Ferroresonance of Grounded Potential Transformers on Ungrounded Power Systems

Karlicek, R. F.; Taylor, E. R.

doi:10.1109/aieepas.1959.4500391

Cited by 24 publications

(4 citation statements)

References 4 publications

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“…When phase-to-ground voltage transformers are connected to an ungrounded neutral system, a ferroresonant circuit is formed between the nonlinear inductance of the voltage transformer and the phase-to-ground capacitance ( Figure 2) [4,[13][14][15][16][17][18][19][20][21][22]. Under these situations, the protective devices associated with these voltage transformers can identify the disturbance as an earth fault, causing undesired misoperations [15,16].…”

Section: B Voltage Transformer Connected To An Ungrounded Neutral Symentioning

confidence: 99%

“…The transformer primary windings are wyeground connected. The measure windings are ungrounded wye and the protective windings are open-delta connected, so the delta voltage is used to relay operation or to detect a phase-to-ground fault[4,[15][16]19].Transient overvoltages or overcurrents due to switching operations or fault situations can initiate the ferroresonance phenomenon in one of the transformers. Values of ferroresonant overvoltages may exceed the normal phase-to-phase voltage.…”

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confidence: 99%

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Ferroresonant Configurations in Power Systems

Valverde¹,

Buigues²,

Mazón³

et al. 2024

RE&PQJ

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Over the last decades, power disturbances have become an important factor on the increase throughout electrical networks, which can exert an important influence over power quality ratios. Amongst them, it is worth mentioning ferroresonance, which is a special case of resonance involving non-linear inductances that mainly affects the functionality of transformers. Its effects are characterized by high sustained overvoltages and overcurrents with maintained levels of current and voltage waveform distortion, producing extremely dangerous consequences. The first step against ferroresonance is always to prevent it from appearing, so it is important to identify those electrical configurations prone to the appearance of the phenomenon. Therefore, this paper analyzes different ferroresonant configurations that may take place in power systems, highlighting some of the most relevant aspects of each configuration.

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Section: B Voltage Transformer Connected To An Ungrounded Neutral Symentioning

confidence: 99%

mentioning

confidence: 99%

Ferroresonant Configurations in Power Systems

Valverde¹,

Buigues²,

Mazón³

et al. 2024

RE&PQJ

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“…Separation of the line prior to opening the ground switch could create a need for special relaying or communications. [9] [10] [14] .…”

Section: Recommendations For Preventionmentioning

confidence: 99%

“…1. [14] 5. High abnormal voltage due to ferroresonance will manifest itself by abnormal transformer sound and, if sufficiently high, by a flash over.…”

Section: Recommendations For Preventionmentioning

confidence: 99%

Review of ferroresonance in power distribution grids

Kamel¹,

Vaziri

Vadhva

2011

2011 IEEE International Conference on Information Reuse &Amp; Integration

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Ferroresonance is a special case of resonance, which can occur when a non-linear inductive reactance is connected in series with a capacitive reactance. In instances of ferroresonance involving electric power distribution facilities, the inductive reactance will be the magnetizing reactance of a singlephase or three-phase transformer. The capacitive reactance will be due ordinarily to the conductor-to-sheath capacitance of primary cable supplying the transformer under favorable conditions. Ferroresonance may be accompanied by abnormally high or low voltages as a result of single pole switching of one or two phases of the source supply to the transformer. Ferroresonance is capable of producing sustained overvoltages with peak magnitudes approaching, or exceeding twice the rated peak voltage, which is harmful and unsafe for the operation of most equipment.In this paper, the various conditions giving rise to occurrence of ferroresonance will be identified. The most prevalent resonance resulting in undesirable voltage conditions will be addressed and analyzed. Also some possible means of preventing occurrence of unsafe ferroresonance in power transformers will be proposed.

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The correction of instrument transformer ferroresonance model in IEC standard and study on resonance interval based on transformer damping

Liu,

Chai,

Zhang

et al. 2023

AIP Advances

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The traditional ferromagnetic resonance model of the inductive voltage transformer in the IEC/TR 61869-102 transformer standard ignores the DC resistance of the transformer. The author believes that ignoring the damping effect of the transformer itself is not justified. Based on this, the model is modified, and the corresponding differential equation is derived. Through simulation and field testing, it is found that the DC resistance of the transformer has a damping effect on resonant overvoltage and resonant overcurrent. Moreover, with an increase in DC resistance, the ferromagnetic resonance region decreases. By increasing the DC resistance of the voltage transformer, it helps to reduce the ferromagnetic resonance interval as well as the inrush current.

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Ferroresonance of Grounded Potential Transformers on Ungrounded Power Systems

Cited by 24 publications

References 4 publications

Ferroresonant Configurations in Power Systems

Ferroresonant Configurations in Power Systems

Review of ferroresonance in power distribution grids

The correction of instrument transformer ferroresonance model in IEC standard and study on resonance interval based on transformer damping

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