Modeling of wind turbine transformers for the analysis of resonant overvoltages

Soloot, Amir Hayati; Høidalen, Hans Kristian; Gustavsen, Bjørn

doi:10.1016/j.epsr.2014.03.004

Cited by 18 publications

(9 citation statements)

References 9 publications

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“…Although the challenges mentioned above still have not been addressed when using WBG-based conversion systems, the similar situations concerning transformer resonant overvoltages caused by cable-transformer interaction have been reported for conventional power systems where (short length) cabletransformer (motor) interaction can cause very high overvoltages. Switching transients, especially for wind applications subjected to more frequent switching operations and earth fault are two transient phenomena that can lead to resonant overvoltages at the LV terminal of a transformer as well as inside HV and LV windings [105][106][107][108][109][110][111]. The increasing number of transformer dielectric failures led to the CIGRE Working Group A2/C4.39 initiation for the computational assessment of impinging overvoltages on transformer terminals and internal stresses.…”

Section: High-frequency Emt Models For Machine Stator Windingmentioning

confidence: 99%

Accelerated insulation aging due to fast, repetitive voltages: A review identifying challenges and future research needs

Ghassemi

2019

IEEE Trans. Dielect. Electr. Insul.

106

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Although the adverse effects of using power electronic conversion on the insulation systems used in different apparatuses have been investigated, they are limited to low slew rates and repetitions. These results cannot be used for next-generation wide bandgap (WBG)-based conversion systems targeted to be fast (with a ⁄ up to 100 kV/μs) and operate at a high switching frequency up to 500 kHz. Frequency and slew rate are two of the most important factors of a voltage pulse, influencing the level of degradation of the insulation systems that are exposed to such voltage pulses. The paper reviews challenges concerning insulation degradation when benefitting from WBG-based conversion systems with the mentioned ⁄ and switching frequency values and identifies technical gaps and future research needs. The paper provides a framework for future research in dielectrics and electrical insulation design for systems under fast, repetitive voltage pluses originated by WBG-based conversion systems.

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Section: High-frequency Emt Models For Machine Stator Windingmentioning

confidence: 99%

Accelerated insulation aging due to fast, repetitive voltages: A review identifying challenges and future research needs

Ghassemi

2019

IEEE Trans. Dielect. Electr. Insul.

106

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“…The Test (T) channel is connected to any tap on the HV side or to the LV terminal to measure the transferred voltage. More details on measurement setup can be found in [22,23]. The sensitivity of measurement results on the voltage probes, tank representation and other phase connections are discussed in [24].…”

Section: Test Setupmentioning

confidence: 99%

Influence of the winding design of wind turbine transformers for resonant overvoltage vulnerability

Soloot

Høidalen

Gustavsen

2015

IEEE Trans. Dielect. Electr. Insul.

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Switching transients and earth faults may lead to resonant overvoltages at wind turbine transformer terminals as well as inside High Voltage (HV) and Low Voltage (LV) windings. The winding design in a transformer could strongly influence the internal voltage distribution as function of frequency, and this has a great impact on risk of insulation failure. In this paper, resonant overvoltages in three winding designs; layer, disc and pancake, are investigated and analyzed for the application in offshore wind farm. To achieve this, a prototype 500 kVA transformer with the three winding types on the HV side and taps for voltage measurements is designed and produced. The measurements show that a HV winding of layer type gives the highest transferred voltage to the LV terminal and that this happens at 1.6 MHz which could be excited for close-up earth faults. Although disc winding seems the least vulnerable when measuring the transferred voltage to the LV terminal, it has higher potential of internal resonances in the HV winding compared to the two other types both voltage-to-ground and voltage drops. Pancake and layer windings have less vulnerability in the case of internal resonances. Pancake windings have modular design characteristic. This advantage eases the repair for offshore wind applications.

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“…When the transient surge waveform contains frequency matched the resonance frequency of the transformer windings, the internal transformer resonance is happened and provides transient overvoltages. However, it can result in insulation breakdown for transformer winding due to the resulted highfrequency overvoltages at the secondary side [3][4][5][6][7][8]. Overvoltage protections such as surge arrestor can be installed at the secondary side of the transformer in order to mitigate such induced overvoltages .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Resonance and Ferroresonance Overvoltages due to Cable-Transformer Interactions

Nassar

Taalab

Izzularab

et al. 2020

ERJ. Engineering Research Journal

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In this paper, the resonance and ferroresonance phenomena are deeply investigated considering two different cable-transformer power systems. The internal transformer resonance overvoltage case is initiated due to a single-phase earth fault, while the studied ferroresonance case is due to a single-phase switching in the source feeding an unloaded transformer via a power cable. The resulted secondary overvoltage and the core flux signatures are used as a classifier, where the transient features are extracted using three algorithms. Although the voltage frequency spectrum and phase-plane diagrams have been previously utilized for the ferroresonance mode evaluation, they are exploited in this paper for the comparison study and accordingly for the detection of resonance and ferroresonance phenomena. Salient features found in the transients extracted using the well-known DWT are used as inputs of the third algorithm. A new detection approach is attained based on the DWT-based transient feature extraction of resonance and ferroresonance overvoltages.

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Modeling of wind turbine transformers for the analysis of resonant overvoltages

Cited by 18 publications

References 9 publications

Accelerated insulation aging due to fast, repetitive voltages: A review identifying challenges and future research needs

Accelerated insulation aging due to fast, repetitive voltages: A review identifying challenges and future research needs

Influence of the winding design of wind turbine transformers for resonant overvoltage vulnerability

Investigation of Resonance and Ferroresonance Overvoltages due to Cable-Transformer Interactions

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