Radio Frequency Sensing of Incipient Arcing Faults within Large Turbine Generators

Harrold, R. T.; Emery, F.T.; Murphy, F.J.; Drinkut, S.A.

doi:10.1109/tpas.1979.319307

Cited by 31 publications

(7 citation statements)

References 6 publications

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“…In 1979, Harrold and his colleagues [44] replaced grounding resistor used by Johnson and Warren [16] with a RFCT, locating at a convenient site on the lead connecting neutral and grounding transformer, to pick up discharge signals, as shown in Figure 5a, i.e., the NCT method. Restricted by In 1979, Harrold and his colleagues [44] replaced grounding resistor used by Johnson and Warren [16] with a RFCT, locating at a convenient site on the lead connecting neutral and grounding transformer, to pick up discharge signals, as shown in Figure 5a, i.e., the NCT method.…”

Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

“…Restricted by In 1979, Harrold and his colleagues [44] replaced grounding resistor used by Johnson and Warren [16] with a RFCT, locating at a convenient site on the lead connecting neutral and grounding transformer, to pick up discharge signals, as shown in Figure 5a, i.e., the NCT method. Restricted by computer technology and signal processing technique, NCT critically relies on the detection frequency range at earlier stage and consequently domain experience and expertise were required for selecting detection frequency range and distinguishing PD from noises.…”

Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

“…In addition, due to low sensitivity of RFCT and attenuation caused by neutral grounding transformer, NCT is only sensitive to severe PD. For these reasons, although demonstrated to be effective, the NCT has not been widely used in North America beyond the RFM [44]. In Europe, positive experience has been reported in [45], although supplementary coupling capacitors at the phase terminals were used to overcome the problems mentioned above.…”

Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

“…To avoid the attenuation resulting from the neutral grounding transformer and consequently increase the detection sensitivity, Harrold et al [44] proposed to replace RFCT with a coupling capacitor, which is in parallel with grounding transformer, to detect the discharge pulses. However, the proposal was not put into practice until 1989 when Mohammed and Mundulas replaced RFCT with a home-made capacitor, with its inner screen connected to neutral point and its outer screen grounding through a 2 kΩ detection resistor, and increasing the detection sensitivity by 40 dB [47].…”

Section: Neutral Capacitor Coupling (Ncc)mentioning

confidence: 99%

“…In addition, typical frequency range at which the noise is negligible, was selected to improve SNR [44]. Currently, hardware filters are widely applied in PD measurement systems to increase the SNR and decrease quantization error of subsequent digitization by an analog to digital converter (ADC), and help anti-aliasing as well.…”

Section: Hardware-based Denoisingmentioning

confidence: 99%

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A Review of Online Partial Discharge Measurement of Large Generators

Luo

Wang³

2017

Energies

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Abstract:Online partial discharge (PD) measurements have long been used as an effective means to assess the condition of the stator windings of large generators. An increase in the use of PD online measurement systems during the last decade is evident. Improvements in the detection capabilities are partly the reason for the increased popularity. Another reason has been the development of digital signal processing techniques. In addition, rapid progress is being made in automated single PD source classification. However, there are still some factors hindering wider application of the system, such as the complex PD mechanism and PD pulse propagation in stator windings, the presence of detrimental noise and disturbances on-site, and multiple PD sources occurring simultaneously. To avoid repetition of past work and to provide an overview for fresh researchers in this area, this paper presents a comprehensive survey of the state-of-the-art knowledge on PD mechanism, PD pulse propagation in stator windings, PD signal detection methods and signal processing techniques. Areas for further research are also presented.

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Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

Section: Neutral Rfct Coupling (Nct)mentioning

confidence: 99%

Section: Neutral Capacitor Coupling (Ncc)mentioning

confidence: 99%

Section: Hardware-based Denoisingmentioning

confidence: 99%

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A Review of Online Partial Discharge Measurement of Large Generators

Luo

Wang³

2017

Energies

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Analysis and localization of abnormal partial discharge activity in generator units

Pemen¹,

Laan²

2006

Int Trans Elec Energy Syst

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SUMMARYThis paper describes methods to monitor partial discharges (PDs) of important power plant components, such as generator stator windings, generator circuit-breaker, and step-up transformer. Two methods have been evaluated under practical conditions, using various sensors: (i) time-domain measurements followed by signal-processing to discriminate between PDs and interference, and (ii) a tunable narrow-bandwidth filter which can be tuned to a frequency where PDs are strong and interference is weak. For several generators, abnormal PD activity was observed. In all cases, the source of these PDs could be located, by means of the transit-time between various sensors. Examples of identified abnormal discharge activity are: (i) discharge activity between phase separations of a statorwinding, (ii) sparking inside a step-up transformer, and (iii) large PDs in a generator circuit-breaker.

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Determining the exact location of partial discharge in coil insulation of high-voltage machine using high-frequency model of the machine

Khezri

Akbari

Saied

2020

IET Science, Measurement &Amp; Technology

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The current study is aimed at investigating the exact location of partial discharge (PD) in coil insulation of a 6 KV/250 KW induction machine. Since measured PD signals have frequency components of kilohertz (KHz) to megahertz (MHz), it is necessary to employ fast and very fast transient models of electrical machines for locating PDs. In this study, a PD current pulse with MHz frequency component is injected to the multi‐conductor transmission line model of each turn of the coil with frequency validity of >1 MHz. Considering coils as an interface between voltage source and finite element region, all circuit and field equations are rewritten to obtain the system final matrix, so that PD pulse is extracted. Experiment and simulation results show high accuracy of developed model to determine the exact location of PD.

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Radio Frequency Sensing of Incipient Arcing Faults within Large Turbine Generators

Cited by 31 publications

References 6 publications

A Review of Online Partial Discharge Measurement of Large Generators

A Review of Online Partial Discharge Measurement of Large Generators

Analysis and localization of abnormal partial discharge activity in generator units

Determining the exact location of partial discharge in coil insulation of high-voltage machine using high-frequency model of the machine

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