On-line diagnostics of high-voltage bushings and current transformers using the sum current method

Lachman, M.F.; Walter, Wolfgang; Guggenberg, P.A. von

doi:10.1109/61.847244

Cited by 49 publications

(17 citation statements)

References 1 publication

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“…The first method reported in the literature we consider is the so called "sum current method" [4]. This approach is based on the Kirchhoff current law, and it analyses the sum of the three currents drawn by known impedances connected to the bushing taps.…”

Section: State Of the Artmentioning

confidence: 99%

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On-line analysis of power transformer bushings

Faifer

Ottoboni

Cristaldi

et al. 2011

2011 IEEE International Instrumentation and Measurement Technology Conference

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The approach to the maintenance of devices and systems has strongly changed in the last years, thanks to the availability of more and more sophisticated technologies. In particular, when the servicing involves very critical processes, a new interesting strategy is represented by the Condition Based Maintenance (CBM). It is based on the continuous observation of some physical parameters which permits to infer the status of the system and thus to detect the need to service it. In this paper a novel monitoring method is proposed. It allows the application of CBM techniques to one of the least reliable components in HV and MV systems: the transformer bushing. Starting from some theoretical and practical considerations, it will be shown that it is possible to measure the capacitance and the power factor of transformer bushing, without putting the plant out of order. It is known that these two parameters are particularly useful to schedule the maintenance activity. This goal can be achieved by superimposing a high frequency sinusoidal voltage between the bushing tap and the ground. Some considerations prove that having chosen a proper frequency, the consequent current is much more sensitive to the bushing capacitance than to the other impedances. Finally the architecture of a measurement system is also presented

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Section: State Of the Artmentioning

confidence: 99%

“…In the literature some papers reporting on-line diagnostic method can be found [2][3][4][5]. All of them perform a dynamic analysis of diagnostic indexes that are someway related to the main characteristic parameters of the bushings [3]: capacitance and power factor.…”

Section: Introductionmentioning

confidence: 99%

On-line analysis of power transformer bushings

Faifer

Ottoboni

Cristaldi

et al. 2011

2011 IEEE International Instrumentation and Measurement Technology Conference

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“…Free-standing CTs continue to be a major concern to the utility industry [2]. Their failure often leads to breakdown of the power system protection scheme.…”

Section: Introductionmentioning

confidence: 99%

Substation automation for replacing faulted CTs in distribution feeders

Haj-ahmed

Campbell²,

Illindala

2014

2014 IEEE International Conference on Power Electronics, Drives and Energy Systems (PEDES)

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Current transformers (CTs) are one of the key constituents of power system instrumentation and measurement, and their failure may lead to a breakdown of the entire protection scheme. The CT replacement or repair may not be feasible every time a CT malfunctions at a remote distribution substation as rural areas generally lack adequate skilled manpower. This paper presents a multi-agent system based substation automation solution to improve the reliability of protection system during any CT failure. It employs a special function protection scheme for making quick replacements of faulted CTs associated with current differential relay (87). The proposed autonomous protection scheme has been tested on a typical American Electric Power (AEP) distribution substation using MATLAB/Simulink and Java Agent DEvelopment Framework (JADE).

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“…It provides a fundamental connection to carry the electric current passing through different potential conductors in electrical equipment [1,2]. OIP bushings ensure complex electrical, mechanical, thermal, and environmental stresses in operation and can easily be violated by insulation defects.…”

Section: Introductionmentioning

confidence: 99%

The Mechanism and Diagnosis of Insulation Deterioration Caused by Moisture Ingress into Oil-Impregnated Paper Bushing

Dai

et al. 2018

Energies

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Abstract:The healthy state of insulation in oil-impregnated bushings is traditionally evaluated by tanδ and capacitance at power frequency and mostly at 10 kV in the test standard. However, there has frequently been insulation accidents induced by moisture ingress (MI) for bushings that have passed the standard. The mechanism and new diagnostic features for MI into bushings were not distinct enough and an accurate test method is urgently needed research. To address this technical gap, a bushing model with a transparent sheath was designed and an ultrasonic humidifier device was adopted to simulate the environment of MI in bushings and recorded by digital camera. The parameters of dielectric dissipation factor, capacitance, partial discharge (PD), frequency domain response, and moisture content in oil were measured at room temperature with time. The results presented that both the increment dissipation factor at low frequency of 0.001 Hz and the increment dissipation factor of 1.2 U m could be used for detecting the earlier insulation defect of oil-impregnated paper (OIP) bushings. The phase resolved partial discharge (PRPD) can serve as the diagnostic basis of the severe state (S 3 ) of insulation deterioration caused by MI into bushings around the phases of 0-117 • , 151-303 • , and 325-360 • . The research findings would provide a useful reference for the condition diagnosis and maintenance of OIP bushings. Especially, the increment detection of Frequency Domain Spectroscopy (FDS) at the frequency of 1 mHz and 10 kHz was recommended firstly for the operative bushings in real sites.

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On-line diagnostics of high-voltage bushings and current transformers using the sum current method

Cited by 49 publications

References 1 publication

On-line analysis of power transformer bushings

On-line analysis of power transformer bushings

Substation automation for replacing faulted CTs in distribution feeders

The Mechanism and Diagnosis of Insulation Deterioration Caused by Moisture Ingress into Oil-Impregnated Paper Bushing

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