Condition Assessment of High Voltage Instrument Transformer Using Partial Discharge Analysis

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Mohd Aizam Talib ◽  
Abu Sufian Abu Bakar Abu Bakar ◽  
S. Gobi Kannan
Keyword(s):  
High Voltage ◽  
Diagnostic Tool ◽  
Economic Activity ◽  
Field Measurement ◽  
Laboratory Experiments ◽  
Partial Discharge ◽  
Incipient Faults ◽  
Instrument Transformers ◽  
Customer Dissatisfaction ◽  
Instrument Transformer

Determining the incipient faults in high voltage apparatus is important because failure without warning can result in damage to adjacent equipment, personnel injures, customer dissatisfaction and disruption to economic activity. The failure of several high voltage instrument transformers during in-service prompted Tenaga Nasional Berhad (TNB) to identify more effective diagnostic tool to predict insulation breakdowns. The viability of partial discharge (PD) measurements in the field on instrument transformers is investigated. This paper presents the results of partial discharge tests that have been carried out under laboratory experiments and field measurement on high voltage instrument transformers.

scholarly journals Experimental determination of partial discharges in a model of a digital instrument transformer by differential method

Vestnik IGEU ◽  
2019 ◽  
pp. 32-42
Author(s):  
A.V. Gusenkov ◽  
V.D. Lebedev ◽  
S.N. Litvinov ◽  
S.A. Slovesny ◽  
A.A. Yablokov
Keyword(s):  
Condition Monitoring ◽  
High Voltage ◽  
Partial Discharge ◽  
Essential Elements ◽  
Differential Method ◽  
Partial Discharges ◽  
Discharge Characteristics ◽  
Reliability Indicators ◽  
Instrument Transformer ◽  
Inductive Sensors

Power facilities are now implementing the concept of smart grid and its essential elements – high-voltage digital current and voltage transformers. However, the implementation of digital technologies is slowed down by the lack of operation experience and reliability indicators. One of the main causes of high-voltage equipment failures is insulation damage. The most informative parameters determined by insulation evaluation are partial discharge characteristics. There are rated values of these characteristics for rotating electrical machines and power transformers measured by external equipment. But the existing method of partial discharge analysis cannot be applied to digital current and voltage transformers as there are no criteria for tripping of the innovative equipment with comprehensive insulation. All this urges us to study the possibility to determine experimentally the characteristics of partial discharges in the insulation of digital current and voltage transformers by using embedded inductive sensors in order to develop a method for condition monitoring of digital current and voltage transformers and improving of their reliability. In this work, we have used a model of digital current and voltage transformers, a high-voltage test unit, a digital multi-input oscciloscope and inductive sensors. The experiment includes: detecting partial discharges in the model of digital current and voltage transformers by the external bridge connection, recording the voltage at which partial discharges occur in the simulated fault area, measuring the corresponding value of the apparent charge of the partial discharge, detecting partial discharges in the model of digital current and voltage transformers by a differential method with the help of embedded inductive sensors. The characteristics of partial discharges in the simulated fault area have been experimentally determined on a model of digital current and voltage transformers. The pulse voltage on the embedded inductive sensor corresponding to the apparent charge of 80 pC was equal to 600 mV at the test voltage of 2,7 kV. Embedded inductive sensors allow implementing the method of insulation condition monitoring for digital current and voltage transformers in accordance with the partial discharge characteristics both at the stages of production and operation extending the potential of the electronic (microprocessor) module and increasing the reliability of digital current and voltage transformers.

scholarly journals Toward a Substation Automation System Based on IEC 61850

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 310
Author(s):  
Shantanu Kumar ◽  
Ahmed Abu-Siada ◽  
Narottam Das ◽  
Syed Islam
Keyword(s):  
High Voltage ◽  
Hierarchical Level ◽  
Automation System ◽  
International Electrotechnical Commission ◽  
Automation Systems ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Conventional Instrument ◽  
Substation Automation ◽  
The Impact

With the global trend to digitalize substation automation systems, International Electro technical Commission 61850, a communication protocol defined by the International Electrotechnical Commission, has been given much attention to ensure consistent communication and integration of substation high-voltage primary plant assets such as instrument transformers, circuit breakers and power transformers with various intelligent electronic devices into a hierarchical level. Along with this transition, equipment of primary plants in the switchyard, such as non-conventional instrument transformers, and a secondary system including merging units are expected to play critical roles due to their fast-transient response over a wide bandwidth. While a non-conventional instrument transformer has advantages when compared with the conventional one, extensive and detailed performance investigation and feasibility studies are still required for its full implementation at a large scale within utilities, industries, smart grids and digital substations. This paper is taking one step forward with respect to this aim by employing an optimized network engineering tool to evaluate the performance of an Ethernet-based network and to validate the overall process bus design requirement of a high-voltage non-conventional instrument transformer. Furthermore, the impact of communication delay on the substation automation system during peak traffic is investigated through a detailed simulation analysis.

scholarly journals Device for online monitoring of insulation faults in high-voltage switchgears

2021 ◽  
Vol 17 (2) ◽  
pp. 155014772199928
Author(s):  
Jiajia Song ◽  
Jinbo Zhang ◽  
Xinnan Fan
Keyword(s):  
Fourier Transform ◽  
High Voltage ◽  
Online Monitoring ◽  
Pulse Current ◽  
Partial Discharge ◽  
Current Method ◽  
Capacitive Sensor ◽  
Accurate Diagnosis ◽  
Partial Discharges ◽  
Urgent Problem

Partial discharges are the major cause of deterioration in the insulation characteristics of switchgears. Therefore, timely detection of partial discharge in switchgear and potential insulation faults is an urgent problem that needs to be addressed in the power supervision industry. In this study, a device was proposed for online monitoring of high-voltage switchgears based on pulse current method and ozone (O3) detection. The pulse current method obtains the PD signal by monitoring the phase holes on the switch indicator. Occurrence of a partial discharge in a certain phase leads to the production of a discharge pulse, which can be coupled out by a capacitive sensor. The current spectrum and the O3 produced by partial discharge were processed via fast Fourier transform for accurate diagnosis of the occurrence of partial discharge and its severity in switchgears. The proposed method allows for convenient acquisition of the partial discharge signal, simple installation of the device, and realization with inexpensive sensors.

scholarly journals Optimised calibration programmes for comparators for instrument transformers

2021 ◽  
Vol 88 (2) ◽  
pp. 122-131
Author(s):  
Christian Mester
Keyword(s):  
Experimental Study ◽  
Operating Principle ◽  
Device Under Test ◽  
Operating Range ◽  
Ratio Error ◽  
Phase Displacement ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Method Of Measurement

Abstract Traditionally, instrument transformers are calibrated using bridges. By definition, bridges use the null method of measurement. The traditional calibration programme for instrument transformer bridges characterise namely this null measurement. Many new commercial comparators for instrument transformer use a very different method. They sample the secondary signals of reference and device under test (dut) transformer independently. Based on the samples, magnitude and phase of both signals are determined. Ratio error and phase displacement are calculated. Consequently, the significance of their calibration using the traditional calibration programme is limited. Moreover, the operating range of modern comparators is much larger than that of bridges. The additional versatility cannot be used without an adapted calibration programme. This article analyses the calibration programmes for both technologies. An experimental study confirms both the suitability of the new calibration programme and the need to chose the calibration programme depending on the technology of the device to be calibrated. The conclusion is very general and applies to all measurement problems where an operating principle is replaced by another – when changing the operating principle, it is important to check the calibration programme and adapt it if necessary.

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