A study of insulation failure in a high voltage current transformer

2005 ◽  
Author(s):  
A.A. Jimoh ◽  
V.S. Mahlasela ◽  
D.V. Nicolae
Keyword(s):  
High Voltage ◽  
Current Transformer ◽  
Insulation Failure

High Voltage Insulation Failure on HV Current Transformer: A Case Study in Diagnosis of HV CT Failure at Bekasi 150 kV Substation

2021 ◽  
Author(s):  
I Gusti Ngurah Mahendrayana ◽  
Imam Makhfud ◽  
Arfan Idha Norgiyanto ◽  
Zainur Oktafian Prabandaru ◽  
Winarno
Keyword(s):  
High Voltage ◽  
Current Transformer ◽  
Insulation Failure ◽  
High Voltage Insulation

Three-Dimensional Potential and Electric Field Distributions in HV Cable Insulation Containing Multiple Cavities

2013 ◽  
Vol 845 ◽  
pp. 372-377 ◽  
Author(s):  
Nabipour Afrouzi Hadi ◽  
Zulkurnain Abdul-Malek ◽  
Saeed Vahabi Mashak ◽  
A.R. Naderipour
Keyword(s):  
Electrical Properties ◽  
Electric Field ◽  
High Voltage ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Low Dielectric ◽  
Underground Cable ◽  
Insulation Failure ◽  
Field Distributions ◽  
Hv Cable

Cross-linked polyethylene is widely used as electrical insulation because of its excellent electrical properties such as low dielectric constant, low dielectric loss and also due to its excellent chemical resistance and mechanical flexibility. Nevertheless, the most important reason for failure of high voltage equipment is due to its insulation failure. The electrical properties of an insulator are affected by the presence of cavities within the insulating material, in particular with regard to the electric field and potential distributions. In this paper, the electric field and potential distributions in high voltage cables containing single and multiple cavities are studied. Three different insulating media, namely PE, XLPE, and PVC was modeled. COMSOL software which utilises the finite element method (FEM) was used to carry out the simulation. An 11kV underground cable was modeled in 3D for better observation and analyses of the generated voltage and field distributions. The results show that the electric field is affected by the presence of cavities in the insulation. Furthermore, the field strength and uniformity are also affected by whether cavities are radially or axially aligned, as well as the type of the insulating solid. The effect of insulator type due the presence of cavities was seen most prevalent in PVC followed by PE and then XLPE.

The Analysis and Discussion of the Actual Case about the Differential Protection Malfunction Caused by the Transient Exciting Current of Large-Scale High-Voltage Main Transformer at the Time of Switching

2013 ◽  
Vol 694-697 ◽  
pp. 785-789
Author(s):  
Yang Gao ◽  
Guo Yan Liang
Keyword(s):  
High Voltage ◽  
Large Scale ◽  
Current Transformer ◽  
Differential Protection ◽  
Instrument Function ◽  
Actual Case ◽  
Test Analysis ◽  
Use Of Data ◽  
Exciting Current ◽  
Transformer Differential Protection

In this paper, based on the choice of voltage level 500kV for large transformer differential protection of maloperation accident actually as an example, discusses how to improve the reliability and the transformer differential protection with the relationship between pressure test. Analysis found that in order to avoid the excitation transient exciting current transformer differential protection sparked the misoperation, on-site technical personnel in the differential protection setting calculation process, make use of data in conformity with the relevant parameters, rules and standards, familiar with differential protection, also need to understand the characteristics of transformer excitation transient exciting current high-voltage tests, the influence of characteristic more should fully exert the modern PC wave record device, instrument function can improve the actual effect of transformer differential protection. This factory for transformer differential protection for setting, protection greatly improves the reliability. This experience is worth popularizing.

scholarly journals Estimation peculiarities of external polymer insulation reliability of gas-filled instrument transformers

2021 ◽  
pp. 3-9
Author(s):  
Liudmyla Zhorniak ◽  
Alexej Afanasiev ◽  
Vitaliy Schus ◽  
Olexij Morozov ◽  
Julia Rudenko
Keyword(s):  
High Voltage ◽  
Accurate Determination ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Operational Reliability ◽  
Current Transformer ◽  
Operating Conditions ◽  
Distribution Law ◽  
Instrument Transformers ◽  
And Performance

In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of operational reliability. In the article, the authors propose a method for estimating the parameters of theoretical distributions for calculating the indicators of the operational reliability of a solid insulating structure of high-voltage devices, which is a supporting insulating cover for high voltage instrument transformers filled with gas as an insulating liquid. This technique makes it possible to estimate the parameters of a new distribution law, which is chosen on the condition that it does not contradict the existing distribution law with its known parameters. The developed technique makes it possible to obtain the values of the indicators of the operational reliability of high-voltage equipment by determining the parameters of theoretical distributions, if the developer is the data of experimental studies or statistical information as a result of monitoring the operation of insulating structures, taking into account the actual operating conditions of such high-voltage devices.  This makes it possible to take into account the influence of external factors and performance characteristics inherent in instrument transformers, both current and voltage. In the proposed methodology, as an example, a supporting insulating casing is considered, which is during operation in the most unfavorable conditions, such as external pollution, humidification, overvoltage, etc. The theoretical conclusions are confirmed by the results of calculations using the example of the design of a current transformer of the ТОГ-362 series. A more accurate determination of the effectiveness of the proposed method for predicting the parameters of theoretical distribution laws can be achieved by performing an additional series of calculations and experimental tests of specific insulating structures. Thus, it was concluded that it is possible to use the results obtained to assess the operational reliability of both gas-filled instrument transformers and similar high-voltage equipment.

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