scholarly journals To the Evaluation of the Insulation State Based on the Analysis of Partial Discharges

2021 ◽  
Vol 2096 (1) ◽  
pp. 012192
Author(s):  
S Yu Tetiora ◽  
N V Silin ◽  
N N Petrunko
Keyword(s):  
Deterministic Model ◽  
Partial Discharge ◽  
Electrical Equipment ◽  
Diagnostic Value ◽  
Point Of View ◽  
Partial Discharges ◽  
Diagnostic Methods ◽  
Application Area ◽  
New Approach ◽  
Discharge Modeling

Abstract The existing partial discharge models, their diagnostic value, and application area are analyzed in the article. The models are considered from the point of view of their improvement or the possibility of creating new diagnostic methods for electrical equipment based on the characteristics of partial discharges. As an example of the implementation of a new approach to partial discharge modeling, a quasi-deterministic model is considered, which makes it possible to obtain information on the real number of cavities in the insulation of high-voltage equipment.

Apparent and True Charges in the Partial Discharge Model at Different Defective Domain Sizes

2021 ◽  
Vol 64 (6) ◽  
pp. 94-100
Author(s):  
Nikolay Ignatev ◽  
◽  
Sergey Tetiora ◽  
Dmitry Turkin ◽  
◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Partial Discharge ◽  
Diagnostic Value ◽  
Partial Discharges ◽  
Active Resistance ◽  
Air Cavity ◽  
Discharge Ignition ◽  
Discharge Model ◽  
Air Cavities ◽  
Solid Insulation

A model of the partial discharges in a sample of solid insulation with air cavity is presented. The material of the insulation is cross-linked polyethylene. The model is based on an active-capacitive equivalent circuit, in which the resistance of the air cavity at the instant of a partial discharge ignition is shunted by the active resistance of the spark. The model takes into consideration the delay of the discharge development. The evaluation of the diagnostic value of the apparent and true charges is carried out. The results of the apparent and true charges relationship with the dimensions and proportions of the air cavity are presented. It is shown that the same magnitude of both true and apparent charges can correspond to the different volumes and shapes of the air cavities in the insulation.

A New Approach for Partial Discharge Modeling in High Voltage Cables Considering Nonlinear Permittivity Using Finite Element Method

2020 ◽  
Vol 12 (4) ◽  
pp. 457-463
Author(s):  
Asaad Shemshadi ◽  
Pourya Khorampour
Keyword(s):  
Finite Element ◽  
High Voltage ◽  
Partial Discharge ◽  
Nonlinear Function ◽  
New Approach ◽  
Novel Technique ◽  
Remote Assessment ◽  
Cable Systems ◽  
Discharge Modeling ◽  
Simple Modeling

Herein, we report a novel technique to develop remote assessment and observation for partial discharge events under high voltage cable systems output. Finite element modeling of the cavities bided in the insulators which are the source of Partial Discharge signals occurred in a 3-d section of a typical 230 KV high voltage XLPE 3-phase cable. All electromagnetic related equations are solved using FEM software. The idea is to consider the permittivity constant in cavities as a nonlinear function during the solving process. This function is related to electric field value inside each cavity. This modeling leads to a new approach in simple modeling of PD phenomena in the H. V. apparatus with the big amount of destructive PD cavities. In continue, the obtained waveform is illustrated respecting to the main power line waveform.

scholarly journals An Innovative Sensor for Cable Joint Monitoring and Partial Discharge Localization

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4095
Author(s):  
Luca Barbieri ◽  
Andrea Villa ◽  
Roberto Malgesini ◽  
Daniele Palladini ◽  
Christian Laurano
Keyword(s):  
Partial Discharge ◽  
Point Of View ◽  
Partial Discharges ◽  
Historical Background ◽  
Induced Current ◽  
Charge Variation ◽  
First Results ◽  
Weak Points ◽  
Joint Monitoring ◽  
A Charge

To enhance grid reliability, weak points must be monitored. One of the weaknesses is the cable joints, which are prone to failure and can cause great losses from both a technical and economical point of view. Joints failures are usually caused by impurities unintentionally added during installation that cause partial discharges (PDs). In time, these discharges erode the insulation and generate treeing up to a destructive discharge between the conductor and the ground shield. For this reason, a method for the early detection of defects in joint installation and their online monitoring is required. A previously developed sensor was improved by adapting it for this purpose. It is based on the measurement of the induced current on a conductor due to a charge variation. It was experimentally tested on an actual joint in which defects were artificially introduced. Results show that the sensor is able to detect partial discharges. Moreover, a method for PD localization was developed. The first results show a coherency between the possible defect location, numerical simulations and historical background.

scholarly journals STUDY AND PERFORMANCE OF PARTIAL DISCHARGE OF MODEL FOR DIFFERENT TYPE INSULATION MATERIALS WITH CAPACITANCE VALUE

2021 ◽  
Vol 8 (12) ◽  
pp. 323-327
Author(s):  
Neetu Baghelkar ◽  
Abhishek Dubey
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Partial Discharge ◽  
Electrical Equipment ◽  
Partial Discharges ◽  
Electrical System ◽  
Insulating Material ◽  
Different Types ◽  
And Performance ◽  
Short Time

The properties of the insulating material must be the best to avoid failure of electrical equipment. Partial discharges act as electrical sparks that occur within insulation and the high-voltage electrical system. The different types of voltage and current pulses are produced, which last for a very short time. Partial discharge is taking place in high voltage power equipment such as cables, transmission lines and transformers, etc.

A simple approach of partial discharge source location in high voltage cables

2017 ◽  
Vol 40 (12) ◽  
pp. 3507-3514
Author(s):  
Jose Ramírez-Niño ◽  
Carlos G Azcarraga ◽  
Alberth Pascacio ◽  
Rito Mijarez ◽  
Joaquin Rodríguez-Rodríguez
Keyword(s):  
Sensor Array ◽  
Partial Discharge ◽  
Source Location ◽  
Simple Approach ◽  
Propagation Direction ◽  
Partial Discharges ◽  
Power Cables ◽  
New Approach ◽  
Discharge Source ◽  
Incipient Faults

This article presents a new approach of partial discharges (PD) source location in power cables. The main advantage of this approach is the detection of the propagation direction of the PD. The method provides a pattern named by the authors PD+D, which, in contrast to the well–known phase-resolved partial discharge (PRPD) pattern, graphically shows the direction of PD propagation and uses the polarity of a sensor array on top of the magnitudes of the positive and negative parts of each PD pulse to detect the direction of propagation, is described in detail. The proposed technique is useful for the evaluation and diagnosis of power cables, since it can identify incipient faults. The attained results that demonstrate the value of this methodology and their scope and limitations are discussed.

scholarly journals A method to reduce partial discharges in motor windings fed by PWM inverter

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 599-604 ◽  
Author(s):  
Daniel Roger ◽  
Sonia Ait-Amar ◽  
Ewa Napieralska
Keyword(s):  
Partial Discharge ◽  
Partial Discharges ◽  
Conducting Layer ◽  
Element Analysis ◽  
New Approach ◽  
Pwm Inverter ◽  
Additional Layer ◽  
Ac Motor ◽  
Critical Zones ◽  
Inception Voltage

AbstractA new approach for designing ac motor windings free of partial discharges (PD) is proposed. The method consists of adding a thin conducting layer on the outer surface of the enameled wire used for building the machine winding. With this additional layer, PDs occur only in critical zones localized near the wire connections rather than randomly in the residual voids between turns. With such deterministic localizations, it is possible to reduce strongly the PD activity by adding small quantities of varnish in the determined critical zones. After studying the validity of the Paschen’s hypotheses for this application, the Paschen’s law is coupled to an electrostatic finite element analysis, for predicting the Partial Discharge Inception Voltage (PDIV), which corresponds to the electronic avalanche ignition in the air of critical zones.

Innovative Solutions for Partial Discharge Measurements

2021 ◽  
pp. 4-11
Author(s):  
Sergey A. GOLUBTSOV ◽  
◽  
Roberto CANDELA ◽  
Keyword(s):  
Diagnostic Method ◽  
Partial Discharge ◽  
Electrical Equipment ◽  
Partial Discharges ◽  
Condition Based Maintenance ◽  
Predictive Diagnostics ◽  
Innovative Solutions ◽  
Cable Systems ◽  
Cable Lines ◽  
Discharge Measurements

The article discusses systems developed using an innovative approach to measuring partial discharges, their advantages over traditional methods of monitoring cable lines and electrical equipment, as well as the principles of their operation. The design of the systems is based on a special broadband sensor-antenna which provides remote recording of both partial discharge pulses and the phase of alternating current flowing in the object of measurement without taking the equipment under test out of operation. Due to the wireless nature and system compact dimensions, partial discharge measurements can perform in previously inaccessible conditions, significantly expanding the capabilities of this diagnostic method. The partial discharge measurements are an up-to-date method for predictive diagnostics of cable systems and are necessary for the condition-based maintenance.

Diagnostic Value of Non-Invasive Prenatal Screening of β-thalassemia by Cell Free Fetal DNA and Fetal NRBC

2019 ◽  
Vol 19 (2) ◽  
pp. 105-111
Author(s):  
Nadia Shafei ◽  
Mohammad Saeed Hakhamaneshi ◽  
Massoud Houshmand ◽  
Siavash Gerayeshnejad ◽  
Fardin Fathi ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Multiple Displacement Amplification ◽  
Diagnostic Value ◽  
Diagnostic Methods ◽  
Beta Thalassemia ◽  
Non Invasive ◽  
Fetal Dna ◽  
Prenatal Diagnostic ◽  
Cell Free Fetal Dna ◽  
Invasive Techniques

Background: Beta thalassemia is a common disorder with autosomal recessive inheritance. The most prenatal diagnostic methods are the invasive techniques that have the risk of miscarriage. Now the non-invasive methods will be gradually alternative for these invasive techniques. Objective: The aim of this study is to evaluate and compare the diagnostic value of two non-invasive diagnostic methods for fetal thalassemia using cell free fetal DNA (cff-DNA) and nucleated RBC (NRBC) in one sampling community. Methods: 10 ml of blood was taken in two k3EDTA tube from 32 pregnant women (mean of gestational age = 11 weeks), who themselves and their husbands had minor thalassemia. One tube was used to enrich NRBC and other was used for cff-DNA extraction. NRBCs were isolated by MACS method and immunohistochemistry; the genome of stained cells was amplified by multiple displacement amplification (MDA) procedure. These products were used as template in b-globin segments PCR. cff-DNA was extracted by THP method and 300 bp areas were recovered from the agarose gel as fetus DNA. These DNA were used as template in touch down PCR to amplify b-globin gen. The amplified b-globin segments were sequenced and the results compared with CVS resul. Results: The data showed that sensitivity and specificity of thalassemia diagnosis by NRBC were 100% and 92% respectively and sensitivity and specificity of thalassemia diagnosis by cff-DNA were 100% and 84% respectively. Conclusion: These methods with high sensitivity can be used as screening test but due to their lower specificity than CVS, they cannot be used as diagnostic test.

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.

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