Porcelain and glass insulators have been used for over a hundred years and although these ma terials have proven themselves resistant to environmental ageing, their pollution performance has often been relatively poor due to hydrophilic surfaces. According to the observed, string efficiency of suspension insulators are affected three factors that are voltage across the string number of discs in the string voltage across disc nearest to conductor. The paper presents a study into the potentials and electric field distribution on insulator strings, which are used for suspension of overhead transmission lines of 400 kv and are stressed by. The following points may be noted regarding the potential distribution over string of suspension insulators.
Pdf investigating the effects of disc insulator type and corona. Potential distribution over a suspension insulator string. Figurea below shows a typical suspension insulator. Let us know how the potential is distributed over each unit of suspension insulator whether is it uniform or nonuniform. Simulation and measurement of the voltage distribution on. Calculation of voltage distribution along porcelain. Porcelain string insulators are widely used in highvoltage transmission lines. Effect of voltage type and polarity on electric field and potential distribution are investigated in this paper. Properties of porcelain suspension insulator for ultra high.
Suspension insulator string is widely used as insulator structures in high voltage overhead. First of all thanks for visiting electrical engineering info now let us discuss p otential distribution in a string of suspension insulators. It shall be noted that the number of discs in suspension insulator can be increased or decreased by adding extra discs or removing a disc. Clevis type distribution suspension insulators for overhead transmission systems in the world. In this project, calculate the voltage distribution along a string of 5 suspension insulators, and determine the efficiency of string and we get efficiency equal to. In the experiment, the sphere gap was used to measure the voltage along insulation string. The number of insulator discs each rated 11 kv required in. Low and high voltage distribution along a cap and pin. Pdf the voltage distribution of insulator strings, which are very common in the. A string of suspension insulators consists of a number of porcelain discs connected in series through metallic links. The figure below shows a 3disc string of suspension insulator. Therefore it is very much essential for insulator string to relate the potential distribution. This paper was the research of 400 kn suspension insulator for ultra high voltage that included alumina of 17 wt%.
We focused on a solution that exceeds rus requirements for this class of product. Influence of voltage type and polarity on electric field distribution along a polymeric insulator under contaminated conditions arshad1, a. For suspension type of insulators, the ratio of voltage across the whole string to the product of number of discs and the voltage across the disc nearest to the conductor is known as string efficiency. The dimension of suspension insulator type 523 is used for the study as shown in fig. We are also the qualified supplier of electrified railway insulato. Also the effect of corona ring on potential distribution over insulator strings with. Aug 24, 2011 ii each unit or disc of suspension type insulator is designed for low voltage, usually 11 kv. Insulation feature transmission line insulator condition. Neural network estimator for electric field distribution on high voltage insulators al abstract this paper introduces, a threedimensional 3d neural network electric fields estimator, which will be used to determine the electric field distribution on high voltage insulator surface.
The following points may be noted regarding the potential distribution over a string of suspension insulators. The porcelain portion of each disc is in between two metal links. Vph the phase voltage across the subsequent units measured from the ground respectively. The measurement of the voltage distribution along high. Calculation of voltage distribution along porcelain suspension. Potential distribution over a string of suspension insulators. In operational high voltage, the nonuniformity of potential distribution across the insulator string is due to the presence of stray capacitance. Potential and electric field distribution of 220kv insulator. A suspension insulator strain consists of a series of alternately insulators and metal parts, which bind each insulator to the next. Comparison of electric field and potential distributions on. The main cause of cracking is due to the stress produced in the porcelain due to unequal expansion and construction produced in cement, steel and porcelain caused by seasonal heat cold, dryness, and dampness or by heating of the insulator. Voltage distribution over suspension insulator string.
The effect of stray capacitance over voltage distribution using kcl at each node it can be found that. Orientcomposite tension insulators composite insulator. List any four errors in induction type energy meter. A suspension insulator string has three units with ground capacitance of 0. The voltage across the nearest disc to the conductor is maximum than others disc. Calculation of potential distribution is extensively performed in the design and development of highvoltage insulators. Farzaneh2 1 school of engineering and built environment, glasgow caledonian university 2canada research chair on atmospheric icing engineering of power networks ingivre. String efficiency of suspension insulator electrical concepts. In these topics, it is discussed the voltage distribution over suspension insulator string. Measurement and simulation of the voltage distribution and. String efficiency of suspension insulators is an important consideration since it decides the potential distribution along the string. National institute of technology rourkela certificate this is to certify that the thesis entitled, measurement of voltage distribution on high voltage suspension insulator string under polluted condition submitted by simanta. The disc near the line conductor is extremely stressed and takes the maximum voltage in the absence of stress. Voltage distribution over suspension insulator string efficiency.
Measurement of voltage distribution on high voltage. Simulation of voltage distribution calculation methods over a. Faulty insulators could appear in the hv transmission line insulator string under the comprehensive effect of electrical, mechanical and environmental factors and they can be detected according to the space potential and electric field distribution variation characteristics around the insulator string. U k 1 where u is phaseneutral voltage over insulator string, umax is the maximum voltage drop on a single disc in insulator string, n is the number of insulator units, and. Therefore it is very much essential for insulator string to relate the potential distribution and electric field distribution to that of the respective ideal string accurately. Composite insulator for transmission and distribution lines. A string of suspension insulator consists of a number of porcelain discs connected in. Depending upon the working voltage, the desired number of discs can be connected in series. Potential distribution over suspension insulator string.
If a protective corona ring inserts capacitances from the line, with the link of the middle. Potential distribution over suspension insulator string eeeguide. Voltage distribution over a suspension insulator string fig. In case of the clean string insulator condition, the string efficiency which the insulator consists of 5, 6, 7 insulator string without guard ring equals 69. In this study, the voltage distribution over an insulator string of suspension insulators and the string efficiency have been investigated with respect to the atmospheric conditions such as wind. Finite element method fem is adopted for this work. Porcelain punctures occur in the region of maximum electrical stress between the metal cap and the.
Voltage distribution in a suspension insulator strain. However, there is a significant thing to be considered in case of these string insulators, known as string efficiency. Via this software the electric field and potential distribution can be calculated very easily once the desirable geometry is accurately designed. We talked about advantages and disadvantages of each type of insulators. An overhead 3phase transmission line, which has phase voltage 30 kv, is hanging from a three insulators suspension strain. Voltage and electric field are the main factors to withstand the insulation. The electrical stress applied to a suspension insulator string is not uniform with the highest stress occurring close to the live conductor. Effects of disc insulator type and corona ring on electric. For the present study, the type of suspension insulator type 523 is chosen. The effect of stray capacitance over voltage distribution stray capacitance causes unequal voltage distribution over the string. A suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. The capacitance between the links and the earth is 0,2 c, where c is the capacitance of an insulator determine the potential distribution along the insulators strain. Single insulator cap and conductor cover for distribution. Mar 16, 2017 evaluation of string efficiency and voltage distribution of 400 kv over a string of glass suspension type insulator in different atmospheric condition ijsrdvol.
String efficiency of suspension insulators and methods of. This video contains the detailed information about power factor improvement. Composite tension insulators are widely used on high voltage distribution and transmission lines and these composite insulators have many advantages and features. Insulator,high voltage insulator,china insulatororient china. Sep 25, 2011 string effeciency and methods to improve string effeciency posted on september 25, 2011 by k10blogger the ratio of voltage across the whole string to the product of number of discs and the voltage across the disc nearest to the conductor is known as string efficiency i. In this paper, the voltage distribution and the electric field of a glass insulator has been measured and calculated using a program based on the finite elements method. A porcelin guy strain insulator is strong enough to hold the high tension of a guy under load because the two holes at right angles overlap each other so that the porcelain is under compression. Mankinds benefit the proceedings of a space congress held november 1519, 197 1, at huntsville, alabama sponsored by the national aeronautics and space administration and the huntsville association of technical societies prepdred at.
Institute for theoretical physics events xwrcaldesc. This constitutes a series of connected capacitors, with each ones capacitance being created by two successive metal connectors clips with the porcelain as a dielectric. Therefore, each disc forms a capacitor c as shown in fig. The computation of electric potential distribution across suspension insulator strings used for high voltage overhead transmission lines is very. The simulation results show that contaminations have no effect of potential distribution on the insulator surface while electric field distributions. Potential distribution over a string of suspension insulators p.
It is well known that under working ac voltage, the voltage distribution along a cap and pin insulator string is very uneven due to the presence of stray capacitances from the caps to the line conductor and especially to the earthed supporting tower. Abstract porcelain string insulators are widely used in highvoltage. Pdf a set of models for investigation of voltage distribution along. Composite tension insulators advantages and features. Neural network estimator for electric field distribution on.
Simulation of potential and electric field due to defective. Single insulator cap and conductor cover for distribution power lines our patented insulator caps and conductor covers have been designed with the recommendations from utility engineers, linemen, and wildlife biologists. In this article, we will be talking about voltage distribution and string efficiency of suspension insulator. Evaluation of string efficiency and voltage distribution of. This is because of the capacitances formed between the metal parts of the insulators and tower structure. We are establish in 1978, and produce insulators and relative until 500kv.
An aep study of 1100 service aged porcelain disc insulators came to the following conclusions. Modeling of high voltage insulator strings through finite element. The slurry was fabricated after ball milling were mixed raw materials. What is difference between conductor and insulator. Influence of voltage type and polarity on electric field. Composite insulator for transmission and distribution lines 10kv composite insulator fig. These capacitances could be made negligibly small by increasing the distance between the. Suspension insulators or string insulators are very widely used in electrical overhead transmission system.
String efficiency of suspension insulator when the voltage is applied across the suspension insulator string, it is unequally distributed across the individual unit. This is a lecture video for diploma 3rd year students of electrical engineering. Due to the presence of shunt capacitor, the voltage across the suspension insulators does not distribute itself uniformly across the each disc. Solved calculation of string efficiency for suspension.
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