Oct 10, 2015 these are my suspension insulators so far. The number of insulator discs each rated 11kv required in a suspension type insulator string of 220 kv line is 16. String efficiency of suspension insulators are affected the environments, the numbers of disc insulators, temperature and mechanical strength, especial electrical properties. Pdf influences of relative humidity on the electric field.
Influences of relative humidity on the electric field and potential on suspension insulator string article pdf available in energy procedia 89. Suspension insulator are consist of number of insulator unit or disc connected in series by metal ring in the form of string each unit is normally designed for a low voltage 11 kv suspension type insulator. Insulators have an ansi 525 type j socket on their structure end and an ansi 525 type j ball on their line end. Mps offers a wide variety of polymer and glass transmission insulators for your power and utility construction needs. High voltage insulators ctc power composite insulator. Over view of line and substation maintenance insulator. A number of units are connected together by steel caps and pins to form an insulator string. Upptcl work cleaning of polycon insulator string suspension and tension of 2 kv chhata kosi 1st and 2nd line under etd mathura, due date.
Structural advantage of using vstrings power line systems. Over view of line and substation maintenance free download as powerpoint presentation. For light lowvoltage lines, say up to 11,000 volts, the shackle insulator is suitable, but for higher voltages a string of suspension type insulators is necessary. Suspension assembly types are introduced in the following. The disc near the line conductor is extremely stressed and takes the maximum voltage in the absence of stress. The neutral and neutral clevis must be covered before any work can be done above. Insulator should have hermatically sealed structure in which the housing material is moulded to cover the interface between the end fittings and the frp rod. We are one of the few companies who can offer both porcelain and polymer products. Scope this standard applies to polymer, suspension insulators used to construct 115 kv transmission lines. Suspension insulator string insulator electricity glasses scribd.
Magdi elsaadawi 6 since the insulator discs are identical, each disc is represented by its mutual capacity c a shunt capacitance c 1 is the capacitance of metal part of the insulator disc to the tower structure ground. Calculation of voltage distribution along porcelain suspension. Dimension not specifying tolerance are only reference. Suspension insulator are consist of number of insulator unit or disc connected in series by metal ring in the form of string each unit is normally designed for a low voltage 11 kv. The insulators could be in suspension or tension made in string form to insulate the conductor from tower. Structural advantage of using vstrings when comparing the relative advantages and disadvantages of using suspension insulators vs. Porcelain punctures occur in the region of maximum electrical stress between the metal cap and the. These strings are used for suspension and tension insulators. Where the tension is exceedingly high, as at long river spans, two, three, or even four strings of insulators in.
The st suspension type classification system was born out of a simple need. 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. Overhead transmission distribution line insulators such as the ultrahigh voltage 750kv largetonnage insulator jointly developed by our xheinsulator and tsinghua university is operated by lanzhou uhv. Suspension assembly is main hardware used for high voltage applications, and it is used with suspension insulators together like tension assembly. An aep study of 1100 service aged porcelain disc insulators came to the following conclusions. Silicone rubber insulators gujarat urja vikas nigam. This constitutes a series of connected capacitors, with each ones capacitance being created by two successive metal connectors clips with the porcelain as a. The conductor is suspended at the bottom end of this string while the top end is secured to the crossarm of the tower. Let us know how the potential is distributed over each unit of suspension insulator whether is it uniform or nonuniform.
A suspension insulator strain consists of a series of alternately insulators and metal parts, which bind each insulator to the next. Figurea below shows a typical suspension insulator. It is one of the main problems that affect the insulator and the cause of flashover of insulators. How can we know the rating of a transmission line by the. The number of discs in series would obviously depend upon the working voltage. A suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. Suspension insulator string is widely used as insulator structures in high voltage overhead power lines. Product search, catalog, cad drawings, station post, polymer, line post, suspensions, rodurflex, step, 3d, models. Plscadd provides several methods for modeling structures. Suspension insulator article about suspension insulator by.
Depending upon the working voltage, the desired number of discs can be connected in series. Scribd is the worlds largest social reading and publishing site. It is generally used for 11 kv line and for extensiv use up to 33 kv. This is because of the capacitances formed between the metal parts of the insulators and tower structure. Prove mathematically that in a string of suspension insulators, the disc nearest to the conductor has the highest voltage across it. Solved calculation of string efficiency for suspension. The voltage distribution across different units of an insulator string and string efficiency can be mathematically determined with the help of an equivalent circuit of the insulator string fig. However, there is a significant thing to be considered in case of these string insulators, known as string efficiency.
The composite insulators shall be socket and ball type with the necessary. Power frequency voltage of feed line is distributed along string elements in unequal. Suspension insulators or string insulators are very widely used in an. Due to the presence of shunt capacitor, the voltage. Voltage distribution over suspension insulator string. For high voltages 33 kv, it is a usual practice to use suspension. If your car or truck bottoms out, you will notice a hard hit that can damage vehicle components located on the undercarriage of the vehicle. String efficiency of a suspension insulator youtube. String efficiency of suspension insulator is defined as the ratio of voltage across the whole string to the product of the number of insulator discs and the voltage across the insulator disc nearest to the line conductor. Cap and pin insulators these are manufactured from porcelain or glass and are based on the same principles as pintype insulators.
Jan 12, 2016 the spring insulators, besides acting as a cushion, also allow the suspension to control the amount of travel or the length that the vehicles front or rear end moves up and down. The following points may be noted regarding the potential distribution over a string of suspension insulators. Nowadays, pea had a problem of suspension insulator string in the transmission line due to pollution. Symptoms of bad or failing spring insulators yourmechanic. Difference between suspension and strain insulatorsorient.
Ssen 60372 locking devices for ball and socket couplings of string insulator units dimensions and tests. Performance of a sting of suspension insulator at 400 kv line. Pdf suspension insulator string is widely used as insulator structures in high voltage overhead power lines. Suspension insulator string free download as pdf file. In the previous article, we have discussed different types of insulators used in an overhead transmission line. Potential distribution over a string of suspension insulators. The number of insulator discs each rated 11 kv required in. All 3 loads and their interactionsshould be used in the evaluation. Orient power insulator has excellent suspension insulator specifications model and suspension insulator properties,meanwhile can supply customers lots of suspension insulator image. A pintype insulator is shown schematically infigure 2. Ssen 603831 insulators for overhead lines with a nominal voltage above 1 000 v part 1. 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.
Suspension insulators ppc insulators standard suspension insulators with high mechanical and electrical strength are designed to meet the most modern demands of high voltage and ehv transmission line usage today. 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. Kumar samal in partial fulfilment of the requirements for the award of. The electrical stress applied to a suspension insulator string is not uniform with the highest stress occurring close to the live conductor. So, in case of a single string is not sufficient to take the load two or more. Insulator, suspension, polymer for 115 kv nominal systems note. Horizonal post insulator properties power line systems. Strain insulator string has single strain string and double strain string. Advantage of suspension type insulator over pin type insulator. There will be two polymer suspension insulators at the base of the pole when the team reaches their event.
String efficiency of suspension insulator when the voltage is applied across the suspension insulator string, it is unequally distributed across the individual unit. The capacitances between each cappin junction and the tower and between the cap and pin of each unit determine the voltage distribution. Rus bulletin 1728f803 viewing instructions there are both bookmarks and links imbedded in this file. Purpose of guard ring in suspension insulator electrical. Potential distribution over a string of suspension. From the figure, it is seen that porcelain portion of each disc is in between two metal links. A suspension insulator string in the test facility consists of 18 normal insulators where a 107m. The failing load is the maximum load attainable under cantilever load testing and is greater than or equal to the. String efficiency of suspension insulators performance tests of insulators. Aug 24, 2011 ii each unit or disc of suspension type insulator is designed for low voltage, usually 11 kv. Normal, antifog and open profile can be used according to pollution degree.
Suspension insulator for voltages greater than 33 kv, it is a usual practice to use suspension type insulators, consisting of a number of glass or porcelain discs connected in series by metal links in the form of a string. Few theoretical and numerical research works on the dynamic. Suspension type insulators are cheaper than pin type insulators for voltages beyond 33 kv. Work cleaning of polycon insulator string suspensi tender.
It consists the number of porcelain insulator units connected with each other by metal links to form a flexible string. Voltage distribution over suspension insulator string efficiency. The equipment shall be of first class quality and designed for continuos satisfactory operation as continuity of supplies of prime importance. The materials that used for made the insulators of overhead line are. The effect of stray capacitance over voltage distribution using kcl at each node it can be found that. So that c 1 m c where m is the ratio between the capacitance to. This seal should never be broken during testing or otherwise.
Since the ultimate mechanical strength is decided by the steel links, and not by the porcelain, this pattern is very strong and has the peculiar advantage that the breaking of a porcelain disc will not allow the line to fall, or, in fact, interrupt the service, if a string of several units is used. Among these are the leakage distance, the 60 hz wet and dry flashover values, and the positive and negative impulse critical values. Transmission insulators archives maclean power systems. Pdf calculation of the electric field on an insulator. Physical equivalence the ultimate strength of porcelain suspension insulators is character.
Insulation feature transmission line insulator condition. Pdf an inspection robot for liveline suspension insulator. C transmission line standards suspension insulator assemblies double string. For instance, if the working voltage is 66 kv, then six discs in series will be provided on the string.
This system allows for much higher insulation value than any pintype insulator. First of all thanks for visiting electrical engineering info now let us discuss p otential distribution in a string of suspension insulators. An inspection robot for liveline suspension insulator strings in 345kv power lines article pdf available in ieee transactions on power delivery 272. We assign numbers starting first on smallest to largest diameter, then least to most number of petticoats, then length of outer skirts and inner petticoats. The exact length required is to be shown on drawings tm1 and tm2 and will reflect actual dimensions of hardware, suspension clamp, and deadend clamps specified. The bookmarks are shown on the left side of the screen. Suspension composite insulator has features of light weight, small. The second broad category is electrical equivalences. The most important difference between suspension and strain insulators is the strength, and the strain insulator string strength is higher than the. Dec 07, 2017 a suspension type string insulator consists of a number of porcelain discs connected in series through metallic links. We offer suspension, line post, braced post, bell equivalents and custom insulator assemblies.
Now count the disc insulator has been used on line then if n is the number used 33 kv discs then the calculation is nx33x1. Suspension insulator string has single suspension string, double suspension string, v type suspension string, and so on. Polymer vs porcelain suspension insulator equivalence. In this article, we will be talking about voltage distribution and string efficiency of suspension insulator.
Types of insulators in transmission lines properties of. String efficiency of suspension insulator electrical concepts. Voltage sharing characteristics of vtype suspension. Flashover performance and process of suspension insulator strings. Suspension insulators or string insulators are very widely used in electrical overhead transmission system. The following figure shows the equivalent circuit for a 3disc string. Now transmission voltage will be next standard transmission voltage which is being used in india. String efficiency of suspension insulators and methods of.
String efficiency of suspension insulator how does a capacitor stores charge but actually, in addition to self capacitance of porcelain disc there also exists capacitance in between the metallic link of suspension insulator and grounded tower body. Characteristics are given for the strings without screens and arcing horns at. Potential distribution over a string of suspension insulators p. 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. Vph the phase voltage across the subsequent units measured from the ground respectively. Pdf a set of models for investigation of voltage distribution along. Line standards tension insulator assemblies single string. The suspension insulator separates the line conductors and supports them electrically. C transmission line standards suspension insulator assemblies single string 78. Characteristics are given for the strings without screens and arcing horns at application of the speci. When our customers think of trouble free transmission insulators with the longevity to outpace life time expectations of the transmission lines supported, they think of porcelain suspension insulators from lapp insulators. We talked about advantages and disadvantages of each type of insulators. With a proven track record of over 80 years of manufacturing, over 30 million units in service, and a reliability record that far exceeds that of similar glass insulators or other porcelain manufacturers, the suspension insulator from lapp insulators provides todays engineers something that is missing from many other manufacturers and products, peace of mind.
Another way to define string efficiency is in terms of flashover voltage. Snow accumulates on the surface of insulator string, causing a decrease in its electrical performance, seriously threatening the. A suspension type string insulator consists of a number of porcelain discs connected in series through metallic links. String efficiency of suspension insulator electrical.
A wide variety of suspension insulator fitting options are available to you, such as application, type, and material. Overhead transmission distribution line insulators. Browsing with bookmarks bookmarks mark parts of a document for quick access. Orientsuspension insulator specifications,suspension. Minimum approach distance must be maintained simulated 12kv voltage. Calculation of potential distribution is extensively performed in the design. A corroded suspension insulator shank gave way, causing the transmission line to fall, hitting the other line conductors and the tower parts, resulting in a short circuit which was not isolated on time, said rolando bacani national transmission corp. Insulators clamp, strain, post, suspension, 2parts building a structure is as simple as selecting the desired element from a library of available elements and telling the program where it attaches to other elements. Thus 100% string efficiency of suspension insulators is an ideal case for which the voltage across each disc will be exactly the same. Abstract porcelain string insulators are widely used in highvoltage transmission lines. All of the products that we offer to our customers are produced by ngks global production network of iso 9001certified factories, including u. Voltage distribution in a suspension insulator strain. Ppc insulators makes one of the widest ranges of ansi approved ballsocket and clevis type distribution suspension insulators for.
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