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. To prevent this form of pin damage, sediver can supply insulators equipped. The greater the string efficiency, the more uniform is the voltage distribution in the each disc insulator. In the ideal case, the value of string efficiency will be 100%, but, in a normal case, it is impossible to achieve 100% string efficiency, yet effort should be made to improve it as close to this value as possible. In an electric power transmission line, a suspension tower is where the conductors are simply suspended from the tower, the mechanical tension being the same on each side in this case, the tower is supposed to carry a downward force, and a lateral force, but not a longitudinal force these may have, for each conductor, an insulator string hanging down from the tower, or two strings making a. Insulators types of electrical insulators in overhead lines. A type of insulator used to support a conductor of an overhead transmission line, consisting of one or a string of insulating units suspended from a pole or. Tension insulator string is divided into suspension type insulator and post type insulator used for high voltage power system consisting of one insulator or more insulators. The compressive load applied to the poststrut member. In suspension insulator numbers of insulators are connected in series to form a string and the line conductor is carried by the bottom most insulator. C transmission line standards suspension insulator assemblies vee string, single string 83. Pdf numerical study on dynamic swing of suspension. However, there is a significant thing to be considered in case of these string.
However, this robot cannot be applied to a tension insulator string, because its constituent insulators are different in diameter and height from those of a suspension insulator string. Pdf suspension insulator string is widely used as insulator. Voltage distribution in a suspension insulator strain. A robot body of the robot mechanism reciprocates along the liveline suspension insulator string and includes upper and lower robot frames configured to encircle the insulator string, a battery module provided to either end of the robot body, an actuation module for moving the robot body along the. In these topics, it is discussed the voltage distribution over suspension insulator string. Suspension type insulator posted on august 24, 2011 by k10blogger for high voltages 33 kv, it is a usual practice to use suspension type insulators shown in figure. String insulator definition of string insulator by. Improved calculation model for swing angle of suspension. Cs type composite silicone insulators up to 750 kv overhead.
Pdf development of advanced insulator inspection robot for. Insulator string article about insulator string by the. Ball and socket, clevis and tongue, form insulator string. It consists the number of porcelain insulator units connected with each other by metal links to form a flexible string. The effect of stray capacitance over voltage distribution using kcl at each node it can be found that. The designing of sheds or petticoats should be such that even when the outer surface is wet due to rain,the inner dry surface provides sufficient leakage resistance. A suspension insulator string in the test facility consists of 18 normal insulators where a 107m. Orientsuspension insulators,disc suspension insulators. If a protective corona ring inserts capacitances from the line, with the link of the middle. In the previous article, we have discussed different types of insulators used in an overhead transmission line.
Insulator string article about insulator string by the free. Us20100100239a1 robot mechanism for inspection of liveline. We talked about advantages and disadvantages of each type of insulators. Tension fitting insulator string 185 300 5095 185240 120 300 120150 185240 359 51 0. Suspension insulators can be divided into three kinds according to their applications. Suspension insulator string free download as pdf file. Each insulator disc is designed to operate for 11kv.
String efficiency of suspension insulator electrical. String insulator definition is a series of two or more suspension insulators flexibly connected. Suspension insulators disc porcelain are the most widely used. Suspension composite insulator has features of light weight, small. This system allows for much higher insulation value than any pintype insulator. From the figure, it is seen that porcelain portion of each disc is in between two metal links. The free body diagram that appears as figure 5 includes all of the parameters associated with the design of the assembly. Voltage distribution over suspension insulator string. Types of insulators in transmission lines properties of.
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. Keywords voltage distribution, insulator string, suspension. Email me at this address if a comment is added after mine. String insulator definition of string insulator by merriam. Suspension insulators have been used widely all over the world for high voltage transmission and distribution overhead lines with the voltage ranging from 10kv to kv.
The voltage is not equally shared between the units in a suspension insulator string. Solved calculation of string efficiency for suspension. Each suspension disc is designed for normal voltage rating. The suspension insulator separates the line conductors and supports them electrically.
E transmission line standards tension insulator assemblies double string 81. Cs type composite silicone insulators up to 750 kv. There are 5 types of insulators used as electrical overhead insulation pin. Insulators for overhead lines composite suspension and tension insulators for a. Suspension insulator article about suspension insulator by. In this article, we will be talking about voltage distribution and string efficiency of suspension insulator. Composite tension insulator string is composed of energysaving insulation resistance, with a compact, easy installation, insulation reliability, stain resistance and strong, significant energysaving advantages, recomended by the majority of users. They consist of a number of porcelain discs connected in series by metal links in the form of a string. Voltage suspension insulator string under polluted condition submitted by simanta. For high voltages 33 kv, it is a usual practice to use suspension type insulators shown in fig. An electrical insulator defects detection method combined human receptive field model according to current regulations 16, the electrical insulation system of the medium voltage power distribution lines includes surges arrestors or insulator strings. Types of insulators in transmission lines electrical4u.
Vph the phase voltage across the subsequent units measured from the ground respectively. Voltage distribution over a suspension insulator string. The number of insulator units used depends on the voltages of the lines. Pin, suspension, and strain insulators are used in medium to high voltage. The number of insulator discs each rated 11 kv required in. String efficiency of suspension insulator when the voltage is applied across the suspension insulator string, it is unequally distributed across the individual unit. For higher voltages, a string of suspension insulators is used. Dec 07, 2017 suspension insulators or string insulators are very widely used in an electrical overhead transmission system. This insulator shall have good mechanical strength to be carrying heavy snow ice loads at the time. Oct 10, 2015 these are my suspension insulators so far. Sediver toughened glass insulators for hvac applications. The capacitances between each cappin junction and the.
Jean new live line tester for porcelain suspension insulators on high. An overhead 3phase transmission line, which has phase voltage 30 kv, is hanging from a three insulators suspension strain. Em strength of insulator unit kn mechanical strength of insulator string alongwith hardware fittings kn 220kv lines with acsr moose 0. 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. Upsweep angle from horizontal of the poststrut member. Suspension insulators or string insulators are very widely used in electrical overhead transmission system. Pdf development of advanced insulator inspection robot. Hubbell power systems is a proud member of the hubbell family. The number of insulator discs each rated 11 kv required.
Aug 24, 2011 suspension type insulator posted on august 24, 2011 by k10blogger for high voltages 33 kv, it is a usual practice to use suspension type insulators shown in figure. 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. Orientsuspension insulators,disc suspension insulators,end. Suspension insulators string was prepared by ahmed shaker. A suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. String efficiency of suspension insulators and methods of. Potential distribution over a suspension insulator string the figure below shows a 3disc string of suspension insulator. Porcelain is also free from porosity, as the deterioration of.
Apr 25, 2018 a suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. Double sheds type, bell shaped type, aero dynamic type ceramic suspension insulator connection. The conductor is suspended at the bottom end of this string while the top end is secured to the crossarm of the tower. However, there is a significant thing to be considered in case of these string insulators, known as string efficiency. Electrical insulators and accessories elsewedy electric.
Pin type insulator consists of single or multiple shells arranged in parallel and mounted on a crossarm of the pole or tower. A suspension insulator strain consists of a series of alternately insulators and metal parts, which bind each insulator to the next. Voltage suspension insulator string under polluted condition submitted by simanta kumar samal in partial fulfilment of the requirements for the award of master of technology degree in electrical engineering with specialization in industrial electronics during 2014 2015. Suspension insulators or string insulators are very widely used in an electrical overhead transmission system. Suspension insulator string costlier than pin and post type insulator. Affordable and search from millions of royalty free images, photos and vectors. 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 kumar samal in partial fulfilment of the requirements for the award of master of technology degree in electrical engineering with specialization in industrial. String efficiency of a suspension insulator youtube. A difference equation formulation is given for the problem of determining the voltage distribution across a string of suspension insulators, taking into account the capacitance cg between the insulator hardware and the guard ring, and the conductance of the insulator. In modern power systems, increasing faults of overhead transmission lines are caused by wind swing discharge especially in weathersensitive regions such as coastal hurricaneprone areas. Therefore, in this types of insulators in transmission lines insulator is not economical beyond 33 kv. The shattering rate of glass shells in service is negligible thanks to the high purity of sediver glass. Composite insulators for medium voltage lines gscc010 rev. 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.
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. String efficiency of suspension insulator electrical concepts. On the top of the insulator the conductor bound into a groove,which is cemented on to a galvanized steel. The number of insulator discs each rated 11kv required in a suspension type insulator string of 220 kv line is 16 your comment on this answer. B transmission line standards horizontal post insulator assemblies 82. Porcelain suspension insulator consists of one or more ceramic shells, metal end fittings, zinc sleeve common types.
Since the vast majority of wind swing discharge accidents occur at the working voltage and existing models established for the suspension insulator wind swing discharge are not adequate to analyse all cases. The disc near the line conductor is extremely stressed and takes the maximum voltage in the absence of stress. The core rod is a boronfree, corrosion resistant ecr glassfiberreinforced plastic rod. Sediver toughened glass insulators are unpuncturable and resistant to overvoltage stresses thanks to a defect free dielectric body and the homogeneity of the glass shell.
Suspension insulator article about suspension insulator. Suspension insulator string insulator electricity glasses scribd. The amplitude of free swing of conductors is larger in suspension. 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. Each insulator of a suspension string is called disc insulator because of their disc like shape. May 22, 2018 therefore, in this types of insulators in transmission lines insulator is not economical beyond 33 kv. Suspension insulator string free download as word doc. Tension load applied by the suspension brace insulator.
Us20100100239a1 robot mechanism for inspection of live. The insulator material should be nonporous, free from impurities and cracks. Figurea below shows a typical suspension insulator. When comparing the relative advantages and disadvantages of using suspension insulators vs.
Tension insulator string is installed in horizontal direction. However, as will be demonstrated in this technical note, there is. Suspension type insulator being economical as compared to pin type insulator for high voltage overhead transmission line. The production process of the rodurflex insulators starts with the extraction of the frp rod. Composite braced line posts mechanical considerations. The dynamic wind load factor for 500 kv transmission lines is proposed to be in the range of 1. They consist of a number of porcelain discs connected in series by. From the figure, it is seen that porcelain portion of. Explicit closedform solution is given for the case in which cg does not vary from unit to unit and the form of tapering needed. Performance analysis of 1200 kv ceramic disc insulator string. Available in 25k, 30k, 50k and 80k tensile strengths.
291 1105 104 135 251 1051 1072 710 1566 1206 887 1320 1065 225 250 1055 189 672 1635 1653 1287 1553 515 488 532 1084 1371 1303 317 309 418