Hubbell power systems is a proud member of the hubbell family. The dynamic wind load factor for 500 kv transmission lines is proposed to be in the range of 1. Porcelain is also free from porosity, as the deterioration of. However, there is a significant thing to be considered in case of these string. String insulator definition is a series of two or more suspension insulators flexibly connected. The production process of the rodurflex insulators starts with the extraction of the frp rod. On the top of the insulator the conductor bound into a groove,which is cemented on to a galvanized steel. String insulator definition of string insulator by merriam. The compressive load applied to the poststrut member. However, there is a significant thing to be considered in case of these string insulators, known as string efficiency.
They consist of a number of porcelain discs connected in series by metal links in the form of a string. May 22, 2018 therefore, in this types of insulators in transmission lines insulator is not economical beyond 33 kv. Potential distribution over a suspension insulator string the figure below shows a 3disc string of suspension insulator. 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. Us20100100239a1 robot mechanism for inspection of liveline. Suspension composite insulator has features of light weight, small. The core rod is a boronfree, corrosion resistant ecr glassfiberreinforced plastic rod. Tension fitting insulator string 185 300 5095 185240 120 300 120150 185240 359 51 0.
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. Performance analysis of 1200 kv ceramic disc insulator 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 kumar samal in partial fulfilment of the requirements for the award of master of technology degree in electrical engineering with specialization in industrial. 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. Pdf suspension insulator string is widely used as insulator. Pin, suspension, and strain insulators are used in medium to high voltage. The amplitude of free swing of conductors is larger in suspension. The suspension insulator separates the line conductors and supports them electrically. Therefore, in this types of insulators in transmission lines insulator is not economical beyond 33 kv. Ball and socket, clevis and tongue, form insulator string. 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. Composite insulators for medium voltage lines gscc010 rev. However, as will be demonstrated in this technical note, there is. E transmission line standards tension insulator assemblies double string 81.
Dec 07, 2017 suspension insulators or string insulators are very widely used in an electrical overhead transmission system. Porcelain suspension insulator consists of one or more ceramic shells, metal end fittings, zinc sleeve common types. String efficiency of a suspension insulator youtube. Insulators types of electrical insulators in overhead lines. Solved calculation of string efficiency for suspension.
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. Electrical insulation can be described in terms of electric strength, volume and. C transmission line standards suspension insulator assemblies vee string, single string 83. Pin type insulator consists of single or multiple shells arranged in parallel and mounted on a crossarm of the pole or tower. Voltage distribution over a suspension insulator string. 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.
In these topics, it is discussed the voltage distribution over suspension insulator string. On the voltage distribution across a string of suspension. Suspension insulator string free download as word doc. Apr 25, 2018 a suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. 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. The greater the string efficiency, the more uniform is the voltage distribution in the each disc insulator. Disclosed herein is a robot mechanism for inspection of a liveline suspension insulator string. It consists the number of porcelain insulator units connected with each other by metal links to form a flexible string. They consist of a number of porcelain discs connected in series by. Suspension insulators disc porcelain are the most widely used. Suspension insulators string was prepared by ahmed shaker. Tension insulator string is installed in horizontal direction.
Voltage distribution over suspension insulator string. Affordable and search from millions of royalty free images, photos and vectors. Suspension insulators can be divided into three kinds according to their applications. For high voltages 33 kv, it is a usual practice to use suspension type insulators shown in fig. To prevent this form of pin damage, sediver can supply insulators equipped. 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. 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. 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. Each insulator of a suspension string is called disc insulator because of their disc like shape.
Pdf numerical study on dynamic swing of suspension. Each suspension disc is designed for normal voltage rating. Us8239064b2 robot mechanism for inspection of liveline. The conductor is suspended at the bottom end of this string while the top end is secured to the crossarm of the tower. Suspension insulator article about suspension insulator by. Types of insulators in transmission lines properties of. Suspension insulator article about suspension insulator. The st suspension type classification system was born out of a simple need. 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.
Electrical insulators and accessories elsewedy electric. We talked about advantages and disadvantages of each type of insulators. Cut to the correct length and visually inspected the rods are wrapped seamlessly with a high temperature vulcanised silicone elastomer htv silicone. When comparing the relative advantages and disadvantages of using suspension insulators vs. Tension load applied by the suspension brace insulator. If a protective corona ring inserts capacitances from the line, with the link of the middle. From the figure, it is seen that porcelain portion of each disc is in between two metal links. String efficiency of suspension insulators and methods of. The number of insulator discs each rated 11 kv required. An overhead 3phase transmission line, which has phase voltage 30 kv, is hanging from a three insulators suspension strain. This insulator shall have good mechanical strength to be carrying heavy snow ice loads at the time. The free body diagram that appears as figure 5 includes all of the parameters associated with the design of the assembly. Pdf development of advanced insulator inspection robot for. Double sheds type, bell shaped type, aero dynamic type ceramic suspension insulator connection.
A suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. Suspension insulators or string insulators are very widely used in an electrical overhead transmission system. Suspension type insulator being economical as compared to pin type insulator for high voltage overhead transmission line. Em strength of insulator unit kn mechanical strength of insulator string alongwith hardware fittings kn 220kv lines with acsr moose 0.
Upsweep angle from horizontal of the poststrut member. Pdf a set of models for investigation of voltage distribution along. Figurea below shows a typical suspension insulator. The number of insulator units used depends on the voltages of the lines. A suspension insulator string in the test facility consists of 18 normal insulators where a 107m. From the figure, it is seen that porcelain portion of. 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. In this article, we will be talking about voltage distribution and string efficiency of suspension insulator. Types of insulators in transmission lines electrical4u. String efficiency of suspension insulator electrical concepts. Voltage suspension insulator string under polluted condition submitted by simanta. String insulator definition of string insulator by.
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. Explicit closedform solution is given for the case in which cg does not vary from unit to unit and the form of tapering needed. 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. 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. 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. 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. The voltage is not equally shared between the units in a suspension insulator string. Suspension insulator string free download as pdf file.
The effect of stray capacitance over voltage distribution using kcl at each node it can be found that. Available in 25k, 30k, 50k and 80k tensile strengths. Orientsuspension insulators,disc suspension insulators,end. Email me at this address if a comment is added after mine. Pdf development of advanced insulator inspection robot. This system allows for much higher insulation value than any pintype insulator. String efficiency of suspension insulator electrical. Jean new live line tester for porcelain suspension insulators on high. Cs type composite silicone insulators up to 750 kv overhead. 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. B transmission line standards horizontal post insulator assemblies 82. The insulator material should be nonporous, free from impurities and cracks. 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. String efficiency of suspension insulator when the voltage is applied across the suspension insulator string, it is unequally distributed across the individual unit.
Orientsuspension insulators,disc suspension insulators. The shattering rate of glass shells in service is negligible thanks to the high purity of sediver glass. 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. Voltage distribution in a suspension insulator strain. Suspension insulator string insulator electricity glasses scribd. Each insulator disc is designed to operate for 11kv. Insulator string article about insulator string by the free. In the previous article, we have discussed different types of insulators used in an overhead transmission line.
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. The capacitances between each cappin junction and the. There are 5 types of insulators used as electrical overhead insulation pin. 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 tower, with the conductor attached to the end. Insulator string article about insulator string by the. For higher voltages, a string of suspension insulators is used. 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. 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.
The disc near the line conductor is extremely stressed and takes the maximum voltage in the absence of stress. Suspension insulator string costlier than pin and post type insulator. Insulators for overhead lines composite suspension and tension insulators for a. Composite braced line posts mechanical considerations. Cs type composite silicone insulators up to 750 kv. A suspension insulator strain consists of a series of alternately insulators and metal parts, which bind each insulator to the next. Vph the phase voltage across the subsequent units measured from the ground respectively. 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. The number of insulator discs each rated 11 kv required in. 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. Improved calculation model for swing angle of suspension. Suspension insulators or string insulators are very widely used in electrical overhead transmission system.
1407 1194 1464 1142 1294 1227 103 1068 1167 1377 324 1070 88 1488 140 143 83 315 749 616 1060 1030 759 518 924 1228 1064 1136 402 295 1478 724 1020 776 594 1066 932 295 44 528