The dynamic wind load factor for 500 kv transmission lines is proposed to be in the range of 1. Development of advanced insulator inspection robot for 345kv suspension insulator strings. The insulator disc between two metallic pins forms a capacitor c which is known as self capacitance. This system allows for much higher insulation value than any pintype insulator. Dec 07, 2017 a suspension type string insulator consists of a number of porcelain discs connected in series through metallic links. The suspension insulator string and the cutting plane of the suspension insulator model 7.
Solved calculation of string efficiency for suspension. Development of cleaning robot system for liveline suspension. Such insulators have several advantages over porcelain and glass insulators, such as lighter weight, easier. 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. For higher voltages, a string of suspension insulators is used. An overhead 3phase transmission line, which has phase voltage 30 kv, is hanging from a three insulators suspension strain. Tension insulator string is installed in horizontal direction.
Structural advantage of using vstrings power line systems. It consists the number of porcelain insulator units connected with each other by metal links to form a flexible string. Porcelain suspension insulator consists of one or more ceramic shells, metal end fittings, zinc sleeve common types. A string of suspension insulators consists of a number of porcelain discs connected in series through metallic links. 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. Ball and socket, clevis and tongue, form insulator string. From the figure, it is seen that porcelain portion of each disc is in between two metal links. Influences of relative humidity on the electric field and potential on suspension insulator string. Potential distribution over a string of suspension insulators. The air insulating medium between metal pin and tower forms another capacitance kc known as capacitance to earth. String efficiency of suspension insulator when the voltage is applied across the suspension insulator string, it is unequally distributed across the individual unit. Potential distribution over a suspension insulator string the figure below shows a 3disc string of suspension insulator. Figure i shows 3disc string of suspension insulators.
The number of insulator discs each rated 11 kv required. The voltage distribution on insulator string determines the flashover. Orientsuspension insulator specifications,suspension. Vph the phase voltage across the subsequent units measured from the ground respectively. If a protective corona ring inserts capacitances from the line, with the link of the middle. Each suspension disc is designed for normal voltage rating. 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. It is generally used for 11 kv line and for extensiv use up to 33 kv. Structural advantage of using vstrings when comparing the relative advantages and disadvantages of using suspension insulators vs. There are many suspension type insulator pdf in orient power website, you can read and download through visiting the website. A suspension type string insulator consists of a number of porcelain discs connected in series through metallic links. 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.
Suspension insulator article about suspension insulator. Whether the composite insulator cluster parachute has breaks and burned areas, and at the same time whether the fitting and grading ring has deformed, twisted, and corroded. The equipotential contours around a 230kv string insulator consisting of. Suspension insulator suspension insulator is an assembly of one or more shells. String efficiency of suspension insulators and methods of. Voltage distribution over suspension insulator string. The effect of stray capacitance over voltage distribution using kcl at each node it can be found that. A suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. 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.
Apr 25, 2018 a suspension insulator is basically a string of number of porcelain disc connected in series though metallic link. 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 this article, we will be talking about voltage distribution and string efficiency of suspension insulator. 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. String efficiency of suspension insulators is an important part in using process by person thinking about. Disclosed herein is a robot mechanism for inspection of a liveline suspension insulator string. Us20100100239a1 robot mechanism for inspection of live. In these topics, it is discussed the voltage distribution over suspension insulator string. Composite insulators for medium voltage lines gscc010 rev. 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. Each insulator of a suspension string is called disc insulator because of their disc like shape.
This program used to analyze and represent the potential field and electric field contours superimposed upon the drawing. As 4436 guide for the selection of insulators in respect of polluted. The use of nonceramic and composite insulators in place of traditional porcelain and glass insulators for line insulation has become widespread in the last 20 years. Us8239064b2 robot mechanism for inspection of liveline. Compared with existing cleaning robots using jets of water or waterair, this robot mechanism is superior in insulation as it uses a porcelainclamping method, and is more useful in. Ngk suspension insulator divided into porcelain suspension insulator and composite suspension insulator used for transmission and distribution systems from 10kv to 500kv. This structure connected in series by fitting into themselves in the form of a string. The number of insulator discs each rated 11 kv required in. 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. This insulator shall have good mechanical strength to be carrying heavy snow ice loads at the time. So that c 1 m c where m is the ratio between the capacitance to. 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.
Affordable and search from millions of royalty free images, photos and vectors. String efficiency of suspension insulator electrical. Ssen 603831 insulators for overhead lines with a nominal voltage. Suspension insulators or string insulators are very widely used in electrical overhead transmission system. Voltage distribution over a suspension insulator string. To evaluate these voltages, string efficiency term is used.
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. Email me at this address if a comment is added after mine. We talked about advantages and disadvantages of each type of insulators. Simulation studies cover electric field and voltage distribution calculation in the vicinity of insulator string. Definitions, test methods, acceptance criteria for post insulator units, standards australia, 2005 12. Specific mechanical load sml three levels of specific mechanical load are specified. The suspension insulator string and the cutting plane of the suspension insulator model as shown in fig. Pdf development of advanced insulator inspection robot.
Influences of relative humidity on the electric field and. Suspension composite insulator has features of light weight, small. Numerical study on dynamic swing of suspension insulator string in overhead transmission line under wind load. Of course, the number of disks varies as it has different creepage distance in each particular case. Suspension insulators or string insulators are very widely used in an. On the top of the insulator the conductor bound into a groove,which is cemented on. However, there is a significant thing to be considered in case of these string insulators, known as string efficiency. Of course, the number of disks varies as it has different. Compared with existing cleaning robots using jets of water or waterair, this robot mechanism is superior in insulation as it uses a porcelainclamping method, and is more useful in mountainous or salt damage areas by.
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. More than 30 years experience in power industry since 1978 as a composite insulator manufacturer in china, advanced manufacturing process, strict quality control test system, iso certificated, excellent communication, considerate services, enable us to be a leading composite insulator manufacturer of composite insulator and polymer insulator. Orientcomposite insulator pdf, download composite insulator pdf. The top of the suspension insulator set is fixed to the cross arm and the bott om of suspension insulator. When ac voltage is applied to the string, the voltage distribution is nonuniform across a string insulator. Pdf development of advanced insulator inspection robot for. 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.
A new cleaning robot system for suspension insulator strings was developed to prevent a power failure, which can have severe effects on the national industry and economy. Whether the insulator string has any serious deviation. Double sheds type, bell shaped type, aero dynamic type ceramic suspension insulator connection. 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. We assign numbers starting first on smallest to largest diameter, then least to most number of petticoats, then length of. A suspension insulator having an insulator body 1 with a shed 2, a pair of connection members 5,7 on respectively the upper and lower sides of the insulator body 1 and a plurality of ribs 4 formed on the lower side of the shed 2, wherein said insulator has dimensions such that the following equations 1 and 2 are satisfied.
Performance of a sting of suspension insulator at 400 kv line. String efficiency of suspension insulator electrical concepts. Gorur, in the electrical engineering handbook, 2005. Each insulator is designed for 11 kv and hence for any operating voltage a string of insulators can be used. The st suspension type classification system was born out of a simple need.
The greater the string efficiency, the more uniform is the voltage distribution in the each disc insulator. The porcelain portion of each disc is between two metal links. The analysis and simulation of voltage distribution over. Figurea below shows a typical suspension insulator. Pdf numerical study on dynamic swing of suspension. Ngk suspension insulator catalogue may tell more information about electrical insulators, including dimensions, insulator drawings and insulator images.
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. 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. Types of insulators in transmission lines electrical4u. Voltage distribution in a suspension insulator strain. On the top of the insulator the conductor bound into a groove,which is cemented on to a galvanized steel. The conductor is suspended at the bottom end of this string while the top end is secured to the crossarm of the tower.
The number of insulator units depends on the operation voltage and other factors such as contamination, mechanical strength, lightning, and altitude. The production process of the rodurflex insulators starts with the extraction of the frp rod. String efficiency of a suspension insulator youtube. Pin type insulator consists of single or multiple shells arranged in parallel and mounted on a crossarm of the pole or tower.
The voltage applied across the string of suspension insulators is not uniformly distributed across various units or discs. Oct 10, 2015 these are my suspension insulators so far. The suspension insulator separates the line conductors and supports them electrically. 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. Optimal corona ring selection for 230 kv ceramic istring. 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. Ssen 60372 locking devices for ball and socket couplings of string insulator units dimensions and tests. If we consider glass suspension string units with the specific number of insulators maintaining for a certain voltage class of transmission line, we can estimate the value of voltage drop on each insulator.