Usage of gas insulated system gis serves as the most convenient option having high reliability, availability, high degree of safety, compact design, long service life etc. Apart from other benefits during construction and operation. Coupled electrothermal transients simulation of gas. High voltage underground cables for power transmission have been in use for many years and number of different technologies have developed over the years. A global leader in highvoltage sf6 gas insulated bus systems.
Grounding devices that prevent electrical shock and lightning arresters that prevent dielectric breakdowns from lightning strikes are also included to enhance safety. The gas insulated transmission line gil is a system for the transmission of electricity at high power ratings over long distances. Sf 6 gas pressure for insulating purpose is generally kept below 2. Also the appli cation of special energy tunnels over long distances will be explained.
This product utilizes the insulating benefits of sf6 gas as opposed to oil. Azzs sf 6 gas insulated transmission line gil deliver economical longdistance power transmission, with superior reliability and a longer lifecycle to reduce ownership costs. Lsis who has been a leader in electricity and automation. Abb substations with gas insulated switchgear gis are unmatched when it comes to compactness, reliability, efficiency and safety, ensuring maximum power availability for utility, commercial and industrial customers. Distribution voltages are typically medium voltage, between 2. The gas insulated transmission lines gil of the second generation are now in services since more than 2 years, with very good service experiences. Highvoltage transmission line and sf6 gasinsulated. Impregnated paper insulated pipe type cables have proven to be most reliable in service life.
Gas insulated lines for ac transmission a compact solution for high power transmission average route width for a transmission. This research work was conducted to examine and determine the suitability of using an hvac gas insulated transmission line gil as a longdistance. An electrical substation is an installation with electrical equipment capable of interrupting or establishing electrical circuits and changing the voltage, frequency, or other characteristics of the electrical energy flowing in the circuits. Sulphur hexaflouride sf6 gas the primary insulating medium.
These can be installed above ground, in trench or tunnel installations. Gas insulated transformers toshiba s gas insulated transformer git is the most technologically advanced product within our transmission and distribution systems group. Provides a highly reliable, simple, troublefree system with a proven long term track record for new bulk power transmission circuits in the 69kv to 500kv range, as an alternative to solid dielectric cables. As vacuum technology is not available for high voltage, so for gis or gas insulated switchgear system above 72. Highvoltage power transmission energy siemens global. Gas insulated metalenclosed switchgear for rated voltages above 52 kv 092011 orequired leakage rate gas compartment tt f th td i 01% t t. The size of gas insulated substation is significantly small compared to conventional substation because a high electronegative property of sf6 gas b high dielectric property of sf6 gas c high insulation property of sf6 gas d all the above. Gas insulated transmission lines gil are a means of bulk electric power. Gas insulated lines an alternative to fluid filled or xlpe cable is the use of gas insulated lines gil. The gil went into service in 1975 and has remained in service without interruption since then, delivering peak energy into. Pdf the paper deals with the possibility of installing a doublecircuit gas insulated transmission line gil in the pilot tunnel of the planned new. Products connection of a 500kvohl to an underground gis with through a 480m deep shaft 2x240m.
Gas insulated transmission lines successful underground. Consistent with toshiba s approach to provide the utmost in quality and performance, the. Insulated transmission lines gil wiley online books. Gis gas insulated substations this figure is showing the layout for a typical ac power transmission and distribution system by a single line diagram. Gas insulated transmission lines gil are a means of bulk electric power transmission at high and extra high voltage. Compact high voltage direct current hvdc transmission. Sf6 gas superior dielectric properties used at moderate pressure for phase to phase and phase to ground insulation preferred for voltage ratings of 72. Gas insulated substation fusion plating equipment for discharges caused by problems in. Customer benefit gas insulated transmission line gil for 500kv.
Secondgeneration gas insulated lines for high power transmission are the best option where environmental or structural considerations rule out the use of overhead transmission lines. Gas insulated transmission lines gil is an established high voltage technology used when environmental or structural considerations restrict the use of overhead transmission lines. A onestop, complete reference text on gas insulated substations gis, largecapacity and longdistance electricity transmission, which are of increasing importance in the power industry today details advanced and basic material, accessible for both. Concept of gil g gas insulated transmission lines gil are a means for bulk power transmission at extra high voltage ehv, e. A typical gas insulated substation is shown in fig. Gil systems installed in a tunnel remain accessible for inspection. They transform voltage from high to low, or vice versa, and provide the ties, transformation, switching and protection of the transmission and distribution systems. A gas tight barrier insulator in switchgear serve for the separation of gas compartments and prevents neighbouring switchgear parts from being affected during maintenance.
The gas insulated transmission line gil was invented in 1974 to connect the electrical generator of a hydro pump storage plant in schluchsee, germany. Simple and inexpensive interfaces are available for almost all types of gas insulated switchgear gis, transformers, oil cables and xlpe cables. Development of 22 kv distribution systems and switchgear 160 conductor for connecting to the cable head at the bottom of the molded case, a current transformer for metering that is built into the epoxy molded insulated housing, a condenser for voltage detection, and three for three phases fourposition vacuum switches. Highvoltage transmission line and sf6 gas insulated substations inspection using computed radiography. Distribution substation a distribution substation transfers power from the transmission system to the distribution system of an area. Standard azz systems are suitable for transmission voltages from 115 kv to 1200 kv, with continuous current ratings as high as 8000 amperes. Iec and ieee standards for highvoltage switchgear and. Underground power transmission on highest reliability level. Transmission cost estimation guide mtep19 1 purpose statement the miso transmission planning process focuses on making the benefits of an economically efficient electricity market available to customers by identifying transmission projects that provide access to electricity at the lowest total electric system cost. This system comprises aluminiumcopper conductors that are supported by insulators contained within sealed tubes. They are a means of bulk power transmission in the ehv range where overhead. For voltages up to 8kv, the pipe can be filled with dry nitrogen gas highpressure gas filled, hpgf, though synthetic.
Compact gasinsulated systems for high voltage direct. Switchgear and controlgear present situation and future evolution mumbai, january, 2008 denis dufournet. Evaluation of gas insulated lines gil for long distance. Operation and maintenance of a gas insulated substation. Very high safety requirements with regard to fire protection. Gil consists of tubular aluminium conductors encased in a metallic tube that is filled with a mixture of nitrogen and sulphur hexafluoride gases for electrical insulation. Development of 22kv distribution systems and switchgear. Figure3 converter rating as a functionof rated dcvoltage and accurrent.
Design and testing uwe riechert, ueli straumann abb technology centre high voltage products zurich, switzerland email. Compact gas insulated systems for high voltage direct current transmission. Substation engineering ais and gis substations beta. Solid insulation cables have limits when it comes to the voltage that can be carried safely, and oil impregnated paper cable are also limited in the capacity. Pdf the gasinsulated line gil is one technical solution to allow the transmission of electricity underground at a high voltage level, yet its. A cathodic protection system is important to further protect the pipe from corrosion. Gas insulated transmission line gil is a system for the transmission of high voltage electricity for long distance. The outstanding features of a gil system are its high transmission capacity, superior electromagnetic compatibility emc to any other trans. Pdf study on the gasinsulated line equivalent model and. More concrete user benefits and solutions for intelligent, digitally controlled power transmission and distribution.
At the beginning of the sf6 insulated technology which leads to gis and gil investigations were made on gas filled high voltage transmission lines, without. Iec 62271203 highvoltage switchgear and controlgear part 203. The input for a distribution substation is typically at least two transmission or subtransmission lines. Siemens provides a wide range of services including the supply of complete packages of highvoltage devices with control and protection systems as well as installation and commissioning of the highvoltage substations. Substations are an important part of the electrical generation, transmission and distribution system. Main components of a gas insulated substation gis you. Pdf compressed gas insulated transmission bus systems.
A common numbering system has been established for highvoltage switchgear. Compressed gas insulated transmission bus systems cgit westboro, inc. Pdf gas insulated transmission lines in railway galleries. Gasinsulated transmission lines gil is an established high voltage technology used when environmental or structural considerations restrict.
The 2nd generation gil is insulated with n 2sf 6 gas mixtures and the design and laying technique is primary dedicated to long distance transmission. With a compact system design, fabricated elbows and a large current capacity, gil offer complete system flexibility. Gas insulated switchgear gis is the name for a unit that houses these components and circuits in a single gas tank with a compact footprint. The increasing demand for hvdc technology requires the adaptation of gas insulated switchgear gis. Highvoltage direct current transmission systems hvdc grid access solutions. In cases where overhead lines are not possible, the gil is a viable technical solution to bring the power transmitted by an overhead line underground without a reduction of power transmission capacity. On the other hand, sf6 gas is the global warming gas, which can affect the ozone layer, and critical to find the exact failure location may also hinder the market. Distribution substations michigan technological university. Undergrounding high voltage electricity transmission lines.