“Kyoto Protocol” set forth in a single of the six greenhouse gases sulfur hexafluoride (SF6) gas emissions into the ambience mainly in the course of the power transmission and distribution equipment, especially high voltage switchgear, transformers, transformers and gas insulated transmission pipelines and other products are within the experimental research, manufacturing, transportation and operation and upkeep generated within the process.

SF6 gas in high voltage electrical products account for approximately the appliance of SF6 gas applications, 80%, while the SF6 gas switch device is currently leading the sector of high voltage switch products, but in addition ultra high pressure and special high voltage switchgear applications and development of the primary directions, so understanding of our environment changes and trends within the protection and control emissions of SF6 gas into the ambience to check the SF6 gas within the power switching devices for power switching applications of significant significance to the event of kit.

Atmospheric environmental protection situation December 11, 1997, 149 countries and regions, representatives, adopted the “Kyoto Protocol” provides for 6 greenhouse gases (GHG), that are: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons , sulfur hexafluoride. This Protocol was February 16, 2005 came into effect, which supplies that in the period from 2008 to 2012, the key industrial greenhouse gas emissions by developed countries in 1990 at the basis of a standard of five.2%, of which the european would be six forms of greenhouse gases emission reductions of 8%, 7% reduction of U.s., and Japan 6%, Canada 6% reduction, Eastern European countries, reduction of five% to eight%; New Zealand, Russia and Ukraine would not have to chop emissions may be stabilized at 1990 levels; Protocol while allowing Ireland, Australia and Norway, respectively, compared with 1990 emissions increased by 10%, 8%, 1%; developing countries have emission reduction obligations.

China on May 29, 1998 signed the “Kyoto Protocol”, August 30, 2002 formally approved the “Kyoto Protocol”, although China has not provided herein emission reduction obligations, but experts predict that China’s C02 emissions will soon overtake the U.S. because the world’s first one, when the time will inevitably be to meet the “Kyoto Protocol” emission reduction provisions. Within the “Eleventh Five Year” period made it clear that to meet the “Kyoto Protocol” obligation, so SF6 gas in other appliances, together with transformers, transformers, load switches, transmission pipelines, etc. The applying and development of SF6 gas into the ambience ought to be considered the emissions, the study of more efficient enterprises to evolve to the industrial development programs.

Characteristics of SF6 gas The study found that at atmospheric pressure under the uniform electric field strength of SF6 gas insulated air thrice, although lower than the insulating oil and the high vacuum state, however the increase of SF6 gas pressure, the insulation strength shall be higher than that of insulating oil, and high vacuum. With air contrast study also found that, within the arc discharge cases, the air temperature gradient is comparatively small, rough arc, SF6 gas, the general temperature is lower, mainly concentrated in hot temperature parts of the arc. Therefore, SF6 gas within the arc bring to a halt in no time after the cooling, insulation and resilience of fine air about 100 times. SF6 gas at the environmental impact of SF6 gas molecular weight is 146, the air density is ready 5 times. SF6 gases within the atmosphere to outlive life is 3200 years. Therefore, SF6 gas is a totally strong greenhouse gases. SF6 is a greenhouse gas CO2 to the ambience of 23900 times.

In addition, SF6 gas switch device within the means of breaking currents will produce arc, the arc will SF6 gas under hot temperature decomposition, but additionally will produce metal vapor arc of contact, due to presence of water in interrupter shall be broken down, decomposed material will produce secondary reaction to form HF, S02, SOF2, SOF4, SO2F4 and other harmful substances. These substances would be corrosive internal metal components, if these substances emitted into the ambience at the person’s body could cause injury and stimulation.

Application and Development of SF6 Gas In 1953, the us first SF6 gas utilized in 115kV load switch devices, in 1958, Westinghouse created a tank along the lines of the compressed air circuit breaker 220kV double pressure type SF6 circuit breaker. The primary of this circuit breaker throughout the SF6 gas from compressed gas cylinders (1.5MPa) the flow of low pressure gas chamber (0.3MPa) and the cooling breaking arc. With this double pyramid structure, also developed the ceramic pole SF6 circuit breaker. Followed by Europe and Japan at the SF6 gas switch device manufacturing technology research has made great progress and development. The emergence of SF6 circuit breaker is a high voltage power system circuit breaking in from the oil circuit breakers, compressed air circuit breaker technology has begun a sequence of technological advances of latest results.

It is with the oil circuit breakers, compressed air circuit breaker advantage is that a single fracture compared with the high voltage, arc quenching ability, breaking current, circuit breaker, light weight, operate small power, high reliability, low maintenance, avoiding the oil circuit breakers susceptible to fire breathing, fuel injection and other undesirable phenomena, as well as structural diversification interrupter chamber (variable air pressure to open far from the ceremony, scheduled to open clear of the pressure air type, self energy type and mixed type) etc.

SF6 gas switch equipment, the continual development of the structure of various forms of products, akin to the tank and ceramic column SF6 circuit breakers, GIS, HGIS, compound etc. Including GIS, HGIS, and complicated type may have a wide range of product layout, these features allow the user within the design of power system substation, it may be selected in keeping with different situations. Since 1979, China started to introduce, or with foreign countries to develop 72.5kV ~ 550kVSF6 high voltage switchgear, after decades of development, SF6 electrical appliances manufacturing enterprises increased year by year. Currently, domestic enterprises can produce medium voltage (12kV), high voltage (40.5kV ~ 252kV), EHV (363kV ~ 550kV), and ultra high voltage (800kV 1100kV) SF6 high voltage switchgear.

Because SF6 gas has excellent insulating and arc quenching performance of the electric installations to realize the industrial oriented, low maintenance oriented operation and space saving, SF6 gas has also begun to high voltage transmission and distribution equipment inside the transformer, transmission pipelines and transformer areas reminiscent of application development. At the present, Japan is the rustic with the most important production of SF6 transformers, Mitsubishi, Toshiba, Hitachi, Fujitsu can produce.

SF6 transformers may be done today levels of 500kV and 300MVA. I even have the domestic production 10kVSF6 transformers, a few of them with foreign companies arrange a three way partnership and feature the 110kV and above, SF6 transformer manufacturing capacity. Along with high voltage SF6 gas circuit breaker inside the transmission and distribution equipment, GIS, load switches, transformers, transformers and gas transmission pipeline is applied, there are a small portion of the SF6 gas is utilized in sports shoes, scuba diving with breathing apparatus, medical field, thermal insulation glass windows, casting technology used to offer protection to the gas, pneumatic tires, and army and other non electrical equipment.

As the sector power industry development, especially in recent times, China’s sustained and rapid development of power industry so as to meet electricity demand, steady increase in grid construction and renovation, making the variety of high voltage power transmission and transformation equipment, demand for an unprecedented growth, increased SF6 gas usage, but additionally a rise of SF6 gas into the ambience emissions. SF6 gas for electricity may be seen that the contribution of the building the greater the contribution to atmospheric greenhouse effect may be increasing.

SF6 gas emissions into the ambience means SF6 gas emissions to the ambience mainly in the course of the power transmission and transformation equipment, pressure testing of recent products, capacity, breaking test, factory test, transfer of kit, transportation, installation, operation, equipment maintenance etc. The us in the course of the period from 1998 to 2002 the production and processing of high voltage circuit breakers installed within the SF6 gas leakage rate were investigated. Consequently, 10% of the circuit breaker leak may exist. Leakage reason: 73% occurred within the gas installation, 21% is because of worn and damaged casing, and six% is because of leakage of gas containers.

SF6 gas emission reduction measures and development trend of SF6 electrical Direction of development of high voltage electrical products, especially the SF6 high voltage electrical products, will be to attenuate emissions of SF6 gas to the ambience, the direction of the event of specific measures include: 1, raising the technological level of producing process equipment, reducing the leakage rate of SF6 electrical equipment. 2, to advertise the miniaturization of SF6 electrical equipment and decrease the quantity of SF6 electrical equipment on the way to reduce using SF6 gas. With the intention to significantly advance the miniaturization of GIS and non SF6 technology, Mitsubishi Electric Co., Ltd. to SF6 gas and thick film dielectric coated electrode composite insulation system as an object to check the insulating properties of high pressure areas. Through thick film dielectric coated together, can achieve curb the dimensions of the metal electrode effect due to the breakdown electric field decline; can reduce the electrode space, the biggest gas field, to realize device miniaturization. So far as possible a high degree of integration, layout and versatile composite electrical appliances or HGIS.

3, developing low pressure of the SF6 switchgear and SF6 gas mix of electrical equipment. Countries on the earth was studying alternatives to SF6 gas for decades abroad on quite a lot of mixed gases (which include SF6 N2, SF6 CO2, SF6 CF4) within the PD characteristics of insulation breakdown characteristics of the study found that for the liquefaction temperatures were particularly low, non toxic and stable N2 gas, mixed with 20% of the SF6 gas and the non uniform electric field within the partial discharge starting voltage (PDIV) and dielectric breakdown voltage (BDV) has increased the opportunity of, and, also present in high gas pressure, can get 100% SF6 gas with roughly the identical insulating properties. So SF6 N2 is regarded as the most popular alternative to SF6 gas. At the moment, the world’s first hybrid gas insulated high voltage lines N2 SF6 in Geneva completed. ABB has developed LTB 72.5 kV a 145kV GCB and HPL72.5 300B1 type GCB may be used either pure SF6 gas is additionally used SF6 N2 gas mixture. When using SF6 N2 mixed gas, at 20 – Rated air pressure 0.7MPa (absolute), it may be utilized in 50 -, while in pure SF6 gas 0.5MPa (absolute), the simplest for 40 -. Toshiba also N2 SF6 mixed gas circuit breaker is studied.

4, within the equipment manufacturing and kit maintenance throughout the use of advanced SF6 gas recovery unit, the recovery through a lot of filters to take away the SF6 gas within the water, oils, dust, and other elements resultant decomposition. Achieve SF6 gas recycling.

5, within the medium voltage (12kV 40.5kV) areas, use of non electrical SF6 and vacuum switchgear, high voltage (40.5kV ~ 252kV) fields to the special high voltage (800kV 1100kV) areas, to develop a vacuum circuit breaker (VCB), to upgrade technology and gear to lessen manufacturing costs VCB, vacuum switchgear to accomplish various high pressure area in order that active rejection vacuum circuit breaker (VCB) of high voltage oriented research work, to succeed in high voltage of VCB and EHV oriented.

6, protection of atmospheric environment, and foster awareness of emission reduction. Japan is the usage of SF6 gas more countries, as a way to implement the “Kyoto Protocol” on SF6 gas emission reduction obligations, NEC Business Association, the Japanese electric industry to reach this goal may be taken positive action. Japan SF6 gas reduction measures is to ascertain a check curb emissions, to switch SF6 gas insulated equipment curb emissions, recycling system, and has taken action to enhance the SF6 gas management system. Germany’s high voltage switching equipment industry is likewise okay developed. Annual use of SF6 gas is ready 1000t. If you want to achieve reduction of SF6 gas emission targets, October 19, 2005, the ability to run industry and electrical equipment manufacturing industry associations and Solvay Fluor GmbH (SF6 gas manufacturing) companies and the German Environment, Nature Conservation and Nuclear Reactor Safety for further provisions of the Federal Ministry of have reached a consensus on their lonesome obligations.

7, to hold out the Clean Development Mechanism (CDM), to realize reduction of SF6 gas.