HGIS (HYBRIDGASINSULATEDSWITCH) is a novel composite apparatus, which assembles breaker, one or more isolating switch, CT, PT, and their control systems together. This combination device can be easily used for indoor or outdoor installation, it is an independent and complete access, line spacing, assembled from a plurality of modules having its own independent air chambers.

        Since the last century, ABB company launched the first HGIS product (the product name referred to as PASS), Mitsubishi, Siemens, ALSTOM company also launched the MITS, HIS, GIM, Hm, and other products. In December 2002, the State power company in Zhuhai, Guangdong calls relative power system experts and convened a national technical seminar for ABB's PASS. And it issued a document (Letter No. 2003-28 production of power transmission) in March 2003 to specify the promotion and application of such products in the country. So far, there are more than 2,000 sets of such equipment into operation in the world, and China owing more than 400 sets.

        China's first HGIS (ABB's PASS) 145KV substation was put into operation in March 2003 in West Sam Guangdong power grid substation. The earliest 72.5KV (ABB's PASS) device was put into operation at the end of 2003 in Heilongjiang; Three provinces in the northeast of China had more than 40 sets of 72.5KV (ABB's PASS) device; Taiyuan, Shanxi Qingxu substation had 252KV equipment (ABB's PASS) at the end of 2005; 550KV equipment (Mitsubishi) was put into operation in 2004 in Dongguan. At present, several large high-voltage switchgear plant are engaged in research and development of domestic HGIS equipment, some manufacturers have passed the type test and put into operation in grid. (Source: high voltage switching network)

GIS products was accepted by operating units after a dozen years’ promotion in the country, and then domestic GIS was developed by domestic manufacturers successively. The HGIS product only took three years to get such a wide range of applications. Why did HGIS product develop so quickly? The reason can be summarized as the following:

First, a high overall economic efficiency

        Saving land and reducing the cost. Compared with traditional substation (ceramic column, also known as AIS products), HGIS saves about 70% of the land, and the comprehensive cost of the same size and type of GIS 1/3, which means that the definition of similar products are between imported equipment and imported equipment, domestic equipment and domestic equipment. Compared with AIS products, considering land for building fees, excavations fees, installation expenses and operating costs, the life cycle of composite cost went down.

Second, advanced technology, reliable operation

        1. In terms of operational reliability, first due to the new manufacturing process, the high pressure aluminum casting technology to make shell makes the working condition of sealing flange improved with its metal surface connected directly, greatly reducing yearly gas leakage rate; secondly, reduce the use of disc insulator (252KV and below voltage class, you can not use the disc insulator) structurally, greatly reduced the failure rate of internal insulation pieces; the use of multi-station disconnector simplifies the internal primary structure, minimizing the vulnerable components; the new-style disconnector operating mechanism, whose mechanical part sealed in a metal can isolated from the outside air in the long-term running, solves the previous air rust problem and guarantees the entire mechanism maintenance-free during the switch life period;

        2. In terms of the operating safety, the multi-station disconnector is structurally designed to prevent misuse with simple operation, low power consumption; the inspection window for HGIS disconnector design makes the site disconnector break point obvious; HGIS bushing manufacturers generally consider two forms: the silicone rubber and ceramics. At present, power system accept silicon rubber, in the highlands and the railway sector ceramic sleeve is adopted. Taking the maintenance of equipment into account, the creepage distance generally exceed the national standard of maximum creepage distance (such as ABB uses 97.5px / kv).

        3. In low-temperature region, SF6 and CF4 mixture gas is used instead of usually mixed N2 and heaters for domestic use.

        4. HSBC boxes generally processed in domestic, use stainless steel shell, the surface coating process, and imported relay normally used to extend the service life.

Third, easy for installation and maintenance

        1. easy to install and debug. HGIS’s major part is completed in the cleaning shop, the second control line is connected via the air plugs, the whole equipment is processed in the plant. The major equipment site does not require purification treatment, evacuation and other processes, just simply entirely assembling and fixing; the air plugs is one-to-one correspondence, even without re-allocating the secondary cable dialing, alignment, do the cable head, wrong insertion does not occur; in general, on-site installation is in the charge of the manufacturer, 145KV and 252KV equipment can be installed in a day .

        2. Easy to maintain. HGIS is basically maintenance-free equipment, manufacturers generally only require 5-7 years to conduct a preventive test. The operating mechanism of circuit breakers and disconnectors as well as CT, HSBC cabinet can be replaced as a whole, the primary equipment replaced separately. The above-mentioned components, if damaged, are generally returned to the manufacturer to replace instead of on-site processing;

        3. For ease of installation, manufacturers generally offer support anchor bolts and primary terminal, and provide sufficient SF6 gas and proprietary tools necessary.

        4. The manufacturer generally sends relative person to the site to solve any problems happen to the equipment, with components replaced instead of dismounting at site.

        5. In order to facilitate the implementation of standardized wiring form, currently HGIS generally is divided into four kinds of wiring types: single bus, double bus, inlet and outlet, double breaker. The cable type and bushing lead pre-manufactured in the manner of modules in the factory. The use of aluminum casting process minimizes the whole size and weight greatly, easier to install on the roof. Its current transformer uses out-cell, easy to install replace.

Fourth, meet the development requirements of environmental protection and intellectualization

        1. Coastal and seriously polluted areas are taken into consideration when designing HGIS all components with relatively high sealing and corrosion level of the operating mechanism and SHBC box.

        2. The stent is generally processed in domestic, its surface uses hot-dip technology. For aesthetic, some power supply bureaus requires spray on the stent to prevent light pollution. HGIS more emphasizes on maintenance-free on-site, the main part at site can be replaced in a short time. What’s more, HGIS is much more reliable, and can save a variety of resources to a greater extent. For example, the decrease of aluminum and SF6 gas using for its smaller volume is 1/5 of the same voltage class GIS, which is benefit to the environment and natural resources saving; besides, it reduces the power supply bureau maintenance work load and greatly improves labor productivity. As the development of localization, HGIS manufacturing costs will be gradually reduced. It can be predicted, HGIS will gradually become the main high-voltage electrical products in high-voltage grid substation construction.