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At the National Power System High-voltage Switch Working Conference, power users criticized the quality of high-voltage isolating switches operating in 35 to 500kV power grids across the country, pointing out four common problems with isolating switches.: First, the contacts are overheated ； Second, the porcelain bottle broke ； The third is motion stagnation ； Fourth, the opening and closing are not in place. The existence of these problems has seriously affected the safe operation of the power grid. At the meeting, all provincial bureaus of the power system and isolating switch manufacturers were required to jointly investigate and analyze the quality of isolating switches in operation, and propose plans and measures to transform currently produced isolating switches and develop new isolating switches. In accordance with the requirements of the National Power System High-voltage Switch Working Conference, Pinggao Electric Company attaches great importance to the quality issues of high-voltage isolation switches and immediately begins research and solutions. Pinggao Electric Co., Ltd. is a large domestic high-voltage switch manufacturing enterprise. It occupies a large proportion in the production and use of isolating switches. Several major problems in the operation of isolating switches also exist to varying degrees. Since the 2000 National High Voltage Switch Working Conference criticized the quality issues of isolating switches and the recent feedback from some provincial bureaus on the quality issues of Pinggao isolating switches, Pinggao Electric has attached great importance to this and has sent designers in charge of isolating switches to participate in the work of the isolating switch modification and improvement groups organized by provincial bureaus of the Institute of Electric Power Research to jointly solve the quality problems of the currently operating isolating switches with users. The company has held many isolating switch quality problem analysis meetings, isolating switch product research and development seminars, and on-site production technology seminars, and mobilized a large number of engineering and technical personnel, design and process experts, and quality engineers to solve the quality problems of isolating switches by combining temporary and root causes. 1. Improvement and improvement of various types of isolating switches currently produced. The company has decided to improve the design and improve the quality of its GW16, GW17, GW7 and GW4 isolating switches. The deadline is to be completed by the end of 2002. The main measures are: 1) Main improvement plans for GW1617-252, 363, and 550 type isolators. Starting from the design, we should improve the shortcomings of the design structure of the existing isolating switch and solve the problem that the conductive tube at the closing position cannot be straightened or the opening and closing position is not in place during the operation of the switch. In view of the product's possible motion stagnation or incomplete opening and closing due to corrosion of some parts, the following improvement measures have been taken: A) All exposed drive shaft materials are changed to stainless steel, and other exposed electro-galvanized parts may change materials or surface treatment methods. B) The brass bushing is replaced with a steel-based surface sintered bronze plus modified polytetrafluoroethylene composite bushing, and the outer surface and ends are tin-plated to prevent corrosion. C) All cotter pins are replaced with stainless steel parts. D) In view of the corrosion defects of the clamping spring, return spring, ejector rod, and connecting tube caused by water intrusion into the conductive tube on some isolating switches, measures such as modifying the processing dimensions of some parts, changing some parts to stainless steel, and applying molybdenum disulfide during assembly were adopted. The copper-aluminum bimetal plate is cancelled, and the conductive surfaces connecting different metals are treated with silver plating or tin plating. There are other improvements to prevent corrosion, prevent overheating of contacts, and avoid motion jamming. 2) GW7-252 type isolating switch. In terms of design, the movement and structural form of the conductive tube is first rotated horizontally and then flipped radially to ensure effective conductive contact between the dynamic and static contacts. Our company already has this structural form with a rated current of 3150A, and plans to design an isolation switch with this structural form with a rated current of 2000A and covering 1600A. In terms of preventing corrosion and movement jamming, similar measures are taken to those of the GW16 and 17 models. During the production process, process discipline must be strictly enforced to ensure the processing accuracy and quality of parts, and assembly and factory testing must be carried out in accordance with the requirements of technical conditions to ensure the physical quality of the product. 3) GW4-126, 252 type isolating switch. Improvements should be made according to the above-mentioned measures to prevent corrosion and avoid motion jamming. The double-column horizontal fracture rotary isolating switch is a widely used isolating switch in 110 and 220kV power systems in my country. Pinggao Electric is developing a new type of isolation switch. The design structure of this new isolating switch is: The conductive rod adopts a self-standing moving contact structure ； The base and connecting rod with adjustment bolts are of non-welded structure. ； The connection between the mechanism output and the main operating rod, the connection between the three-phase linkage pull rod, and the connection between the ground knife transmission rod all adopt flexible connection structures. ； All bolts and nuts are made of stainless steel. The new 126kV2000A isolating switch has completed type testing and will be available to users within the year. 4) Develop a newly designed electric operating mechanism and adopt a newly designed and manufactured reducer plus motor overall structure ； The auxiliary switch is a cam plus micro switch structure ； Use high-reliability, long-life electrical components ； The design of the mechanism box has ensured reliable sealing, no rust on the surface, and convenient wiring and adjustment inside the box. The mechanism has completed type testing, with an output power of 1,000Nm and a mechanical life of 10,000 times. It can be used to operate various types of isolating switches, and can be used to transform old isolating switches and replace the original operating mechanism. The agency will also make it available to users within the year. 2. New concepts on the R&D and design of isolating switches. Isolating switches are important switching equipment for switching and switching lines in the power system. Its reliability and manufacturing quality also play a very important role in the safe operation of the power system. Manufacturers should eliminate the ideological tendency of not paying attention to or not improving the R&D, design and manufacturing technology of isolating switches. They should develop and design new isolating switches with the concept of isolating switches and circuit breakers being equally important and pursuing high technology, high reliability and high quality. 1) In the design of the conductive circuit, the self-standing contact system uses a new copper alloy material to replace the contact finger (contact piece) and spring structure. It uses the elastic force of the conductive rod itself and the normal current-carrying electrodynamic force to coordinate the dynamic and static contact sizes reasonably to keep the conductive circuit in an effective electrical contact state and avoid overheating of the contacts. 2) The bearings and sleeves of the rotating parts are designed to ensure that the isolation switch does not rust and remains lubricated during the movement during its life cycle. New fully sealed lubricated bearings or dry lubricated composite sleeves must be selected. As for the material of shaft and shaft pin, stainless steel should be used as much as possible. 3) Because the welds or solder joints of structural parts often retain acid after the pre-painting treatment, during outdoor operation, the welds or solder joints will first corrode and then expand, forming large-area rust. Therefore, in order to prevent corrosion of the isolating switch structural parts, the fixed connection of the base (frame), connecting rod and bolts should adopt a non-welded structure. 4) The body structure above the porcelain bottle and its moving or transmission parts should be sealed in the shell or tube as much as possible to prevent the invasion of rain, snow, moisture, dust, etc., which may cause rust and corrosion of parts and even affect the normal operation of the isolating switch. 5) Silicone rubber composite insulator is a new type of insulator that can replace porcelain bottles. It has the characteristics of strong anti-pollution flashover ability, light weight and high strength, and is not easy to break or break. It is now widely used in electrical equipment such as suspension and rod-type pillar insulators, current transformers, outlet bushings, etc. in power systems. Silicone rubber composite rod-type insulators suitable for use in isolating switches should be developed and the use of isolating switches equipped with silicone rubber composite insulation should be promoted. 6) Do not allow users to connect the linkage rod and the main transmission rod by welding on site. Flexible connection methods should be used as much as possible. First, to prevent rust and expansion of the welding joint. ； The second is to facilitate installation and adjustment. 7) The principle of the electric operating mechanism of the isolating switch is not complicated, but it is not easy to design and manufacture a highly reliable mechanism. The key point is the overall structural design of the reducer, which must have sufficient output power, torque and angle range to operate the isolation switch. Then there is the auxiliary switch, which adopts a new structure, such as a cam plus a micro switch, which can ensure that the switch is in place and is easy to adjust. The selection of electrical components should be components with high reliability and long life. ； The design of the mechanism box should consider reliable sealing, no rust on the surface, and user-friendly wiring and adjustment inside. 3. Improve manufacturing process technology and ensure the quality of isolating switch products. Based on the high starting point of isolating switch structural design, that is, the use of new structures, new materials, strict dimensional tolerances of parts and special processing requirements, etc., the manufacturing process should be strict to ensure the processing accuracy of parts, material heat treatment, and surface anti-corrosion and anti-rust requirements. It can be said that after the technological transformation of the factory in recent years, the addition of CNC processing equipment, welding production lines, heat treatment production lines, aluminum silver plating production lines, surface spraying production lines, etc., the process and equipment conditions for the production of high-quality isolating switches are now available. As long as strict process discipline and strict quality management are required, domestic manufacturing plants are fully capable of producing high-tech, high-reliability, and high-quality isolating switches that meet the needs of power users.