Development of 66kV Isolation Switch V Type Porcelain Column Fracture Insulation Protection Frame

The mechanical strength of old 66kV disconnect switches (V-type porcelain column type) in outdoor substations has been affected by weather and daily operation for a long time, and the change of internal force of porcelain column caused by external force during open and closed circuit operation is very likely to cause porcelain column fracture, which poses a safety hazard to the safety of people and equipment.In order to ensure the safety of personal and equipment during operation and maintenance of the switch, this paper proposes a kind of insulation protection frame for 66kV disconnecting switch V-type porcelain column fracture. The simple structure, flexible operation, safety and reliability of this protective frame have been proved by practice that after using this protective frame in work, the efficiency of work is obviously improved and the safety of personal and equipment is effectively guaranteed.


Introduction
There are still a certain number of V-type porcelain column disconnect switches in the operating 66kV substations. Due to the quality of the product, the age of operation, the aging of the porcelain column, the influence of outdoor bad weather, and the wear and tear of long-term operation, many cases of porcelain column fracture have occurred, causing great safety hazards to people and equipment.
In response to the above problem, this paper proposes an insulation protection frame for 66kV disconnector switch V-post fracture. This insulating protective frame is designed according to the characteristics of the reversing operation of the site operator and the operation requirements of the 66kV disconnecting switch V-type porcelain column, combined with the safety distance between the human body and the 66kV live body during the operation of the operator. The developed protective device has been tested and verified to meet the requirements of various regulations and standards and various technical conditions for operating 66kV disconnecting switch V-type porcelain column, and has a simple structure, convenient construction, which is safe and reliable. [1,2] 2 Insulation protection frame principle and structure

Design principles
According to the characteristics of field operation and the operation requirements of 66kV isolation switch V porcelain column, combined with the operation of the human body and 66kV charged body in the operation of various types of safety distance, design both in line with various types of regulations, standard requirements and meet the operation of isolation switch V porcelain column of various technical conditions, simple and durable, convenient construction, safe and reliable protection device. Figure 1 shows a sketch of the structure of the insulated frame.The names of the parts are as follows: 1. epoxy resin tube insulation frame, 2. universal wheel, 3. silk net, 4. metal connection clamps. As shown in Fig. 1, the insulation protection frame of the isolation switch V-post fracture includes a desktop insulation frame composed of epoxy resin tubes, the main structure is simple, strong load-bearing, and the main body is made of epoxy resin tube insulation material, which can be decomposed for easy preservation and use. There are four universal wheels under the insulating frame, and the surface of the insulating frame has obliquely set silk net. [3,4] The protection frame is used in combination of two docking (a single one in Figure 1), forming a type mesh table for easy catching, and the docking is connected with metal connecting clamps for easy fixing.

Principle and structure
The universal wheels can support the whole insulated protective frame, which is convenient for the protective frame to move around the site. The silk net is made of insulating material to catch the falling switch when it breaks and falls to prevent discharge to the ground. Since the direction of fall after the isolation switch is broken is uncertain, so two "isolation switch type porcelain column broken insulation protection frame" need to be docked and used, and the docked two "isolation switch type porcelain column broken insulation protection frame" are fixed with metal connection clamps, which can also prevent The protective frame is prevented from being pushed down after the disconnecting switch breaks or falls. [4,5]  epoxy resin insulation frame: the main structure is simple, strong load-bearing capacity, the main body is made of epoxy resin insulation material, the main body of the protection frame can be easily decomposed, colleagues are easy to save and use.

Easy transportation for on-site operations
The bottom adopts universal wheels, which is convenient for transportation and can be moved freely according to the needs at the work site. Save time and effort, flexible and mobile.

Economical and durable
The protection main material is made of insulating material (silk net). Material price is suitable, durable, can withstand the weight of broken porcelain column, while insulation effect is better.

Stable protection effect
Isolation switch type porcelain column broken insulation protection frame need two pieces of butt use, using metal connection clamps. The safety factor is high.

. Main material
The main body is made of epoxy resin Φ50mm, Φ30mm insulating tube and Φ 10mm silk insulating rope, the overall mass is lighter and meets both mechanical and insulating strength requirements.

Transportation
The overall protective frame is assembled with moving wheels at the bottom, which is convenient to install once and use flexibly for many times, and convenient for operating personnel to operate.

Universality
The mounting position of the protective frame takes into account the versatility of different forms of disconnect switches and facilitates their use for other forms of disconnect switches

Safety Effect
Insulation protection frame in the protection of the operator from the porcelain column fracture to bring dangerous factors, but also to ensure that the porcelain column how to fracture to avoid falling to the ground after a single-phase short circuit or due to the diversion swing caused by the phase short circuit and further expansion of the accident hazard. [6] Fig. 6. Insulation protection frame field application effect picture

Insulation protection frame all kinds of test results
According to the electrical test standard of 66kV insulated tools specified in Q/GDW1799. GB/T18037-2000 Basic technical requirements and design guidelines for tools for energized operation.
After the above test verification, this insulated protective frame meets all the standard requirements.

Insulation pole frequency withstand voltage test
66kV insulated pole class test 175kV frequency withstand voltage per meter for 1 minute without overheating, flashover or breakdown.

Insulation rope high voltage insulation test
66kV insulated rope type test every 0.5m withstand 105kV high voltage test without overheating, flashover and breakdown.

Safe and effective distance requirements for insulated rod-type appliances
The safe and effective distance of 66kV insulated poletype appliances is not less than 1.0m.

Insulation rope class appliance safety effective distance requirements
66kV insulated rope-like appliances safe and effective distance of not less than 0.7 meters.

Expert group acceptance opinions
State Grid Baishan Power Supply Company organized the acceptance of the project "66kV isolation switch V-type porcelain column fracture insulation protection frame" on March 12, 2015. The acceptance team listened to the reports, examined the actual application and, after full and serious discussion, formed the following acceptance opinions.
The protective frame can meet the actual needs of field use, and the protection effect is remarkable. The test results prove that the device works reliably, is simple and easy to use, has a reasonable design and obvious economic benefits, has reached the domestic advanced level, and has good prospects for promotion and application.

Applications and social benefits
66kV isolation switch V-type porcelain column fracture insulation protection frame is applied to Songjianghe 220kV substation. 66kV V type porcelain column type isolation switch is simple, convenient, flexible and reliable to operate, replace and transform. A total of 40 sets of 66kVv-type porcelain column disconnect switches were replaced and operated 165 times. It ensured the personal safety of the operating personnel in the operation and reduced the safety hazards caused by the porcelain column breakage to the person and the equipment.
66kV isolation switch V-type porcelain column fracture insulation protection frame is applied to Baishan 220kV substation. It makes the transformation and operation of 66kVv-type porcelain column disconnect switches more simple, convenient, flexible and reliable. A total of 4 sets of 66kVv-type porcelain column disconnect switches were replaced and operated 69 times. It ensured the personal safety of the operating personnel in the operation and reduced the safety hazards caused by the porcelain column breakage to the person and the equipment.

Conclusion
66kV isolation switch V type porcelain column breakage insulation protection frame can ensure the safe distance between the operator and the charged body when the personnel operate, and ensure the safety of the person and equipment when the porcelain column breaks, the use of protection frame is simple, reliable, flexible and useful. It is simple, reliable and flexible when used. It is put into production to meet the actual needs of the site. It brings safety to the operation, overhaul and replacement of 66kV disconnect switches (V-type porcelain column type) and other forms of disconnect switches.