FKN12-12D/T630-20 indoor AC High voltage load switch (hereinafter referred to as FKN12-12D Load switch) is a three-phase High Voltage switchgear with a rated voltage of 12KVand a rated frequency of 50Hz, used for switching load current, closed-loop current, no- load transformer and cable charging current, and switching sho circuit current. Load switches equipped with grounding switches can withstand sho-circuit currents.

FKRN12-12D/T125-31.5 AC high Voltage Load Switch Fuse combination is an Indoor High Voltage Switchgear equipment that combines FZN12-12D load switch with S-po LAJ-12 (XRNT po-10) high voltage current limiting fuse.

It can reliably disconnect any current up to the sho-circuit current, load switch disconnect working current, fuse disconnect sho-circuit current, and jointly disconnect any overcurrent between working current and full sho-circuit current. At the same time, the fuse uses its impactor to open the load switch.

1.Model and meaning

2.Environmental conditions for use

Air temperature: -25~+40 ° C

Altitude: not exceeding 1000m

Relative temperature: daily average not exceeding 95%, monthly average not exceeding 90%;

Eahquake intensity: not exceeding magnitude 8

Installation location: a place without re, explosion hazard, chemical corrosion, and severe vibration Pollution level: II

3.Main purpose

FKN12-12D compressed air load switch, FKRN12-12D series compressed air load switch fuse combination, suitable for control and protection of power equipment such as transformers, cables, overhead lines, etc. in three-phase distribution systems of 12KVand below; Especially suitable for terminal substations and Box type substations in urban and rural power grids. And it is applicable to the control and protection of ring networks and dual radiation power supply units. e FKN12-12D series compressed air load switch can switch between load current and overload current. e FKRN12-12D series compressed air load switch fuse combination can switch load current, overload current, and sho-circuit current of the circuit.

4.Main technical parameters

5.Appearance and installation dimensions

Analysis of High Voltage Isolation Switch Materials

Materials Used in High Voltage Isolating Switches: An In-Depth Analysis

High-voltage isolating switches are essential components in electrical transmission and distribution systems, providing safe operation and maintenance by isolating specific sections of a power circuit. These switches work under extreme conditions, including high electrical stress, environmental challenges, and mechanical wear. The performance and durability of high-voltage isolating switches largely depend on the materials used in their construction. This article explores the various materials used in the fabrication of high-voltage isolating switches, highlighting their properties, functions, and why they are chosen for these critical applications.

The Role of Materials in High-Voltage Isolating Switches

The materials used in high-voltage isolating switches must withstand not only high mechanical and electrical stress but also environmental conditions such as humidity, temperature fluctuations, and corrosion. Each component of the isolating switch, including the contacts, Insulators, actuators, and enclosures, requires specific material properties to ensure efficient and safe operation.

High-voltage isolating switches perform a key role in disconnecting circuits without causing arcs or damaging the system. Therefore, understanding the materials that comprise these switches can help in the design of safer and more reliable electrical systems.

1. Contact Materials

The contacts of high-voltage isolating switches are crucial for their performance. These components are responsible for making or breaking the electrical connection. As high-voltage switches are often required to operate under load, the contacts need to be made of materials that offer both excellent electrical conductivity and durability. The following materials are commonly used:

• Copper (Cu):Copper is one of the most common materials used for electrical contacts due to its excellent electrical conductivity, corrosion resistance, and mechanical properties. Copper contacts ensure minimal electrical resistance when the switch is closed, allowing for efficient power transmission. However, copper can oxidize over time, which may increase the risk of arcing during operation.

• Copper Alloys:Pure copper can degrade due to high temperatures and oxidation. To overcome this, copper alloys such as copper-tungsten (Cu-W) or copper-silver (Cu-Ag) are used in some high-voltage switches. These alloys enhance the material’s hardness, thermal conductivity, and resistance to arcing. Copper alloys also offer better mechanical strength than pure copper, ensuring the longevity and reliability of the switch.

• Silver (Ag):Silver is another excellent material for contacts due to its superior electrical conductivity. Silver contacts are often used in high-voltage isolating switches where low contact resistance is required. However, silver is soft and can wear down over time under mechanical stress, so it is often used in conjunction with other materials to provide better durability.

• Tungsten (W):Tungsten is known for its ability to withstand high temperatures and resist wear. Tungsten contacts are often used in switches that need to handle high currents or switch under difficult conditions. Tungsten’s high melting point makes it an excellent material for preventing arcing when contacts are separated.

2. Insulating Materials

The insulators in high-voltage isolating switches are designed to prevent the flow of electricity between conductors and ensure that parts of the switch are safely isolated. Insulation is crucial to prevent electrical leakage and protect both operators and the equipment. Common materials used for insulators in these switches include:

• Porcelain:Porcelain is one of the most widely used insulating materials in high-voltage systems. It has excellent dielectric properties, allowing it to resist high voltages without breaking down. Additionally, porcelain is strong, durable, and resistant to environmental factors such as temperature fluctuations and UV radiation. However, porcelain can be brittle and may crack under mechanical stress, which is why it is often used in specific designs that provide adequate support.

• Glass:Glass insulators are commonly used for their transparency, ease of inspection, and high dielectric strength. Glass can withstand high mechanical stress and is particularly useful in outdoor applications where durability and environmental resistance are required. Although glass is resistant to corrosion, it can break under impact, which is a limitation in some applications.

• Polymer (Composite) Insulators:Polymer-based insulators are increasingly used in high-voltage isolating switches due to their lightweight, high mechanical strength, and excellent electrical insulating properties. Composite Insulators are made from a combination of materials such as fiberglass and silicone rubber. These insulators offer better resistance to cracking and contamination compared to traditional porcelain and glass insulators. They are particularly useful in environments where moisture or dust accumulation can degrade the performance of other insulators.

• Epoxy Resin:Epoxy resin is another material used for insulation in high-voltage isolating switches, particularly in the construction of certain internal components like bushings and insulating barriers. Epoxy resin is known for its high dielectric strength and ability to withstand chemical corrosion, making it ideal for switches in harsh environments.

3. Actuator and Mechanism Materials

The actuator and mechanical components of high-voltage isolating switches must be durable and capable of handling the mechanical stresses involved in opening and closing the switch. These components often operate in extreme environments, requiring materials that offer strength, durability, and resistance to wear.

• Steel:Steel is commonly used in the construction of the mechanical parts of the isolating switch, including the frame, levers, and actuators. Steel offers high tensile strength, making it capable of handling the mechanical loads placed on the switch. Stainless steel is often chosen for its corrosion resistance, ensuring that the switch can continue operating even in moist or corrosive environments.

• Aluminum Alloys:Aluminum alloys are used in the construction of certain components of the isolating switch due to their lightweight properties and corrosion resistance. Aluminum is often used for housings, covers, and other non-load-bearing components. Its ease of fabrication also makes it a popular choice for switch manufacturers.

• Bronze:Bronze, an alloy of copper, is sometimes used in the moving parts of high-voltage isolating switches because of its excellent resistance to wear and corrosion. Bronze is commonly used for components that will undergo frequent movement or require long service life.

4. Arc Suppression Materials

When a high-voltage isolating switch opens, there is always the risk of an electrical arc forming between the contacts. Arcing can lead to equipment damage and even pose a safety hazard. To mitigate this risk, arc suppression materials are often incorporated into the switch design.

• Arc Chutes:Arc chutes are often used to extinguish arcs by rapidly cooling the arc and guiding it away from the contacts. Materials like ceramic and composite resins are used in arc chutes for their ability to absorb and dissipate the heat generated by the arc.

• Silicone Rubber:Silicone rubber is often used in arc suppression due to its excellent dielectric strength, high resistance to heat, and durability. It can be used in combination with other materials to create arc extinguishing barriers.

5. Enclosure and Housing Materials

The enclosure or housing of high-voltage isolating switches must be robust enough to protect the internal components from environmental damage, such as moisture, dust, and temperature extremes. The materials used for housings need to provide insulation, durability, and mechanical protection.

• Polycarbonate:Polycarbonate is often used in the housings of isolating switches due to its high impact resistance, UV stability, and electrical insulating properties. It is transparent, allowing for easy visual inspection of the switch’s condition.

• Steel and Stainless Steel:The outer housing of the switch is frequently made from steel or stainless steel, both of which offer durability and protection against physical impacts. Stainless steel, in particular, is chosen for its resistance to corrosion, which ensures that the switch remains functional in harsh outdoor environments.

Conclusion

The materials used in high-voltage isolating switches are selected for their specific properties that ensure the efficient, safe, and reliable operation of the switch in demanding electrical environments. From the contact materials such as copper alloys and tungsten to the insulators made of porcelain, polymer, and epoxy resin, each material serves a critical purpose in ensuring the switch functions properly under high voltage and mechanical stress. The selection of appropriate materials is essential for the longevity and performance of isolating switches, which play a crucial role in the safety and maintenance of electrical power systems worldwide.

Common problems with high-voltage isolation switches

Common Issues with High Voltage Isolator Switches

High Voltage Isolator Switches are critical components in electrical power systems, ensuring safe isolation of circuits for maintenance or during faults. However, like all electrical equipment, they can encounter issues that affect their performance and reliability. Below are some common problems associated with high voltage isolator switches.

1. Insufficient Isolation

One of the most critical functions of an isolator switch is to provide complete isolation between circuits. However, in some Cases, an isolator may fail to provide full isolation. This could be due to poor maintenance, incorrect installation, or wear and tear over time. Inadequate isolation can lead to the risk of accidental electric shock or equipment damage during maintenance activities. Ensuring proper maintenance and regular inspection can mitigate this issue.

2. Corrosion of Contacts

Corrosion of the switch contacts is a common issue, especially in outdoor environments or areas with high humidity or salt exposure. Over time, corrosion can cause resistance at the contact points, leading to reduced efficiency and potential failure of the isolator switch. To prevent this, isolator switches should be constructed using corrosion-resistant materials, and regular inspection and cleaning are necessary.

3. Mechanical Failures

High voltage isolator switches are exposed to mechanical stresses, and wear and tear can cause mechanical failure. Problems such as misalignment, damaged gears, or issues with the operating mechanism can prevent the switch from opening or closing properly. These failures can result in difficulties during maintenance operations and may require costly repairs. Regular servicing and proper maintenance procedures are essential to prevent such failures.

4. Failure to Indicate Position Properly

Many high voltage isolator switches are equipped with position indicators to show whether the switch is open or closed. If the position indicator malfunctions, it can cause confusion and create a safety hazard. Operators might mistakenly believe the circuit is isolated when it is not, or vice versa. Regular calibration and testing of position indicators are important to ensure their accuracy and proper functioning.

5. Arc Formation During Operation

Although high voltage isolators are not designed to interrupt load currents, improper operation or switching under high load conditions can cause arc formation. These arcs can damage the isolator and other nearby equipment. To prevent this, isolator switches should only be operated when there is no current flowing through them. It’s also important to ensure that the switch is rated for the specific voltage and current levels of the system in which it is used.

6. Overheating

Overheating is another potential problem, especially in high voltage isolator switches used in high-current applications. Overheating can result from excessive current flow, poor contact connections, or environmental factors such as high ambient temperatures. Over time, overheating can cause Insulation degradation, leading to reduced performance or failure of the switch. Properly rated isolators, adequate ventilation, and regular maintenance can help prevent overheating issues.

7. Inadequate Maintenance and Inspection

Neglecting routine maintenance and inspection can lead to a variety of problems with high voltage isolator switches. Without regular checks, issues such as dirt accumulation, corrosion, and wear can go unnoticed, reducing the efficiency and safety of the isolator. Ensuring that maintenance schedules are adhered to and that switches are thoroughly inspected at regular intervals is essential for preventing long-term issues.

8. Contamination of Insulation

The insulation materials used in high voltage isolator switches are critical to their safe operation. Over time, dirt, dust, moisture, or other contaminants can accumulate on the insulating surfaces, reducing their effectiveness. This can lead to insulation breakdown, arcing, or even short circuits. To avoid this, it is important to regularly clean the insulating components and ensure that they remain free from contamination.

9. Voltage Surges

High voltage isolator switches are often exposed to voltage surges, such as lightning strikes or switching surges, which can cause insulation damage or even complete failure of the switch. Surge protection devices and proper system grounding are essential to safeguard isolator switches from the effects of these transient voltages. Regular inspections can also help identify any weaknesses in the insulation that may be susceptible to surge-related damage.

10. Aging and Wear

Over time, all electrical components undergo aging and wear. High voltage isolator switches are no exception, and their performance may degrade due to the natural effects of aging. The materials used in the construction of isolators, such as metal contacts and insulating components, may deteriorate with prolonged exposure to electrical stress and environmental factors. Replacing aging components or the switch itself at the appropriate time is important for ensuring continued reliable operation.

11. Environmental Factors

Environmental factors, such as extreme temperatures, high humidity, salt exposure, and pollution, can significantly affect the performance of high voltage isolator switches. These factors can accelerate corrosion, insulation degradation, and mechanical wear. Installing isolator switches in protective enclosures or using weather-resistant materials can help mitigate the impact of environmental factors.

Conclusion

While high voltage isolator switches are vital for the safe and reliable operation of electrical power systems, they are not immune to issues. Problems such as insufficient isolation, corrosion, mechanical failures, and contamination can compromise the effectiveness of these switches. Regular maintenance, proper installation, and the use of quality materials are essential to avoid these common issues. By addressing potential problems proactively, operators can ensure that isolator switches function safely and efficiently throughout their lifespan.