220kV Cable Outdoor Termination – Factory

1. What Is a 220kV Cable Outdoor Termination?

A 220kV cable outdoor termination is an important accessory in high-voltage power transmission systems. It connects underground XLPE power cables to overhead transmission lines, transformers, and outdoor substations.

Many power projects use underground cables to transmit electricity over long distances. However, these cables must connect to outdoor electrical equipment at certain points. Therefore, engineers need reliable outdoor cable terminations to complete these connections.

A 220kV outdoor cable termination has several important functions. First, it controls the electric field at the end of the cable. In addition, it provides insulation between the high-voltage conductor and the grounded structure. It also protects the cable connection from rain, moisture, dust, and UV radiation.

Because a 220kV system operates at a very high voltage, the termination must provide excellent insulation and mechanical strength.

A well-designed 220kV cable outdoor termination helps prevent partial discharge, electrical breakdown, and surface flashover. As a result, it improves the safety and reliability of the entire power transmission system.

2. Applications of 220kV Outdoor Cable Terminations

220kV outdoor cable terminations serve many types of high-voltage power projects. They are especially useful when underground cables need to connect to outdoor electrical equipment.

Here are some common applications.

High-Voltage Substations

Outdoor cable terminations connect 220kV underground cables to transformers, circuit breakers, disconnectors, and busbars.

In large substations, these accessories help link underground transmission systems with outdoor electrical equipment. Therefore, their insulation and connection quality directly affect system reliability.

Underground-to-Overhead Cable Connections

Many cities use underground power cables to save space and improve the appearance of urban areas. However, underground cables sometimes need to connect to overhead transmission lines outside the city.

In this situation, engineers install outdoor cable terminations at the connection point. These accessories provide the required insulation and electrical connection between the two systems.

Power Plants

Large thermal power plants and hydropower stations often use high-voltage transmission systems. For example, a power plant may use 220kV underground cables to connect its substation to the main grid.

Outdoor terminations help complete these connections. Moreover, they support safe and stable power transmission during normal operation.

Solar and Wind Power Projects

Large solar farms and wind power stations need reliable connections to the national grid. Some projects use underground 220kV cables to transfer electricity from their substations to the grid connection point.

As a result, 220kV outdoor cable terminations can play an important role in renewable energy projects.

Industrial Power Networks

Steel plants, mining facilities, and petrochemical factories may require large amounts of electricity.

In some cases, these facilities use 220kV underground cable systems. Outdoor cable terminations provide reliable connections between the cables and the main electrical equipment.

3. Main Components of a 220kV Cable Outdoor Termination

A 220kV cable outdoor termination contains several key components. Each part has a specific function. Together, they provide electrical insulation, field control, mechanical support, and protection against outdoor conditions.

3.1 Stress Control Cone

The stress control cone is one of the most important parts of a high-voltage cable termination.

When technicians remove the outer semiconductor layer of an XLPE cable, the electric field becomes concentrated near the edge of the conductor screen. This area may experience high electrical stress.

Without proper stress control, partial discharge may occur. Over time, this discharge can damage the cable insulation.

Therefore, the stress control cone helps spread the electric field more evenly. It also reduces electrical stress around the cable insulation.

Manufacturers use specially designed silicone rubber and other electrical insulation materials to achieve this result.

3.2 Insulating Housing

The insulating housing separates the high-voltage conductor from the grounded supporting structure. It also provides the required external insulation.

Manufacturers mainly use two materials for 220kV outdoor cable terminations:

• Porcelain
• Silicone rubber composite

Both materials provide reliable insulation. However, they have different physical properties and installation needs.

3.3 Silicone Rubber Sheds

Composite outdoor cable terminations use silicone rubber sheds to increase the creepage distance.

Creepage distance means the shortest distance along an insulating surface between two conductive parts.

Outdoor conditions can affect insulation performance. For example, rain, dust, salt, and industrial pollution may create a conductive layer on the surface.

However, silicone rubber has excellent water-repellent properties. Water tends to form droplets instead of spreading across the entire surface.

As a result, silicone rubber sheds help improve insulation performance in wet and polluted environments.

3.4 Conductor Connector

The conductor connector joins the cable conductor to the external electrical equipment.

Manufacturers can supply connectors for copper or aluminum conductors. The correct design depends on the cable structure and the connection interface.

A suitable connector must provide good electrical contact and enough mechanical strength. In addition, its size must match the cable conductor.

3.5 Base Plate and Grounding System

The base plate supports the outdoor termination and connects it to the installation structure.

Meanwhile, the grounding system provides a safe path for fault current. It also helps maintain electrical safety during system operation.

For this reason, engineers must check the grounding design during the project planning and installation stages.

4. Porcelain vs. Composite 220kV Outdoor Cable Termination

Manufacturers offer two main types of 220kV outdoor cable terminations: porcelain and composite.

Both types can serve high-voltage transmission projects. However, customers should consider the installation environment, mechanical needs, and maintenance requirements before making a choice.

Porcelain Outdoor Termination

Porcelain outdoor terminations have a long history in high-voltage power systems.

Porcelain offers good insulation and high mechanical strength. Furthermore, it can provide stable performance over many years when manufacturers use suitable materials and production methods.

However, porcelain is heavy and may break if workers handle it incorrectly. Therefore, transportation and installation require extra care.

Composite Outdoor Termination

Composite outdoor terminations use a fiberglass-reinforced core and an external silicone rubber housing.

Compared with porcelain products, composite designs offer several benefits. First, they weigh less. Second, they provide excellent water-repellent performance. In addition, workers can transport and install them more easily.

For projects in coastal areas, industrial zones, and polluted environments, composite outdoor terminations offer important advantages.

Therefore, many modern power transmission projects consider composite insulation a practical solution.

5. Technical Parameters of a 220kV Cable Outdoor Termination

Before selecting a 220kV cable outdoor termination, buyers should check its electrical and mechanical parameters.

The following table provides a general technical reference. Actual values depend on the cable design and project requirements.

One important point is that a 220kV power cable system normally uses equipment with a highest voltage of 245kV.

However, buyers should not select a termination based only on the rated voltage. They must also check the cable insulation diameter, conductor size, insulation level, and installation environment.

For example, a 220kV cable with a 630 mm² copper conductor may need a different termination design from a cable with a 1,000 mm² aluminum conductor.

Therefore, customers should provide complete cable parameters before requesting a quotation.

6. International Standards for 220kV Cable Terminations

International standards help manufacturers control product quality and ensure reliable operation.

For 220kV XLPE cable accessories, IEC 62067 is one of the most important standards.

IEC 62067

IEC 62067 applies to power cables with extruded insulation and their accessories for rated voltages above 150kV up to 500kV.

Therefore, this standard covers 220kV XLPE cable systems and their accessories.

IEC 60287

IEC 60287 provides methods for calculating the current-carrying capacity of power cables.

Engineers use this standard to study cable temperatures and load conditions. In addition, it helps them select suitable cable sizes for different projects.

IEC 60270

IEC 60270 describes methods for measuring partial discharge in electrical insulation systems.

This test helps manufacturers check insulation quality. It also plays an important role in high-voltage cable accessory testing.

Depending on the project, customers may also request additional national or international standards. Therefore, manufacturers should confirm the applicable standards before production.

7. Installation Process of a 220kV Outdoor Cable Termination

Correct installation directly affects the service life and operating safety of a 220kV cable termination.

Because this product works at high voltage, only trained and qualified technicians should carry out the installation.

The general installation process includes the following steps.

Step 1: Check the Cable

First, technicians check the cable type, conductor size, insulation diameter, and metal screen structure.

They also inspect the cable surface to make sure it has no visible damage. In addition, the installation team should check the product drawings and installation tools before starting work.

Step 2: Remove the Outer Cable Layers

Next, technicians remove the outer sheath, metallic screen, and other cable layers according to the installation drawing.

During this process, they must protect the XLPE insulation from scratches and mechanical damage.

Step 3: Prepare the XLPE Insulation

After removing the required cable layers, technicians carefully prepare the XLPE insulation surface.

They clean the surface and check its condition. Moreover, they must follow the manufacturer’s instructions for cutting dimensions and surface preparation.

Even small scratches or dirt particles can affect electrical performance. Therefore, technicians must keep the working area clean.

Step 4: Install the Stress Control Components

Technicians install the stress control cone and related components according to the specified dimensions.

Accurate positioning is important because these components control the electric field around the cable insulation.

Step 5: Assemble the Insulating Housing

Next, technicians install the porcelain or composite housing.

They also check the sealing components, internal connections, and mechanical support. Meanwhile, the installation team must make sure that all parts match the manufacturer’s drawings.

Step 6: Connect the Cable Conductor

Technicians connect the cable conductor to the terminal connector.

They must use the correct crimping or bolted connection method. In addition, they should check the contact surface and tightening torque.

Step 7: Complete Grounding and Final Inspection

Finally, technicians connect the metallic screen and grounding components to the grounding system.

They then inspect the complete installation and perform the required electrical tests.

Only after the project team confirms that all requirements have been met should the system proceed to energization.

8. Testing of 220kV Cable Outdoor Terminations

Testing helps confirm the electrical and mechanical performance of a 220kV cable outdoor termination.

For high-voltage cable accessories, manufacturers and project owners may require several types of tests.

Partial Discharge Test

This test checks whether the insulation system produces unwanted partial discharge under specified electrical conditions.

Low partial discharge levels help show that the insulation system has good electrical quality.

AC Voltage Withstand Test

The AC voltage test checks whether the termination can withstand the required power-frequency voltage.

It helps engineers evaluate the electrical strength of the insulation system.

Lightning Impulse Test

Lightning impulse testing checks the ability of the insulation system to withstand high-voltage surges caused by lightning.

This test is important for outdoor power equipment because lightning can create serious electrical stress.

Switching Impulse Test

For extra-high-voltage applications, switching impulse performance also plays an important role in insulation design.

The project specification determines the required test conditions.

Thermal Cycling Test

This test checks the performance of the cable accessory under repeated heating and cooling conditions.

During the test, the accessory experiences changes in temperature that simulate cable operating conditions.

In addition, manufacturers may perform dimensional inspections, material checks, and sealing inspections.

For 220kV cable systems, type tests and prequalification tests should follow the applicable requirements of IEC 62067.

9. How to Choose a Reliable 220kV Cable Termination Manufacturer

Choosing the right manufacturer is important for every high-voltage transmission project.

However, price should not be the only factor. Buyers should also consider product quality, technical support, and manufacturing experience.

Here are five important points to check.

1. High-Voltage Manufacturing Experience

First, check whether the manufacturer has experience producing 220kV or 245kV cable accessories.

A supplier with high-voltage project experience can better understand cable structures, insulation requirements, and installation conditions.

2. Type Test Reports

Next, request the relevant type test reports.

Make sure the tested product has the same main design and technical configuration as the product you plan to purchase.

3. Material Quality

Material quality directly affects the service life of outdoor cable terminations.

Therefore, check the silicone rubber, porcelain housing, stress control materials, connectors, and sealing components.

4. Technical Documents

A professional manufacturer should provide complete technical documents.

These documents may include:

• Product datasheets.
• Technical drawings.
• Installation manuals.
• Type test reports.
• Quality certificates.
• Inspection records.

With these documents, buyers can review the product design and check whether it meets project requirements.

5. Installation Support

Finally, check whether the supplier can provide technical assistance during installation.

For large 220kV transmission projects, professional installation guidance can help reduce mistakes and improve project efficiency.

10. DOS Cable – 220kV Outdoor Cable Termination Manufacturer and Supplier in China

DOSENSE Cable is a professional manufacturer and supplier of high-voltage cable accessories in China. We provide cable connection solutions for power transmission and distribution projects around the world.

Our product range includes:

• 220kV outdoor cable terminations.
• 245kV high-voltage cable terminations.
• GIS cable terminations.
• Indoor cable terminations.
• High-voltage cable joints.
• Composite and porcelain cable accessories.
• Cable installation tools and accessories.

For 220kV XLPE cable systems, DOS can provide customized outdoor termination solutions according to conductor size, insulation diameter, cable structure, and project requirements.

We also offer technical drawings, product datasheets, installation manuals, and technical support for international customers.

Whether you are an EPC contractor, power utility, electrical engineering company, or cable distributor, DOSENSE aims to provide reliable cable accessories for your high-voltage projects.

Are you looking for a reliable 220kV Cable Outdoor Termination Manufacturer in China? Contact DOSENSE Cable for product information, technical specifications, and competitive quotations.