Abstract: GB/T 18890.2-2015 is a key Chinese national standard specifying the requirements for cross-linked polyethylene (XLPE) insulated power cables with a rated voltage of 220kV (Um=252kV). As an updated and upgraded version of the former GB/Z 18890.2-2002, this standard has transformed from a guiding technical document to a recommended standard, incorporating numerous advanced technical requirements to adapt to the development of the power industry. This article elaborates on the core content of GB/T 18890.2-2015, including its scope of application, main technical specifications, test requirements, and significant technical changes compared to the previous version. It also discusses the standard’s role in ensuring the reliability of high-voltage power transmission and its supporting role in international trade under the “Belt and Road” initiative.

1. Introduction

With the rapid development of the power industry and the continuous expansion of high-voltage power transmission networks, the demand for reliable and high-performance 220kV power cables has become increasingly prominent. GB/T 18890.2-2015, officially released on October 9, 2015, and implemented on May 1, 2016, was formulated by the Shanghai Electric Cable Research Institute, the National Quality Supervision and Inspection Center for Electric Wires and Cables, and other well-known domestic institutions and enterprises. This standard is part of the GB/T 18890 series, which is divided into three parts: Part 1 (Test Methods and Requirements), Part 2 (Power Cables), and Part 3 (Cable Accessories). As the specialized specification for cables in the series, GB/T 18890.2-2015 provides comprehensive technical guidance for the design, production, testing, and application of 220kV XLPE insulated power cables, playing a crucial role in regulating the industry and improving product quality.

2. Scope and Basic Information

2.1 Scope of Application

GB/T 18890.2-2015 specifies the model designation, technical requirements, test and acceptance rules, packaging, transportation, and storage of fixedly installed 220kV (Um=252kV) XLPE insulated power cables. This standard is applicable to single-core cables used under normal installation and operating conditions. Notably, it does not apply to cables used under special conditions, such as submarine cables. The scope of application also covers different types of cable sheaths, including lead sheaths, aluminum sheaths, and metal-plastic composite sheaths, with specific requirements for their application scenarios.

2.2 Basic Standard Information

The standard is classified under China National Standard Classification (CCS) K13 (Electrical Wires and Cables) and International Standard Classification (ICS) 29.060.20 (Insulated Cables). It is supervised by the China Electrical Equipment Industrial Association and issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China and the Standardization Administration of China. In response to the growing demand for international trade and overseas projects under the “Belt and Road” initiative, a foreign language version plan for this standard was launched in March 2025, with the Shanghai Electric Cable Research Institute Co., Ltd. undertaking the translation work, aiming to facilitate the application of Chinese standard cables in global projects.

3. Core Technical Requirements

3.1 Service Characteristics

GB/T 18890.2-2015 adds specific provisions on the service characteristics of cables, including cable current-carrying capacity, which provides important parameters for the selection and application of cables in actual power transmission projects. The standard also clarifies the environmental requirements for cable operation, which are mainly determined by the performance of the cable’s metal sheath and plastic outer sheath. For example, lead-sheathed cables are suitable for environments with severe corrosion but no nitric acid, acetic acid, organic matter (such as peat), or strong alkaline corrosives, and where mechanical forces (tension, pressure, vibration, etc.) are not significant. Aluminum-sheathed cables are applicable to environments with mild corrosion and the need to withstand a certain degree of mechanical force, such as direct connection to transformers, installation on bridges, ramps, and shafts.

3.2 Product Nomenclature

The standard specifies the coding, model, and name of cables, including the addition of codes and names for metal-plastic composite sheathed cables, which was not covered in the previous version. This standardized naming system facilitates the identification, selection, and management of cables in production, sales, and application processes. For example, the standard clarifies the marking method for copper wire shielding, enabling clear distinction of cable types and characteristics.

3.3 Key Technical Specifications

In terms of technical requirements, GB/T 18890.2-2015 has made significant improvements and additions compared to the previous version:

• Conductor Requirements: The standard adds technical requirements for segmented conductors, which helps improve the current-carrying capacity and reduce energy loss of cables.
• Insulation and Semiconductive Shielding: It specifies the minimum thickness requirement for the semiconductive shielding layer, ensuring the uniformity of the electric field distribution and improving the insulation performance of cables. Appendix B of the standard provides detailed performance requirements for insulation materials and semiconductive materials, which is an important supplement to material selection and quality control.
• Water Blocking Requirements: The standard adds requirements for buffer layers, longitudinal water-blocking layers, and radial water-blocking layers, enhancing the water resistance of cables and extending their service life in humid environments.
• Sheath Materials: Modified requirements for lead sheath and aluminum sheath materials are put forward, and the definition of metal-plastic composite sheaths is added. For plastic outer sheaths, two types are specified: Type 02 (PVC) for lines with general fire protection requirements and certain insulation requirements for outer sheaths, and Type 03 (PE) for directly buried cable lines with higher insulation requirements for outer sheaths. For low-temperature environments below -20°C, chemical liquid immersion sites, and occasions requiring low toxicity during combustion, PE outer sheaths are recommended.

4. Test and Acceptance Requirements

GB/T 18890.2-2015 modifies and improves the cable test items and requirements compared to the 2002 version, covering routine tests, sampling tests, and type tests. Routine tests are conducted on each cable to verify its basic performance, including conductor resistance measurement, insulation resistance measurement, and partial discharge test. Sampling tests are carried out on randomly selected samples from the same batch of products, involving tests such as sheath thickness measurement and metal shield resistance measurement. Type tests are performed to verify the overall performance of the cable design, including long-term withstand voltage tests and water permeability tests.

The standard also specifies strict acceptance rules, requiring that cables must meet all the requirements specified in the standard before leaving the factory. For unqualified products, they shall not be delivered. In addition, detailed provisions on packaging, transportation, and storage are given to ensure that the cable performance is not affected during the circulation process. For example, PVC outer sheath cables should not be laid when the ambient temperature is lower than 0°C 24 hours before laying; if laying in lower temperatures, appropriate heating measures should be taken.

5. Significant Technical Changes from the Previous Version

Compared with the former GB/Z 18890.2-2002, GB/T 18890.2-2015 has the following major technical changes:

1. Change in Standard Nature: Transformed from a guiding technical document to a recommended national standard, enhancing its authority and mandatory nature in industry regulation.
2. Expansion of Technical Content: Added definitions of metal-plastic composite sheaths, service characteristics, and cable current-carrying capacity; supplemented technical requirements for segmented conductors, copper wire shielding, buffer layers, and water-blocking layers.
3. Adjustment of Material Requirements: Deleted the chapter on materials in the 2002 version, and instead incorporated material requirements into relevant technical clauses; modified the requirements for lead and aluminum sheath materials, and added performance requirements for semiconductive materials in Appendix B.
4. Improvement of Test Requirements: Modified cable test items and methods, added metal shield resistance measurement and wrinkle metal sheath outer thickness measurement methods, and improved the scientificity and comprehensiveness of tests.
5. Update of Application Conditions: Revised the cable use conditions in Appendix A, clarifying the applicable scenarios of different types of sheathed cables and providing more detailed guidance for actual installation and application.
6. Addition of References: Supplemented relevant domestic and international standards and technical documents to enhance the standard’s compatibility and international alignment.

6. Significance and Application Prospects

GB/T 18890.2-2015 plays a vital role in ensuring the safe and reliable operation of 220kV power transmission systems. By standardizing the technical requirements and test methods of XLPE insulated power cables, the standard helps improve the overall quality level of domestic high-voltage cables, reduce equipment failure rates, and ensure the stability of the power grid. In addition, with the advancement of the “Belt and Road” initiative, Chinese high-voltage power equipment and technology are increasingly going global. The formulation and promotion of the foreign language version of this standard will help remove technical barriers in international trade, facilitate the export of domestic cable products, and enhance the international influence of Chinese standards in the field of power cables.

In conclusion, GB/T 18890.2-2015 is a comprehensive and advanced national standard that reflects the latest technical level and development needs of the domestic 220kV XLPE insulated power cable industry. Its implementation is of great significance for promoting the healthy development of the power cable industry, improving the reliability of high-voltage power transmission, and supporting international energy cooperation.

References

[1] GB/T 18890.2-2015, Power cables with cross-linked polyethylene insulation and their accessories for rated voltage of 220 kV (Um=252 kV)—Part 2: Power cables[S].

[2] GB/T 2952.2-2008, Cable outer sheaths—Part 2: Outer sheaths for metal-sheathed cables[S].

[3] GB 50217-2007, Code for design of power engineering cables[S].

[4] IEC 60949, Calculation of thermally permissible short-circuit currents, taking into account non-adiabatic heating effects[S].

[5] IEC 62067:2011, Power cables with extruded insulation and their accessories for rated voltages above 150 kV (Um=170 kV) up to 500 kV (Um=550 kV)—Test methods and requirements[S].