Overview
IEC TS 62271-313:2025 defines the requirements for direct current (DC) circuit-breakers used in high-voltage switchgear and controlgear applications. Published by the International Electrotechnical Commission (IEC), this technical specification applies to DC circuit-breakers designed for indoor or outdoor installation at direct voltages of 100 kV or higher. These devices are integral components within DC transmission and distribution systems, supporting both unidirectional and bidirectional current flow, according to system needs.
The standard provides comprehensive guidance on the design, construction, testing, and operation of DC circuit-breakers, ensuring their reliability, safety, and performance in high-voltage environments. Key areas include switching device characteristics, operating devices, primary auxiliary circuits, control systems, power electronic switches, and energy dissipation equipment.
Key Topics
IEC TS 62271-313:2025 covers a wide range of topics essential for the correct specification and use of high-voltage DC circuit-breakers, including:
- Service Conditions: Requirements for normal and special operating environments, such as altitude, temperature, pollution, vibration, humidity, and wind speed.
- Ratings: Definitions and guidelines for rated direct voltage, insulation level, continuous current, short-circuit withstand current, auxiliary circuit voltages, and operating sequences.
- Design and Construction: Guidance for the use of materials (liquids and gases), earthing, auxiliary equipment, protection mechanisms, and enclosure integrity.
- Type and Routine Tests: Specified procedures for dielectric testing, resistance measurement, current-carrying capability, electromagnetic compatibility (EMC), mechanical performance, tightness, and environmental durability.
- Safety and Environmental Impact: Safety aspects for manufacturers and users, consideration for high-energy components, and guidance on minimizing environmental impact.
- Installation and Maintenance: Recommendations for transport, storage, installation, operation, and preventive maintenance of DC circuit-breakers.
- Selection and Tenders: Information on providing technical details and system requirements during procurement and specification processes.
Applications
DC circuit-breakers as defined in IEC TS 62271-313:2025 are crucial in the following fields:
- High-Voltage Direct Current (HVDC) Transmission: Protecting and controlling HVDC lines and equipment during normal operation and fault conditions.
- Substations for DC Distribution: Enabling safe disconnection and sectionalizing in DC substations responsible for large-scale renewable integration or interconnection between AC and DC grids.
- Utility and Industrial Power Systems: Applied in power systems handling bulk transmission of energy, especially where reliability and fast interruption of direct current are essential.
- Bidirectional Power Flow Networks: Supporting the growing need for flexible grid operation, including energy storage integration and microgrid operations.
- Critical Infrastructure: Ensuring protection and continuity in electric railways, large data centers, and other installations relying on high-voltage DC supply.
Related Standards
The guidance in IEC TS 62271-313:2025 is supported by several related standards within the IEC 62271 series and beyond. Notable references and complementary documents include:
- IEC TS 62271-5:2024: High-voltage switchgear and controlgear - general technical requirements and switching device classifications.
- IEC 62271 series: Covers various types of AC and DC switchgear, including testing protocols, safety, and performance evaluation.
- IEC 60076: Power transformers - for integration of circuit-breakers with transformer systems in substations.
- IEC 61000 series: Electromagnetic compatibility (EMC) - requirements for immunity and emission relevant to switchgear controls.
For engineers, specifiers, and asset managers, adopting IEC TS 62271-313:2025 ensures that high-voltage DC circuit-breakers are selected, installed, and maintained according to international best practices, optimizing safety, reliability, and system performance in modern power grids.