IEC 60099-9:2014

Overview

IEC 60099-9:2014 is an international standard issued by the International Electrotechnical Commission (IEC) addressing the design, testing, and performance requirements of metal-oxide surge arresters without gaps specifically intended for use in HVDC (High Voltage Direct Current) converter stations. This standard applies to non-linear metal-oxide resistor type surge arresters without spark gaps, designed to limit overvoltages in HVDC converter stations including two-terminal, multiterminal, and back-to-back types, with operating voltages up to 1100 kV.

The scope covers various arrester housings such as porcelain, polymer, and gas-insulated metal-enclosed (GIS) types, especially when used as DC bus and DC line/cable arresters. However, it excludes arresters for voltage source converters. It also differentiates from IEC 60099-4, which covers arrester testing on AC systems without significant harmonics, describing that AC filter arresters at converter stations should be tested per this standard.

Key Topics

• Surge arrester identification and classification: Guidelines for clear identification and classification suitable for HVDC applications.
• Service conditions: Specifications for both normal and abnormal operating environments including electrical, mechanical, and environmental stresses.
• Performance requirements:
  • Insulation withstand of arrester housing.
  • Reference and residual voltage characteristics.
  • Internal partial discharge limits.
  • Seal integrity and leak rate.
  • Current distribution in multicore designs.
  • Long-term stability under continuous operating voltage.
  • Thermal energy and repetitive charge transfer capability.
  • Short-circuit performance and mechanical load resistance.
• Electromagnetic compatibility and end-of-life criteria for reliable operation.
• Testing procedures:
  • Type (design) tests covering insulation, mechanical, environmental, thermal, and electrical performance.
  • Routine and acceptance tests ensuring quality for production units.
  • Detailed test methods for conditions such as bending moment, weather aging, seal leaks, and partial discharges.

This comprehensive framework ensures surge arresters effectively protect HVDC converter stations from overvoltages that could damage critical components.

Applications

IEC 60099-9:2014 surge arresters are essential for safeguarding components in HVDC converter stations. These applications include:

• Protection of HVDC converter equipment - limiting voltage spikes on DC busbars, line/cable connections.
• Use in porcelain and polymer housed arresters, providing mechanical robustness and environmental resistance.
• Gas-insulated metal-enclosed (GIS) arresters for specialized compact installations within converter stations.
• Suitable for two-terminal and multiterminal HVDC schemes, as well as back-to-back converter configurations.
• Tested and optimized for continuous operation at high DC voltages (up to 1100 kV), ensuring stability and longevity in harsh electrical environments.
• Ensures compliance with global safety and reliability standards in power system infrastructures.

Related Standards

• IEC 60099-4: Surge arresters for AC power systems - relevant for CS converter stations' AC system arresters.
• IEC 60099 series: Comprehensive standards covering various types of surge arresters across AC and DC power applications.
• IEC 60694: Common specifications for high-voltage switchgear and controlgear - applicable to supporting infrastructure.
• IEC 60587: Electrical insulating materials - tests on thermal endurance, relevant to polymer housed arrester components.

Practical Value

Implementing IEC 60099-9 compliant surge arresters ensures:

• Enhanced reliability and operational safety of high-voltage DC converter equipment.
• Minimized equipment downtime and maintenance costs due to superior overvoltage protection.
• Increased system stability in HVDC grids, helping to manage transient events and power quality.
• Alignment with international best practices for testing and certification, facilitating procurement and regulatory approvals.

By adhering to IEC 60099-9:2014, engineers and asset managers can confidently select and deploy surge arresters engineered for the demanding requirements of modern HVDC converter stations.