GB/T 37008-2018 in English

Background and Significance of Standard Formulation

With the widespread application of flexible DC transmission technology in large-scale renewable energy grid connection and long-distance energy transmission, the performance of bridge arm reactors as core components is directly related to the safety and reliability of the system. The formulation of GB/T 37008—2018 standard aims to standardize the technical requirements, test methods and use conditions of reactors for flexible DC transmission to ensure the stable operation of equipment under complex working conditions.

This standard was proposed by the China Electrical Equipment Industry Association and managed by the National Technical Committee for Transformer Standardization, which fully reflects the industry consensus and technological progress.

Technical Evolution Analysis of Flexible DC Transmission System

Compared with traditional high-voltage DC transmission, flexible direct current transmission (VSC-HVDC) has stronger voltage regulation capability and adaptability, and is especially suitable for renewable energy access and island power supply. As a key component of modular multilevel converter (MMC), the design of bridge arm reactor needs to take into account the carrying capacity of AC/DC composite current.

Compared with traditional AC reactors and smoothing reactors, reactors for flexible DC transmission face greater technical challenges, which are mainly reflected in:

• Temperature rise control under AC/DC composite current
• Insulation tolerance under complex harmonic environment
• Capacity to withstand short-term overload and transient fault current

Key technical requirements for bridge arm reactors

The design of bridge arm reactors must meet the following key requirements:

• Temperature rise control: The temperature rise of the hot spot of the winding and the temperature rise of the metal structure must not exceed the specified values in Table 2 and Table 3 respectively.
• Insulation level: The end-to-ground withstand voltage strength must meet the requirements of GB/T1094.3, and the tolerance under DC bias voltage is particularly critical.
• Harmonic adaptability: The reactor must remain stable in a multi-harmonic environment, especially the carrying capacity of 50Hz and 100Hz currents.

Standard Implementation Recommendations

To ensure that the arm reactor meets the requirements of GB/T 37008-2018, the following measures are recommended:

1. Strictly select the model according to the standard requirements to ensure that the parameters match the system requirements.
2. Fully consider the thermal effect of AC/DC composite current during the design phase, and verify the temperature rise control scheme through simulation.
3. Strengthen insulation tests and lightning impulse tests to ensure the tolerance of equipment in complex power grid environments.
4. Pay attention to the coordinated work of the arm reactor and the converter valve to optimize the overall system performance.