Solutions-GoLead Intelligent

Background and Challenges

With the widespread deployment of HVDC transmission systems, ultra-high-voltage (UHV) converter stations have become critical backbone components of power grids. During switching operations, converter transformers and filter banks often generate severe inrush currents and switching overvoltages. At the same time, the complex electromagnetic environment within converter stations imposes stringent requirements on the anti-interference capability of protection equipment. The main challenges include:

High Irush Current During Converter Transformer Switching

Instantaneous inrush currents can exceed 10 times the rated current, significantly affecting equipment service life and power quality.
Strong Electromagnetic Interference

The complex electromagnetic environment in converter stations demands high immunity and misoperation suppression capability from protection and control devices.
High Risk of Switching Overvoltage in Filter Banks

Switching of capacitor banks is prone to resonance and overvoltage, potentially leading to insulation damage and protection malfunctions.

Overview

Leveraging microprocessor-based inrush current suppression products with over 70% market share, and supported by the core “residual flux–bias flux mutual cancellation” algorithm, GoLead Intelligent has developed an integrated protection system featuring precise residual flux prediction, adaptive bias flux compensation, and smart phase control.

This solution covers critical scenarios including converter transformer switching, filter bank operation, and DC fault isolation, ensuring smooth equipment operation and highly accurate system protection.

Key Technologies

High-Efficiency Inrush Current Suppression

Based on a dynamic magnetic flux balance model, the system performs real-time online identification of magnetic flux states and circuit breaker characteristics, accurately calculating the optimal closing angle with a control error of ≤ 0.5°.
Residual Flux–bias Flux Mutual Cancellation Technology

Based on a dynamic magnetic flux balance model, the system performs real-time online identification of magnetic flux states and circuit breaker characteristics, accurately calculating the optimal closing angle with a control error of ≤ 0.5°.
Strong Environmental Adaptability

The devices support a wide operating temperature range of –20°C to +55°C and feature a fully electromagnetic compatibility (EMC)–oriented design, enabling reliable operation in harsh environments such as strong electromagnetic interference, high altitude, and high humidity.
Smart Analysis Platform

The supporting HMI/software platform provides inrush current analysis, event recording and waveform capture, and remote monitoring and control, offering comprehensive data support for converter station operation, maintenance, and fault analysis.

Application Results and Cases

The solution has been successfully deployed in multiple ±800 kV and ±1100 kV HVDC converter stations, where it has reduced average inrush current during converter transformer energization by over 70%, virtually eliminated maloperations during filter bank switching, and maintained an annual device failure rate below 0.2%.

By significantly enhancing operational stability and protection accuracy, the solution provides critical support for the safe and reliable operation of China’s UHVDC projects, enabling large-scale, long-distance transmission of clean energy.

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