Introduction  With the continuous improvement of the strategic position of clean energy, more and more new energy power generation equipment is connected to the power grid, but its power quality is unstable, which has a great impact on the AC (Alternating-Current) transmission grid. Flexible DC (Direct-Current) transmission networks can effectively isolate AC and the DC networks, and have good development prospects. The key component of flexible DC power transmission is the converter valve. The key component of flexible DC power transmission is the converter valve with fully controlled IGBT components as the core. Therefore, the safe and stable operation of IGBT (Insulate-Gate Bipolar Transistor) components plays an important role in the stability of the entire flexible DC system. In order to improve the safety and operational stability of IGBT components, it is necessary to control their operating current and voltage to avoid overcurrent and overvoltage damage. At the same time, it is necessary to control the temperature and humidity of the environment, equipment corrosion resistance to improve operating conditions.

  Method  Therefore, both internal and external strategies were adopted. Starting resistors, reactors, lightning arresters, etc. were installed internally to control the current and voltage of the circuit. Externally, air conditioners were set, the room tightness was improved, and equipment anti-corrosion treatment was equipped to ensure a good working environment.

  Result  By configuring starting resistors, reactors, lightning arresters and other facilities in the internal circuit, the circuit current and voltage are limited, and then the overcurrent multiple and overvoltage multiple acting on the IGBT components are controlled under extreme conditions. By controlling the temperature and humidity of the room where the IGBT is located and the corrosion resistance of the equipment, a suitable environment is provided for the operation of the IGBT components, which is helpful to improve the safety and operational reliability of the IGBT components.

  Conclusion  Flexible DC transmission can well solve the power transmission problem of new energy power generation facilities with poor power quality. And by optimizing the internal strategy of the flexible DC transmission system circuit and the external strategy to improve the suitability of the operating environment of the IGBT components, the safety and operational reliability of the IGBT components and even the entire flexible direct current system are improved.