At 14:00 on December 20, following the command of the test site, the artificial single-phase short-circuit grounding test of Ningxia Power Grid 220kV Hesan Line was successfully completed, and the new fast-switching fault current limiting device for the 750kV No. 2 transformer of Helanshan Substation was completed correctly. The action marked the successful completion of the system characteristics verification test of the first new fast switching fault current limiting device applied to the 750 kV power grid, and the formal trial operation of the grid connection.



The load and grid structure of the Northwest Power Grid present the characteristics of “overall dispersion and partial concentration”. The rapid looping of the 750 kV power grid greatly shortens the electrical distance between the load centers, and the centralized development of large DC and large energy bases doubles the installed capacity in the near area Increase, the problem of short-circuit current exceeding the standard is prominent. Temporary measures such as optimizing the startup mode, changing the network topology by optimizing the startup mode, connecting the line or pulling and stopping the components, are likely to cause problems such as decreased reliability and increased power supply guarantee pressure. To this end, the Northwest Division of State Grid has carried out exploration and practical work from multiple perspectives such as feature recognition, operation control, and new technology application. It actively cooperates with State Grid Ningxia Electric Power in joint research and continuous innovation, and conducts network trials in accordance with the company’s new technologies (products). Operation management requirements, take the lead in researching and developing a fast switching fault current limiting device that is applied to the 750 kV power grid on a trial basis. At the same time, as one of the series of tests to verify the characteristics of the new energy grid system with a high proportion of the Northwest Power Grid, the action performance and control effect of the new generation of grid structure parameter flexible control technology equipment are carried out by carrying out the live test and the short circuit test. The systematic verification has also opened up new methods and new ideas for short-circuit current limiting measures.

In the next step, the Northwest Division of State Grid will continue to organize the trial operation of equipment connected to the grid, and continue to accumulate operating data and experience to ensure the safe and stable operation of the power grid and equipment. At the same time, take the initiative to take advantage of the location and power grid in the northwest, and actively pilot the application of new equipment and new technologies such as voltage source energy storage and grid-type wind turbines to contribute dispatching wisdom and strength to the construction of the "five-type" power grid in the northwest.