The wind and sunshine in the 'Shage Wilderness' are following the power' highways', crossing mountains and rivers, lighting up thousands of households thousands of miles away. In Zhumadian, Henan, there is a special power hub - the Yunan converter substation, which has silently guarded the Central China power grid for over 2100 days and safely delivered nearly 100 billion kilowatt hours of clean hydropower and photovoltaic power from the western region to Henan. On March 25th, accompanied by the roar of machines, this hub ushered in an important moment of "strengthening muscles and bones": the "twin brother" 1000 kV Yunan Substation main transformer expansion project next to it broke ground, injecting surging new power into this crucial energy artery.

Why expand?

The Yunan converter substation is not an ordinary substation. It is the first ultra-high voltage AC and DC "combined" super station in China to be built at the same time and location, with unified operation and maintenance management. The DC section (± 800 kV Yunan Converter Station) is the terminal station of the Qinghai Henan UHVDC project, specifically designed to receive clean power from the northwest plateau; The communication part is the key hub of the Central China ultra-high voltage "Japanese" ring network, responsible for "distributing" clean electricity. Since its commissioning at the end of June 2020, it has delivered a total of 96.8 billion kilowatt hours of clean electricity to Henan, equivalent to one-fifth of the province's annual electricity consumption, making it a true hero in ensuring supply during the peak summer season.

However, with the high-quality development of Henan's economy and society, the demand for electricity continues to rise. At the same time, the country is accelerating the construction of the "Shagehuang" large-scale wind and photovoltaic base, and more green electricity from the west urgently needs to be sent out. The transmission capacity of the original substation is gradually becoming saturated, and there is an urgent need for expansion and upgrading to more smoothly receive and absorb the "green energy express" from afar. So, the expansion project with the code name "Yunan Expansion" emerged, becoming the first ultra-high voltage project to start construction during the "15th Five Year Plan" period of Henan Power Grid.

How to 'strengthen the body'?

The "Yunan Expansion" project is essentially a "heart bypass" and "bone strengthening" of the ultra-high voltage "AC side". Its core task is to add a set of main transformers with a capacity of up to 3 million kVA to the 1000 kV Yunan substation, which is like adding a super large "substation core" to a transportation hub.

In addition, the project will also simultaneously build four electrical "connection ports" of ultra-high voltage and ultra high voltage levels (two 1000 kV intervals and two 500 kV intervals), and upgrade the supporting voltage regulation and control system. These measures will bring about a qualitative leap in the throughput and regulation capabilities of substations. After the project is put into operation, the voltage stability support capacity of the bus of the Yunan converter station will be significantly enhanced, and the grid structure of the entire Central China region will be stronger, making the "artery" of cross regional power transmission more unobstructed.

What is the significance?

The 'Yunan Expansion' project, although not massive, has profound significance. Firstly, it directly enhances the power supply capacity of key hubs. After the project is put into operation, the power supply capacity of the southern Henan region is expected to increase by 50% directly, which will greatly alleviate the power supply pressure in the southern Henan region and provide stronger energy security for local economic development.

Secondly, it paves the way for large-scale adoption of new energy. After expansion, this hub can more efficiently and safely receive clean electricity from distant places such as the "Shage Wilderness" base in the west, optimize the allocation of energy resources nationwide, and allow more wind and solar power to replace traditional fossil fuels. This is an important step in promoting China's green and low-carbon energy transformation.

State Grid Henan Electric Power Company stated that it will take the construction of this project as an important practice in promoting the three-year action plan to tackle the root cause of safety production, strictly control high-risk operations, ensure "zero error" in the interface between new and old equipment, strengthen the management of key links such as equipment installation and commissioning, and make every effort to create a high-quality and safe project. It is expected that by June 2027, this upgraded version of the power super hub will be fully completed and put into operation. At that time, green energy from afar will continue to light up the Central Plains with even stronger "horsepower".Editor/Yang Meiling