PVTIME – The Ningxia-Hunan ±800 kV UHV DC transmission project has recently entered service. As the world’s first “green power artery”, it is a key part of China’s West-to-East Power Transmission strategy, as it is powered mainly by new energy from the desert, Gobi and wasteland areas. It will deliver 36–40 billion kWh of clean electricity per year, meeting one-sixth of Hunan Province’s total power demand.
Sungrow has supplied 1.27GW of high-power string inverters to the Ningxia PV mega-base, which is the project’s energy source. These inverters can operate in the face of extreme temperature differences and high levels of sand and dust, resolving three key technical issues: weak grid operation, voltage fluctuations and frequency deviations. This ensures stable, long-term connection and transmission of PV power.
The rising penetration of new energy in desert bases has increased the complexity of weak grids, putting more pressure on the stability of the new power system and creating the main barrier to large-scale green power transmission. Sungrow’s innovative inverters address this issue by operating stably under ultra-weak grid conditions (SCR = 0.97), suppressing 0.1 Hz–2.4 kHz wide-frequency oscillations and stabilising grid voltage/frequency within 0.85–1.15 times the rated voltage. This improves anti-disturbance performance and keeps PV power connected. The inverters can also handle UHV DC high/low voltage ride-through faults without interruption to power supply (covering 0–1.3 times rated voltage), which exceeds national standards and has passed the Qinghai-Henan UHV field tests.
The inverters also have a rapid power control system with an active power response of ≤30 ms and a reactive power response of ≤20 ms. This system adjusts the frequency and voltage quickly to restore grid stability during UHV power imbalances.
For those extreme conditions and unmanned operation, the inverters have IP66 protection (sealed chambers that block sand and dust) and a smart air duct system with 24/7 monitoring, active fault alerts, and automatic dust removal, which cuts maintenance costs. Combined with smart IV scanning, this ensures long-term efficient operation.
Sungrow’s inverters are currently used in large PV bases in complex areas such as high-altitude regions, deserts and coastal beaches. They support UHV lines such as the Qinghai-Henan and Ningxia-Hunan lines, as well as global energy interconnection projects. Looking ahead, Sungrow intends to drive innovation further to advance the Dual Carbon goals and boost global energy interconnection.
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