Low Voltage Traverse Performance Testing of Huawei Inverter Passing through Tibet Academy of Electrical Sciences

Recently, good news came from Deqin photovoltaic power inverter station in Tibet. Huawei’s smart photovoltaic solution passed the performance test of LVRT at one time. It is the first inverter enterprise to pass the test in the environment of Tibet power grid. Deqin Photovoltaic Power Station has also become the first photovoltaic power station in Tibet to optimize the performance of power grids such as on-site low voltage crossing.
This test is carried out jointly by the National Grid and Tibetan Electrical Academy. It is based on the National Standard GB/T 19964-2012 “Technical Regulations for the Access of Photovoltaic Power Stations to Electric Power Systems”, and puts forward more stringent requirements for the access of photovoltaic grid-connected inverters to Tibetan grid. In order to reduce the impact of short-circuit faults on Tibet’s power grid and enhance the ability of photovoltaic power plants to support the stable operation of the grid, several photovoltaic inverters enterprises participated in the test. Huawei is the only enterprise that has passed the test.
Due to the particularity of Tibet power grid, this test standard is stricter and more difficult than the national standard GB/T 19964-2012 “Technical Regulations on the Access of Photovoltaic Power Stations to Power Systems”, while Huawei passed it directly and smoothly.

1. Continuous active current output capability is required during LVRT: Huawei Inverter achieves precise output of active current through AI-supported intelligent grid-connected control algorithm, and under the premise of stable control of reactive current output during LVRT, by improving active current control capability. The grid-connected stability of inverters under LVRT transient and steady-state impact is guaranteed, and the continuous output of active and reactive power inverter supports the rapid restoration of power grid.
2. The LVRT end-inverters should have the ability of active power fast recovery: Huawei Inverter can quickly identify LVRT status through advanced Fault-Crossing detection algorithm, and ensure continuous power output through real-time and fast power inverter control when LVRT restores. After the end of LVRT, the active power restores to the pre-fault level within 0.5 seconds, which reduces the risk of active power/frequency instability caused by LVRT.
3. Stricter LVRT duration requires that more than 70% of Un inverters have the ability of continuous grid-connected operation. Huawei inverters also have LVRT curves to set interfaces. Through hardware and software design, the inverters can operate reliably in a wide voltage range, and support the long-term grid-connected operation ability of light LVRT70% Un.
   As early as 2014, Huawei’s 200 MW photovoltaic power station in Qinghai Gonggong successfully passed the field LVRT test. In the weak grid environment of India, Middle East, North Africa and other countries, Huawei’s smart photovoltaic solutions have shown excellent performance in Fault-Crossing capability, which has been highly evaluated by the owners. This time, more rigorous LVRT tests were successfully passed in Tibet power inverter grid environment, which once again shows that Huawei is in the absolute leading level in the friendliness of photovoltaic grid-connected, leading photovoltaic from adapting to the grid to supporting the grid.