The World's Most Powerful String Inverter of 385kW Developed by Kehua Passed the HVRT and LVRT Test in One Go


Recently, Kehua's SPI series 1500V/350kW string inverter passed the High Voltage Ride Through (HVRT) and Low (zero) Voltage Ride Through (LVRT) tests and obtained the certification report at one time.


The testing requirements of HVRT and LVRT certification are very stringent.

In terms of dynamic reactive power support, when high and low penetration of parallel network voltage occurs, the test requires the inverter to issue the target reactive current within 60ms, the overshoot should be less than 20%, the regulation time should be less than 150ms, and the control error should not exceed 5% of the rated current.

In terms of active power control, the inverter output active power should remain unchanged when the parallel network voltage is high through; after the parallel network voltage is low through recovery, the active power should be recovered at 30% of the rated power per second.

In terms of reactive power limitation, the maximum effective value of dynamic reactive current should not exceed 1.05 times of the rated current when the inverter has three symmetrical high and low wear faults of reactive current; the maximum effective value of dynamic reactive current should not exceed 0.4 times of the rated current when asymmetrical faults occur.


The test data shows that Kehua 1500V/350kW inverter has strong capability of fault ride-through.

When a high or low pass-through fault occurs in the AC voltage measurement of the inverter, such as three-phase symmetry or single-phase asymmetry, Kehua 1500V/350kW inverter can generate power without interruption and quickly send reactive current to support the grid, increasing the stability of the grid. When the high and low pass-through faults are over, the inverter quickly restores the power generation before the faults to ensure maximum power generation revenue.




Kehua is one of the first companies to develop and market high power string inverters. Kehua's 1500V/350kW inverter is currently the largest string inverter in the world in terms of single power. Since its launch in June last year, it has been highly recognized by customers and has won more than 2GW of bids.


In addition to the excellent fault ride-through capability, Kehua's 1500V/350kW inverter also takes into account the overall ventilation and heat dissipation, anti-corrosion and dustproof factors, and adopts high protection level design, which can adapt to various harsh natural environments, with high efficiency, high protection and high reliability. It has won the favor of institutes and customers with five advantages. 


Advantage 1: High efficiency industry-leading conversion efficiency

Kehua 1500V/350kW inverter adopts special SVPWM high-efficiency control algorithm and efficient and innovative three-level topology, excellent MPPT algorithm, and well-known brand devices to ensure the inverter has the maximum conversion efficiency.


Advantage 2: High protection  IP66 high protection level and C5 anti-corrosion design

Kehua 1500V/350kW inverter is equipped with IP66 protection grade design, C5 anti-corrosion design, excellent aluminum alloy plate and C5 spraying process, PCBA board with enhanced triple-proof coating treatment and increased design of electrical safety regulations, which can cope with complex climate and installation environment and ensure the overall reliability of the equipment.


Advantage 3: High adaptability  fully adaptable to large size components

The DC input of Kehua 1500V/350kW inverter can be adapted to large size and high power modules, which can be connected with more than 1.2 times of capacity matching ratio, and the maximum capacity matching ratio can reach 1.5 or more. The inverter undergoes strict device selection and temperature rise testing, and adopts good communication and heat dissipation design, and has 110% overload capacity to ensure the "throughput" capability under high capacity ratio. 


Advantage 4: High intelligence  intelligent design + multiple reserved interfaces

Kehua 1500V/350kW inverter is equipped with I-V curve scanning function, which can accurately identify 14 kinds of failure categories and complete 100MW-level square array inspection in 15 minutes to help power plants operate efficiently. The product has reserved power supply and communication interface for tracking bracket, which can further strengthen data interconnection with tracking system, solve tracking system error, optimize system algorithm, adjust the best tilt angle of the system, and improve power generation. PLC communication method is adopted to save communication cost.

The product is also equipped with fault recording, key device life prediction and intelligent online upgrade functions to help power plant intelligent operation and maintenance management and cost reduction and efficiency. In addition, the inverter also has optional reserved energy storage interface to reduce the construction cost of adding energy storage later.


Advantage 5: High friendliness  excellent grid adaptability and reliable operation of weak grids

Kehua 1500V/350kW inverter adopts three-level design, which has lower current harmonics and improves power quality. The product can quickly respond to the primary frequency regulation of the grid and has night SVG function to reduce the investment cost of the power plant. Its excellent grid system adaptability enables stable operation under SCR 1.1 weak grid environment and adapts to various power plants.

In addition, the inverter can flexibly select 3.15MW, 4.55MW and 9.1MW square array design to meet the needs of many types of large ground power plants, and expand the square array within a reasonable range to achieve cost reduction and efficiency increase, reducing the cost of electricity by more than 2%. 


It is not coincidence that Kehua passed the HVRT and LVRT test of China Electric Power Research Institute. With 34 years of experience for renewable energy, Kehua began to implement the concept of PV + ESS for the Future. For now, Kehua has received the TOP 10 solar inverter brands used in term-loan financed projects from Bloomberg and No.5 world storage inverter supplier from IHS Markit. Kehua will continue to create green energy with R&D strength and devote to let the world enjoy a zero-carbon life safely. 

Read More >