Advanced Technologies, Expert Implementation 


RXPE Circuit

June 2021


RXHK has won the contract for supply of Active Power Filter (APF) Equipment for the Fujian- Guangdong Interconnection Project


RXHK has successfully won the bid for Lot 1: Supply of Active Power Filter Equipment for the State Grid of China Corporation (SGCC) Fujian- Guangdong Interconnection Project. The scope of supply includes two sets of three-phase 88kV Active Power Filter connecting to the 500kV AC filter terminals.  The scheduled delivery date is 30th April 2022.

The Fujian-Guangdong Interconnection Project is the only B2B LCC-HVDC project investment by State Grid in the past ten years, and it is also a landmark project for the deepening cooperation between State Grid and China Southern Power Grid. It is the first time a high voltage active power filter will be utilized in HVDC converter station.

Whilst LCC-HVDC valve technology is currently able to deliver high power rating converters than VSC-HVDC it does have the drawback of higher harmonic emissions.  The dynamic adaptive filtering technology to be provided by RXHK, based on VSC converter technology, will be installed at the Fujian-Guangdong Interconnector B2B Converter station and will improve the HVDC converter station filtering effect by more than 10%. The APF technology also provides a lower footprint solution than conventional filter arrangements.

FGIP Annotated Graphic.JPG

The two APF systems to be delivered by RXHK will provide two separate control modes:

Control Mode 1:Harmonic Voltage/Impedance Control

  • Measure 500kV Bus voltage, reduce 3rd, 5th & 7th harmonic voltages
  • Use impedance control to adjust the 11th, 13th and higher characteristic harmonics.
  • This control mode is suitable for situations where either HVDC transmission power is low, or the power system impedance is large.

Control Mode2:  Harmonic Current Compensation Control

  • The APF operates as a harmonic current source, counteracting the harmonic current output from the LCC converter station.
  • Requires to accurately measure the LCC converter current, and compensate the time delay of current measurement and signal transmission, in order to have a good control result.
  • This control mode is suitable for situations where either HVDC transmission power is high, or the harmonic current is large.

The Fujian-Guangdong Interconnection Project will be the first LCC-HVDC project in Fujian Province. The completion of the project will greatly improve the delivery of renewable energy, supporting the energy transition and support the optimization of energy resources allocation more widely across the SGCC network.