Fujian-Guangdong - Back-to-Back Converter Station

Overview

The Fujian-Guangdong HVDC is, designed to interconnect the power grids of Fujian and Guangdong provinces. This back-to-back LCC-HVDC (Line Commutated Converter project was completed and put into operation on September 30, 2022.

Technical Specifications

The project features two back-to-back LCC-HVDC units with a rated voltage of ±100kV and a rated capacity of 1000MW each. A new converter station was built in Mapu Township, Fujian Province, to facilitate this interconnection. The total transmission capacity of the project is 2000 MW.

The converter station is connected to an AC transmission line with a total length of 303 kilometers. It connects to the Guangdong Jiaying and Fujian Donglin 500 kV substations through two AC 500 kV lines, respectively. This interconnection allows for the mutual aid between the two provinces during periods of surplus or shortage of electricity.

Features

The project incorporates several notable features:

1. A suspension back-to-back quadruple valve tower, specifically designed for this project. This innovative structural design arranges all AC and DC bus interfaces of the quadruple valve tower on the same side, significantly simplifying the layout of the valve hall equipment.

2. The valve cooling protection and control system employs the new generation UAPC3.0 platform, which offers faster operation speed, higher reliability, and a smaller chassis size.

3. An AC electronic voltage transformer capable of high-precision harmonic voltage measurement, with small measurement delay and high temperature stability.

4. An AC section power loss protection device using adaptive fault criteria, which accurately identifies faults, optimizes the configuration of the stability control system, and ensures safe and stable operation of the power grid.

Active Power Filter Technology

An important technical aspect of the project is the implementation of high voltage active power filter (APF) technology. The APF equipment, connected to the 500kV AC filter terminals, includes two sets of three-phase 88kV Active Power Filters. This technology improves the HVDC converter station filtering effect by more than 10% and provides a lower footprint solution than conventional filter arrangements.

The APF systems offer two separate control modes: Harmonic Voltage/Impedance Control and Harmonic Current Compensation Control. The dynamic adaptive filtering technology, based on VSC (Voltage Source Converter) technology, effectively addresses the higher harmonic emissions typically associated with LCC-HVDC valve technology.

Performance and Impact

Since its commissioning, the Fujian-Guangdong interconnection project has demonstrated excellent performance. As of early 2023, it had transmitted over 10 TWh of electricity, with Fujian sending 6 TWh to Guangdong and Guangdong sending 4 TWh to Fujian. This bi-directional power flow capability enhances the flexibility and reliability of power supply between the two provinces.

The project was the first to realize an interconnection between the State Grid and China Southern Power Grid through back-to-back DC technology. It promotes the optimal allocation of power resources over a wider area and improves the delivery capacity of clean energy from Fujian Province.