The first 50MVar renewable energy distributed synchronous condenser in China successfully completed a 168-hour trial operation in a 330 kV Xuming substation and was officially put into operation recently. This also marks the successful delivery of NR's first distributed synchronous condenser protection & control system, which will escort the output of clean energy in Qinghai for a long time in the future and contribute to the realization of China's carbon-neutral goal.
NR continues to lead the development of distributed synchronous condenser protection & control technology after the batch application of the new generation 300MVar large synchronous condenser protection & control system of the State Grid.
Transmission end of power supply
Distributed synchronous condenser can be configured at the power supply of renewable energy
At a clean energy base located at the transmission end of ± 800 kV Qingyu HVDC project, the installed capacity of renewable energy power supply accounts for more than 60%. There are problems such as huge uncertainty and large fluctuation, resulting in large changes in reactive power demand at the transmission end of power supply, weak voltage support and stability problems to varying degrees, which restricts the transmission capacity of Qingyu HVDC.
The distributed synchronous condenser can be configured locally at the power supply side of renewable energy. It has the advantages of wide distribution, high integration and flexible operation. It can effectively solve the problem of insufficient reactive power support and stability in the renewable energy area, realize steady-state, transient and sub-transient regulation at the same time, and become the "stabilizer" of clean energy delivery.
SFC startup system
The protection & control system is the "brain" for the orderly start & stop and safe operation of the synchronous condenser. It plays an important role in the renewable energy export project.
As the core equipment, the SFC startup system is responsible for dragging the speed of the condenser to above the rated speed to realize the idle speed synchronization and grid connection. Its successful speed increase is the prerequisite for the successful operation of the condenser.
Xuming substation has 5 distributed synchronous condenser and 2 sets of SFCS. Each set of SFCs can drag every machine to speed up to realize the 2 SFCS with 5 condensers function. This is the first application in China, and the control difficulty is several times higher than the conventional mode.
Great challenges to the DCS system
Based on the existing experience, the project team sorts out the drive sequence control process in advance, identifies the isolation logic between multiple machines, and optimizes the initial position detection, initial torque and other parameters to ensure the success of unit drive at first time.
The DCS system is required to conduct overall control and monitoring throughout the operation of the condenser
The DCS system is required to conduct overall control and monitoring throughout the operation of the condenser. The distributed condenser is quite different from the centralized condenser in terms of cooling mode and operation sequence, such as the control of the air conditioning system and the unit without jacking the oil pump, which brings great challenges to DCS.
The project team actively analyzes the new features and requirements of the distributed condenser and cooperates with all parties to jointly formulate the most reasonable control process and logic to ensure the smooth start of the unit.
NR condenser project team
NR condenser project team has completed the application of 21 centralized 300MVar condenser projects and accumulated rich experience in development, design, and engineering commissioning. During the implementation of the distributed condenser project, these experiences of control interface, sequence control process, logic configuration, and protection strategy help a lot.
The operation of the first unit is just the beginning, and there will be a large number of units to be implemented in the future. The project team will continue to provide customers with high-quality products and services.
