In the sprawling landscape of China’s power grid, an unusual phenomenon has been causing ripples of concern. Low-frequency power oscillations, akin to the subtle hum of a badly tuned engine, have been detected in the LUXI back-to-back (BTB) VSC-HVDC project. These oscillations, if left unchecked, could threaten the stability of the entire power system, a scenario that energy professionals dread. But fear not, for a team of researchers, led by Ke Wang from the Dispatching and Control Center of China Southern Power Grid, has been delving into the heart of this issue, seeking to understand and mitigate these oscillations.
The culprit, as it turns out, is a complex interplay between the voltage source converter-based high-voltage direct current (VSC-HVDC) systems and the dynamic response of synchronous generators. “The interaction between VSC-based frequency control and the synchronous generators is the root cause of these low-frequency power oscillations,” Wang explains. The turbine and governor systems in these generators act as stabilizers, providing positive damping. However, the DC voltage-controlled VSC station introduces negative damping, a counterproductive force that can exacerbate oscillations.
To tackle this issue, Wang and his team developed a combined approach using small-signal modeling and the damping torque method. This innovative method allows for a detailed analysis of the damping behavior of DC power in VSC-HVDC systems. “Our findings provide a clear path forward for addressing these oscillations and ensuring the stability of our power systems,” Wang asserts.
The implications of this research are far-reaching, particularly for the energy sector. Asynchronous interconnection of power grids is becoming increasingly common, driven by the need to integrate renewable energy sources and enhance grid resilience. However, this interconnection can lead to complex dynamic interactions, as seen in the LUXI project. The methods developed by Wang and his team offer a way to understand and mitigate these interactions, paving the way for more stable and reliable power systems.
The research, published in Energies, which is the English translation of the journal name, could shape future developments in the field. Energy companies and grid operators could adopt these methods to analyze and improve the damping behavior of their own systems, ensuring stability and reliability. Moreover, the findings could inform the design of future VSC-HVDC projects, leading to more robust and resilient power systems.
As the energy sector continues to evolve, driven by the need for sustainability and reliability, research like Wang’s will be crucial. It provides the insights and tools needed to navigate the complexities of modern power systems, ensuring a stable and reliable energy future for all. So, the next time you flick a switch and the light comes on, remember, there’s a lot of complex science and engineering going on behind the scenes to keep that light shining steadily.