In the dynamic world of energy transmission, the integration of renewable energy sources into existing infrastructure is both a challenge and an opportunity. A recent study published in ‘Frontiers in Electronics’ (translated to English as ‘Frontiers in Electronics’) by Maolan Peng of the Electric Power Research Institute, CSG EHV Power Transmission Company, Guangzhou, China, sheds light on a critical aspect of this integration: the active identification of short-circuit capacity in Line Commutated Converter High Voltage Direct Current (LCC-HVDC) systems.
The study addresses a pressing issue in the energy sector: the variability of renewable energy sources, such as wind and solar, can cause significant fluctuations in the short-circuit capacity provided by the AC system. This variability poses a challenge for maintaining grid stability and reliability. Peng’s research proposes a novel method to actively identify the short-circuit capacity in LCC-HVDC systems, taking into account the integration of renewable energy.
The method involves establishing an equivalent AC system based on Thevenin’s theorem and calculating the equivalent electromotive force. By computing the sensitivity of the voltage at the point of common coupling (PCC) to the active and reactive power flowing through the PCC, the study identifies key factors affecting the identification of the equivalent resistance and reactance. This sensitivity analysis is crucial for understanding how changes in renewable energy integration impact the system’s short-circuit capacity.
Peng explains, “The proposed method combines the switching of filters and changes in DC power to actively identify the short-circuit capacity. This approach provides a theoretical basis for developing control strategies for LCC converter stations under different AC system strengths.”
The implications of this research are far-reaching. As the energy sector continues to shift towards renewable sources, the ability to accurately assess and manage short-circuit capacity will be vital for maintaining grid stability. Peng’s method offers a practical solution for energy providers to adapt to the increasing integration of renewable energy, ensuring that the grid remains robust and reliable.
The study’s findings were verified through a simulation model of an LCC-HVDC system with grid-following wind power integration, built in PSCAD/EMTDC. The results demonstrated that the proposed method is applicable to AC systems with different impedance characteristics. Moreover, the research showed that as the integration of grid-following renewable energy increases, the short-circuit capacity provided by the AC system tends to decrease.
This research not only advances our understanding of LCC-HVDC systems but also paves the way for future developments in the field. As renewable energy sources become more prevalent, the ability to actively identify and manage short-circuit capacity will be essential for the stability and efficiency of the energy grid. Peng’s work provides a valuable tool for energy providers, helping them to navigate the complexities of integrating renewable energy into existing infrastructure.
