In the heart of China’s rapidly expanding power grid, a silent yet formidable challenge is brewing: excessive short-circuit currents. As the nation’s electrical infrastructure grows to meet the demands of urbanization and economic development, so too does the risk of short-circuit currents that can overwhelm circuit breakers and jeopardize the stability of the power system. This issue is not unique to China; it’s a global concern that has sparked a wave of research and innovation in the energy sector.
At the forefront of this research is Shuqin Sun, a professor at Jilin University’s College of Instrumentation and Electrical Engineering. Sun and her team have been delving into the intricacies of short-circuit currents, seeking ways to control and mitigate their impact on power grids. Their latest findings, published in a recent study, offer a comprehensive analysis of structural changes in power grids as a means of limiting short-circuit currents.
The problem is stark. “In many developed regions, both domestically and internationally, some substations have already experienced short-circuit current levels that exceed the maximum interrupting capacity of circuit breakers,” Sun explains. This raises serious concerns about the safe and stable operation of power grids worldwide.
Sun’s research, published in Energies, focuses on eight specific measures to alter the structure of power grids, each with its own set of advantages, disadvantages, and applicable conditions. These measures include electromagnetic ring network breaking, bus splitting, line interruption, and line coupling, among others. By constructing an impedance matrix using the additional branch method, Sun and her team analyzed the control effects of these measures on short-circuit currents.
One of the key findings is the importance of layered and zoned management of the power grid. This approach, while fundamental, is a long-term solution that requires a high level of grid development. “The layered and zoned management of the power grid is an inevitable trend in the long-term development of the grid,” Sun notes. However, it’s not without its challenges, including potential losses in supply reliability for lower-level grids.
Bus-splitting operations, on the other hand, offer a more immediate solution. This measure is cost-effective and simple to implement, targeting specific substations to limit short-circuit currents. However, it lacks the flexibility and reliability of double-bus connections and can lead to uneven load distribution.
Line interruption is another measure that shows promise. It’s easy to operate and doesn’t incur significant costs, but it can lead to overloads in other lines and waste grid resources. DC transmission offers high controllability over short-circuit currents but comes with high requirements for power mutual assistance and supply reliability.
Each measure has its pros and cons, and Sun emphasizes the need for a comprehensive approach. “While each current-limiting measure effectively limits short-circuit currents, it also brings about corresponding issues for grid operation,” she says. “Therefore, in addition to short-circuit calculations, comprehensive consideration should be given to stability calculations, power flow calculations, and economic costs.”
The implications of this research are far-reaching. As power grids continue to expand and interconnect, the risk of excessive short-circuit currents will only grow. Sun’s work provides a roadmap for energy companies and grid operators to navigate this challenge, offering practical solutions that can be tailored to specific conditions and requirements.
Moreover, this research could shape future developments in the field. As energy systems become more complex and interconnected, the need for innovative solutions to manage short-circuit currents will only increase. Sun’s work lays the groundwork for further exploration and innovation, paving the way for a more stable and reliable power grid.
In an era where the demand for electricity is ever-increasing, and the complexity of power grids is reaching new heights, Sun’s research serves as a beacon of insight and innovation. It’s a testament to the power of scientific inquiry and the potential it holds to transform the energy sector. As we look to the future, one thing is clear: the work of researchers like Sun will be instrumental in shaping a more stable, reliable, and sustainable power grid for all.
