Enhanced Power System Stability using Fast, Distributed Power Electronics Control

逆变器耦合可再生能源发电的日益普及正在迅速改变大规模电力系统的动态。由于逆变器连接的发电取代了同步电机，电网失去了惯性、电压支持和振荡抑制。这些对系统稳定性的潜在不利影响已经引起了系统运营商、监管机构和研究界的高度关注。系统的稳定性往往会限制电力在廉价资源地区和高负荷地区之间的转移。例如，加州约25%的电能从其他州进口，其中相当大一部分来自华盛顿州的直流电(DC)。2017年，华盛顿州提前一天的平均批发价比加利福尼亚州的价格低约40%。这些价格差异的原因主要是因为对稳定的担忧限制了这两个地区之间的输电量。该项目提出了一种新的方法，通过更仔细地控制电力电子设备来提高系统的稳定性，从而产生可观的经济和环境效益。由此产生的资金节省可能达到数亿美元，因为可以在不同地区之间实现更自由的电力流动，并提高可再生资源的利用率。该项目将邀请本科生和研究生参与拟议的研究活动，并开发集成电力电子控制方法的新课程。该项目将为逆变器开发新的控制算法和硬件架构，使其能够以即插即用的方式进行部署，并提高电力电子接口和同步发电电网的稳定性。我们将通过确保算法和硬件是健壮的、完全分散的并补充同步机器的动态来实现这一目标。我们研究了系统的电压和频率控制。在电压控制方面，我们诊断了目前电网中现有逆变器控制方法的缺点，并设计了新的控制器，以保持稳定性，避免不利交互，并利用数字控制逆变器的算法灵活性。在频率控制中，我们采用了一种鲁棒控制方法来设计逆变器的时域响应，以显式地优化频率响应，并实施来自与逆变器相连的资源的功率和能量约束。我们将建造一个验证和实验的试验台。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The increasing penetration of inverter-coupled renewable generation is rapidly changing the dynamics of large-scale power systems. As inverter-connected generation displaces synchronous machines, electric grids lose inertia, voltage support, and oscillation damping. These potential adverse impacts on system stability have received significant attention from system operators, regulators and the research community. System stability often limits power transfer between areas of cheap resources and high load areas. For example, California imports about 25% of its electrical energy from other states, of which significant amount comes from the state of Washington through direct current (DC) interties. In 2017, the average wholesale day-ahead price in Washington State was about 40% lower than the prices in California. The reason for these price differences is mainly due to the stability concerns that limit the amount of power transferred between the two areas. This project proposes new approach that would have substantial economic and environmental benefits by improving stability of systems through more careful control of power electronics. The resulting monetary savings could amount to hundreds of millions for allowing more unconstrained power flow between different regions and higher utilization of of renewable resources. The project will engage undergraduate and graduate students in the proposed research activities and develop new courses integrating control methods in power electronics. This project will develop novel control algorithms and hardware architectures for inverters so they can be deployed in a "plug-and-play" manner and improve the stability of a grid with both power electronic interfaced and synchronous generation. We will accomplish this goal by ensuring that the algorithms and the hardware are robust, completely decentralized and complement the dynamics of the synchronous machines. We study both voltage and frequency controls for a system. In voltage control, we diagnose the shortcomings of existing inverter control methods on the grid today, and engineer novel controllers that preserve stability, avoid adverse interactions, and leverage the algorithmic flexibility of digitally controlled inverters. In frequency control, we adopt a robust control approach to design the time domain response of inverters to explicitly optimize the frequency response and enforce power and energy constraints coming from the resources connected to the inverters. We will construct a testbed for validation and experimentation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.