Protection and Control of Power Grids with up to 100% Penetration of Renewable Energy Sources

近年来，可再生能源占全球新增电力装机容量的80%以上，引发了电网运营的范式转变。这些电源的逆变器接口具有非常规的故障响应，威胁着当今保护系统的可靠性。涉及基于逆变器的资源(IBR)的扰动数量的稳步增长证明了这一点。随着发电结构转变的加剧，与IBR特性兼容的保护系统的严重缺失威胁着电网可靠性下降的新时代。同时，较高的IBR渗透率使得保护装置和逆变器控制器的运行越来越相互依赖。应对这些挑战需要的不仅仅是只保护或只控制的办法；还需要一种既涉及保护又涉及控制的多方面、但连贯的办法。因此，拟议的研究计划解决了未来网格的以下基本要求。1.发展以IBR为主或仅由IBR供电的电网保护系统：当IBR渗透率较低时，IBR主要对其直接联络线的继电保护产生负面影响。由于输电网络中IBR联络线的数量有限，IBR尚未严重破坏保护系统的整体完整性。然而，当IBR的份额上升时，它们的影响将蔓延到整个电网。这将把保护挑战提升到一个全新的水平，因为现有继电器的核心设计最初是为了传统电网而设计的。该计划的目标是根据IBR的故障行为对保护系统进行重大重新设计。2.针对以可再生能源为中心的电网的故障情况设计逆变器控制方案：为了提高保护的可靠性，电网代码(GCs)试图使IBR故障电流可预测。然而，由于以下原因，今天的GC仍然存在IBR故障电流的不确定性：(I)GC中的一些细微但关键的盲点；(Ii)GC对一些紧急逆变器控制策略保持沉默；以及(Iii)一些IBR不受某些GC条款的限制，以适应其控制的僵化。该计划将(I)阐明GC的故障电流要求中迄今未知的方面，(Ii)确定下一代GC的必要变化，以及(Iii)开发满足这些GC要求的控制方案。除了为加拿大能源部门创造经济机会外，该项目提供的技术和HQP还实现了绿色能源的大规模电网集成，缓解了气候变化的环境和社会经济影响。

Renewable energy sources have accounted for more than 80% of new electricity capacity added globally in recent years, triggering a paradigm shift in the operation of power grids. The inverter interfaces of these sources have unconventional fault responses and threaten the reliability of today's protection systems. This is evidenced by the steady growth in the number of disturbances that involve inverter-based resources (IBRs). As the shift in the generation mix intensifies, the critical absence of protection systems that are compatible with the characteristics of IBRs threatens a new era of declining grid reliability. Meanwhile, higher IBR penetration makes the operation of protective devices and inverter controllers increasingly interdependent. Addressing these challenges requires more than an either protection-only or control-only approach; a multifaceted, yet coherent, approach involving both protection and control is needed. Accordingly, the proposed research program addresses the following fundamental requirements of the future grid. 1. Development of protection systems for power grids supplied mainly or only by IBRs: When the IBR penetration is low, an IBR negatively affects primarily the relays of its direct tie-line. Since the number of IBR tie-lines in transmission networks is limited, IBRs have not yet seriously undermined the overall integrity of protection systems. When the share of IBRs rises, however, their impact will spread across the grid. This will elevate the protection challenges to a whole new level as the core design of existing relays was originally intended for the legacy power grid. This program will target a major redesign of the protection systems based on the IBRs' fault behaviour. 2. Devising inverter control schemes for the fault conditions of renewable energy-centric grids: To increase protection reliability, grid codes (GCs) attempt to make the IBR fault currents predictable. However, today's GCs still include uncertainties about the IBR fault current due to (i) some subtle but critical blind spots in the GCs, (ii) the GCs' silence about some emergent inverter control strategies, and (iii) some IBRs' undesired exemptions from certain GC provisions to accommodate the inflexibility of their control. This program will (i) shed light on so-far-unknown aspects of the GCs' fault current requirements, (ii) identify necessary changes in the next generation of GCs, and (iii) develop control schemes that satisfy these GC requirements. In addition to creating economic opportunities for Canada's energy sector, the technologies and HQPs delivered by this program enable large-scale grid integration of green energy sources, alleviating the environmental and socio-economic repercussions of climate change.