当前，电力系统在转型发展过程中已表现出高比例新能源装机和高比例电力电子化的“双高”特征，系统形态、特征显著变化。新型“双高”电力系统中大量电力电子设备及控制环节参与的宽频动态交互产生了频率跨度广的宽频振荡问题，已经严重威胁电力系统稳定运行和设备安全，正成为制约电力工业发展的关键稳定性问题和重大技术挑战。宽频振荡具有频率范围宽广及幅频时变的特点，可能因系统运行方式变化而穿越、演变成中高频振荡、次/超同步振荡和低频振荡等不同模式。由于系统模型维数极高、运行方式组合爆炸以及振荡稳定性复杂多变等特征，宽频振荡在控制上不同于传统机电动态主导的低频振荡，迫切需要适用于宽频振荡问题的新型稳定控制技术。为此，本文从振荡产生与抑制原理、自适应阻尼控制策略、振荡抑制措施配置与协同等三方面入手，提供解决变流器并网系统宽频振荡的新理论、新方法和新的装备技术。在振荡产生与抑制原理方面，从功率角度阐明了振荡产生和抑制过程的机理、即工频功率和非工频振荡功率之间的跨频变换，为振荡抑制的有效性提供了理论支撑，提出了基于振荡功率判据的振荡溯源方法，并在实际系统案例中实现了振荡源判别和抑制效果评价。在自适应振荡控制方面，提出了基于“即测-即辨-即控”思路的自适应阻尼控制方法，快速、准确辨识振荡特征，根据振荡特征在线构建等效电路模型以实时调节控制结构和参数，能有效抑制不同场景下从数Hz到上千Hz的宽频振荡。在抑制措施配置和协同方面，提出了考虑振荡参与程度和控制容量成本的网侧阻尼控制器配置方法，并确定了位置和容量设计的实用化原则，实施并测试了基于陷波器的机组侧振荡抑制措施，提出了机组侧抑制措施配置比例的优化方法，弥补了机组侧抑制措施需逐一升级机组的劣势，进一步，提出了多阻尼控制器的协同设计方法，可以在更小容量下实现更优抑制效果。在装置技术方面，针对变流器并网系统的宽频振荡，研制了自适应阻尼控制器样机，并通过硬件在环仿真测试对其基础功能和自适应抑制效果进行了验证，为进一步工程应用奠定了基础。
In recent years, the rapid development of new energy generation and flexible direct current transmission technology has led the power system to exhibit the "dual-high" development trend with a high proportion of new energy and a high proportion of power electronic devices. The wideband dynamic interaction involving numerous power electronic devices and control loops in the new "dual high" power system has resulted in a wideband oscillation issue across a broad frequency range. The wideband oscillation poses a severe threat to the stable operation and equipment safety of the power system, emerging as a pivotal stability concern and a significant technical obstacle impeding the power industry's progress.Wideband oscillations are characterized by a broad frequency range and time-varying amplitude and frequency, which can transition and evolve between different oscillation forms such as low frequency, sub/super-synchronous, and mid-high frequency with changes in system conditions. Due to the extremely high dimensionality of system models, explosive combinations of operating modes, and the intricate and variable oscillation stability, controlling wideband oscillation is much more challenging than traditional low-frequency oscillation phenomena dominated by electromechanical dynamics. Consequently, there is an immediate requirement for novel stability control techniques tailored to solve wideband oscillation issues. This paper addresses this need by presenting new theories, methods, and equipment to resolve wideband oscillation in converter-embedded power systems. It covers three main aspects: understanding the generation and mitigation principles of oscillations, implementing adaptive techniques for oscillation suppression, and the configuration and coordination of oscillation suppression measures.In the research on the generation and suppression principles of oscillations, the paper elucidates that the mechanism of the oscillation generation and suppression process is the cross-frequency transformation between fundamental-frequency power and non-fundamental-frequency (oscillation) power from the power perspective. This clarification offers theoretical underpinning for the effectiveness of oscillation suppression. Then, an oscillation source tracing method based on oscillation power is introduced. Oscillation source identification and suppression effect evaluation in real system cases are carried out.In the research on the adaptive oscillation control, the paper proposes an adaptive damping control method based on the "measure-identify-control" approach. The oscillation characteristics are identified promptly and precisely. By constructing an equivalent circuit model online based on oscillation characteristics, the adaptive damping control adjusts the control structure and parameters in real time, effectively mitigating wideband oscillations from several Hz to over a thousand Hz in different scenarios.In the research on the configuration and coordination of suppression measures, the paper first presents a grid-side damping controller configuration method considering oscillation participation factors and control capacity costs. The practical principles for the design of controllers’ position and capacity are established. The generator-side oscillation suppression measures based on notch filters are implemented and tested in an actual system. A configuration method for the implementation ratio of generator-side suppression measures is proposed, which compensates for the drawbacks of updating every generator. Further, a coordination design method for multiple damping controllers is presented, achieving better mitigation effects with smaller capacity.In the researches on the equipment technology, aiming at the wideband oscillations in converter-embedded systems, an adaptive damping controller is developed. By conducting hardware-in-the-loop simulation tests, the controller equipment’s basic functionality and adaptive suppression effects are validated, establishing the groundwork for further engineering applications.
