| 摘要: |
| 构网型静止无功发生器(static var generators, SVG)具备电压源特性，可增强弱网系统的稳定性和电压主动支撑能力。配置部分储能的SVG还可以实现惯量支撑。针对储能型SVG(energy-storage static-var-generator, ESVG)在构网型控制下易发生过流的问题，基于ESVG的拓扑结构分析了级联H桥与储能系统间的联合控制机理。在构网型ESVG的限流机制和现有限流策略的基础上，提出了一种适用于电网对称故障的自适应虚拟导纳限流策略。该策略不仅能够维持ESVG的电压源特性，还显著降低了瞬态过电流和过电压。此外，还增添了暂态虚拟阻抗的清零环节，以保证限流策略的可靠性。通过电流闭环控制器分析了虚拟阻抗比对稳定性的影响。最后，通过仿真结果验证了理论分析的正确性及所提限流策略的有效性。 |
| 关键词: 构网型控制 ESVG 自适应限流 电压源模式 虚拟导纳 |
| DOI：10.19783/j.cnki.pspc.240544 |
| 投稿时间：2024-05-06修订日期：2024-07-28 |
| 基金项目:国家自然科学基金面上项目资助(52277094)；国家电网公司科技项目资助(5500-202158475A-0-5-ZN) |
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| Adaptive current limiting strategy based on grid-forming and energy-storage SVG |
| WANG Feng,XU Jianzhong |
| (State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources
(North China Electric Power University), Beijing 102206, China) |
| Abstract: |
| Grid-forming static var generators (SVGs) possess voltage-source characteristics that can enhance the stability and proactive voltage support capabilities of weak grids. The SVG with partial energy storage can provide inertia support. To address the problem that an energy-storage static var generator (ESVG) is prone to overcurrent when employing grid-forming control, this paper analyzes the joint control mechanism between the cascaded H-bridge and the energy storage system, based on the ESVG topology. Building on the current limiting mechanism and existing limiting strategies of the grid-forming ESVG, an adaptive virtual admittance current limiting strategy suitable for symmetrical faults is proposed. The strategy not only maintains the voltage-source characteristics of the ESVG but also significantly reduces transient overcurrent and overvoltage. Additionally, the strategy incorporates the clearing of transient virtual impedance to ensure its reliability. The effect of the virtual impedance ratio on stability is analyzed by a current closed-loop controller. Finally, the correctness of the theoretical analysis and the effectiveness of the proposed current limiting strategy are verified by simulation. |
| Key words: grid-forming control ESVG adaptive current limiting voltage-source mode virtual admittance |
