【目的】针对大规模新能源接入造成主网惯量降低，进而使配电网支撑能力不足并影响配电网电压-频率耦合特性的问题，文章深入研究了分布式光伏（distributed photovoltaic，DPV）接入配电网后的暂态电压-频率耦合机理，旨在为高渗透率新能源接入的配电网稳定运行优化与控制策略制定提供理论依据。【方法】基于IEEE 33节点系统，分析DPV接入配电网前后暂态电压和频率的响应特性，发现新能源主导的暂态发展过程中电压和频率的动态耦合特性凸显，且低惯量下频率问题更突出。通过深入研究暂态电压跌落与频率波动的内在原因，明确DPV与并网系统的交互行为是电压-频率耦合的关键因素。进一步从功率平衡角度，量化主、配网有功变化间的动态联系，揭示暂态过程中电压-频率耦合机理。【结果】仿真验证表明，DPV的暂态响应特性主导了暂态过程中电压的变化，并进一步扰动频率。在低惯量系统中，DPV的低压穿越（low voltage ride-through，LVRT）过程不仅决定了电压的跌落与恢复形态，其无功支撑行为更会间接扰动系统频率。暂态过程中，电压变化引起配电网侧有功供需关系改变，破坏了系统有功平衡，此不平衡量经由主网-配电网功率交互，最终体现为系统频率波动，明确了电压变化对频率产生扰动的主导路径。【结论】文章量化描述了电压与频率的耦合关系，揭示了耦合机理的本质是“电压波动→有功失衡→频率响应”的动态传递过程。DPV无功-有功耦合特性加剧了电压-频率耦合的复杂性。该机理的明晰为后续设计抑制频率波动的电压-频率协同控制策略提供了理论基础。

[Objective] In response to the insufficient distribution network support and altered voltage-frequency coupling characteristics caused by the reduced inertia of the main grid due to large-scale renewable energy integration，this paper studies the transient voltage-frequency coupling mechanisms in distribution networks with distributed photovoltaic （DPV） integration. It aims to provide a theoretical basis for the development of an optimization and control strategy for the stable operation of distribution networks with high renewable energy penetration. [Methods] Based on the IEEE 33-bus system，the transient voltage and frequency response characteristics before and after DPV integration were analyzed. It was found that the dynamic coupling between voltage and frequency becomes more pronounced during renewable energy-dominated transients，with frequency issues being more critical under low-inertia conditions. The underlying causes of transient voltage sags and frequency fluctuations were explored，clarifying that the interaction between DPV and the network is a key factor in voltage-frequency coupling. From the perspective of power balance，the coupling mechanism between voltage and frequency during transients was elucidated by quantifying the dynamic relationship between active power variations in main grid and distribution networks. [Results] Simulations demonstrated that the transient response characteristics of DPV dominate voltage changes and further disturb frequency during transients. In low-inertia systems，the low-voltage ride-through （LVRT） process of DPV not only determines the voltage sag and recovery but also indirectly disturbs system frequency through its reactive power support. During transients，voltage changes alter the active power supply-demand relationship on the distribution network side，disrupting active power balance and leading to frequency fluctuations through power interactions between main grid and distribution networks. This clarifies the dominant path through which voltage changes disturb frequency. [Conclusion] This paper quantitatively describes the coupling relationship between voltage and frequency and reveals that the coupling mechanism is essentially a dynamic transmission process of "voltage fluctuation→active power imbalance→frequency response". The reactive-active power coupling characteristics of DPV exacerbate the complexity of voltage-frequency coupling. The clarification of this mechanism provides a theoretical basis for the development of voltage-frequency coordinated control strategies to suppress frequency fluctuations.