随着变电站智能化的不断演进，站内通信网络流量激增，而与一次设备关联的业务又有严格的实时性要求，这对通信流量的综合调度提出了新的挑战。时间敏感网络（time-sensitive networking, TSN）技术能够保障变电站高可靠低时延业务传输需求，近年来备受关注。首先，对TSN技术中的HOLD & RELEASE机制“保护带”带宽资源有效利用问题进行研究，通过重新设定“保护带”内帧传输条件，改进HOLD & RELEASE机制，实现带宽资源的动态利用；然后，结合IEEE Std 802.3br-2016标准，给出改进后HOLD & RELEASE机制的实现过程。最后，通过仿真算例验证了所提算法的可行性和有效性。仿真结果表明，改进后的HOLD & RELEASE机制在不产生任何额外开销的条件下，可有效提高变电站内通信网络的带宽利用率。

With the continuous advancement of substation intelligence, communication network traffic within substations has surged. Strict real-time requirements associated with primary equipment operations present new challenges for comprehensive traffic scheduling. TSN(time-sensitive networking) technology, which ensures the high reliability and low latency transmission demands of substations, has gained significant attention in recent years. The issue of effective bandwidth resource utilization within the "protection band" of the HOLD & RELEASE mechanism in TSN technology was addressed. The frame transmission conditions within the "protection band" were redefined, leading to the proposal of an improved HOLD & RELEASE mechanism to achieve dynamic utilization of bandwidth resources. The implementation process of the improved HOLD & RELEASE mechanism was outlined in conjunction with the IEEE Std 802.3br-2016 standard. The feasibility and effectiveness of the proposed algorithm are verified through simulation examples. The simulation results demonstrate that the improved HOLD & RELEASE mechanism significantly enhances the bandwidth utilization of substation communication networks without incurring any additional overhead.