Condition monitoring of power transmission lines is an essential aspect of improving transmission efficiency and ensuring an uninterrupted power supply. Wherein, efficient inspection methods play a critical role for carrying out regular inspections with less effort & cost, minimum labour engagement and ease of execution in any geographical & environmental conditions. Earlier various methods such as manual inspection, roll-on wire robotic inspection and helicopter-based inspection are preferably utilized. In the present days, Unmanned Aerial System (UAS) based inspection techniques are gradually increasing its suitability in terms of working speed, flexibility to program for difficult circumstances, accuracy in data collection and cost minimization. This paper reports a state-of-the-art study on the inspection of power transmission line systems and various methods utilized therein, along with their merits and demerits, which are explained and compared. Furthermore, a review was also carried out for the existing visual inspection systems utilized for power line inspection. In addition to that, blockchain utilities for power transmission line inspection are discussed, which illustrates next-generation data management possibilities, automating an effective inspection and providing solutions for the current challenges. Overall, the review demonstrates a concept for synergic integration of deep learning, navigation control concepts and the utilization of advanced sensors so that UAVs with advanced computation techniques can be analyzed with different aspects of implementation.

输电线路的状态监测是提高输电效率、保证不间断供电的重要方面。其中，高效的检查方法对于以更少的精力和成本、最少的劳动力投入以及在任何地理和环境条件下易于执行的定期检查发挥着关键作用。较早地优选使用手动检查、滚线机器人检查和直升机检查等各种方法。如今，基于无人机系统（UAS）的检查技术在工作速度、困难环境下编程的灵活性、数据收集的准确性和成本最小化方面逐渐提高其适用性。本文报告了输电线路系统检查的最新研究以及其中使用的各种方法，以及它们的优点和缺点，并进行了解释和比较。此外，还对用于电力线路检查的现有目视检查系统进行了审查。除此之外，还讨论了用于输电线路检查的区块链实用程序，这说明了下一代数据管理的可能性，自动化有效的检查并为当前的挑战提供解决方案。总体而言，该评论展示了深度学习、导航控制概念和先进传感器的利用协同集成的概念，以便可以通过实施的不同方面来分析具有先进计算技术的无人机。