Situation awareness of power transmission lines is a comprehensive information acquisition technology integrating such new information technologies as cloud service-based data operation & maintenance supporting platform, IoT information collection network, and wide-area secure communication network. All data is collected to the State Grid's cloud platform through a secure wireless communication network. The cloud platform organizes the data required based on the customized data services of each user's mobile terminal APP, and pushes the data to the user's mobile terminals in real time. The situation sensing system for power transmission lines consists of the following subsystems, each of which can be executed individually or in combination depending on the actual situation.

• Tower position and tilting sensing subsystem: real-time sensing of the precise position of tower tips, the displacement and swing of tower tips, the tilting of towers and other tower status information;

• Strain clamp temperature sensing subsystem: real-time sensing of strain clamp temperature, clamp stability of overhead ground wires, conductor temperature and conductor current information; 

• Arrester state sensing subsystem: real-time sensing of the full leakage current and resistive current of arresters and their harmonic components, and real-time sensing of action times of arresters; 

• Wire sag and galloping sensing subsystem: real-time sensing of movement trajectory, galloping, swing amplitude, and swing frequency of spacers; real-time sensing of the distance between the spacers and the ground; and real-time monitoring of the working temperature of conductors; 

• Conductor icing sensing subsystem: real-time sensing of insulator tension, and integration with micro-climate information to give early warning of conductor icing;

• Micro-climate sensing subsystem: real-time sensing of ambient temperature and humidity, precipitation, illuminance, wind speed and wind direction and other micro-climate elements around towers, and provision of climate information for other subsystems; 

• Life-cycle asset management subsystem: recording of manufacturing, installation, operation, overhaul, and scrapping information of line equipment to provide basis for smart operation and inspection; 

• Subsystem for smart inspection and safety auxiliary system: real-time guidance for operation and inspection personnel to patrol the lines based on operation requirements, automatically reading data of surrounding sensors, automatically warning dangerous approach and high-precision positioning, preventing entering the wrong bays by mistake to ensure the safety of operation and inspection personnel, and giving remote automatic alarm for falls to ensure the safety of personnel.