what are the black boxes on power lines
The black boxes on power lines are usually **functional devices in the power or communication system**.
The specific types and uses depend on their installation locations, voltage levels, and the systems they belong
to. The following are several common types:
1. High-voltage Transmission Lines: Intelligent Monitoring Devices
- **Drone Nest (such as the "Dragon Nest" system)**
- **Function**: Integrates solar panels, charging devices, and edge computing equipment, supporting
automatic line inspection by drones, data transmission, and fault analysis.
- **Application**: Intelligent inspection of high-voltage transmission networks, real-time monitoring of the
line status (such as loose bolts and overheating conductors), and ensuring the safety of the power grid (such
as power supply guarantee for the Beijing Winter Olympics and large-scale events).
- **Infrared Live-line Detection Device**
- **Function**: Combines infrared temperature measurement, visible light imaging, and data transmission
to remotely monitor abnormal line current, voltage, and temperature, achieving unmanned inspection.
2. Medium and Low-voltage Distribution Lines: Protection and Connection Devices
- **Fuse Box**
- **Function**: When a short circuit or overload occurs in the line, the fuse melts to isolate the faulty
section and protect the power grid. It is commonly found near distribution transformers and has a gray or
black box appearance.
- **Splice Box**
- **Function**: Used for the connection and tapping of cable lines. It contains wire connectors and insulating
materials inside and has waterproof and dustproof properties. It is commonly found at the branch points of
medium and low-voltage distribution lines.
- **Load Switch or Circuit Breaker**
- **Function**: Interrupts normal load or fault current, and some integrate an arc extinguishing function
(such as a vacuum circuit breaker), which is used for line control and protection.
3. Communication Utility Poles: Optical Cable Splice Cabinets and Signal Devices
- **Optical Cable Splice Cabinet**
- **Function**: It is the central hub of the optical fiber network, containing optical fiber connectors,
optical splitters, etc. inside, realizing the distribution and transmission of optical signals and supporting
communication services such as broadband and telephone.
- **Signal Amplifier/Lightning Arrester**
- **Function**: In cable TV or communication lines, it is used to enhance the signal (amplifier) or prevent
lightning strikes (lightning arrester). It is commonly a black box located in the middle of the utility pole.
4. Other Special-purpose Devices
- **Smart Meter Box**: Used for measuring the electricity consumption of users in low-voltage distribution
and supports remote meter reading.
- **Fault Indicator**: Indicates the location of line faults and assists in quickly troubleshooting faults.
How to Distinguish?
- **Location**:
- High-voltage power lines (thick wires at the top): Intelligent monitoring devices or high-voltage switches.
- Medium and low-voltage power lines (thinner wires in the middle): Fuse boxes, circuit breakers.
- Multiple thin wires at the bottom: Communication devices (optical cable splice cabinets, telephone junction
boxes).
- **Identification**: Power devices usually have the logo of the power company, and communication devices are
marked with the names of operators (such as China Mobile, China Telecom).
**Conclusion**: The black boxes on power lines are key components for ensuring the safety of the power grid
and the stability of communication, covering four major functions of **monitoring, protection, connection, and
communication**. The specific types need to be judged in combination with the installation location and the
attributes of the system. If there are potential safety hazards (such as a damaged box body), you should contact
the corresponding power or communication company for handling.
