I. Requirements Analysis

Conductor sag is one of the primary indicators for assessing the health of power lines. Beyond stress factors, meteorological conditions in the environment surrounding overhead lines also influence sag magnitude, with temperature having a particularly noticeable effect. During summer months, elevated temperatures reduce the distance between the conductor and the ground. Excessive sag diminishes this clearance, potentially creating a risk of contact and electric shock. Conversely, insufficient sag increases the likelihood of accidents such as wire breakage, both of which compromise power supply stability and safety beneath the lines. To enhance sag monitoring capabilities, improve line safety and information management efficiency, and ensure reliable power supply for residents, Dingxin Smart Technology has introduced the Beidou Wind Drift and Sag Online Monitoring Device for Transmission Lines.

II. Working Principle

The Beidou Wind Deflection Sag Online Monitoring Device for Transmission Lines is primarily used to measure the distance to ground, sag angle, and deflection angle of transmission lines. When monitoring jumper sag, the sensor is installed on the jumper; when monitoring insulator sag, the sensor is installed at the bottom or top end of the insulator string; when monitoring phase-to-phase sag within a span, the sag monitoring device is installed between the two conductors requiring monitoring within the span. The sag sensor utilizes laser sensing technology and low-power wireless transmission. Powered by high-voltage power capture, the sensor continuously collects sag data in real time. This data is transmitted instantly to the monitoring center via 4G/5G/GPRS/WIFI/OPGW fiber optic networks. Alarms are triggered when measured values exceed preset thresholds.

III. Features and Functions

1. Capable of directly measuring conductor sag or distance to ground, or collecting relevant measurement values such as conductor inclination angle, temperature, tension, and images that can be used to derive conductor sag or distance to ground through value transfer.

The sag and ground clearance status quantities of conductors shall be stored and computed, with the calculation results transmitted via communication networks to the condition monitoring system (typically applicable when only one sag monitoring device is installed at a site).

(in situations where no other monitoring devices are present), or a condition monitoring proxy device;

2. Equipped with automatic data collection functionality, it automatically gathers parameters related to conductor sag or distance to ground at preset time intervals.

3. Equipped with controlled data acquisition capabilities, it can respond to remote commands to initiate data collection based on the configured acquisition method, automatic acquisition time, acquisition interval, and number of data points.

4. For online sag acquisition units, it is advisable to include functions for collecting power supply voltage and operating temperature data.

5. Equipped with network time synchronization capability. The unit shall be capable of receiving time synchronization commands from the condition monitoring system, synchronizing time once daily with an error not exceeding 5 seconds. The unit clock's time deviation shall be less than 1 second within a 24-hour period.

6. Equipped with data validity check and analysis capabilities, it performs preprocessing on collected data, automatically identifying and filtering out erroneous data.

7. Capable of performing primary calculations on raw measurement data to derive intuitive state data for conductor sag and ground clearance;

8. The system shall be capable of storing sag and ground clearance status data for at least 30 days, and it is recommended to store raw measurement data for over 30 days.

9. Output information includes: wire sag, ground clearance status, power supply voltage, operating temperature, alarm signals, device heartbeat packets, response information, and communication connection status (including signal strength).

IV. Product Specifications

Serial Number	Category	Project Name	Technical Specifications
1	Overall Performance	Complete System Configuration	Master Control Unit, Sag Monitoring Unit, Communication Unit, Power Supply Unit, Mounting Bracket, and Auxiliary Materials
		Overall quality	Less than 30 kg (including solar panels and mounting brackets)
		Material	Stainless steel body + hot-dip galvanized bracket
2	Sag Monitoring Unit	Communication frequency	470M
		Angle measurement range	－90°～90°
		Distance measurement accuracy	±1 cm, measurement range 200 m
		Operating temperature range	-40°C to +70°C
		Installation Method	Wire clamp fastening
		Longest measurement cycle	20 minutes
		Average power consumption	Power consumption ≤40μA (3V) 25°C (Expected lifespan >10 years)
		Antenna	External antenna, height ≤5mm
		Battery capacity	13000mAh High-Temperature Lithium-Ion Battery
		Housing Material	aluminum alloy
		External Dimensions	≤Φ180 mm
3	Communication Unit	Communication method	All-network 4G/5G/WiFi/Beidou communication module/wireless transmission
		Data Security	Communication with the main site can utilize a dedicated VPN channel, with optional encrypted transmission.
		Access Protocol	Compatible with monitoring platforms of provincial power companies such as China Southern Power Grid and State Grid
4	Power Supply Unit	Battery capacity	60Ah/12V
		Solar Panel Power Rating	100W/18V
		Power supply duration	The device can maintain normal operation for 15 days without external power supply.
5	Other parameters	Work Environment	Operating temperature: -40°C to +70°C; Relative humidity: 5% to 99% RH
		Overall service life	Over 8 years
		Protection Rating	IP66