Online monitoring renovation

What problem is being solved?

The operational status of conventional SF6 density relays is determined through manual periodic inspections, which require dedicated personnel and incur significant labor costs. However, regular inspections often fail to promptly detect abnormal conditions in the equipment.
Some high-voltage switchgear instruments are installed at elevated positions, making it difficult to read the data accurately during manual inspections. According to the data in the "High Voltage Switch Industry Yearbook," SF6 gas leakage accounts for a significantly higher proportion of failures compared to other types among all failure categories. Therefore, monitoring the gas density of SF6 equipment serves as an effective method for assessing equipment condition and maintenance, greatly enhancing the stability of the equipment.

Why provide this service?

According to the "Technical Specification for Digital Telemetry Instruments in Smart Substations": "SF6 digital density relays are recommended for promotion and application in voltage levels above 35kV.". ”
The online monitoring retrofit has the following advantages:
* Monitor the density, temperature, and pressure changes in each gas chamber in real time to enhance data reliability. By analyzing trends through backend data and graphs, leakage risks can be detected;
* It reduces the workload of maintenance personnel and saves operational management costs;
* Monitor leakage trends online to enhance the effectiveness and cost-efficiency of switch maintenance, promptly identify and repair leaks, and reduce the potential hazards of SF6 leakage to personnel and the environment;
* By utilizing real-time online methods, the occurrence of equipment accidents caused by the failure of density relays to issue alarms is prevented.
* Provide data support for future artificial intelligence and big data analytics.

Related experience and operational procedures

1. The conventional SF6 density relay with only contact output has been upgraded to a remote transmission density relay.
2. Install a hub for remote signal access and acquisition, install a DC24V power supply to supply power to remote signals.
3. Laying RS485 shielded cables from remote transmission density relays to hubs and switch power supplies.
4. Install intelligent IED devices for remote signal aggregation and protocol conversion, which can support IEC61850, IEC104, Modbus, CDT, etc.
5. Online monitoring platform configuration, real-time display of SF6 gas density, pressure, and temperature, supporting alarm settings, historical queries, etc.