Density table verification

What problem is being solved?

According to statistics, over 70% of electrical equipment failures are caused by a lack of effective maintenance and upkeep. Due to various reasons such as equipment vibration and aging, the performance of SF6 gas density relays may change or even lose their monitoring function during long-term operation.
For example, after a long period of inactivity, there may be phenomena such as pointer movement jamming or inflexibility, poor contact of contacts, etc. Some may also experience a decrease in temperature compensation performance. When the ambient temperature changes, it may cause SF6 gas density relays to malfunction. Therefore, timely verification is necessary to ensure that the stability of SF6 density relays meets the standard.

Why provide this service?

Regularly verifying SF6 density relays in operation can provide important reference for equipment operation and maintenance. It can transform passive maintenance into active prevention, routine maintenance into professional maintenance, and improve the safety and reliability of equipment.
According to industry standards, there are periodic verification requirements for density relays.
DL/T 596-2021 Preventive Testing Regulations for Power Equipment
1-220Q6115243948
DLT393-2021 State Maintenance Test Code for Power Transmission and Transformation Equipment
5.3.2.6 Calibration of Gas Density Meter (Relay)
Perform this project when the data shows abnormalities or reaches the manufacturer's recommended calibration cycle. Verify according to the requirements of the equipment technical documents.

Related experience and operational procedures

Equipment: Langsongkeli VDA-01 automatic calibrator, connector box
Condition: The density relay must have a three-way valve to achieve online calibration, which can close the main air circuit and has a calibration interface. Otherwise, it can only be disassembled for calibration, or it can be combined with the calibration during the modification of the three-way valve.
Steps for online calibration of meters:
1. Remove the rain cover and remove the electrical contact aviation plug.
2. Close the three-way valve.
3. Connect the calibrator, gas pipeline, and calibration interface.
4. Turn on the calibrator to verify the contact action value.
5. Measurement of contact resistance and insulation resistance of contacts.
6. Open the valve and restore the electrical contact plug.