Digital Gas Relay for Transformer

Product Overview

The digital gas relay is a new-generation intelligent device developed in compliance with the latest requirements of State Grid Corporation of China for digital remote-transmission products deployed in smart substations. Retaining all functions of conventional gas relays, it is embedded with high-precision sensors to collect gas accumulation data, transmit the data to terminals and display readings on-site, which drastically cuts down operation and maintenance workload and improves inspection efficiency. It can locally store more than 10,000 pieces of raw data, meeting the specifications for digital meters of State Grid smart substations.

Operating Conditions

(1) Permissible operating temperature: -40°C ~ 105°C; the mounting plane inclination shall not exceed 4 degrees.
(2) Installation method: The pipeline axis of the relay shall be parallel to the transformer tank cover. The end connecting to the oil conservator can be slightly elevated, while its axis shall be horizontal.

Working Principle

The relay is fully filled with transformer oil during normal operation, with its float kept in an upward tilted position. When a minor internal fault occurs in the transformer, gas generated by decomposed transformer oil accumulates in the air chamber at the upper part of the relay, lowering the oil level and driving the float down to the liquid surface. The magnet mounted on the float actuates the reed switch to close the signal circuit and trigger an alarm.
In case of a severe transformer internal fault, the instantaneous surge of pressure inside the oil tank creates an oil hammer that strikes the baffle plate. Once the baffle rotates to a preset limit position, its built-in magnet closes the reed switch to activate the tripping circuit, cutting off the transformer power supply directly without prior alarm to protect the transformer from damage. This product adopts high-precision sensors to detect the above operating information in real time and upload data to the monitoring terminal.

Technical Parameters

Seismic resistance: The relay will not malfunction under sinusoidal vibration at a frequency of 4–20 Hz and an acceleration of 4g.
Ingress Protection (IP) Rating: IP55.
Note: The product is inherently rainproof. A rain shield for special applications is sold separately.
Sealing performance: No leakage shall occur when the relay is fully filled with transformer oil and pressurized to 200 kPa at ambient temperature for a continuous duration of 20 minutes.