From local to short circuit: How can gas relays accurately identify internal faults in transformers? (with engineering case analysis attached)

1.Why is gas relays called a ‘fault language translator’

During transformer operation, all internal faults will ‘speak first’ – through gas and oil flow.
The value of gas relays lies in:

Transform invisible physical changes into executable electrical signals.

2.Correspondence between internal fault types and gas characteristics

This is also why gas relays are often used in conjunction with DGA (Dissolved Gas Analysis).

3.Detailed explanation of gas relays alarm and trip logic

3.1 Alarm Stage

Slow accumulation of gas
The float slowly sinks
Contact closure → Send alarm
Operations personnel can conduct inspections and plan power outages

3.2 Trip Stage

Sudden increase in oil flow velocity
Instantaneous deflection of baffle
Trip circuit closed
Circuit breaker action, protecting equipment

4.Engineering case analysis (real-life scenarios)

Case 1: Partial discharge not taken seriously

Alarm signal appears
Failure to timely sample and analyze
Interturn short circuit occurs after 3 months
Economic losses have increased fivefold

Gas relay alarm is not a “false alarm”, but a “warning”.

Case 2: Oil flow tripping to avoid explosion

Internal short circuit
Instantaneous tripping of gas relays
The pressure has not reached the burst threshold
The transformer casing is intact

Gas Relays

5.Common misconceptions and technical misjudgments

Alarm not processed
Installation tilt causes misoperation
Residual air in pipelines
Neglecting regular testing

6.New trend: Intelligent gas relay

New directions that have emerged in recent years include:

• Electronic oil flow sensor
• Digital measurement of gas volume
• Remote monitoring interface
• Linkage with SCADA/EMS system

7.Key technical terms in export and bidding documents

Common requirements for overseas projects:

• Dual contact output
• seismic performance
• Long life micro switch
• Third party type testing

8.Summary

Gas relays are not complicated, but they understand the internal language of transformers.
The correct selection, installation, and attention to alarm information often determine the “upper limit of life” of a transformer.

Luoyang Datang Energy Technology Co., Ltd. is a high-tech enterprise integrating R&D, manufacturing and supply of power equipment such as transformers, new energy components, distribution cabinets and inverters. With technological innovation as the core, we focus on creating high-reliability and high-performance power solutions to serve global customers. With a strict quality control system and international standard certification, we continue to output excellent products and enable customers to build safe and stable power systems.