Transformer Buchholz Relay

Technical Specifications for Transformer Buchholz Relay

Parameter Item	Technical Specifications	Remarks
Product Model	QJ-80/QJ-100/QJ-150	Multiple pipe diameter options, specific models per our latest specifications
Applicable Pipe Diameter	DN80/DN100/DN150	Matched to transformer capacity, contact us for detailed specifications
Working Pressure	≤0.05MPa	Normal transformer tank operating pressure
Sealing Pressure	≥0.1MPa	Airtightness test pressure
Contact Capacity	AC 250V/5A, DC 220V/1A	Control circuit rated parameters, specific parameters per latest technical data
Contact Quantity	Gas alarm 1 pair, Trip 1 pair	Separate contacts for signaling and tripping
Operating Oil Velocity	0.6-1.5m/s	Trip protection operating oil flow velocity, customizable per requirements
Reset Oil Velocity	0.3-0.6m/s	Trip protection reset oil flow velocity
Gas Alarm Volume	150-300cm³	Adjustable as needed, contact us for specific adjustment range
Housing Material	Cast aluminum alloy	Corrosion-resistant explosion-proof structure
Sealing Material	Nitrile rubber	Transformer oil resistant sealing rings
Operating Temperature	-40℃~+60℃	Environmental temperature adaptation range
Protection Rating	IP54	Dust and splash water protection
Insulation Resistance	≥100MΩ	Contact to housing insulation resistance
Dielectric Strength	AC 2kV/1min	Insulation withstand voltage test standard
Service Life	≥20 years	Design service life

Note: Above parameters are for reference only. Specific technical specifications are subject to our latest product documentation. Please contact us for detailed specification sheets.

Application Cases for Gas Actuated Relay Systems

Power Transformer Protection Applications

A 220kV main transformer protection system utilizing QJ-150 type Buchholz relay has successfully detected and handled 3 minor internal faults over 15 years of operation, effectively preventing equipment damage and power outage incidents while ensuring safe and stable grid operation.

Industrial Transformer Monitoring Cases

Large steel enterprise 35kV distribution transformer groups employ QJ-100 type gas protection relays for protection. Through gas alarm early warning functionality, winding overheating issues were timely identified and addressed, extending transformer service life and reducing maintenance costs.

Distribution Transformer Installation Examples

Urban distribution network 10kV transformers widely adopt QJ-80 type Buchholz gas relays. The miniaturized design facilitates installation while high reliability ensures safe distribution system operation with significantly reduced failure rates.

Selection Guide for Transformer Gas Protection Relays

Model Selection Based on Transformer Capacity

• QJ-80: Suitable for 10kV and below, capacity ≤1600kVA distribution transformers
• QJ-100: Suitable for 35kV, capacity 1600-8000kVA power transformers
• QJ-150: Suitable for 110kV and above, capacity ≥8000kVA main transformers

Selection recommendations are subject to our latest selection manual. Please contact us for detailed selection guidance.

Pipe Diameter Matching Requirements

Buchholz relay pipe diameter must match transformer oil pipe diameter to ensure smooth oil flow and detection accuracy. Installation must consider pipeline routing and maintenance space requirements.

Installation Environment Considerations

Selection must consider installation environment factors including temperature, humidity, and altitude. Special environments can be accommodated with customized corrosion-resistant and high-temperature resistant products.

Frequently Asked Questions About Transformer Buchholz Relays

How to distinguish between gas alarm and trip operations?

Gas alarm operation occurs when internal transformer gas accumulation reaches the set volume threshold, serving primarily as an early warning with signal output but no tripping. Trip operation occurs due to severe internal transformer faults causing violent oil flow impact, directly tripping to disconnect the transformer.

What are the installation position requirements for Buchholz relays?

Gas protection relays must be installed in the connecting pipeline between transformer tank and conservator, maintaining horizontal installation with inclination not exceeding 1°. Installation height should facilitate observation and maintenance with adequate surrounding operational space.

What is the maintenance cycle for Buchholz relays?

Annual visual inspection and contact testing are recommended, with comprehensive overhaul every 3-5 years. Under normal operation, transformer gas relays require minimal maintenance, mainly involving housing cleaning and sealing performance inspection.

How to handle Buchholz relay false operations?

First check installation levelness and pipeline vibration interference. Investigate transformer for actual faults; if no faults exist, adjust operating parameters. Replace relay or improve installation environment if necessary.

What precautions apply when replacing Buchholz relays?

Before replacement, transformer must be de-energized and oil drained below gas relay level. When installing new relay, ensure sealing performance, adjust levelness properly, and perform functional testing after oil refilling to confirm normal operation.

Service Commitment and Contact Information

Our Service Commitment

We provide comprehensive technical support and after-sales service for transformer Buchholz relay products:

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