Currently, gas leak detectors used at power sites are mainly divided into two categories: NDIR infrared quantitative leak detectors and halogen qualitative leak detectors. The handheld SF₆ gas leak detector is a classic pump-suction halogen qualitative detection device. Featuring high sensitivity, ultra-fast response, low operation and maintenance costs, and all-weather portability, it has become the primary equipment for routine operation and maintenance, batch inspection and rapid leak location at grassroots power departments. It can meet the demands of regular leak detection in substations of all levels, power equipment manufacturing, power tests and other related scenarios.
I. Core Working Principle
The handheld SF₆ leak detector is developed based on the high-precision halogen ion sensing principle, which can accurately detect SF₆ gas as well as various halogen gases such as R12, R22 and R134a. Equipped with a built-in miniature mechanical pump, it actively draws air samples from the detection area. When the gas to be tested enters the sensor chamber, halogen gas will change the ionic current parameters inside the sensor.
The microprocessor performs high-speed signal acquisition, amplification, filtering and other processing, and converts gas concentration variations into visual gear signals as well as audible and visual alarms, so as to quickly capture and pinpoint gas leak points.
Integrated with a dedicated intelligent signal processing algorithm, the device effectively eliminates interference caused by minor dust and common air impurities on site. Supported by multi-level sensitivity adjustment, it can not only quickly troubleshoot severe leaks but also accurately detect potential micro-leaks.
The pump-suction sampling mode is immune to on-site airflow, delivering excellent detection stability. It is applicable to hard-to-reach areas such as equipment dead corners and narrow cavities that cannot be covered by conventional detection methods. In addition, the device completes self-check and preheating within only 2 seconds after power-on without long standby, greatly improving the overall efficiency of on-site power inspection.
II. Core Performance Parameters and Advantages
(1) Key Technical Parameters
Developed and manufactured in strict accordance with industrial standards for power detection equipment, all core parameters fully comply with the requirements of on-site power operation and maintenance.
- Detectable media: SF₆ and various halogen gases
- Detection range: 1 ~ 1000 ppm
- Minimum detection limit: 1 ppm
- Ultimate sensitivity: 3 g/year; Certified sensitivity: 14 g/year
- Response time: ＜ 1 s; Reset time: approx. 1 s
- Probe: 35.5 cm flexible stainless steel probe, bendable for narrow and concealed spaces
- Power supply: 3V size C alkaline battery
- Continuous working time: up to 30 hours
- Net weight: 560 g, lightweight for one-hand operation
- Operating temperature: 0 ℃ ~ 52 ℃
- Operating humidity: ≤ 85% RH, suitable for various complex working conditions including outdoor areas and distribution rooms
(2) Main Advantages
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Multi-level sensitivity adjustment for all-level leak detection
It supports 7 sensitivity gears with a maximum 64-fold sensitivity amplification. Operators can switch gears according to actual leak levels. The design prevents sensor damage from high-concentration gas impact and enables detection of micro-leaks, fitting all types of leak scenarios.
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Active pump-suction sampling for full coverage and stable detection
The built-in precision micro air pump provides stable and uniform suction for remote detection. It performs well at equipment dead corners and narrow cavities with strong resistance to ambient airflow, far outperforming conventional diffusion-type detectors in stability.
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Dry battery power supply for superior outdoor adaptability
Powered by general dry batteries, the detector can be used immediately on site without pre-charging. It eliminates the risks of power outage and insufficient battery life of rechargeable devices, ideal for regular inspection in field areas with no power supply and easier for maintenance.
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Intelligent audible & visual alarm for quick leak grading
The alarm frequency changes adaptively with gas concentration — the higher the concentration, the faster the alarm. Operators can directly judge leak severity and locate leak points efficiently to accelerate hazard elimination.
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Durable and reliable for complex working conditions
Optimized for vibration resistance and anti-interference, the device adapts to dusty environments with large temperature differences at power sites. It features low failure rate, easy later maintenance and long service life, suitable for long-term and frequent inspection work.
III. Standard Application Scope
With core functions of qualitative leak detection, accurate leak location and hidden hazard identification, the detector complies with industrial specifications and is applicable to standardized leak detection across multiple industries and scenarios.
(1) Core Power Operation & Maintenance Scenarios
It is widely used for routine inspection, periodic preventive leak detection, air tightness re-inspection after major equipment maintenance and re-check after gas refilling for mainstream power equipment in substations, including GIS combined electrical appliances, SF₆ circuit breakers, voltage/current transformers, SF₆ gas-insulated switchgears and ring main units.
It accurately detects potential hazards at high-risk leak points such as sealing surfaces, welds, valves, gas filling ports and porcelain bushing roots. It is also applied to factory air tightness testing, commissioning and calibration of power equipment, as well as on-site testing, technical comparison and practical training for power-related work.
(2) Extended Industrial Applications
Beyond the power sector, the detector is suitable for halogen gas leak detection in other industries, including SF₆ high-voltage switchgear inspection for traction substations in rail transit, air tightness testing of gas-filled equipment in the electrical manufacturing industry, and leak troubleshooting for halogen gas containers and pipelines in chemical plants and laboratories, presenting excellent universality.
IV. Application Boundaries
This is a professional qualitative leak detector designed to quickly locate leak points and identify potential operational risks. It fully meets the requirements of standard qualitative testing such as daily inspection, hazard troubleshooting and equipment commissioning for power facilities.
It is not applicable to quantitative detection including high-precision annual leak rate calculation, arbitration tests for project handover and accurate measurement of environmental emissions. Such high-precision quantitative work shall be performed with NDIR infrared quantitative leak detectors.
V. Applicable Standards & Industrial Regulations
The whole process including production, inspection, on-site operation and result judgment of the handheld SF₆ leak detector strictly follows current national and power industry standards to ensure compliant operation of power equipment. The main applicable codes are listed as follows:
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DL/T 846.6—2018 General Technical Specifications for High-Voltage Test Equipment — Part 6: Sulfur Hexafluoride Gas Leak Detector
Serves as the core basis for production and performance verification, specifying technical indicators such as sensitivity, detection limit, response time and anti-interference. All parameters of this detector fully comply with the standard.
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JJF 1363—2012 Calibration Specification for Sulfur Hexafluoride Gas Leak Detectors
Defines requirements for metrological calibration. The detector shall be professionally calibrated every year with a valid calibration certificate to ensure traceability and accuracy of test results and meet compliance requirements for power tests.
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GB/T 11023—2019 High-Voltage Switchgear and Controlgear — SF₆ Sealing
The core standard for on-site leak judgment, stipulating air tightness requirements and qualified annual leak rate for single gas compartments of SF₆ electrical equipment. It also specifies that no alarm during qualitative detection indicates qualified sealing.
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DL/T 603—2017 Code for Operation and Maintenance of Gas-Insulated Metal-Enclosed Switchgear
Regulates leak detection cycles, handling procedures for leak hazards, gas refilling thresholds and routine maintenance requirements for GIS equipment, providing standardized operation guidelines for daily leak detection.
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DL/T 596—2017 Preventive Test Code for Power Equipment
Clarifies the cycle, key contents, data recording rules and hazard rectification requirements of periodic leak tests for SF₆ electrical equipment, acting as the fundamental regulation for preventive leak detection.
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DL/T 639—2016 Guidelines for Safety Protection of Personnel Engaged in Operation, Testing and Maintenance of SF₆ Electrical Equipment
Specifies safety protection requirements, on-site ventilation conditions and emergency response procedures for leak detection, effectively guaranteeing personal safety of field operators.
