Laboratory Diagnostic Services

Dissolved Gas Analysis (DGA) is widely accepted as the most reliable tool for the earliest detection of incipient faults in fluid filled electrical apparatus. Under normal operating conditions very little decomposition of the dielectric fluid occurs. However, when a thermal or electrical fault develops, dielectric fluid and solid insulation will partially decompose. Analysis of the quantity of each of the fault gases present in the fluid will identify fault processes such as corona, sparking, overheating and arcing.

Benefits

• Pre-emptive fault detection
• ID deteriorating conditions
• Reduce unplanned failures
• Prioritize maintenance schedules
• Maximize warranty benefits
• Identify problems early
• Critical for CBM & RCM programs
• Recommendations for follow-up
• Tests
• Inspections

Features

• Comprehensive test report
• Diagnostic interpretation
• State of the art equipment
• Accurate detection limits
• Better reproducibility
• Trending of current & historical DGA analysis
• DGA reports available via email, fax & online
• In-house experts available to assist in DGA analysis interpretation

The ability of an insulating fluid to serve as an effective insulator and coolant is adversely affected by deterioration.

To ensure safety, continuity of service and efficient low-cost maintenance, insulating fluids must be regularly monitored with a program of physical, chemical & electrical testing.

Whether the fluid is mineral oil, silicone, less flammable hydrocarbons, Askarel, natural or synthetic esters, AVO offers technical expertise and guidance for all tests performed.

Benefits

• Improve service continuity
• Preempt insulation fluid problems
• Minimize costly repairs

Features

• ID insulation fluid properties: physical electrical & chemical
• Comprehensive diagnostic report

The EPA has designated Polychlorinated Biphenyls (PCBs) an environmental hazard. The EPA has concluded that PCBs are both toxic and persistent.

AVO uses EPA Method 8082a in the USA, and ASTM D4059, or M.A.400-BPC in Canada. AVO is accredited to ISO/IEC 17025 for PCB in insulating fluid analysis. AVO has a proven history of providing accurate results. Our investment in state-of-the-art Gas Chromatographs (GCs) means:

— Quick
— Accurate
— Reliable

Benefits

• Evaluate environmental hazard
• Meet regulatory standards

Features

• Identify PCB levels, type, saturation
• Comprehensive written report
• Meets EPA and Canadian SOR/2008-273 requirements

The degree of polymerization (DP) of paper can be determined in the laboratory utilizing ASTM method D-4243. Acquisition of a paper sample is an invasive and expensive procedure that requires taking the unit off line.

Furan analysis is a non-invasive alternative. The procedure is based on the determination of oil soluble cellulose decomposition products.

AVO Diagnostic Services can isolate these compounds from an oil sample and analyze them with High Performance Liquid Chromatography, HPLC. Knowing the insulation condition is key to loading and life expectancy of the transformer.

Benefits

• Determine loading capacity
• Estimate life expectancy
• Avoid transformer down-time
• Eliminate invasive & expensive procedures to acquire paper samples

Features

• Non-invasive alternative
• Determine insulation condition-based on correlation between the concentration of furanic compounds and DP

Metal analysis pinpoints the location of faults within transformers and provides other vital information about a transformer’s operation. Whether testing for excessive wear in oil circulation pumps or the condition of LTC or OCB contacts, a diagnostic analysis can be quickly and accurately performed.

Benefits

• Pinpoint fault locations
• Prevent major failures
• Reduce outage time and maintenance spending
• Determine equipment condition

Features

• Analyze 8 metals (iron, copper, aluminum, lead, silicon, silver, tin & zinc)
• Other metals available by request
• Low detection limits

It is generally accepted that the degree of paper insulation degradation or ageing correlates with a transformer’s useful or end-of-life determination, and having an understanding or clear picture of the chemical, physical, and electrical condition of the insulation system is essential to effectively managing its operation.

In the last decade, research at Hydro Quebec found that methanol offered the greatest potential in the ageing measurement of oil-impregnated insulation in power transformers. They demonstrated the link between the generation of methanol in oil and the degradation process of the paper.

Benefits

• Methanol correlates as an early-stage paper degradation marker
• Combined with a furan analysis, the combination of the two approaches can offer a better assessment across the entire lifespan of the insulation.
• Methanol testing can be used with both Kraft and Thermally Upgraded Kraft (TUK) solid insulation in electrical equipment systems.
• Current GC-Headspace technology utilized at AVO Diagnostic Services requires a small liquid sample (approx. 20 mls.) and offers the detection and reporting of methanol and ethanol at low part-per-billion levels
• Allows for the early detection of cellulose degradation markers and the full-life assessment of solid insulation