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An industry need

Kinectrics applies and has developed several highly effective diagnostic techniques in response to an industry need to perform condition assessment on power equipment. Major diagnostic techniques and their specific applicability are discussed below. These advanced diagnostic techniques provide information on the aging, condition and management of power equipment.

• Asset management

Kinectrics uses several proprietary computational tools to assess the effect of maintenance policies on equipment condition, performance and their related risk implications. These tools allow users to derive the rate of the equipment aging process as a function of the temperature loading. This method allows an effective analysis and determination of optimum maintenance and refurbishment policies.

• Partial discharge (PD): electrical and acoustic

Partial discharges are formed as a result of an excessive local electric field which can originate either from a stress enhancement (sharp point), or weakening of the insulation (e.g., bubble). While paper is known to have excellent resistance to PD, carbonization will progress over time and ultimately lead to failure. This phenomenon can be detected both electrically and acoustically.

• DC return voltage, dielectric spectroscopy measurements

These techniques are variations on dissipation factor measurements, but performed at frequencies other than power frequency, thereby providing enhanced diagnostic information. Data can be obtained at a broad range of frequencies (hence the name dielectric spectroscopy), or by a more involved test arrangement, as done for the return voltage measurement (RVM). For RVM, the test object is dc charged then discharged, and the open circuit voltage subsequently attained is measured. This measurement is repeated many times over varied time scale to obtain information at different frequencies.

• Frequency response analysis (FRA)

Frequency Response Analysis (FRA) is used as a tool for evaluating the condition of transformer windings. Transformer windings require strong clamping forces to resist mechanical deformation during system faults. As winding materials age, the clamping forces tend to relax, leaving the unit vulnerable to system disturbances. Also, resonant vibration associated with load currents can lead to mechanical abrasion of the insulation. Understanding which transformers require immediate attention contributes to effective condition assessment. Kinectrics’ experience with FRA testing indicates that major fault-induced winding deflections can be detected at the terminals.

• Power factor testing

Power factor, dissipation factor and tan d measurements are performed routinely on paper oil insulation systems, to assess the losses which are indicative of the presence of more conductive species resulting from paper and oil deterioration and/or moisture ingress.

• DGA, furan and moisture content of the oil

Gasses dissolved in insulating oils are generally the result of deterioration of the insulation systems (paper and oil). Extensive research has been undertaken by Kinectrics to interpret the significance of gases measured and more particularly, their ratios. In simplified terms, hydrogen and acetylene are formed as a result of arcing/discharges, while ethylene is associated with overheating. Carbon monoxide and dioxide are found as a result of breakdown of the paper insulation. Thermal breakdown of the paper also creates a number of heavier furanic derivatives, which are present in small quantities, but provide useful markers because of their specificity as a paper breakdown byproduct.

• SF₆ gas analysis

SF₆ insulated systems produce a variety of gasses as a result of aging and deterioration of the insulation systems. Many of the byproducts of SF₆ degradation are both corrosive and toxic and must be handled with care when equipment requires servicing. Byproducts can also be used as markers of the aging/deterioration process and provide information on the condition of the equipment. Contamination (air, moisture) and byproducts (SOF₂, etc.) can be readily determined from samples taken from the power equipment.

Superior technical expertise

An independent company, Kinectrics’ expertise is founded on nine decades’ experience solving the most advanced technical challenges for Ontario Hydro, one of North America’s largest utilities. Through past research and development activities on many aspects of substation equipment, Kinectrics has developed extensive expertise in the behavior and aging of equipment and insulation systems. Our condition assessment techniques range from simple, low-cost solutions to large full-scale systems for gathering data on equipment.

Kinectrics provides fast, comprehensive testing services at market competitive prices.

Related Services

• Failure analysis
• Transformer leak repair
• Technology scans for condition assessment techniques and tools
• Technical consultation
• Interpretation of diagnostic data
• Insulation systems
• General consultation

At Kinectrics we understand how technology affects performance, the environment, safety and economics of today’s complex energy industry.

For more information, contact

Steve Cress, 416.207.6000 x6557, steve.cress@kinectrics.com

Noboru Fujimoto, 416.207.6000 x 6250, noboru.fujimotor@kinectrics.com