Las principales pruebas de diagnóstico de cable incluyen descargas parciales (DP), tan delta (y sus variantes), método de tensión de retorno (MTR), y pruebas de corriente de relajación isotérmica (CRI).
Mientras que las pruebas de tan delta y sus variaciones pueden categorizarse como sensibles a problemas locales o globales mientras que la medición de DP lo es sólo a problemas locales. Debería tenerse en cuenta que las DP no son detectables en el campo por arborescencias acuosas, pero sí lo pueden ser, si las arborescencias son eléctricas. “Las arborescencias acuosas pueden dar lugar a la formación de arborescencias eléctricas como resultado de un impulso tipo rayo, sobretensiones de conmutación, o niveles y duraciones excesivas de las tensiones de prueba.” (IEEE 400.2 – 2013)
Tan Delta testing, also known as Power Factor and Dissipation Factor testing, involves the use of state-of-the-art instruments that give the user a wide range of results for qualitative cable assessments, such as degradation and lifetime estimations on MV and HV systems.
Partial discharge activity is an indication of incipient insulation faults and is widely regarded as one of the best ‘early warning’ indicators of deterioration in medium and high voltage insulation. PD diagnostics has therefore become a well-established method of quality control for new assets, as well as the condition assessment of service-aged systems.
Megger has an extensive history of manufacturing and supplying PD test equipment to many top industrial organisations for transformer, switchgear and cable testing. These partial discharge testers can take the role of quality assurance for product manufacturing or off-site plant analysis and mapping at almost any voltage the customer requires.
Partial discharge test and monitoring systems can be supplied in the form of handheld tools, as well as bigger, transportable diagnostic products. Megger’s broad range of equipment provides solutions for almost all types of MV and HV assets, from battery operated online PD handheld units, to full, extra high voltage (EHV) on-site testing systems.
Megger employs some of the world’s greatest experts in cable testing and diagnostics. With such a variety of possible testing and diagnostic methods, Megger can help you determine the appropriate techniques and equipment for your cable assessment needs.