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On line and off line Insulation diagnosis  
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On line and off line Insulation diagnosis  
  LCOE has been conducting on site tests on high voltage equipments since 2005. These tests are performed in portable facilities, some of which have been designed and developed in their own facilities.
The most advanced technology in insulation analysis for high voltage equipment through partial discharges measuring is used. Nowadays this is the most efficient technique for the assessment of the equipments insulation.
Measurings are performed in the tests prior to the put into service of the equipments (off-line techniques) and also during their ordinary performance (on-line techniques), in this case, through the periodic monitoring of partial discharges in the insulation.
Telephone number: (+34) 91 491 8168 Ext. 210email: sramos@lcoe.etsii.upm.es
  Accreditations and Recognitions
ENAC Accreditations: 3/LE130 Tests in the Industrial Sector  View certificate   View Technical Annex
  Off-line tests
  LCOE has several portable facilities to perform off-line tests:
  • Off-line tests for cables. There are three resonant generators in portable laboratories to measure partial discharges (PD): a 36 kV-17 A generator, a 265 kV-82 A generator and a 680 kV-3 A generator to test cables from 10 m to 10 km.
  • Off-line tests on power transformers. There are two portable facilities to measure induced current in power transformers: the facility to test medium voltage power transformers up to 120 MVA (mounted on a six metre-long container) and the facility to test power transformers up to 700 MVA (mounted on a thirteen-metre long trailer)
  • GIS off-line tests. There is a specific facility to perform GIS tests, that consists of a 680 kV-3 A resonant generator with three reactances (250 kV each of them).

  On-line tests
  LCOE uses partial discharges measuring technology that is appropriate for "on line" measures.

Depending on the facility, several gauges (HF, VHF and UHF), several filter techniques (filter by measurement frequency, Wavelet filter, etc.) to differentiate electric noise from DP signs , different techniques of location of the position of discharges (reflectometry, GPS, etc.) and different ways of identifying every DP with the fault or cause that produces it are used.

LCOE provides insulation monitoring services in portable facilities and in static facilities, through DP measuring in electric facilities. This allows analyzing DPs evolution in time and assessing their critical nature.
  Tests and measurements according to IEC 60060-3  
  Put into service of high voltage lines
  • 260 kV- 83 A Resonant generator
  • 680 kV-3 A Resonant generator
  • Main insulation test
  • DP measuring
  • Dielectric test of the envelope
  • Resistance measurement of the conductor and the shield

  On site tests on power transformers
  • Transformers up to 500 MVA
  • Tests on complete facilities (GIS+ lines)
  • Test on induced overcurrent
  • Partial discharges measuring

  Measuring on shield overcurrents in GIS substations
  • Overcurrents measuring in substations
  • Transient modelling through ATP

  Insulation systems diagnosis
  • Permanent or temporary monitoring through partial discharges
  • Integral systems for lines or GIS substations
  • Periodic reports of diagnosis and discharges assessment

Tel: 91 562 5116 - Fax: 91 561 8818
Tel: 91 601 1240 - Fax: 91 695 7876
Tel: 91 491 81 68 - Fax: 91 491 81 69
Tel: 93 151 4620