Date: January 2011
Company: SDP / SANTIAGO – Metropolitan Area.
Maintenance to dry transformer encapsulated in epoxy resin:
– We realize works of diagnose to transformers, located in S/E Interior Facilities and outdoors; M.T. Cells and General Board: The purpose is to notice the system failures to be able to correct them, if necessary.
– Thermographic sample to each of the terminals of connection of the intervened transformers, to identify free terminals or any possible inconvenience. The action can be realized whether in the working schedule or on holidays.
– Our professionals move with the necessary equipment to the customers’ facilities to do the action: Maintenance of prevention.
– Measuring of protection and service meshes, with the energized transformers and with measuring instrument induction-type. (GROUND RESISTANCE CLAMP-ON).
– Measuring of voltages of service and phases sequences to each of the transformers.
– Disconnection of high voltage networks with the equipment or SF6 Cells corresponding to each of the transformers.
– Verification of the placement of protection grounds of the manoeuvre cell of each transformer.
– Disarming the lid of the exterior cabinet of the transformer to have access to the active zone, nucleus and coils, of the equipments. It is marked the position of lids or, it is marked to build them after.
– Disconnection of the medium and low voltage cables and the grounding connection is added to the cover of the transformer that are connected to the transformer terminals.
– Cleaning and aspiration of the dust.
– Transformers are cleaned with dielectric diluent Cold Solvent, with dielectric rigidness 26 KV.
– High voltage terminals of the transformer are cleaned and lubricated.
– Adjustment and tightening of perneria and connections linked to the equipment, with torque key in function of the thermography realized previously.
– Revision of perneria to transformers anchoring.
– Measuring of the insulating resistance, with Megger Digital, between High coil to nucleus, low coil to nucleus and between high and low coils.
– Measuring of the coils resistance with digital instruments, in the position of tap service.
– Proves of relationship of transformation are realized, with TTR instrument, in the position of tap service.
– Inspection of the insulating state of the coils of the transformer for possible cracks.
– The inspection is realized with digital camera.
– All the cables of medium and low tension and ground to the transformer, providing a special care for the cable attachments that in the thermography appeared as poor connected or damaged.