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Distribution transformers are the most expensive asset of your electrical network. Their lifetime significantly affects service reliability, maintenance intervals and your overall maintenance budget. Nevertheless, because actual operating conditions such as thermal stresses, unbalanced loads, harmonic impacts and atmospheric contaminants represent a significant burden, distribution transformers very often end up being prematurely damaged in operation. At Jiangsu Ryan Electric, we designed longevity into our entire product portfolio. Here is how to make distribution transformers last in operation thanks to innovative technologies and extensive testing:
Premium Materials and Robust Insulation Systems
The key to any durable transformer is the inherent quality of its core materials and insulation system. To this end, our distribution transformers are built with premium quality grain-oriented silicon steel cores exhibiting minimized hysteresis and eddy-current losses that help prevent long-term thermal strain. We’ve dedicated similar effort to building a superior insulation system. Our cast resin and VPI distribution transformers benefit from use of high-performance epoxy resin which boasts a strong resistance to thermal aging and moisture thereby prohibiting partial discharge and tracking even when used in tropical climates. Likewise, our oil-immersed distribution transformers come fitted with either highly purified mineral oil or readily available bio-degradable alternative fluids which boast a long oxidation stability and thus limit the rate at which cellulose insulation degrades. We strive to use materials resistant to both thermal aging and chemical breakdown to ensure our transformers can function correctly for decades.
Precision Manufacturing and Automated Quality Control
Reliability is engineered in the manufacturing area. Our automatic winding machines provide a stable tension for consistent layering in our windings, preventing the weak areas caused by air voids that lead to premature electrical stress failure. Our vacuum pressure impregnated (VPI) construction in our dry type transformers reaches a virtually void-free condition, while the solid insulation for our oil-immersed transformer assembly has been dried by both stringent moisture control procedures and the removal of residual water by vacuum drying. Our in-process inspections for all distribution transformers include the testing of electrical values including winding resistance, turn ratio, and insulation resistance. Our dual CNAS accredited 35 kV and 110 kV testing facilities can uncover all potential manufacturing defects, ensuring no transformer leaves our factory with the possibility of early life failures.
Comprehensive Type Testing Beyond Industry Norms
Even if simple tests might assure minimum electrical functionality, real-life robustness is confirmed by type- and special-tests which mimic an extreme operation conditions. In case of Ryan Electric all new distribution transformer designs are submitted to full range of type-tests (impulse lightning voltage withstand, temperature rise, short circuit current, partial discharge measurements) according to IEEE, IEC, CSA standards. The maximum level can be tested up to 110 kV / 132 kV, in our testing stations. Our tests are complemented by thermal shock cycle tests or humidity exposure, ensuring the distribution transformer’s ability to stand up against the most critical climatic conditions – a hot, humid coastal area, as well as a freezing mountain climate. By setting this high standard of electrical reliability and performance, we are making sure that the best possible product arrives at your job-site, regardless of the expected conditions.
Intelligent Design for Thermal Management and Maintenance Access
Temperature is the number one destroyer of distribution transformers. Each 10°C lower at the hotspot in a transformer’s insulation can essentially double its life expectancy! The internal structure of both our oil filled and dry type transformers has been optimized to enhance the circulation of air and oil. With air cooled units, our natural and forced air designs will get that hot oil away from your transformer. With our oil immersed range we promote a greater natural convection through clever core and winding designs. We build the transformer from the outside in with accessible tap changers and high quality bushing terminals, which include appropriate fittings for easy oil sampling and diagnostics. Our substation type and pad mounted distribution transformers come in fully corrosion protected enclosures with seals against dust ingress, which extend the internal components life expectancy by further preventing condensation and helping to promote an on going maintenance program that keeps your transformers in service long past the expected life time.
Distribution transformers manufactured with rigorous, long-life principles can provide superior field-service reliability through the combined use of quality materials, high-precision fabrication, extensive testing and considered thermal management. Jiangsu Ryan Electric can harness the collective experience of its joint-venture, its certified testing facilities and its worldwide installation base to provide distribution transformers that will provide you with years of reliable service, reduce replacement cycles, and keep your essential systems running while minimizing lifecycle costs.