Optimization Techniques of Substation Capability Applying Natural Ester Liquid-Filled Transformers

Natural ester liquids, applied as insulating liquids, have demonstrated performance improvements in power transformers. While the early adopters were motivated by the fire safety and improved environmental footprint, the main driver nowadays is the increased thermal class of the insulating paper when immersed in natural ester fluids. This allows increasing the temperature rise limits without compromising transformer life and reliability. This paper expands this benefit beyond the transformer capability ("a variable performance box") providing analysis of the system wide impact (outside the box). Thanks to the fact that the same system demand can be supplied through a natural ester transformer having a base rating lower than what would be required if using mineral oil, with the adjacent components, system configuration and overall protections optimized accordingly. The main discussed impacts will be IEEE transformer standards compliance; transformer average winding temperature rise versus life and reliability; medium voltage switchgear costing; weight reduction for floating ship production operation; civil engineering construction cost reduction; N-1 designs; questionable need for fire walls and suppression systems between transformers; medium voltage power cable cost reductions; total installed system cost reduction.