Electricity + Control March 2019

HAZARDOUS AREAS + SAFETY

Financial considerations Historical technology and traditional approaches leave firms exposed to the eventful failure and re- sulting costs associated with repairing or replacing the fire damaged infrastructure. Worse, in order to have a favourable return on investment, first investment cost must be minimised; forcing con- sideration of true owning costs over the life of the equipment to be minimised (or ignored complete- ly). For example, normal accounting costs associ- ated with reactive approaches may include: • Site selection and preparation • Substation design • Purchase and installation of transformer (and spare) • Purchase and installation of fire suppression equipment (deluge system or fire wall) • Infrastructure installation (cable, protective re- lay systems, cable towers, etc.) • Insurance premiums Other (long term) costs that may not normally be accounted for include: • Maintenance cost of fire mitigation systems • Rehabilitation of fire suppression system and site conditions (replacement of damaged in- frastructure, bus/cable, bracing, pipes, towers, etc.) • Emergency replacement costs of transformers - if used, unknown quality of transformer - if used, unknown insulation life expectancy • Lost revenue for longer than required down time • Site remediation of oil vented during initial fail- ure mode When total ownership costs are considered, the small premium for less-flammable liquids is easi- ly justifiable. Risk mitigating professionals under-

stand and advocate the use of less-flammable liq- uids in transformers because it reduces their long term exposure to damage and future insurance claims. FM Global ® recognises there is a significant opportunity to mitigate catastrophic risk and advocates the use of less-flammable liquids in transformers, as indicated in its Loss Preven- tion Data Sheets (for example, less flammable liquids are even suitable substitutes for costly deluge systems or increased spatial separation distances, resulting in a significantly reduced initial investment, as well as long term mainte- nance costs). That tables are also referenced by IEC 61936-1. [1] In addition, the US National Electric Code (NEC 450.23) recognises that the probability of a trans- former fire occurring when filled with less-flam- mable liquid is much lower than when filled with mineral oil and it permits indoor applications of less-flammable filled transformers without requir- ing traditional fire vaults. Conclusion The above analysis indicates that K-class dielectric liquids provide increased margin of safety. This combined with the flawless track record of less flammable liquids makes proactively specifying (or retrofilling) substation transformers with K-class liquid the best solution for mitigating risk associat- ed with transformer failures. The objective is to prevent the fire from occur- ring. The property that directly impacts fire preven- tion is fire point. References [1] IEC 61936-1, “Power installations exceeding 1 kV ac – Part 1: Common rules, International Electrotechnical Commission, 2010.

Roberto Ignacio da Silva (roberto_ignacio@cargill.com) has an MSc in Energy Policy from the Uni- versity of Sao Paulo's Institute of Energy and Environment. He holds a BSc in Mechanical Technology from Sao Paulo State Technological College, a BSc in Mechanical Engineering from Braz Cubas University and an MBA in engineering and management products and services from the University of Sao Paulo.

24 Electricity + Control

MARCH 2019