IEEE 980:2013 pdf free download – IEEE Guide for Containment and Control of Oil Spills in Substations
5.6 Other sources
Station service,voltage, and current transformers, oil circuit reclosers, capacitor banks, and other pieces ofelectrical equipment typically found in substations,may contain small amounts of insulating oil. Althoughthey may contain less oil than the qualified threshold in 40 CFR, they may be considered as sources of oil.
6. Criteria
Based on the applicability of the latest regulatory requirements,or when unacceptable risk factors havebeen identified, a program may be put in place to mitigate the problems. Typical criteria for implementingoil spill containment and control programs incorporate regulatory requirements, corporate policy, frequencyand duration of occurrences,cost of occurrences，safety hazards，severity of damage,equipment type,potential environmental impact, substation location, and quality of service requirements.
The decision to install secondary containment at new substations (or to retrofit existing substations) isusually based on predetermined criteria. The 1992 IEEE survey addressed the factors used to determinewhere oil spill containment and control programs are needed.Based on the 1992 survey, the criteria inTable 1 are considered when evaluating the need for secondary oil containment. A similar survey wasdistributed among IEEE members and industry peers in 2012 (see Annex C). This survey represented amuch smaller sample set than that of the 1992 survey (only 27 respondents); however in general, the resultsgenerally supported the conclusions of the 1992 survey.
As for specific numerical limits,57% of the respondents install secondary containment when the maximumvolume of oil per individual tank exceeds the 660 gal 40 CFR, Part 112 limit (at time of survey), with arange of 3000 gal reported.Note that in the 2012 survey，several respondents indicated an individualcontainer volume criteria of 50 gal or 55 gal, a much lower threshold than what was found in the 1992survey.Over 82% of respondents also limit the total volume of oil in the substation to the 1320 galspecified in 40 CFR, Part 112, with a range of 1500 gal reported. The 1992 IEEE survey provided no clearcut limit for the proximity to navigable waters.Relatively equal support was reported for several choicesover the range of approximately 1500 ft. The 2012 survey results reconfirmed the fact that proximity tosurfacc water is a commonly utilized criterion.
Rarely is all of the equipment within a given substation provided with secondary containment. Table 2 liststhe 1992 survey results identifying the equipment for which secondary oil containment is provided.
None of the remaining equipment surveyed in 1992,which included voltage and current transformers,capacitors, and all mobile devices, received a rating higher than 15%.
The focus is clearly on the equipment that contains the largest quantities of oil (see 5.1).As for specificminimum voltage and/or megavolt-ampere (MVA) criteria above which a user always installs secondarycontainment, a wide range of figures was reported.For voltage, the minimum criterion was most often115kV,with a range of 69 kv to 345 kV reported.For MVA, the minimum criterion was most often10 MVA, with a range of 5 MVA to 45 MVA reported.
Other criteria not captured in Table 2, but reported by some respondents in the 2012 survey，includemodeling software to determine potential for oil spills to migrate off-site and into surface water and theindividual piece of clectrical cquipment being equipped with Supervisory Control and Data Acquisition(SCADA) monitoring capabilities.
Each substation should be evaluated by considering appropriate criteria to determine the need for oil-containment systems (both new and retrofit).Substations with planned equipment change-outs may beconsidered for retrofits at the time of the change-out.