Contents i Secondary Unit Substations …

1 CA08104001 EFor more information, visit: 2016 ContentsSecondary unit Substations Secondary Below 1000 14iii12345678910111213141516171819202100 1 Secondary unit Substations Secondary Below 1000 VSecondary unit Substations Secondary Below 1000 VTransformer Fluids and NEC ComplianceTransformer Product Selector .. Cooling Classes .. Fluids Comparison .. Electrical Code (NFPA 70 NEC) Requirements.. OverviewDOE 2016 Requirements .. of Distribution Systems .. Terminal Compartment .. MVS Load Interrupter Switchgear .. Switchgear Assembly, Type MSB .. Substation Transformers .. Dry-Type Transformers.. Coil Transformers .. Epoxy Cast Resin Transformers.

2 DS Low Voltage Metal-Enclosed Switchgear .. C Switchboards .. unit Substation Plug-and-Play .. Temp Controller .. DimensionsComposite Floor Plans .. with Air Terminal Chamber (ATC).. Switching Equipment .. and Losses .. Secondary Equipment .. c h n i c a l D a t aTransformers .. Equipment .. Equipment .. Eaton s Product Specification Guide, available on CD or on the Format: .. 19952010 Section 16311 Section 26 11 Primary Switch and DSII Low Voltage Metal-Enclosed more information, visit: 2016 Secondary unit Substations Secondary Below 1000 VSheet 14iii123456789101112131415161718192021 Transformer Fluids and NEC ComplianceProduct Selection002 Transformer Product SelectorTable Transformer Product SelectorTransformerMaximum VoltageAvailablekVACAGTa bTypesApplicationConsiderationsStandards and CertificationsPrimary SecondaryUnit Substation Transformer Dry-TypeSecondary unit Substation (provides Secondary system voltage) kV600 kVA 3750 kVA14 VPI An economical choice suitable for most commercial appli-cations.

3 Technology characterized by design flexibility and overload safety factor. Vacuum pressure impregnation with polyester Coil Lowest maintenance for most commercial and industrial applica-tions. By hermetically sealing the windings in epoxy, higher levels of performance and environmental robust-ness are achieved in high moisture, dust laden, and chemical contaminated For applications with high shock and vibration or cold climates, RESIBLOC delivers a differentiated solution. Coils are insulated with epoxy and reinforced with glass-fiber is part of a close-coupled assembly that includes both primary andsecondary , fire-resistant and nonpolluting to the containment nor fire suppression required for indoor availableSeismic Zone 4 certificationUnit Substation Transformer Liquid-FilledSecondary unit Substation (provides Secondary system voltage)

4 KV600 V300 kVA 3750 kVA14 Mineral Oil Typical outdoor Applied where flammability is a FR3 Specified where flammability, clean-up and life extension are a is part of a close-coupled assembly that may include both primary and Secondary short-circuit tank design is impervious to the footprint, greater efficiency, nonpolluting to the environment when filled with Envirotemp FR3 Complies with ANSI and , CSA 88UL, FM availableSeismic Zone 4 certificationCA08104001 EFor more information, visit: 2016 Secondary unit Substations Secondary Below 1000 VSheet 14iii123456789101112131415161718192021 Transformer Fluids and NEC ComplianceCooling Classes003 Cooling Classes of TransformersThe cooling classes of transformers have changed, and are explained in Table The IEEE transformer cooling designations were changed to become consistent with the IEC standards (IEC 60076-2: 1998).

5 The new classifications are described in IEEE for liquid-filled transformers. IEEE describes dry-type new cooling designations have four-letter descriptions that describe the type of oil, how the oil is internally circulated, what is used to cool the oil, and how the oil is externally example: ONANT able IEEE Transformer Cooling Classes Table Cooling Classes Comparisons, Past/Present Designations Table Dry-Type Transformer Cooling Classes Note: In the IEC symbols, N indicates N A NFirst Letter Internal Cooling MediumIn Contact With WindingsO= Mineral oil or other fluid withfire point m300 CK= Insulating liquid with fire pointL300 CL= Insulating liquid with no measurable fire pointSecond Letter Circulation Mechanism forInternal Cooling MediumN= Natural convection flow through coolingequipment and in Forced circulation through coolingequipment ( , cooling pumps)

6 Andnatural convection flow in Forced circulation through coolingequipment, directed from the coolingequipment into at least the main Letter External Cooling MediumA= AirW= WaterFourth Letter Circulation Mechanism forExternal Cooling MediumN= Natural convectionF= Forced circulation fans (air cooling) or pumps(water cooling)DesignationsPreviousPresent OAFAOA/FA/FAONANONAFONAN/ONAF/ONAFOA/FA/ FOAOA/FOAOA/FOA/FOAONAN/ONAF/OFAFONAN/OD AFONAN/ODAF/ODAFFOAFOWFOAFOWOFAFOFWFODAF ODWFD escriptionClassIEC EquivalentVentilated self-cooled AAANV entilated forced-air-cooledAFAAFV entilated self-cooled/forced-air-cooledAA/FAAN/AFN on-ventilated self-cooledANV Sealed self-cooledGA more information, visit.

7 2016 Secondary unit Substations Secondary Below 1000 VSheet 14iii123456789101112131415161718192021 Transformer Fluids and NEC ComplianceFluids Comparison004 Transformer Fluids ComparisonTable Fluid Advantages and DisadvantagesTable Fluid Properties Comparison AdvantagesDisadvantagesMineral Oil Low transformer cost Good dielectric performance Low maintenance cost Good heat dissipation Good cold climate performance Preventative maintenance DGA historical data available Higher installation cost Potential vaults required for indoor installations per NEC low fire point 160 C l30% BiodegradabilitySilicone Fluid Low heat release Reduced smoke Low flame Self extinguishing Good dielectric performance Low toxicity Moderate viscosity High stability Non-biodegradable Not suitable for use with internal Bay-O-Net fuses Transformer cost Disposal cost Viton gaskets required Retrofil applications High transformer cost High moisture absorptionEnvironmentally Friendly Fluids High fire point 360 C High flash point 330 C Compatible with mineral oil Excellent retrofil fluid (compatible with oil up to a 10% mixture)

8 Excellent dielectric performance 99% biodegradable Renewable resource Greater tolerance to moisture Excellent switching medium Excellent cold weather performance Significant extension of transformer insulation life Transformer cost (lower than silicone fluid) Pour point ( 15 C to 25 C) transformer energized with full load with top oil temperature at 50 C with no dielectric problems no crystals formed at 68 CAir Non-flammable No fluid analysis necessary Zero environmental impact Transformer cost (oil is better dielectric than air)PropertyMineralOilSiliconeFluidEnvir onmentally Friendly FluidsSpecific gravityFlash point CFire point (cSt.)

9 100 C40 C0 C312761638901045300 Pour point CDielectric strength, kVDissipation factor (%) 25 C 15 more information, visit: 2016 Secondary unit Substations Secondary Below 1000 VSheet 14iii123456789101112131415161718192021 Transformer Fluids and NEC ComplianceNEC Requirements005 NEC Requirement Guidelines for the Installation of TransformersNEC (NFPA) RecognitionThese guidelines focus on the requirements of Article 450 of the National Electrical Code (NEC ). Articles and 22 describe the installation of dry-type transformers; Article describes the installation of less-flammable liquid insulated transformers; and Articles and 27 describe the installation of mineral-insulated transformers.

10 Typical applications of fire concern include installations indoor, on rooftops, near buildings, bush and forest fire prone areas, and in pedestrian traffic RequirementsMineral-Oil Insulated TransformersPer NEC for mineral oil insulated transformers installed outdoors, in cases where the transformer installa-tion presents a fire hazard, one or more of the following safeguards shall be applied according to the degree of hazard involved:1. Space separation 2. Fire-resistant barriers3. Automatic fire suppression systems4. Enclosures that confine the oil of a ruptured transformer tankPer NEC , mineral oil insulated transformers installed indoors shall be installed in a 3-hour rated vault per Article 450, Part oil insulated transformers are most commonly installed TransformersInformation regarding installation of dry-type transformers indoors is referenced from NEC According to NEC Article , dry-type trans-formers that are completely enclosed, excluding ventilating openings, may be installed indoors without further requirements.