Section 13 — Electrical

Medium Voltage Metal Enclosed Switches (ME Switches)

IPE Engineering Practice IPE-EP-13-25-1

Document number: IPE-EP-13-25-1 · Section: 13 — Electrical

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SCOPE

This practice, including the Medium Voltage Metal Enclosed Switches (ME Switches) Data Sheets, EP 13–25–1 DS, covers the minimum requirements for assemblies of indoor and outdoor, type MEI switchgear with ratings of 4.16 KV thru 35 KV, 3 phase, 3 wire, 60 hertz, for operation on either ungrounded, low resistance or solidly grounded systems, as specified on the Data Sheet.

This Practice is appropriate for attachment to an inquiry or purchase document when accompanied by the referenced IPE Engineering Practices and completed Data Sheets.

Any deviation to this Practice shall be in accordance with the procedure given in EP 1–1–3.

REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

DEFINITIONS

Contractor – Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.

Inspector – A Inflection Point Engineering, LLC appointed engineer or inspector.

Manufacturer – The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.

Owner – Inflection Point Engineering, LLC.

Owner’s Engineer – A Inflection Point Engineering, LLC appointed engineer.

3.6 Purchaser – The party placing a direct purchase order. The Purchaser is the Owner’s designated representative.

4.0 SERVICE CONDITIONS

MEI switchgear assemblies shall perform satisfactorily when operated indoors or outdoors either intermittently or continuously in an atmosphere typical of petroleum plants. MEI Switchgear assemblies shall be suitable for use in 112F maximum ambient, –22F minimum ambient conditions, and at an altitude of 3300 feet or lower.

DESIGN, CONSTRUCTION AND MATERIALS

• Basic Construction
• Enclosures
• The enclosure design shall provide controlled access, tamper resistance, protection from ingress of rodents, insects and weeds.
• The basic enclosure material shall be 11 gauge or thicker steel sheet. The enclosure shall comply with ANSI C37.20.3.
• All structural joints and butt joints shall be welded, and the external seams shall be ground flush and smooth except where additional height or depth requires the use of fabrication splits.
• Each bay containing high–voltage components shall be a complete unit in itself, with full side sheets resulting in double–wall construction between bays.
• The base shall consist of continuous structural–steel channel extending completely around all four sides of each bay and welded or bolted at each corner.
• Doors shall be 11–gauge or thicker steel sheet and be of the bulkhead–type construction.
• Doors over 40 inches in height shall have three or more concealed galvanized or stainless steel hinges with stainless steel hinge pins. Doors 40 inches in height or less shall have two or more hinges.
• Each door shall be equipped with a stainless steel or copper free aluminum door handles. The door handle shall be pad–lockable and the door mechanism shall have a three point latch system.
• Doors providing access to interrupter switches or interrupter switches with power fuses shall be provided with a wide–view window, constructed of a mar–resistant and impact–resistant material, to facilitate checking of switch position without opening the door.
• All doors shall be provided with a sturdy, corrosion resistant self–latching door position holder.
• Door openings and openings for hinged bolted panels (and bolted panels providing access to low–voltage components) shall have resilient compression gasketing at the top and both sides to prevent water from entering the enclosure.
• Outdoor enclosures

• Outdoor enclosures shall be rain tight, corrosion resistant and in full compliance with ANSI/IEEE C37.20.3 and associated Appendix A.
• Gasket seals shall be provided at the top and side edges of adjoining bays to prevent water entry between the double walls.

• Roofs shall be weather sealed in place with suitable gasketing.
• Roofs shall be sloped to the rear (away from front and/or bus entry for transformer applications) for precipitation run–off.
• All hardware shall be corrosion resistant.
• Bus openings between bays shall be lined with neoprene channel gaskets as an additional protection against entrance of water, unless labyrinthine metal rain shields are provided between adjacent bays.
• Painting: The switchgear enclosures shall be cleaned, primed and painted with the Manufacturer’s standard finish coat of paint. The Manufacturer shall supply one quart of matching paint per assembly for field “touch–up” after installation. Paint shall be in aerosol cans with non–CFC propellant and supplied with MSDS sheets.
• Equipment Identification/Nameplates
• Externally visible permanent nameplates shall be provided identifying each instrument, instrument switch, meter, relay, control switch, indicating light, potential transformer compartment and circuit breaker compartment. The identification shall be the same as on the drawings. Nameplates shall be either stainless steel or lamicod plastic tags, white with black letter (3/8 inch high minimum letter size) secured with screws or re–useable plastic rivets, as specified by the Owner.
• Each MEI compartment shall have a corrosion resistant nameplate that shall include the Manufacturer’s shop order number, unit serial number, switch load ampacity rating, interrupting ampere, nominal voltage class and momentary ampere.
• Equipment and terminal blocks within the compartments shall be suitably identified and shall have the same identification as on the drawings. Identification shall be made with lamicoid tags, white with black letters and secured with glue, screws or equivalent.
• Bus phasing as well as protective relays shall be laid out and labeled on white lamicoid tags with black letters in accordance with ANSI C37 as follows: A, B and C phase arranged from front to back, top to bottom, left to right, as viewed from the main switching device operating mechanism side.
• Provisions for Handling Storage and Field Erection
• Each “shipping section” shall be furnished with permanent or removable steel channel base plates that will permit using pipe rollers or dollies without damaging the frame steel of the equipment.
• Each “shipping section” of stationary structures shall be furnished with removable lifting angles and/or plates suitable for crane hooks or slings so lifting and erection can be done without danger of dropping or damaging the equipment.
• Equipment shall be packed, crated and rigidly braced to protect it from the weather and damage during outdoor storage.

• When specified on the Data Sheets, provisions shall be made for the customer to energize the space heaters of each shipping section during storage at the job site. The electrical connection point shall be readily available without uncrating the equipment and shall be clearly identified as to location and the electrical service requirement.
• All equipment shall be furnished assembled to the extent practicable, and for easy field assembly, where factory assembly is not practicable. All nuts, bolts, gaskets and hardware should be furnished together with complete instructions for field assembly. The Manufacturer shall minimize unassembled equipment.
• Space Heaters: Space heaters and thermostats shall be provided as specified on the Data Sheet.
• Surge suppression shall be provided, when specified on the Data Sheet. Arrestors shall be station class zinc oxide, or metal oxide type.
• Wiring
• Control wiring
• Stranded #14 AWG (minimum) copper conductors covered with 600V XHHW, XHHW–2, SIS or MTW insulation shall be used.
• Compression type terminal lugs with insulated sleeves and spade tongue type (except ring tongue type on all CT circuits) shall be used.
• Terminal blocks shall be suitable for holding spade and ring type lugs. Blocks shall be rated 20 amp, 600V. All spare (unused) terminal spaces shall have screws inserted.
• The terminal blocks for the first termination of current transformers shall be of the shorting type. The terminal block shall be located in the switchgear low voltage compartment and shall be accessible from the front of the switchgear without exposure to energized high voltage equipment.
• The ground connection for current transformers shall be made at the first terminal block, and not at the CT.
• Provide adequate space for the customer’s wiring.
• Control/metering switch wiring shall be brought out to terminals, so that it may be easily jumpered for test purposes.
• Low voltage metering wires shall be armored or enclosed in metal troughs where they pass through primary compartments.
• Power Cable Wiring
• Line and load side copper power bus or feeder cables shall enter/exit the MEI switchgear as indicated on the Data Sheet.
• Power cable racking support shall be provided for all power cable inside MEI equipment.

• Space, mounting and electrical connection provisions shall be provided in both incoming (where applicable) and outgoing cubicles for making stress cones on shielded power cable.
• Metering and Protective Relaying
• Metering
• Metering (type and quantity) shall be as shown on the drawings and/or Data Sheets.
• Each incoming main and bus section in the switchgear shall be provided with a voltmeter and a voltmeter switch to determine the incoming line voltage and individual bus voltage on each phase. The voltmeter switch shall have an “off” position.
• Each feeder switch in the line–up shall be provided with an ammeter and an ammeter switch to determine the load current in each phase. The ammeter switch shall have an “off” position.
• Analog meters, when provided shall be switchboard type, taut band, with a minimum 250 scale.
• If remote ammeters are specified, they shall be supplied from current transducers.
• Potential transformer secondary leads supplying remote meters shall be individually fused at the potential transformer.
• Protective Relays
• Fault tripping relays shall trip via a manual re–settable lockout relay. The lockout relay shall be mounted on the front of the MEI switchgear.
• Lockout relays shall have a white “push to test” light to indicate a lockout relay operation/trip. The white light shall be centered on the lockout relay handle and located above the relay.
• Protective relays with appropriate CT’s/sensors shall be supplied, as indicated on the Data Sheet.
• Instrument and Control Transformers
• Current Transformers
• Current transformers shall comply with ANSI C57.13.
• Current transformers shall have 5 ampere secondaries.
• Accuracies shall be in accordance with ANSI Standards for the metering and relay applications shown on the drawings. 1200/5 and larger current transformers shall be C200 class or higher.
• Current transformers shall be mounted in the MEI switchgear stationary part.
• Potential Transformers
• Potential transformers shall comply with ANSI C57.13.
• Potential transformers shall be mounted in a separate compartment or superstructure.

• Potential transformers may either be fixed or mounted in a draw out drawer. In all cases the potential transformer fuses shall be mounted in a drawout drawer. The transformers and (or high side fuses) shall be mounted on a drawout mechanism that is linked to the potential transformer compartment door. When the compartment door is closed, the transformers shall be completely isolated and the primary and secondary disconnect contacts engaged with their respective stationary contacts to complete the circuit. On opening the door, the transformer and/or high side fuses shall be automatically withdrawn, breaking the primary connection, and for drawout potential transformers the secondary connections and grounding the primary P.T. connections. The primary connection shall be disconnected before the transformer or its primary fuses become accessible. A similar arrangement shall be provided for the primary fuses of control power transformers.
• Transformers shall be protected with current–limiting primary fuses, and shall be designed to withstand the basic impulse level of the MEI switchgear assembly.
• Transformers shall have 120 volt secondaries and ANSI accuracies and burden capabilities for the duty indicated on the drawings and/or Data Sheet.
• Interrupter Switches
• Interrupter switches shall have a two–time duty–cycle fault–closing rating equal to or exceeding the short–circuit rating of the integrated switchgear assembly.
• MEI interrupter switches shall be in compliance with the applicable portions of ANSI/IEEE standards (C37.30 through C37.35).
• Interrupter switches shall be operated by means of an externally mounted, non–removable handle. The handle shall have provisions for padlocking in the open position only. Interrupter switches intended for power operation shall be operated by means of a switch operator expressly designed to be compatible with the interrupter switch.
• Interrupter switches shall utilize a quick–make, quick–break mechanism installed by the switch Manufacturer, which shall swiftly and positively open and close the interrupter switch independent of the switch handle or switch operator operating speed.
• Interrupter switches shall be completely assembled on a single rigid mounting frame.
• Interrupter switch contacts shall be of silver–to–silver construction, for optimum current transfer, and shall be backed up by stainless steel springs to provide constant high contact pressure.
• Interrupter switches shall be provided with a single blade per phase for circuit closing including fault closing, continuous current carrying, and circuit interrupting. No spring–loaded auxiliary blades shall be permitted.
• Circuit interruption shall be accomplished by use of an interrupting unit that is positively and inherently sequenced with the blade position. It shall not be possible for the blade and interrupting unit to get out of sequence. Circuit interruption shall take place completely within the interrupting unit, with no external arc or flame. Any exhaust shall be vented in a controlled manner through a labyrinthine muffler or a de–ionizing vent.
• Power Fuses
• Power fuses shall be of the solid material expulsion type and shall utilize refill–unit–and–holder or fuse–unit–and–end–fitting construction.

• For MEI switchgear rated up through 270 MVA at 4.16 KV, 600 MVA at 13.8 KV, 860 MVA at 25 KV, and 1000 MVA at 34.5 KV, fuse mountings shall be the disconnect style. Non–disconnect style fuse mountings shall be permitted only where higher ratings are required. All power fuses shall be provided with grounding provisions, as a minimum, on the load side of the fuses.
• Fusible elements shall be non–aging and non–damageable so that it is unnecessary to replace unblown companion fuses on suspicion of damage following a fuse operation.
• Fusible elements for refill or fuse units, rated 10 amperes or larger, shall be constructed and designed to avoid mechanical damage due to stresses from surges.
• Each refill unit or fuse unit rated 300 amperes or less shall have a single fusible element to eliminate the possibility of unequal current sharing in parallel current paths.
• Power fuses shall have minimum–melting time–current characteristics which are permanently accurate to within a total of 10% in terms of current. Time–current characteristics shall be available which will permit coordination with protective relays, automatic circuit re–closers, and other fuses.
• Power fuses shall be capable of detecting and interrupting all faults (down to minimum melting current), under all realistic conditions of circuitry, with line–to–line or line–to–ground voltage across the power fuse, and shall be capable of handling the full range of transient recovery voltage severity associated with these faults.
• All arcing accompanying power fuse operation shall be contained within the fuse, and all arc products and gases evolved during fuse operation shall be vented through exhaust control devices that shall effectively control fuse exhaust.
• Power fuses shall be equipped with blown–fuse indication that shall provide visible evidence of fuse operation while installed in the fuse mounting.
• Each bay containing power fuses shall be equipped with grounding provisions on the ground bus.
• MEI Power Bus
• MEI switchgear and bus extensions shall be copper with TIN plated joints.
• Unless specified otherwise on the Data Sheet, buses shall be completely isolated, insulated and fully clad with a flame retardant, non–hydroscopic, high dielectric insulation. Joints and terminations shall be insulated using boots and/or tapping.
• All outdoor bus 4.16KV to 34.5KV, and indoor buses rated 15 KV and above shall have non– hygroscopic, track resistant, high strength porcelain sleeves and supports. Indoor buses rated below 15 KV shall have non–hygroscopic track resistant high strength porcelain or cycloaliphatic epoxy sleeves and supports.
• Buses shall be mechanically braced for the symmetrical short circuit closing and latching rating of the largest rated MVA switch in each assembly.
• The bus size of the main horizontal buses shall be continuous throughout its length and designed to carry the full load current of the largest switch in the assembly.
• MEI Flange Connected to H.V. Side of Transformers

• The MEI load bus location, power bus interconnection point and any switch flange requirements shall be coordinated with the transformer Manufacturer with supply responsibility as indicated on the Data Sheet.
• Flexible copper connectors required to connect the MEI switchgear to the transformer high voltage bushings shall be coordinated, designed and supplied by the party identified on the Data Sheet.
• Insulated power cable shall not be used as the connector between the MEI switchgear and the transformer.
• MEI as Part of a Medium Voltage Motor Control Center (E–2 Controller) Lineup
• When enclosures/cubicles housing interrupter switches (load break, non–load break, fused or non–fused) are inserted in an E–2 controller lineup, the construction of the controllers and switch enclosers shall be fully preserved.
• Connection of the MEI switchgear copper bus to the controller copper bus shall be with solid copper bus and flexible copper connector. All connection joints shall be TIN plated and all bus joints insulated per paragraph 5.7.2. Insulated power cable shall not be used as the connector, and is not considered an acceptable “flexible connector”.
• The medium voltage motor control center Manufacturer shall be responsible for the MEI switchgear/MCC cubicle compatibility as well as the power bus connections, unless specified otherwise.
• Ground Bus

A 1/4” x 2” or larger, copper ground bus shall be located in the bottom front of the equipment compartment and run the entire length of the switchgear, affording connecting to all units and equipped with solderless #2/0 cable connectors at each end.

• Key Interlocks

Key interlocks shall be provided in the quantities and locations as specified on the Data Sheet and/or attached drawings.

• Electrically Operated MEI Switchgear
• Control power voltage and source shall be as indicated on the Data Sheet.
• Close and trip circuits on each unit/switch shall be separately fused.
• Fuse blocks shall have dead front pullout type holders.
• MEI switchgear control power circuits shall be segregated as follows:
• Each main and tie shall have the source provided by a separate (dedicated) circuit.
• Each power bus shall have the source provided by a separate (dedicated) circuit.
• Open/close control shall be via local MEI switchgear front panel mounted NEMA rated, oil tight, pushbuttons suitable for the application. Provisions for the Owner’s remote open/close pushbutton control shall be provided.

TESTING AND INSPECTION

• Testing

• All tests shall be done at the Manufacturer’s plant, unless approved otherwise by the Owner.
• Testing shall be done on completely assembled equipment, interconnection wiring shall be via actual wiring harness supplies with the job and not temporary test jumpers.
• Factory tests, unless specified otherwise, shall be done using rated voltages and/or current.
• Testing shall include the following:
• Standard ANSI production tests.
• High potential tests on main buses, interrupter switches, control power buses, and control wiring.
• Operational test of each interrupter switch. Control wiring shall be energized and electrically operated devices shall be operated in both normal and test positions. Switches shall also be manually operated.
• All current transformers and associated secondary circuits shall be verified via primary current. Verification of metering and relay current circuit operation shall be accomplished via primary current and voltage (low voltage, high current source is acceptable as the current source).
• Operation of key and electrical interlock systems shall be tested.
• Electrical resistance of current path test.
• All current transformer ratios and polarities shall be verified per ANSI 57.13.1. The ratio shall be verified per the voltage or current method. Polarity shall be determined by the AC voltage test method. The DC voltage test method shall not be used to verify CT polarity.
• Operation of space heaters and thermostats shall be tested with the heaters energized at rated voltage.
• Witness Testing

When witness testing is specified, the Owner’s Engineer shall witness the complete testing of all items outlined in Section 6.1.

DRAWINGS AND DATA REQUIREMENTS

All drawings provided for this equipment shall show equipment as specified and ordered. Typical drawings are not acceptable, unless they are revised to show only the equipment being furnished. Drawings shall be supplied in the quantities and format shown on the Data Sheets.

• Information to be Supplied with Quotation
• Specific listing of any exceptions to those requirements specified.
• Equipment or features included but not necessarily specified.
• Sketches showing:
• Equipment layout/orientation with dimensions.
• Proposed three line and elementary diagrams.
• Weight of equipment and recommended lifting methods.
• Number of Days of Field Service allowed (when specified) and Cost Per Day.
• Complete lists and descriptive data of all equipment and accessories proposed shall be included and any components not manufactured by the Seller submitting the proposal shall be so noted as well as the Manufacturer and type proposed.

• Quote must be for equipment as specified, including any requested alternatives. Manufacturer recommended alternatives shall be provided with associated add/deducts.
• Itemized list of unassembled equipment (see para 5.1.3.5).
• Cost for witness testing, if specified.
• Information to be Submitted for IPE Approval after Receipt of Order Complete
• Structural Drawings showing:
• Arrangements and front panel layouts.
• Dimensional plan and elevation, front view, and other elevation views if pertinent.
• Conduit entrance locations and dimensions for both top and bottom entrance.
• Bus bar locations and configurations.
• Incoming and outgoing power cable terminator positions.
• Purchaser’s wiring terminal block locations, and all other terminal block locations.
• Arrestor location.
• Identify all items that will require field assembly.
• Anchor bolt locations.
• Grounding connections.
• Weight of equipment.
• Approved lifting, handling methods.
• Three Line Diagrams: Three line diagram shall show all:
• Instrument and potential transformers.
• Meter and meter switches.
• Protective relays.
• Other pertinent devices.
• Detailed Connection (Wiring) Diagrams showing:
• All wiring within each unit.
• All interconnecting wiring between units.
• Identification of all terminal blocks.
• Clear identification, by some distinguishing method, of all wiring that is to be installed by the Owner. This shall include spare auxiliary contacts and relay contacts which shall be wired to terminal blocks for future use.
• Tabular wiring diagrams are not acceptable. Wiring diagrams as well as wire marks, devices and terminal blocks shall use a destination address identification system.
• Elementary diagrams for electrically operated switches.
• Detailed listing of all nameplates.
• Within 60 days of receipt of order, provide a priced list of recommended spare parts for the equipment as ordered (see paragraph 8.0).
• Certified Information to be Supplied
• All information requested in paragraph 7.2.
• Installation, Maintenance and Operating Instructions: Installation, Maintenance and Operating Instructions shall cover all of the equipment furnished including all protective device curves.
• Material List: A material list shall be furnished listing the quantity, rating, type and Manufacturer’s catalog number of all equipment in each unit.

• Test Reports for testing outlined in Section 6.1.
• Spare Parts Listing.
• When specified on the Data Sheet, certified information shall be supplied as outlined in Table 1.

SPARE PARTS

A complete spare parts recommendation based on the total purchase order is required within 60 days after the Manufacturer receives the purchase order. Spare parts recommendations shall include:

• A complete spare parts list, including parts locations diagrams or drawings.
• Lists of priced spare parts as recommended by the Manufacturer to be on hand during start–up and the first year’s operation.

SHIPPING

• “Preparation for Shipment” shall be in accordance with the Manufacturer’s standard, unless otherwise noted. The Manufacturer shall be solely responsible for the adequacy of the “Preparation for Shipment” provisions employed in respect of material and application, to provide materials and application, to provide materials to their destination in ex–works conditions when handled by commercial carrier systems.
• When shipped separately, power fuses shall be individually crated and tagged with their rating and model number.
• Each “shipping section” of stationary structures shall be provided with a permanently attached, readily visible, identification tag.
• Space heaters, when provided, shall be wired to a terminal block that is accessible for connection to the Owner’s temporary power supply without having to uncrate the switchgear for space heat energization during storage. The terminal block shall be clearly marked as to function, voltage and load requirements.

10.0 TABLES

TABLE 1

CERTIFIED INFORMATION REQUIRED IN ELECTRONIC FORMAT FOR MEDIUM VOLTAGE METAL ENCLOSED SWITCHES (ME SWITCHES)

PER EP 13–25–1

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