AAC_SPEC_543005[1]

AAC_SPEC_54300503 APPROVED 5 November 1999 Page 1 of 19

Anglo Technical Division accepts no liability for any damage whatsoever that may result from the use of this material or the information contained therein, irrespective of the cause and quantum thereof.

AAC SPECIFICATION 543005

ISSUE 3

MOBILE MINI SUB-STATION FOR UNDERGROUND RETICULATION COPYRIGHT

CONTENTS PAGE

1 SCOPE 2

2 TECHNICAL REQUIREMENTS TO BE SPECIFIED BY THE ENGINEER 2

3 DEFINITIONS 2

4 REQUIREMENTS 2 4.1 GENERAL 2 4.2 CORROSION PROTECTION 4 4.3 MEDIUM VOLTAGE EQUIPMENT 4 4.4 LOW VOLTAGE EQUIPMENT 5 4.5 CONTROL AND INSTRUMENT WIRING 6 4.6 TRANSFORMER COMPARTMENT 6 4.7 NEUTRAL EARTHING RESISTOR 8 4.8 NEUTRAL EARTH RESISTANCE MONITOR 8 4.9 ADIT SENSITIVE EARTH FAULT RELAY 8 4.10 NOTICE BOARDS 8 5 QUALITY ASSURANCE PROVISIONS 9

APPENDIX A : RELATED DOCUMENTS 10

APPENDIX B : RECORD OF AMENDMENTS 10

APPENDIX C : DATA SHEET TO BE COMPLETED BY THE COMPANY: 11

APPENDIX D : OUTLINE OF MOBILE MINISUB 16

APPENDIX E : CONNECTION DIAGRAM OF MINISUB (MOBILE) 18




ISSUE 3


1 SCOPE

This specification covers the manufacture, factory testing and delivery of mobile mini sub-stations for underground reticulation on gold mines.

2 TECHNICAL REQUIREMENTS TO BE SPECIFIED BY THE ENGINEER

Title, reference and issue of this specification.

Detail drawings of the following: • Chassis • Transformer core supports • Tap change switch

3 DEFINITIONS

For the purpose of this specification, the following definitions shall apply: -

APPROVED : Approved by the Engineer in writing

BS : British Standard

SABS : South African Bureau of Standards

IEC : International Electrotechnical Commission

MEDIUM VOLTAGE (MV) : 1000 Volts or higher

LOW VOLTAGE (LV) : Below 1000 Volts

The following terms are defined in the General Conditions of Contract:

AAC, Company, Contractor, Engineer.

4 REQUIREMENTS

4.1 GENERAL

The basic design of the mobile mini sub-station shall be in accordance with outline drawing No.Y2341 and shall consist of a welded steel unit of 5 mm gauge, except where specified, on a robust fabricated chassis.

4.1.1 Construction: The unit shall be a totally enclosed vermin type, well ventilated and designed so that easy access can be obtained to all equipment for installation, maintenance and replacement purposes.

4.1.2 Compartments: The mobile mini sub-station shall be constructed in three separate compartments: a. Medium voltage b. Transformer




ISSUE 3


c. Low voltage

All three sections shall be bolted or welded to a common undercarriage to form a compact unit.

4.1.3 Roof covering: The unit shall be provided with a drip proof bolt on roof, (3,2 mm thick steel to SABS 1431 grade 300WA) covering the entire sub-station.

4.1.4 Lifting brackets: Four box type non-removable lifting brackets or lugs shall be provided for off-loading and general handling, suitably mounted on the unit to prevent: a. The unit becoming top heavy when lifted. b. Damage to the unit when rope slings are used during the lifting operation.

Additional lifting facilities shall be provided and Approved before fabrication commences. Slinging brackets shall be bolted on as shown on drawing Y2341.

4.1.5 Towing brackets: The unit shall be provided with two robust towing brackets designed to allow for the fitting of standard cast steel type buffers. See the data sheet for height and type of buffer.

A drawbar shall be fitted as shown on drawing Y2341.

4.1.6 Wheels: If wheels are to be fitted they shall be of the type specified on the data sheet. The Contractor shall supply the wheel manufacturer with the total mass of the unit.

4.1.7 Overall dimensions: The maximum height of unit from crown of rail shall not exceed 1550 mm, width 1300 mm, length 2400 mm buffer to buffer.

4.1.8 Medium voltage access: Access to the MV section shall be through a weatherproof hinged door at the end of the compartment. The opening dimensions of which shall allow the operator an unobstructed view of all switch operations, earth blade positions, live line indicators etc.

The transparent earthing indicator bottles shall be clearly visible when the earth switch is in the closed or open position by means of a reflective angle stainless steel plate behind and above the bottles.

The switch shall be positioned to ensure that all switch operations can be carried out using the standard operating handles provided by the switchgear manufacturer.

Bullet type hinges (12mm x 100mm) shall be fitted on the compartment door. There shall be at least three hinges per door.

The fixings and fastenings of the side doors shall only be unlocked from inside the compartment through the end door which shall be provided with a handle and a catch suitable for padlocking from outside.

4.1.9 Cable access: Cable access to the MV section shall be: i. directly below, or ii. from the side, or iii. at an angle below the cable termination of the MV switch.




ISSUE 3


The aperture necessary for the cable entry shall be closed with a removable split plate, the split plate being cut on site to the diameter of the incoming feeder. Dry type MV cable termination to be used.

4.1.10 Low voltage access: Access to the LV section shall be through weatherproof hinged (bullet type, at least 3 hinges per door) double doors at the end of the compartment of suitable dimensions and be provided with a handle and catch for padlocking from outside.

4.1.11 Cover plates: A removable inner split plate shall be provided for covering of all live LV parts. Toggles of the MCBs shall protrude through the upper half of the plate and the lower half to provide access to the lower portion of the MCB for connecting purposes. Holes shall be left in any plates covering any earth leakage relays to enable the reset button to the operable with the doors open.

4.1.12 LV cable glands: The bottom of the LV compartment shall be of steel plate set at an angle of 45° ± 2°. Onto this plate shall be mounted removable gland plates suitable for the reception of the cable glands specified in the data sheet.

4.1.13 Handling: The unit shall be designed to withstand robust handling and shall be supported to permit transportation at a position of 90° to the horizontal.

4.1.14 Earthing: An earth bar of minimum dimensions 25mm x 3mm shall bond the housing - MV switch - transformer and continue through to the MV compartment with terminal studs for earthing of outgoing LV feeders and the transformer neutral via the earth fault limiting resistors installed.

A separate section for protection relays shall be provided on the earth bar. (To prevent inadherent disconnection of the protection circuit when cables are installed or disconnected).

4.2 CORROSION PROTECTION

Corrosion protection shall be in accordance with the requirements of AAC 164/50 and CPS 122. The finish coat shall be orange code B26 to SABS 1091. Both ends shall be a black background with diagonal yellow stripes code B49 to SABS 1091

4.3 MEDIUM VOLTAGE EQUIPMENT

4.3.1 Rating: All equipment in the MV compartment shall be rated for 20 kA at 6600V or 18 kA at 11000V.

4.3.2 Switchgear: The insulation shall be SF6. The switchgear shall comply with the following: a. Arrangement of the switchgear shall be suitable for mounting in the mobile mini sub-

station, considering the maximum dimensions in Clause 4.1.7.

The support bracket on the ring main unit shall be a 3-way angle iron type on both sides of the ring main unit. Top support brackets shall be fitted to both sides of the ring main unit, fixing it to the mini sub-station side walls.

b. The type of switchgear shall be as selected in the data sheet. It shall comprise fault make load break switches, fused fault make load break switches or circuit breakers.




ISSUE 3


c. Neon indicators for "Cable Alive" indication with capacitive dividers shall be provided.

d. Integral earthing shall be provided. e. A visual inspection aperture shall be provided so that the following positions of

contacts of the isolating devices can be clearly seen: i ON position

ii OFF position

iii EARTH position.

f. A cable box shall be provided for paper (PILC) or cross linked polyethylene (XLPE) insulated three core cable, as indicated in the data sheet. The cable shall be of cross section 95 mm² (diameter ± 60 mm). Should clearance from the gland plate to the top of rail be less than 900 mm, an angular cable box shall be provided. The cable box shall be suitable for side entry or on the bottom by means of an angled entry.

g. All cable gland plates shall be removable and left for drilling on site, unless specified for drilling in the data sheets.

4.3.3 Fuses: Fuses shall be striker pin type for protecting the primary (MV) side of the transformer.

Fuses shall be fault rated for 20 kA at 6600V or 18 kA at 11000V as necessary and sized as in the data sheet. Three spare fuses mounted in clips in the HT compartment shall be supplied with each mini sub-station.

4.3.4 Transformer MV connections: Suitable lengths of 11/6,35 or 6,6/3,8 kV single core copper conductor PVC/PCV or PVC/XLPE insulated shall be used as "flexible" connections between the outgoing terminals of the fuse switch or circuit breaker and the MV terminals of the transformer. The terminations shall be shrouded and heat shrink elbows are permissible.

4.3.5 MV cable glands: The type of cable glands provided on the cable connection shall be as indicated in the data sheet.

4.4 LOW VOLTAGE EQUIPMENT

All equipment in the LV compartment shall be rated for a fault level of not less than that specified in the data sheet:

4.4.1 Standard

3 x 600A - Copper busbars

1 x voltmeter 0-600V Elima 96 x 96 mm to indicate LV busbar voltage

3 x fuses 2 Amp HRC for voltmeter protection

1 x voltmeter selector switch

1 x auxiliary transformer 550V/110V, 500VA, 1 phase




ISSUE 3


2 x 10A HRC fuses for auxiliary transformer primary protection

3 x 600/5 Amp Class 1 CT Epiring wired to the red, yellow and blue phase and to indicate the total LV load

3 x Ammeter Elima Type FB1A 0-600A 96 x 96 mm for operation from 600/5 C.T.s (maximum demand type)

1 x EPC designed CT for Adit protection (for rating see data sheet)

1 x 5 amp EPC Type Adit earth fault relay fed from C.T.

4 x 27 ohm earth resistors each shall be continuously rated for 10 Amperes for the neutral earthing connected in series paralled to give a 27 ohm resistance unless otherwise specified.

1 x neutral earthing resistance monitor type Nerm 500, including indication

4.4.2 Outgoing feeders: The ratings and quantities of the following equipment shall be specified in the data sheet: i. Approved MCBs, complete with direct acting o/c protection and fitted with 500V

shunt trip coil. ii. Earth leakage relay iii. C T Epiring wired to the yellow phase iv. Ammeter Elima type FB 1A 96 x 96 mm fed from the C.T. v. Engraved labels shall be fitted above each outgoing circuit breaker.

• Circuit breaker No1 - Outgoing feeder No 1

• Circuit breaker No 2 - Outgoing feeder No 2

vi. The letters on the labels shall be at least 15mm high. vii. The labels shall be fitted by means of steel rivets. viii. All fuses, instruments, etc, shall be labelled in the same way.

4.5 CONTROL AND INSTRUMENT WIRING

All wiring shall be 7 strand 2,5 mm² grey or black, numbered at each end and adequately supported by either cleats or tube. (See drawing Y2342)

4.6 TRANSFORMER COMPARTMENT

The transformer shall comply with the latest edition of AAC 514/3 for oil filled units or AAC 514/5 for dry type units. The transformer shall be oil filled, sealed, or alternatively, of the dry type.

The tank cover for oil filled sealed units shall be bolted to the tank.

4.6.1 Electrical specifications

Capacity kVA (see data sheet)




ISSUE 3


Ratio (see data sheet)

Frequency 50 Hz

Cooling ONAN

Number of phases 3

Vector group DYN 11

Off load tap change ± 10%, ± 5%, 0%

The tap change switch shall have padlock facilities. An engraved riveted label shall be fitted next to the tap switch reading: “Only operate when the primary side of the transformer is isolated”

Impedance

- Up to 500 kVA 4,0 - 5,0%

- Up to 630 kVA 4,5 - 5,5%

Temperature rise

- Windings (by resistance) 65°C (ambient 40°C)

- Top Oil (by resistance) 60°C (ambient 40°C)

Losses

No Load Load

kVA Rating Loss (W) Loss (W)

200 520 2 700

250 620 3 200

315 720 3 800

400 910 4 500

500 1 100 5 400

630 1 300 6 400

Total loss deviation 10% declared

Total component loss deviation 15% declared




ISSUE 3


The transformer shall be designed to withstand mechanical or electrical damage from a short circuit connected directly to its secondary terminals and with nominal 3-phase volts applied to the primary terminals for 1 second. Type test certificates of the transformer tested shall be provided and all essential dimensions etc and equipment used in the transformer shall be specified for use in subsequent units.

This test and the stripping of the transformer after testing shall be witnessed by the Engineer.

4.6.2 Fittings: Rating and diagram plate (order number to be indicated on duty plate).

Oil level gauge.

Earth terminal.

Pressure release valve.

4.6.3 Transformer neutral: Transformer neutral shall be wired with 16mm² PVC/PVC insulated copper conductor 600/1000V grade through the EPC CT designed for Adit protection, through the earth resistor to earth.

4.6.4 Busbar clearances: Busbar clearances shall be in accordance with BS 159 Standard Class B. All busbar, transformer connections etc, shall be properly insulated.

4.7 NEUTRAL EARTHING RESISTOR

Four 27 ohm suitably designed and fabricated resistors shall be provided each being continuously rated for 5000 watts to carry a current of 10 amperes continuously with a temperature rise not exceeding 375o C.

The resistors shall be made from chrome, iron, aluminium alloy resistance wire wound onto a grooved and fluted ceramic body and shall be housed, mounted and connected by the movement of a set of retained links so that a maximum earth fault current of 10 amperes can be selected.

4.8 NEUTRAL EARTH RESISTANCE MONITOR

The neutral earth resistance monitor type NERM with indicator, shall have its main connection between the transformer neutral terminal and the earth busbar in the LV compartment and the trip circuit connected so that any increase or decrease in neutral earth resistance will trip the MV circuit breaker controlling the transformer primary winding.

4.9 ADIT SENSITIVE EARTH FAULT RELAY

The earth fault sensing element of the relay shall consist of an encapsulated current transformer (see data sheet for rating) connected between the transformer neutral terminal to the "top" end of the neutral earthing resistance. The 5 ampere ADIT relay shall have its current element set at 16% and its time element at 2,5 seconds.

4.10 NOTICE BOARDS

The following notice boards shall be fitted to the sub-station on the outside of both of the longer sides of the mini sub-station.




ISSUE 3


a. Danger sign (lightning bolt – SABS WW7) Extra High Voltage, secured to the outside of the MV panel door.

b Water extinguisher prohibition sign (SABS PV4) c. Notice prohibiting unauthorised persons from handling or interfering with electrical

apparatus. d. A notice containing the procedure in case of fire on either side of the mini sub-

station. e. A notice giving directions for the resuscitation of persons suffering from the effects

of electrical shock on either side of the mini sub-station. (SABS EC14) f. A notice prohibiting unauthorised entrance to the mini sub-station. g. Electrical drawing fixed to inside of both HT and LT doors. h. Fit an engraved brass label (riveted), mounted on the inside of the MV ring main unit

compartment reading:

Ensure that the feeder feeding this mini sub-station is isolated and withdrawn.

In the case where this mini sub-station is fed from a previous mini sub-station, this feeder shall be isolated and earthed at the previous mini sub-station.

Check that the neon indication is off.

The earthing switch shall now be switched to the earth position – cable side.

Test with Approved MV phasing sticks that the supply to this mini sub-station is isolated - dead.

Maintenance or repairs on this mini sub-station can now take place.

NOTE: The above brass label shall be engraved in 15mm high lettering.

5 QUALITY ASSURANCE PROVISIONS

AAC QAP 100 shall apply.




ISSUE 3


APPENDIX A : RELATED DOCUMENTS

AAC Drawings : Y2342 – Connection diagram of mobile mini sub-station

Y2341 – Outline of mobile mini sub-station

AAC 164/50 : Corrosion protection of steelwork with coatings

AAC 514/3 : Oil filled distribution transformers

AAC 514/5 : Dry type distribution transformers

BS 159 : Specification for high-voltage busbars and busbar connections

CPS 122 : MIO epoxy and acrylic finish

SABS 1091 : National colour standards for paint

APPENDIX B : RECORD OF AMENDMENTS

Issue 2 : Revised to standard format.

Notice board requirements amended.

Encapsulated CT for ADIT added.

Integral earthing requirements included.

Issue 3 : Clause 6 deleted as Test and Inspection is covered in AAC QAP 100

Appendix D and E added

(B. Jones 199-11-03)




ISSUE 3


APPENDIX C : DATA SHEET TO BE COMPLETED BY THE COMPANY:

Put x in appropriate block

1. RATINGS

Transformer 11 000 6 600

Primary voltage (volt)

Transformer Secondary voltage (volt)

550

Transformer rating (kVA) 630 500 400 315 250 300

2. BUFFERS

Type Mine Steel Cast Steel

Supply buffers Yes No

Height – crown of rail to centre of buffer (mm) 290 320 390

3. WHEELS see section 2.1.6

Type No wheels to be fitted

Roxor cannon

Wheel diameter (mm) 230 305

Rail gauge (mm) 610 762 914




ISSUE 3


4. M.V. SWITCHGEAR

4.1 Ring main unit with circuit breaker on transformer T – off feeder

Use VIP – 12 protection relay Merlin Gerin – type RM6 – 2I x 1B – (IDI)

Other (specify)

OR

4.2 Ring main unit with fuse switch on transformer T – off feeder

Merlin Gerin – type RM6 – 2I x 1Q (IQI)

Other (specify)

5. M.V. FUSE RATINGS

VOLTAGE TRANSFORMER RATING

DIN TYPE QTY GEC TYPE QTY

11 kV 200 kVA 25A 25A

250 kVA 25A 32A

315 kVA 40A 40A

400 kVA 40A 45A

500 kVA 40A 50A

630 kVA 63A 63A

6,6 kV 200 kVA 40A 40A

250 kVA 40A 50A

315 kVA 40A 63A

400 kVA 63A 80A

500 kVA 63A 100A

630 kVA 80A 100A




ISSUE 3


6. M.V.CABLE GLANDS

Rand mines (PILC cables)

Compression gland (XLPE cables)

Clampblock (XLPE cables)

Captive cone gland (PILC cables)

7. LOW VOLTAGE EQUIPMENT (OUTGOING FEEDERS)

7.1 If Mitsubishi circuit breakers are to be used then arc barriers shall be used on the top and bottom of the CB’s

7.2 Fault Level Rating

18kA 35kA

7.3 18ka Breaker Selections

Qty Manufacturer Fame Size Rating A Shunt Trip Thermal Magnetics

Mitsubishi NF-100SPA 50 Yes Fixed Fixed




7.4 35kA Breaker Selections

Qty Manufacturer Fame Size Rating A Shunt Trip Thermal Magnetics

Mitsubishi NF100SHA 50 Yes Fixed Fixed

Mitsubishi NF100SHA 100 Yes Fixed Fixed

Mitsubishi NF400SHA 400 Yes Adjustable Adjustable




ISSUE 3


7.5 Earth Leakage Relays

250 mA Instantaneous MS1 earth leakage relay

500 mA Instantaneous MS1 earth leakage relay

375 mA EPC curve 1 Elsec relay with Transcore

500 mA EPC curve 2 Elsec relay with Transcore

100/5 CT Epiring Class 3




Max demand ammeter 100/5 Elima type FB IA 0-100A 96 x 96mm







ISSUE 3


8. L.V. CABLE GLANDS

SM

COMPRESSION

EMES No. D3

EMES No. B4

Note: Gland plates shall be drilled to size as specified. If unspecified then they should not be drilled.

9. ADIT EARTH FAULT RELAY

Current transformer ratio

10/5 50/5




ISSUE 3


APPENDIX D : OUTLINE OF MOBILE MINISUB




ISSUE 3





ISSUE 3


APPENDIX E : CONNECTION DIAGRAM OF MINISUB (MOBILE)




ISSUE 3


Documents

AAC_SPEC_543005[1]