SUB – STATIONS

The supply voltage will be either 33KV or 11KV. The breaking capacity shall be 1500MVA and 750MVA respectively. If the power required is more than 4MVA or there is no 11KV supply from the national network a 33KV to 11KV or 33KV to 400V station should be supplied and erected according to the state organization of electricity requirements and specifications and the contractor is responsible to get their approval for that.

1) 11/0.400 KV Sub Stations

The Contractor shall supply, install and test the following equipment for each sub – station, The Contractor may separate the power supply for the low lift pump house as well as the L.T. switchboard (with a typical sub-station) and build a suitable building for the transformer and switchgear (if required). The same shall be applicable for Boosting Stations.

a) Take - off Points

Consist of 2 x 10m tubular steel poles, brackets, pin insulators, lightning arrestors, hand operated three pole H.T. link switch, H.T. link fuses of the suitable rating, cable boxes and H.T. cables (XLPE).

The take - off points will be fixed near the guard room. In case of 33KV sub-station this will be eliminated and it will be connected directly from sub-station to H.T. switchboard.

b) H.T. Switchboard

The switchboard shall comprise five No. panels each housing an automatic CB of the draw out type with skeleton compartment for future extension. The circuit breaker shall be according to BS 116 latest Edition having breaking capacity 750MVA at 11KV and impulse level of 75KA and CB will be vacuum or SF6 type. The 11KV system is un earthed but all allowances must be taken and required equipment should be supplied for converting the system to an earthed systems. In case there is more than two transformers within the site the required panel should be supplied within this switchboard.

Panels No. 1 for incoming supply

• The CB shall be rated 630A • 3 No. 144mm ammeter

• No. 144mm voltmeter and selector switch

• No. Current transformers for operating t h e protection and instrumentation

• 1 No. T.P. isolating voltage transformers.

• 1 No. 1 DTH over current and earth fault relay with over current and earth fault settings.

• 1 No. 1 DMT under voltage relay for supply failed alarm. • 1 No. test terminal block.

• 1 No. healthy trip lamp and push button. • 1 No. 110 DC shut trip and auxiliary switch.

• 1 No. Set of spare auxiliary switches 3 normally open and 3 normally closed.

• 1 No. unit cable sealing for box for 3 -core incoming cable. • 1 No. pilot cables terminating box.

• 1 No. alarm disconnecting relay with indicating lamp and reset button.

• 1 No. alarm bell remotely mounted (operated from battery system).

• 1 No. discrepancy switch, incorporating indicating lamps.

Panel No. 2 -Transformer No. 1 - FEEDER

- Same as Panel No. 1 except that: - CB rate 400A.

- 1 No. Bochloz relay with 2 elements for "surge trip" and gas "alarm".

- 1 No. excess oil temperature trip relay with the elements for "alarm" and "trip" stages.

Panel No. 3 Transformer No. 2 - Feeder

- Same as Panel 2

Panel No. 4, Panel No. 5 for automatic power factor correction

c) DCs Supply

Complete set of DC supply consist of nickel alkaline type with required electrolyte and distilled water, crater, stands, stand insulator, inter-cell and inter raw connection, battery charger, panel for battery ,panel for DC feeders, accessories and spares (2 hydrometers, 2 thermometers to read 0°C - 70°C, 2 large containers for mixing the electrolyte, 2 moving voltmeters 3-0-3 volts, complete set of maintenance equipment, one complete of spare part.

d) Two No. oil immersed transformers each rated 1.25 of full load of the plant 11/0.4KV Vector Group DY 11 with L.T. neutral brought out and solidly earthed, ONAN type, off load tape charger +4.5% +5% - on the 11KV side, rating plate bi-directional mending temperature indicator with centigrade pointer and indicating maximum pointers each indicating pointer having two sets of adjustable contacts, oil temperature indicator same as above, thermometers pocket with captive cap, explosion vent of double diaphragm type with portholes type sight bath type, gas, actuated relay, double float, drain valve complete with sampling cock, vacuum valve, filter valve, conservator, terminal boxes on H.T. and L.T. sides.

e) The 0.4KV side of each transformer shall connected by means of bus bars inside suitable conduit to CBs in the main distribution switchboard all the H.T. cables from the take off point to the transformers shall be (XLPE) type.

f) At least 4 earthing points are required to earth the neutral point of the transformers with all the necessary cables and electrodes.

The Contractor shall supply the low lift pump house and filter building with separate transformers if required and build suitable rooms if it is necessary. H.T. switchgear should be in the same H.T. board for main pump house.

NOTES: Iraqi standard transformers (11/0.4KV) are: 1000KVA, 630KVA,

400KVA, 250KVA & 100KVA.

2) H .T. LINES

The Contractor shall include in his price to supply and erect an over head H.T. or ground cable between treatment plant and low lift pump house if required. The poles will be tuber steel 10m high and conductors of copper. All technical specification will be according SOE requirements.

The contractor is required to survey the rout along the raw water delivery pipe. In case that the low lift station or other stations are within the site, a ring system by means of cables should be provided.

3) 33/11KV or 33/0.400KV step Down Sub Station

The Contractor shall supply a complete step down intermediate sub-station 33/11KV or 33/0.400KV complete from take off points to 11KV or 400V. Feeders out door type CBs will have vacuum or S.F.6 type. Breaking capacity of the system will be 1500MVA and all the

system equipment shall be in accordance to SOE requirement and there approvals. Each station will be equipped with 33KV, 11KV CB as spare. The Contractor is responsible for civil works for the control room, and fence of 50x50 meters, will all required cables near the fence up to each 11KV or 400V transformer site and feeding point for low lift, filters building and workshop transformers.

CLAUSE ELEVEN