Two-semi-trailer mobile substations (230/ 66/20) kV with one 66 kV GIS incoming and one 20 kV GIS incoming metal enclosure without truck.
Scope of the two-semi-trailer mobile substation as following:
- one main semi-trailer is with One main transformer (230 /66/20) kV (60/40/20) MVA including of One earthing transformer (66/0.4) kV -(250) KVA and 1 set of 230kV GIS switchgear.
- one following semi-trailer is with 66 kV HGIS switchgear and 20KV HGIS incoming feeder and with complete terminal plug in cable 630mm2 for incoming,
- Accessories is with 3X15M XLPE flexible cables (400) mm2 /Cu/ connecting between the transformer and 66 kV incoming feeder with complete terminal plug-in cables.
- Control room is with Control, protection and measuring devices and 230VAC to 110VDC 100AH Panel, and LV cables.
- Semi-Trailer size is within L16mXH4.75mXW4m, Axial load is 13 ton for single axial with the ability to hydraulic direct of axials. with an easily removable portal for connecting of (230-66-20) kV and an easily removable safety fence and Spare parts acc including of Maintenance tools and materials for safety operation acc.
- STRUCTURAL SUPPORTS In the scope of supply is complete with all the necessary supporting frame works which should satisfactorily protected against corrosion
2. CONNECTION TO (230-66) kV OVERHEAD LINES AND UNDERGROUND CABLES:
2.1 Connection to 230 kV GIS bay from network side 230 kV will be Bushing SF6/air.
2.2 Connection to 66 kV GIS incoming bay from network side 66 kV will be Bushing SF6/air.
2.3 The said materials shall include the following:
2.3.1 All insulators (post, suspension and tension) with their fittings and arcing gaps to be erected on the portal.
2.3.2 Lightning rods to be mounted on the portal complete with suitable cross section earthing wire for connection between lightning rods and terminals of earthing mesh.
2.3.3 All additional insulators, T-connectors bimetallic elements and any other fittings that may be needed either on the substation equipment or (230-66) kV network.
3.CONNECTION FROM MAIN TRANSFORMER TO INCOMING ( 66-20 )kV:
3.1 the connection between main power transformer 230 kV and 230 kV GIS bay is SF6
3.2 the connection from main transformer 66 kV and 20 kV to 66 kV incoming and 20 kV incoming is by cable
4.EARTHING SYSTEM :
4.1 An effective earthing system is provided for the substations. It shall be designed that in case of any fault, whether inside or outside the substation, the voltage to earth of any part that is supposed to be earthed shall be within the limits stated by the IEC regulations.
4.2 The measured earth resistance is not exceed 0,5 Ohm.,The earthing system is designed as to keep the "step" and "touch" potentials within acceptable limits, thereby ensuring safety to the personnel.The design is based on taking into consideration that the soil specific resistivity at substation site is about ( 500 ) Ohm-m .
4.3 The strip connections to the earth plates, rods or pipes is melted. Earthing strip connecting the various equipment to be earthed to the earthing pit, be of copper conductors and shall be arranged in an orderly manner ground the substation equipment. The cross-section of the earthing equipment shall be sufficient to carry the maximum short circuit current of the system and 1 sec. duration
4.4 All parts of apparatus, tanks, tank covers, as well as one side of all the secondaries of current and potential transformers is earthed. There are provided sufficient earthing sockets for connecting earth terminals on isolating links, operating handles, and insulating jaws for fuse changing. The transformers, apparatuses , and leads of the switchgear are protected from direct lightning strikes by a system of lightning rods ( basically 24 rods per mobile substation
5. SUBSTATION LIGHTING :
5.1 The main lighting circuit shall be fed from the low voltage AC supply 220V (phase to neutral) and shall be installed in all parts of the substation. A separate emergency lighting circuit shall be fed from the D.C. supply and shall be automatically connected in case of failure of the A.C. supply. Emergency lighting lamps shall be located in appropriate positions to ensure continuity of operation and control.
5.2 Emergency lighting lamps (flashing and phosphoric lamps) shall be located in appropriate positions at the sites, front, rear , of three parts of the mobile substation and it should be fed from the tractor batteries .
Both circuits shall be installed in three parts of the mobile substation.
5.3 Fluorescent lighting and filament lamps shall be installed in three parts of the mobile substation and the intensity of illumination shall not be less than 300 lux at the (230) & ( 66 ) kV and ( 20 ) kV. Control room shall be ≥ 450 lux The intensity of illumination of emergency lighting shall not be less than 50 lux. For external lighting the illumination intensity shall be of the outdoor-drip proof (not less than 50 lux).
5.4 Lighting Distribution Panels: A main lighting distribution board shall be installed feeding the sub-distribution panels in the different parts of the mobile substation. The distribution panels shall be complete with the necessary switches, C.B, protection, etc...
5.5 Lighting Connections and Appliances :The wiring is carried out by rubber or P.V.C. installed wires places in steel tubes .Separate systems being used for the A.C. and D.C. circuits. Power sockets of suitable rating shall be provided in appropriate positions in both parts of the mobile substation
6.SEMI-TRAILER UNITS WITHOUT TRUCKS :
6.1The mobile substations IS consist of two semi-trailers. The first one is for 230 kV GIS switchgear , main transformer , and for the earthing transformer. The second is for incoming GIS 66 kV and 20 kV GIS , battery sets, chargers, control , AC/ DC panels, protections, signals.
Both trailers is suitable for locating the mobile substation equipment while providing for necessary clearances ; as fixed in IEC norm and for the sufficient clear passages so as to guarantee safety of personnel as well as cases of operation and maintenance . The color should be yellow.
6.2 It is equipped with the necessary number of axles to limit the applied load down to ( 13 ) metric tons per axle . It achieve the following max. speeds during transportation :
30 KM/h on paved road , 10 KM/h on unpaved roads .
6.3 Semi-trailer is made by rugged reliability designed and built by reputable manufacturer to give long trouble-free service under the worst climatic conditions:
6.4 the semi-trailer is without truck with
- Pay load .
- Max. width not to exceed ( 4 ) m .
- Max. length not to exceed ( 16) m .
- Max. height not to exceed ( 4.75 ) m .
- Max. load at each axle not to exceed ( 13 ) tons .
- Outriggers of both semi-trailers able to hold the total load preferable hydraulic operation system.
6.5 Kingpin: According to the European standards its preferable to be ( 3.5 ) inch . Both trailers should achieve the following:
Outrigger : mechanical .
Suspension: leaf spring .
Spare Tires: two with portals
- PORTAL :
7.1 The required mobile substations shall be equipped with a beam steel portal of an easily removable type . It shall be used for the entry of a single circuit , three phase A.C.S.R. conductors ( 550/70-240/40 ) mm2 and to fix the (230-66) kV sealing end in case of connecting with ( 230-66 ) kV underground cable .it should keep enough place for this reason and suitable clamp .
7.2 The portal members shall be of steel hot-dip galvanized and provided with bolts , nuts , plain washers , spring washers , two sets of stubs per portal and suitable clamps for fixing the underground cables .
8. SAFETY FENCE: Mobile substations is equipped with all elements and materials to form a safety fence of an easily removable type and of ample dimensions to guarantee the safety of personnel .
8. PRE-MADE KIOSK ( Shelter ) :
Pre-made kiosk ( shelter ) is supplied with the mobile substation with suitable isolating , for environmental conditions ( heat , dust , etc…. ) and with air conditioning . Taking into consideration that the protection , control , AC,DC will be installed in it keeping suitable operation temperature range ( -5,+55 ) C .
9. SITE CONDITIONS :
The climatic conditions of the site is subtropical .
The tropical climate prevails in summer and temperate climate in winter
Operation Range :
-Maximum ambient temperature : +55 C
-Minimum ambient temperature : -5 C for indoor equipment .
- 10 C for outdoor equipment .
- Maximum wind velocity : 35 m/s
- Prevailing wind direction : north-west .
- Relative air humidity , average : 70-80 %
- Altitude :≤1000 m
- Seismicity :0.1 g
Storage Conditions :
- Maximum ambient temperature : +70 C
- Minimum ambient temperature :
- ( -5 C ) for indoor equipment .
- (-10 C) for outdoor equipment.
Relative air humidity average : 95 %
10.AUXILIARY POWER SUPPLY :
The equipment shall be designed to operate under the voltage range as follows :
1- ( 220 ) VDC - 30% + 10% for :
* Circuit breakers trip coils .
* Protection .
* Emergency lighting .
2- ( 220 / 380 ) VAC - 20% + 10% single phase or/and three phase for :
* Transformers fans .
* Heating , ventilation , air conditioning , lighting .
3- ( 220 ) VDC - 20% + 10% for :
* Control and interlocking circuit
* Operating mechanism C.B .
* C.B.Closing coil .
11. PROTECTIONS :
only numerical relays for all relays and insist on the relays passing the type tests successfully .
1-Relays :
Only offers of numerical relays which satisfy the following conditions will be
acceptable .
1-1 The relays shall conform to all relevant IEC standards and especially
IEC 255
1-2 Type test certificates from an international and independent organization
shall be submitted with the offer for all relays .
1-3 Reference list demonstrating that at least ( 3 ) relays of each type have been
in successful service for at least three years shall be submitted with the offer
1-4 The relays shall be guaranteed for at least two years from the date of
commissioning .
1-5 The offerer shall give guarantee period five years for spare elements .
1-6 The relays shall be able to be monitored from a PC .
1-7 The offerer shall provide evidence of full ISO 9000 certificate .
2- Protection cabinets :
2-1 Relays shall be mounted on standard 19 inch racks in sealed cabinets
with transparent local front door .
2-2 As the site atmosphere is very dusty , the protection class of panels
shall be of protection degree ≥IP41( indoor ) , ≥IP53 ( outdoor ) in accordance
with IEC 529 .
2-3 Cabinets shall be so designed that their internal temperature does not
exceed the allowable operating temperature of the protection relays as specified
in this specification for any operative duty .
2-4 The offerer shall provide internationally witnessed test certificates
which demonstrate
12. CONTROL SYSTEM FOR SUBSTATIONS:
Audited Supplier 
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