Download Supply of Electric Power to the ESO VLT and E-ELT

ANNEX 1 to Preliminary Inquiry Ref. PI/ESO/11/00096/YWE
Supply of Electric Power to the ESO
VLT and E-ELT Observatory
1. Scope and purposes
The European Organisation for Astronomical Research in the Southern Hemisphere (ESO) is
currently operating the VLT Observatory at Cerro Paranal, II Region, Chile. The VLT Observatory
will be extended with the installation of the European Extremely Large Telescope (E-ELT) at
Cerro Armazones to form the ESO “VLT and E-ELT Observatory”, hereinafter referred to as “the
Observatory” (see Figure 1 at the end of this Annex 1).
The electric power needs of the Observatory are estimated to be large enough to justify a grid
connection. More specifically, the estimated total power needs of the Observatory are:

Instantaneous peak power:
12.5 MVA

Max power demand:
7.8 MVA

Average yearly energy consumption: 40 GWh/year
 Locations:
The global needs listed above are split between two locations, Paranal and Armazones, which
have a straight distance between them of around 20 km. A high-voltage to medium-voltage
(HV/MV) substation (S/S) is to be located at Paranal downhill area. Grid connection of
Paranal S/S shall be done by means of a high-voltage (HV) overhead line (Grid-to-Paranal S/S
overhead line); Armazones S/S shall be interconnected to Paranal S/S by means of a mediumvoltage (MV) double-circuit line (MVL) (preferably underground) (Paranal-to-Armazones line) to
minimize the environmental impact.
The respective needs of the above two locations are as follows:
Paranal area
A high-voltage to medium-voltage substation (Paranal S/S) is to be located at Paranal downhill
area (detailed location to be defined in cooperation with the future contractor in charge with
Task 2).

Instantaneous peak power:
2.5 MVA

Max power demand:
1.8 MVA

Average yearly energy consumption:
10 GWh/year

Distribution nominal voltage:
10 kV

Altitude:
Around 2200 m
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ANNEX 1 to Preliminary Inquiry Ref. PI/ESO/11/00096/YWE
Armazones area
A medium-voltage substation (Armazones S/S) is to be located at an area around the Armazones
summit.

Instantaneous peak power:
10.0 MVA

Max power demand:
6.0 MVA

Average yearly energy consumption:
30 GWh/year

Distribution nominal voltage:
15 kV (TBC)

Altitude:
Around 3000 m
Remark: During E-ELT construction period remarkably lower power needs are expected.
A power generating station is currently operating at Paranal, which is used to supply the Paranal
area power demand. For the time being this station is comprised of one multi-fuel turbinegenerator set (rated about 2.6 MWe at the site) and of three diesel-generator sets (3x 856 kWe)
all directly connected to the MV (10 kV) distribution network of Paranal. This facility will be used
as standby power generation system after the connection of the Observatory to the grid.
2. Technical description
The whole project consists of the following parts (see also the indicative simplified single-line
diagram in Figure 2 at the end of this Annex 1):
a. Construction of Paranal S/S, including one HV incoming line bay, one HV/15 kV power
transformer bay, one HV/15 kV 12.5 MVA transformer, 15 kV busbars, two 15/10 kV
transformers bays, two 15/10 kV 5 MVA transformers and two 15 kV underground cable
line bays to transfer power to Armazones. In all the above the nominal voltage Un = 15 kV is
to be confirmed (TBC) whereas Un = 10 kV is nominal voltage of Paranal MV power system.
The bays shall be complete, including all civil and electrical infrastructure, required
isolators, circuit-breakers, current transformers (CT), voltage transformers (VT), surge
arresters, earth electrode, etc. The substation capacity is to be chosen so as to have the
capability to cover the complete Armazones needs from the Paranal generation facility
after isolation of the Grid-to-Paranal overhead line.
As a part of the supply described by the present Preliminary Inquiry, the future contractor
shall also install a double-circuit 10 kV underground cable line (MVL), each circuit to be
rated 5 MVA, between the existing Paranal power generating station and the Paranal S/S,
including the installation of the cables terminations and the execution of the site dielectric
tests. The actual connection of these cables to the existing MV switchgear of Paranal power
generating station will be realized by ESO under a separate contract.
Interface limits shall be the cable terminations of the 10 kV double-circuit cable line to be
connected to the existing 10 kV switchgear of Paranal power generating station, as shown
in Figure 2 at the end of this Annex 1.
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ANNEX 1 to Preliminary Inquiry Ref. PI/ESO/11/00096/YWE
The use of MV switchgear instead of MV busbars and bays can be accepted.
All required measuring, control and protection equipment for the S/S shall be included in
the contractor’s scope of supply.
For the sake of redundancy, the substation area shall be provided with all civil and electrical
infrastructure (area, fencing, foundations, ducting, oil catch basin, etc., earth electrode,
etc.) for a possible future extension so as to include a second overhead line from the Grid
and a second HV/MV power transformer bay having the same characteristics as outlined
above (see Figure 2 at the end of this Annex 1).
Proposed alternative substation layouts and operating schemes which offer similar or
better functionality to the one of the attached drawing can be accepted. So companies are
encouraged to suggest improvements.
b. Construction of Armazones S/S, including two MV isolator bays. The bays shall be complete,
including all required civil and electrical infrastructure, CTs, VTs, surge arresters, earth
electrode, etc.
Interface limits shall be the Armazones cable connection terminals of the MV isolator as
shown in Figure 2 at the end of this Annex 1.
The use of indoor MV switchgear instead of MV isolator bays can be accepted.
All required measuring, control and protection equipment for the S/S shall be included in
the contractor’s scope of supply.
c. Construction of the Paranal-to-Armazones MV double-circuit (preferably underground) line
(MVL). The line shall be fully redundant, that is, each single circuit shall be capable to
transmit at least 10 MVA instantaneous peak power. Contractor’s scope of supply shall
include the connection of the cables to the Paranal S/S and Armazones S/S.
d. Construction of the Grid-to-Paranal HV overhead line, capable to transmit at least
12.5 MVA instantaneous peak power and connection of the HV OHL to Paranal S/S.
e. Supply of electric power and energy to the Observatory.
f.
Provide corrective and programmed regular preventive maintenance to the entire power
supply system (i.e., Paranal S/S, Armazones S/S, Grid-to-Paranal S/S HV OHL, Paranal S/S-toArmazones S/S MVL, Paranal S/S-to-Paranal power generating station MVL), so as to
minimise power outages and their effects.
3. Note

The whole design, construction, operation and maintenance shall secure at least compliance
with the Chilean “NTSyCS” (that is, the Chilean “Norma Técnica de Seguridad y Calidad de
Servicio”) at the previously defined interface points (see Figure 2 at the end of this Annex 1).
___oOo___
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ANNEX 1 to Preliminary Inquiry Ref. PI/ESO/11/00096/YWE
Figure 1: II Region of Chile – VLT and E-ELT Observatory
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ANNEX 1 to Preliminary Inquiry Ref. PI/ESO/11/00096/YWE
Figure 2: Possible connection Grid-Paranal-Armazones
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