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Home / Technical Articles / Example of 33/11 kV substation on-site assessment report

Substation Assessment

This technical article presents the shorten version of the report of an on-site assessment at the 33/11 kV Shatt Al Arab substation built in Iraq back in 2005. The assessment covered all work completed at that time, so it wasn’t a complete substation commissioning.

Example of 33/11 kV substation on-site assessment report
Example of 33/11 kV substation on-site assessment report

Work Completed

Work completed at the time included the construction of the 33/11 kVsubstation switchgear facility, guardhouse, fencing, exterior lighting, and installation of two 33kV to 11kV transformers (31500 kVA), two auxiliary transformers, neutral grounding system, 11 kV switchgear, and 33 kV switchgear.

The installation of substation electrical equipment was completed prior to site assessment. High voltage power to the facility was not connected at the time of the visit. Therefore, operation of the systems could not be assessed.

Required design drawing and specifications included:

  • Plot plan for the substations and associated feeders
  • Single-line diagrams including protective devices
  • Substation yard steel structural support shop drawings
  • Substation civil and site drainage drawings
  • Substation yard and building foundation drawings
  • Main transformer foundation and fire wall drawings
  • Substation building architectural and structural drawings
  • Substation building equipment layout
  • Substation grounding grid drawings
  • Substation raceway layout drawings
  • Substation building plumbing, electrical, fire protection, and HVAC drawings
  • Underground feeder plan and sections
  • Cable schedule
  • Three-line diagrams
  • DC schematic diagrams
  • Circuit breakers, re-closers, line switchers, line sectionalizers, switchgear control and relaying wiring and connection drawings
  • Protection relay settings and coordination studies
  • Load flow and short circuit calculations
  • Catalog cuts of major equipment items

Table of content:

  1. Construction of substation building
  2. Construction of perimeter fencing, gates, exterior lighting, and guardhouse
  3. Delivery and installation of substation equipment
    1. 33 kV switchgear
    2. 11 kV switchgear
    3. 33/11 kV transformers
    4. 11/0.4 kV auxiliary transformers
    5. Neutral grounding resistor system

1. Construction of substation building

The contract and approved design included new construction of a substation building to house the 33 kW switchgear, 11 kW switchgear, and associated monitoring and control equipment. Requirements included office space, a bathroom facility, HVAC systems, fire alarm, internal lighting, and a septic system.

The 90% design drawings required a 22.280 meter (m) by 8.720 m building with a reinforced concrete slab foundation, below grade electrical cable trays, exterior block walls with exterior stucco and interior gypsum, and a reinforced concrete flat roof.

The on-site assessment verified the construction of the facility was complete and that the construction appeared to be consistent with the contract and design requirements.

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2. Construction of perimeter fencing, gates, exterior lighting, and guardhouse

The contract and approved design included the new construction of a perimeter fence with entrance gates, guardhouse, and exterior lighting.

The 90% design drawings required a perimeter fence on reinforced concrete footings, block construction with exterior stucco and paint. Two iron entry/exit gates were included in the perimeter fence design.

Design drawings required a 4.220 m by 7.220 m guardhouse building with reinforced concrete slab foundation, exterior block walls with exterior stucco and interior gypsum, and a reinforced concrete flat roof.

Design drawings required the installation of exterior light poles on a reinforced concrete foundation.

The on-site assessment verified the construction of the guardhouse, exterior fence, and exterior lighting was completed and the construction appeared to be consistent with the contract and design requirements.

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3. Delivery and installation of substation equipment

3.1 One 33 kV switchgear

The contract and design required the purchase of a 33 kV switchgear and installation of the switchgear into the newly constructed substation building.

The 90% design and associated specifications required a 7 bay switchboard rating of 36 kV, 1250 A and 25 kA, 3 seconds. The on-site assessment verified the installation of the seven bay 33 kV switchgear.

Details from the associated factory nameplate were not obtained during the site assessment. However, the equipment and installation appeared to be consistent with the contract, design, and specifications.

Figure 1 shows site photo of the 33 kV switchgear located inside the substation building.

33 kV Switchgear
Figure 1 – 33 kV Switchgear (click to enlarge photo)

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3.2 One 11 kV switchgear

The contract and design required the purchase of an 11 kV switchgear and installation of the switchgear into the newly constructed substation building. The 90 % design and associated specifications required a 22 bay unit with switchboard rating of 12 kV, 2000A, and 31.5 kA, 3 seconds.

The on-site assessment verified the installation of the 11 kV switchgear. Details from the associated factory nameplate were not obtained during the site assessment. However, the equipment and installation appeared to be consistent with the contract, design, and specifications.

Figure 2 shows the photo of 11 kV switchgear located inside the substation building.

11 kV switchgear
Figure 2 – 11 kV switchgear (click to enlarge photo)

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3.3 Two 33 kV to 11 kV transformers

The contract and design required the purchase of two 33 kV to 11 kV transformers and installation of concrete pads, firewalls and the transformers onto the pads. The 90% design and associated specifications required two transformers with on-load tap changers, with rated power of 31,500 kVA and rated voltage of 33 (+5,-7)×1.5%/11.5 kV be installed.

The on-site assessment verified the installation of two 33 kV to 11kV transformers on concrete pads with firewalls between the two transformers.

The associated factory nameplates list the transformers as outdoor three phase transformers with onload TAP changer – type UBB RT 200/400 13 Pos. – constant flux regulation. The listed ratings are: frequency 50 hertz (Hz), rated power 31500 kVA, rated voltage 33 (+5,-7) × 1.5%/11.5 kV, and current 551.0/1581.4 A.

The on-load tap changer nameplate lists the company name as ABB Power Technologies AB, type UBBRT 200/400.

The equipment and installation appeared to be consistent with the contract, design, and specifications.

Figure 3 shows the photo of the factory nameplate of one of the two 33 kV to 11 kV transformers. Figure 4 shows the factory nameplate of one of the two on-load TAP changers.

Factory nameplate of 33 kV to 11 kV transformer
Figure 3 – Factory nameplate of 33 kV to 11 kV transformer (click to enlarge photo)
Factory nameplate of on-load TAP changer
Figure 4 – Factory nameplate of on-load TAP changer (click to enlarge photo)

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3.4 Two 11 to 0.4 k auxiliary transformers

The contract and design required the purchase and installation of two 11 kV to 0.4 kV auxiliary transformers. The 90% design and associated specifications required the two transformers to be rated at 250 kV.

The on-site assessment verified the installation of two 11 kV to 0.4 kV transformers on concrete pads.

The associated factory nameplate lists the transformers as a three phase Newton Poggibonsi 250 kV 50 Hz unit. Nominal Voltage for primary is listed at 11 ±2×2.5% kV and for secondary is listed at 0.41 kV. Nominal Current is listed at 13.1 A for the primary and 352 A for the secondary.

Figure 5 shows the photo of one of the two installed 11 kV to 0.4 kV auxiliary transformers. Figure 6 shows the associated factory nameplate.

The equipment and installation appeared to be consistent with the contract, design, and specifications.

11 kV to 0.4 kV auxiliary transformer
Figure 5 – 11 kV to 0.4 kV auxiliary transformer (click to enlarge photo)
Factory nameplate of 11 kV to 0.4 kV auxiliary transformer
Figure 6 – Factory nameplate of 11 kV to 0.4 kV auxiliary transformer (click to enlarge photo)

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3.5 Grounding system

The contract and design required the purchase of two neutral grounding units and installation of the units. The 90% design and associated specifications required a neutral earthing resistor of 300 A rated current for 30 seconds rated time.

The on-site assessment verified the installation of two grounding units

The associated factory nameplates list the grounding units as Telema S.P.A. Neutreal Grounding Resistors 041245. Specifications are OHMIC value at 20° C of 21.1 Ω ±10%, current 300 A for 30 seconds, 15 A continuous duty, voltage 11.5/square route (3) kV, insulation voltage of 12 kV, and a frequency of 50 Hz.

Figure 7 shows the photo of one of the two installed neutral grounding units. Figure 8 shows the associated factory nameplate.

The equipment and installation appeared to be consistent with the contract, design, and specifications.

Grounding resistor system
Figure 7 – Grounding neutral resistor system (click to enlarge photo)
Factory nameplate of grounding neutral resistor
Figure 8 – Factory nameplate of grounding neutral resistor (click to enlarge photo)

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Source: Report of site assessment Shatt Al Arab Substation Basrah, Iraq

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author-pic

Edvard Csanyi

Electrical engineer, programmer and founder of EEP. Highly specialized for design of LV/MV switchgears and LV high power busbar trunking (<6300A) in power substations, commercial buildings and industry facilities. Professional in AutoCAD programming.

7 Comments


  1. Përparim HOTI
    Aug 26, 2019

    Ju falemderoj për kontributin tuaj.
    Respekte Përparimi


  2. layla abdulaa murad
    Aug 25, 2019

    THANKS A LOT FOR YOU . . YOU HELP ME SO MUCH TO INCREASE MY KNOWLEDGE ABOUT MY JOP .FOR MOOR SUCCESSES S WITH BEST REGARD


  3. Mohammed Shareef
    Jul 23, 2019

    Great work , I know this SS , Thanks for sharing


  4. Amita kumari
    Jul 18, 2019

    Thank you .


  5. Aijaz Saleem
    Jul 18, 2019

    Its a very elaborative report encompassing the each component of the susbstation,if it is possible send me the detailed commissioning procedure as well to my e mail address.
    Looking forward towards your input.


  6. Thulani Mugoba
    Jul 17, 2019

    This is a very good article thank you.


  7. Hasanain A. Abdulrazzqaq
    Jul 17, 2019

    Thanks for sharing

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