Erection and Commissioning of Power Supply Transformers by Suppliers

1. PURPOSE – This technical specification is about requirements for the supervision of erection and complete commissioning by the supplier of medium and high voltage power transformers.

Erection and Commissioning of Power Supply Transformers by Suppliers

This specification applies to the medium or high voltage (primary side 10,000 volts and above) power transformers of rating 5 MVA or greater, purchased by Company , for main electrical supply on plants where Company  is responsible for site construction.

3. RELATED DOCUMENTS

3.1      International Electrotechnical Commission (IEC)

61936          Power Installations exceeding 1 kV a.c. Part 1

4. Power Supply Transformers Erection

4.1      Supplier shall provide the services of a specialist engineer at site to supervise erection of the transformer.

4.2      Supplier shall provide non-standard lifting tackle and special tools as necessary.

4.3      Supplier’s erection supervisor shall be responsible for the correct assembly of component parts and erection of the complete transformer on the foundation.

4.4      Company  will provide fitters and welders as required by supplier’s erection supervisor.

4.5      Company  will provide crane facilities and standard tools.

4.6      Final installation of the transformer and accessories must be completed to the mutual satisfaction of the transformer supplier’s erection supervisor and Company  engineer.

4.7      On completion of the erection work, the supplier must submit to Company  an Erection Certificate for the transformer, giving details of mechanical assembly and installation work completed.

4.7.1   The Erection Certificate shall be formally transmitted by e-mail in Adobe Acrobat electronic format, (.pdf) to the Company  resident site engineer for record.

4.8      In addition, the Erection Certificate shall confirm that all applicable ancillary equipment is fitted on the transformer (for example, instrument and instrument transformers, protection switches, conservator, piping and valves, circulating oil pumps, cooling air fans, tap- changer equipment, and control panels).

5. Power Supply Transformers Commissioning

5.1      Supplier shall provide the services of a specialist engineer at site to completely commission the transformer.

5.2      Supplier shall provide transformer ‘top up’ oil as necessary to complete the installation before the commencement of commissioning activities.

When specified, the Supplier shall be responsible for organising and supervising the use of portable vacuum dehydration-filtration equipment for the conditioning of transformer oil before energisation.

5.3      Supplier shall provide all test instruments necessary for commissioning work. The Supplier shall give prior notification of the test equipment that is proposed to be used during the test, and shall make available at site copies of the test equipment calibration certificates.

5.4      Company  will provide fitters and electricians as required by the supplier’s commissioning engineer.

5.5      Final testing and commissioning of the transformer must be completed to the mutual satisfaction of the transformer supplier’s commissioning engineer and Company  engineer.

5.6      On completion of the commissioning work, supplier must submit to Company  a Commissioning Certificate for the transformer giving details of all electrical test results, performance figures, and instrument settings. Minimum data requirements are as follows:

• Oil dielectric strength test figures
• Oil analysis test figures
• Winding insulation resistance test figures
• Separate source voltage withstand test figures (test only to be performed by special agreement)
• Protection switch contact set point figures
• Transformer performance figures recorded during initial energising and part-load operation

The Commissioning Certificate shall be formally transmitted by e-mail in Adobe Acrobat electronic format, (.pdf) to the Company  commissioning engineer for record.

5.7      In addition, the Commissioning Certificate shall confirm that all associated ancillary equipment is correct and satisfactory, as applicable, in terms of installation and operation (for example, external cable connections, operation of cooling system and valves, operation of instruments and protection switches, operation of tap-changer equipment, and operation of control panels).

5.8      If any defects or deficiencies still exist at the time that the supplier’s commissioning engineer leaves site, these must be listed in full detail and formally transmitted by e-mail to the Company  resident site engineer.

6. GENERAL

6.1      Where the formal transmittal by e-mail of any documentation is not possible, two hard copies may be formally handed over with a transmittal or covering letter to the Company  engineer for record.