Erection and Commissioning of Medium Voltage Switchgear by Suppliers

1. PURPOSE This is about requirements for the complete erection and commissioning by the supplier of medium voltage switchgear. In this article we will be discuss about scope of work between switchgear supplier and company resident engineer upon performing of following duties switchgear erection, switchgear commissioning and general scope of switchgear installation.

2. Erection and Commissioning of Medium Voltage Switchgear by Suppliers

This specification applies to medium voltage (3000 volts and above) switchgear, purchased by company, for electrical supply distribution 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. SWITCHGEAR ERECTION

4.1      Supplier shall provide the services of a specialist engineer at site, together with necessary skilled and unskilled labour, to supervise and execute complete erection of the switchgear.

4.2      Company will provide lifting tackle and labour for off-loading and transporting switchgear into the switchroom.

4.3      Supplier shall provide all tools, standard and special, necessary for erection work.

4.4      Erection shall include the following work by the supplier as applicable in the particular circumstances:

• • Setting in position, levelling, and grouting of switchgear base mounting channels and truck runners into foundation.
  • Assembly of switchgear panels and busbars, and fitting of instruments.
  • Setting in position, levelling, and bolting down switchgear fixed frame portion onto prepared foundation.
  • Internal connection of bus wiring and instrument secondary wiring.
  • Filling of circuit breaker tanks or poles with SF6 gas, where applicable.
  • Fitting of circuit breaker moving trucks into switchgear fixed frame portion.

4.5      Interconnecting cables from the switchgear to external equipment, including switchgear battery and charger unit and remote control panels, will be installed by Company and not by the switchgear supplier.

4.6      Final erection of the switchgear must be completed to the mutual satisfaction of the switchgear supplier’s erection supervisor and Company resident site engineer.

4.7      On completion of the erection work, the supplier must submit to Company an Erection Certificate for the switchgear, giving details of all mechanical assembly and electrical installation work accomplished. Minimum data requirements are briefly as follows:

• Switchgear panels are assembled, levelled, and bolted to foundation.
• All busbars are assembled, torqued to the correct setting and ductor tested. All bus wiring connected.
• All instrumentation equipment (for example, instrument transformers, meters, and relays) are fitted and connected.
• All circuit breaker trucks are fitted into switchgear panels.
• All circuit breaker tanks or poles are filled with SF6 gas where applicable.

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

5. SWITCHGEAR COMMISSIONING

5.1      Supplier shall provide the services of a specialist engineer at site to execute complete commissioning of the switchgear.

5.2      Company will provide an electrician to assist the supplier’s commissioning engineer, if required.

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.

The switchgear supplier shall also provide a temporary battery and charger unit on site, for initial power supply to circuit breaker spring charging, close and trip circuits.

5.4      Commissioning shall include the following work with respect to switchgear circuits and operation:

• • Circuit breaker tests (as applicable)
  • Power frequency high voltage withstand test
  • Insulation resistance test
  • Primary injection tests on current transformers and connected relays
  • Secondary injection tests (only to be performed by special agreement)
  • Adjustment of protection and control relays to operating set point
  • Adjustment and functional operation of switchgear component parts including, but not limited to, circuit breaker mechanisms, earthing switches, and interlocks.

5.5      Interconnecting cables from the switchgear to external equipment, including switchgear battery and charger unit and remote control panels, will be commissioned by Company and not by the switchgear supplier.

5.6      Final commissioning of the switchgear must be completed to the mutual satisfaction of switchgear supplier’s commissioning engineer and resident site engineer.

5.7      On completion of the commissioning work, the supplier must submit to a Commissioning Certificate for the switchgear giving details of all electrical test results, instrument and relay settings, and circuit breaker operation. Minimum data requirements are briefly as follows:

• • SF6 dielectric strength test figures (as applicable)
  • High voltage withstand test figures
  • Insulation resistance test figures
  • Primary injection test figures
  • Secondary injection test figures (as applicable)
  • Protection relay set point figures
  • Time delay relay set point figures

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

5.8      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, circuit breaker tank or pole filling (as applicable), circuit breaker mechanism operation, external cable connections, and external busbar connection].

5.9      If any defects or deficiencies still exist at the time the supplier’s commissioning engineer leaves site, these must be listed in full detail and formally transmitted by e-mail to the Air Products resident site engineer. Before leaving site, the supplier’s commissioning engineer must also formally transmit by e-mail a copy of all commissioning test results to the resident site engineer.

5.10    On completion of the commissioning activities, copies of protection relay setting programs or software used during commissioning shall be formally transmitted by e-mail to the commissioning engineer for record.

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 engineer for record.

Commissioning: Substation, High-Voltage, Oil/Vacuum/Gas Circuit Breakers