IEC 62271-1 (2017) requires the manufacturer to supply instructions for transport, storage, erection and final inspection, and lists the data the user and the manufacturer must exchange before installing. For gas-filled equipment, it sets the maximum dew point at commissioning.
Short answer
Switchgear can be damaged before it is energized: by moisture in storage, by poor lifting or by a connection under stress. IEC 62271-1, 2017 edition, devotes clause 11 to making sure that transport, storage and installation are done according to the manufacturer’s instructions. Those instructions are an obligation of the manufacturer: it must supply the appropriate version of the manual, with the transport and storage instructions in good time before delivery.
This guide walks through the chain of clauses 11.2 to 11.3: receiving, lifting, erection, connections and final inspection, and the data the user and the manufacturer must agree on before starting.
Transport and storage
If the temperature and humidity conditions of the order cannot be guaranteed during transport, storage or installation, the standard calls for a special agreement between manufacturer and user. Before energizing, the insulation may need protection against moisture absorption from rain, snow or condensation, and transport vibration may need to be considered. For long-term storage of maintenance parts, the manufacturer must propose special packing according to the customer’s specification (clause 11.2).
Unpacking and lifting
Each complete piece of equipment must carry suitable lifting means and an external label showing the correct lifting method and its maximum mass in kg, fully equipped. Special lifting devices must withstand the mass of each transport unit. Special precautions go in the installation manual. An example from the standard: lifting supports or bolts that must not be left exposed to the weather are removed on site (clause 11.3.2).
Erection and connections
- Assembly. If the equipment does not ship fully assembled, all transport units must be clearly marked and the assembly drawings accompany the equipment (11.3.3).
- Erection. The instructions must give details of location and foundations to prepare the site, and the total mass of the apparatus with its fluids, the mass of the fluids and the mass of each unit lifted separately (11.3.4).
- Connections. The instructions cover the connection of conductors, with advice to avoid overheating, unnecessary stress and lack of clearance. They also cover the auxiliary circuits, the gas or liquid systems with the size and layout of the piping, the earth connection and the auxiliary contacts available to the user (11.3.5).
Gas-filled equipment: the dew point
In controlled or closed pressure systems with a gas mixture, the manufacturer defines the percentages of each gas and their tolerances. During commissioning or maintenance, the maximum moisture content of the gas at the filling pressure for insulation is verified by dew point measurement. For measurements at temperatures other than 20 °C, the correction factors of the manufacturer’s manual are used.
The dew point inside the compartment must not be higher than:
| Equipment | Maximum dew point (measured at filling pressure and at 20 °C) |
|---|---|
| With adsorbent material | -10 °C |
| Without adsorbent material | -15 °C |
The standard expects these values to leave a dew point below -5 °C during service life. It explains that the measurement is specified at a given temperature because water can pass between the gas and solid materials when the temperature changes. The filling procedure with mixed gases is defined by IEC 62271-4 (clause 11.3.6). If you are interested in gas handling, see the guide on SF6 handling and the one on SF6 gas analysis.
Final inspection of the installation
Once the equipment is installed and all connections are finished, the manufacturer’s instructions must include:
- A plan of recommended on-site tests to establish correct operation.
- The adjustment procedures needed to achieve that operation.
- Recommendations on the measurements worth making and recording to decide future maintenance.
- For closed pressure systems, a qualitative on-site tightness test (sniffing) on all connections assembled in the field. Clause 8.5.3 calls for a detector with a sensitivity of at least 10⁻⁸ Pa·m³/s.
- The instructions for final inspection and commissioning.
Annex H, informative, gives guidance for on-site electromagnetic compatibility measurements. The values recorded here, such as the contact resistance, are the baseline compared at every maintenance. To organize that file, see the commissioning dossier.
- Receiving. Condition of packing, labels and transport units
- Lifting and unpacking. With the means and mass the label indicates
- Erection and connections. Foundations, conductors, auxiliaries, gas and earth
- Final inspection. On-site test plan and tightness test
- Commissioning. Measurements recorded as the baseline
Data the user must provide (11.3.8)
- Site access limitations.
- Local working conditions and restrictions, such as safety equipment and working hours.
- Availability and capacity of lifting and handling equipment.
- Availability, number and experience of local personnel.
- Pressure vessel rules that apply during installation and testing.
- Interface requirements with high-voltage cables and transformers.
- If it is an extension: the provisions for it in the existing primary and secondary equipment, the operating conditions or restrictions in service and the local safety rules.
What was already tested in the factory is summarized in the routine tests of switchgear. The enquiry that originated the order is explained in data to specify switchgear, and the follow-up in switchgear maintenance and failure report. To keep the inspection record you can use the commissioning checklist.
The map of standards for primary equipment testing places this part among the others of IEC 62271.
Data the manufacturer must provide (11.3.9)
- Space needed to install and assemble.
- Size and weight of the components and of the test equipment.
- Cleanliness and temperature conditions of the installation and preparation area.
- Number and experience of the personnel needed.
- Installation and commissioning schedule.
- Electric power, lighting, water and other needs.
- Proposed training for installation and service personnel.
- In extensions: which existing components must be taken out of service and with what precautions.
- Gas filling procedure (mixtures) and dew point verification, if needed.
What not to do
- Do not store the equipment outdoors if the order does not provide for it: moisture reaches the insulation before energizing.
- Do not lift the equipment by a point the label does not indicate.
- Do not skip the tightness test of the connections assembled on site.
- Do not energize without saving the measurements of the final inspection: they are the basis of maintenance.
When to call us
At Tiza Group we inspect and test installed switchgear on site, record the baseline and deliver it in a traceable dossier. This field work is done in Colombia, or elsewhere on request. See our FAT and SAT testing and medium-voltage switchgear testing services. Write to us and we will send you a quote.
Related guides
- Routine tests of switchgear in the factory
- Switchgear maintenance and failure report
- Data to specify switchgear: enquiry and order
- Medium-voltage switchgear: parts, functions and tests
- SF6 handling: recovery and filling units
References
- IEC 62271-1, High-voltage switchgear and controlgear - Part 1: Common specifications for alternating current switchgear and controlgear, 2017 edition, clauses 11.1 to 11.3, 8.5.3 and Annex H (informative).
- IEC 62271-4, cited by clause 11.3.6 for filling with gases.
Frequently asked questions
Who writes the installation instructions?
The manufacturer. IEC 62271-1, 2017 edition, clause 11.1: it must supply the appropriate version of the manual for transport, storage, installation, operation and maintenance. The transport and storage instructions are given in good time before delivery, and the installation, operation and maintenance instructions at the latest with delivery.
What dew point is acceptable for the gas when commissioning gas-insulated switchgear?
Measured at the filling pressure for insulation and at 20 °C, the dew point of the compartment must not be higher than -10 °C in equipment with adsorbent material, nor higher than -15 °C in equipment without it (clause 11.3.6). The standard expects that, during service life, the dew point measured at 20 °C stays below -5 °C.
What must the final inspection after installation include?
A plan of on-site tests to establish correct operation, the adjustment procedures needed, the measurements worth recording for future maintenance decisions, a qualitative tightness test (sniffing) on the connections assembled on site if the system is a closed pressure system, and the instructions for final inspection and commissioning (clause 11.3.7).