4.2　General Items

4.2.1　The conditions of body inspection of transformer shall be in accordance with the following requirements:

1　The main items of inspection and the surrounding environment of body inspection shall comply with the technical product specification.

2　The body inspection may not be carried out under the following circumstances:

1）The manufacturer requires not inspecting the body.

2）The transformer is built on site，or is transported in a short distance without violent vibration，sudden braking，serious bumping or striking，etc.

4.2.2　The transformer body shall be placed conforming to the following requirements:

1　The top cover of transformer with a gas relay shall have a ascending grade of 1.0-1.5% along the gas flow of the relay.

2　The transformer shall be installed at a correct position with complete accessories.For the oilimmersed transformer，its oil level shall be at proper value and there shall be no oil leakage.For the transformer equipped with rollers，its braking device shall be used to fix the rollers securely in place after the transformer is placed at the right place.

4.2.3　The installation of main accessories shall be in accordance with the following requirements:

1　The gas relay and temperature detector shall be checked and calibrated prior to installation.They shall be correctly and securely installed，and properly connected.

2　The drive mechanism and its accessories of on-load tap changer shall be securely fastened（fixed）.Its mechanical interlocking and the electrical interlocking of the limit switch shall work reliably，with an operation sequence meeting the product requirements.

3　The oil-water system of the heat radiator and the cooler shall pass the pressure test.

4　The oil conservator shall be well sealed，well-ventilated smoothly.The indication of oil level pointer shall be consistent with the vacuum oil level.The oil-filled bushing shall be tested for its usability，with a normal oil level and without oil leakage.The end of bushing shall be grounded.Both the highpressure bushing and the connections of leading-out wire shall be installed according to the manufacturer's requirements.

4.2.4　Oil filling shall be conducted in accordance with the technical product specification.

1　The standing time shall comply with the requirements specified in Table 4.2.4 after the oil filling is completed and before the voltage is applied.

Table 4.2.4　Standing time（h）after the transformer is filled with oil

2　The gas in the relevant parts of transformer，after the standing，shall be released for several times until all the residual gas is let out completely using the submersible pump.

4.2.5　Overall airtight inspection:The oil conservator shall be subject to an overall airtight test by air pressure or oil pressure after the transformer is installed.The applied pressure shall be 0.03MPa which the cover of oil box can withstand.The test shall last for 24h without oil leakage occurring.The transformer may not be subject to an overall airtight test if it is transported as a whole.

4.2.6　The trial run of transformer:The trial run shall be carried out in accordance with those specified in Article 2.1.5 of this code.The transformer shall work normally after being subject to 5 times of voltage shock switching-on.The duration shall not be less than 10min after the first switching-on.The excitation inrush current shall not induce the unwanted operation of protective device.