Should be conducted by a testing unit licensed by the local power supply department

The test standards comply with national specifications, local power supply department regulations and product technical requirements.

Simulation tests should be conducted separately

Operation, control, interlocking, signaling and protection should be correct, safe and reliable

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Overcurrent protection setting

Overload alarm setting

Three-phase one-time reclosing setting

Zero sequence overcurrent protection setting

Overvoltage protection setting

After passing the inspection by the power supply department, the power supply will be sent indoors. After power inspection and phase calibration, it will be correct.

Turn on the high-voltage incoming line switch to check whether the high-voltage voltage is normal. Turn on the switch of the transformer cabinet to check whether the transformer has power. Turn on the low-voltage incoming line switch to check whether the low-voltage voltage is normal. Turn on the switches of other cabinets respectively.

After running without load for 24 hours, if there are no abnormal phenomena, go through the acceptance procedures and hand it over to the construction unit for use. At the same time, submit technical information such as construction drawings, construction records, product certificate instructions, test reports, etc.

Can be transported by roller rolling and winch hauling

When lifting the transformer, the rigging must be inspected and qualified, and the wire rope must be hung on the hook of the oil tank. The lifting ring on the upper part of the transformer top cover is only used for lifting core inspection. It is strictly forbidden to use this lifting ring to lift the entire transformer.

When transporting the transformer, high and low voltage insulating porcelain bottles should be covered to protect it from damage.

During the transportation of the transformer, there should be no severe shock or vibration. When using mechanical traction, the traction point should be below the center of gravity of the transformer, and the transportation inclination angle should not exceed 15° to prevent tilting from deforming the internal structure.

When using a jack to lift a large transformer, the jack should be placed on the jack bracket of the oil tank. The lifting operations should be coordinated, the force on each point should be even, and the pads should be placed in time.

Iron core inspection

Winding inspection

Insulation screen inspection

Lead wire insulation inspection

Inspection of non-excitation voltage regulating switching device

Inspection of on-load voltage regulating switching device

Insulation barrier inspection

Inspection of the oil circulation pipeline and the lower yoke insulation interface

Insulating oil test or SF6 gas test

Measure the DC resistance of the winding together with the bushing

Check the voltage ratio of all taps

Check the three-phase connection group of the transformer

Measure the insulation resistance of cores and clamps

Measure the insulation resistance and absorption ratio of the winding and bushing

AC withstand voltage test of windings and bushings

Impact closing test at rated voltage

Check phase

When the transformer is put into use for the first time, it can be closed by impact at full voltage. The impact closing should be put in from the high voltage side.

The transformer should undergo no-load and full-voltage impact closing for 5 times, and there should be no abnormality; after receiving power for the first time, the duration should not be less than 10 minutes; during full-voltage impact closing, the excitation inrush should not cause malfunction of the protection device

After the oil-immersed transformer is charged, check that all welds and connection surfaces of the oil system should not see any oil leakage.

Before parallel operation of transformers, the phase should be checked

During the trial operation of the transformer, attention should be paid to the inrush current, no-load current, primary and secondary voltages, and temperature, and the trial operation records should be kept.

The transformer can be put into load operation only after it has been operated without load for 24 hours and there are no abnormal conditions.

open box to check

Core pulling inspection

Drying of electric motors

Inspections during trial operation

Inspection before trial operation

Each conductor is only allowed to have one joint within each span, but conductors and lightning protection wires are not allowed to have joints where they cross roads, rivers, railways, important buildings, power lines and communication lines, etc.

Wires of different materials, different cross-sections or different twisting directions can only be connected within the jumper on the pole.

The mechanical strength of the joint shall not be less than 90% of the strength of the conductor itself. The resistance does not exceed 1.2 times the resistance of the same length of wire

Jumper connections at tension poles, branch poles, etc. can be connected using T-shaped wire frames and parallel groove wire clips.

The crimping method of overhead lines can be divided into clamping connection, hydraulic connection and explosion pressure connection.

Measure the insulation resistance of insulators and lines

Measuring the power frequency parameters of lines above 35kV can be carried out according to professional requirements such as relay protection and overvoltage.

Check that the phases on both sides of the line should be consistent

Impact closing test

Measure the ground resistance value of the tower and it should comply with the design requirements.

Wire splice testing

Set up lightning cable

Increase the number of insulator strings to strengthen insulation

Reduce the ground resistance of the tower

Installation of tubular air-termination devices or discharge gaps

Install automatic reclosing

Adopt arc suppression circle grounding method

Settings of lightning-terminating wires for transmission lines with different voltage levels

Use lightning rods or wires to prevent direct lightning strikes

Use air-termination devices to limit the overvoltage amplitude of intruding lightning waves. Valve-type air-termination devices are usually used in substations. Power stations generally use metal oxide air terminals

On the incoming lines close to the substation, a 1~2km lightning line protection must be erected to limit the lightning current flowing through the connector and limit the steepness of the intrusion wave