What aspects does the transformer load tap switch check?

Test steps

1, switch contact resistance measurements after being hoisted out switch, use A clean transformer oil to wash, containment, observe the toggle switch is the position of the dominant flow contact contact in singular side (or dual side), the measurement should be the dominant flow measuring contact through to state A single, B and C only number for side (or dual side) of the contact resistance measurements and measurement After completion, the three-phase data were recorded respectively. Then, use A special tool to switch the switch to the other side, and measure the contact resistance of double A, double B and double C (or singular side). After the measurement, record the three-phase data respectively. Remove the test wiring and finish the contact resistance measurement.

2. Measurement of transition resistance of switch: observe that the current contact position of the main flow contact of switch is on the singular side (or even side), select the opposite contact position of the main flow contact, that is, the measurement should be carried out when the main flow contact is disconnected. Use single-arm bridge (or digital multimeter) to measure the transition resistance of A single side, B single side and C single side (or even side). After the measurement, record the three-phase data respectively. Then use A special tool to convert the switch to the other side, and measure the transition resistance of A double, B double and C double side (or singular side). After the measurement is completed, record the three-phase data respectively. Remove the test cables, and the measurement of transition resistance of group A singular transition resistance of group B even transition resistance is completed.

3. Switching switch transition waveform measurement:

Using on{{0}}load tap switch parameter comprehensive tester wiring, schematic diagram only shows A phase wiring, the other two phases only according to the same method for short connection, only B, C on the instrument respectively connected to the corresponding short wiring can be,0 phase public use without connecting again.

(1) Place the on-load tap switch parameter comprehensive tester in a suitable position, and ground the tester shell reliably. Switch on the power supply of the tester, check the starting state of the tester, set the instrument and options according to the requirements of the on-load tap switch parameter comprehensive tester manual, and start the instrument into the measuring state after setting and options are completed.

(2), transfer switch to the other side, the instrument measuring and waveform displayed on the screen, the operation instrument of single, dual function buttons on the transition resistance and dynamic resistance, is always switching time, access time, t2 t1 singular set of resistance and odd number resistance bridge time, access time, three-phase time t3 double array resistance and contact vibration bounce over the same time, Read, judge according to the standard and manufacturer's regulations, select the printing function for waveform printing and saving.

4. Measuring transition process with winding:

(1) Use the discharge rod to discharge the tested transformer

(2) Remove the high pressure, medium pressure and low pressure leads of the main transformer

(3) the transformer ratio tester is placed in the suitable position of the measured transformer, and the metal shell of the tester is reliably grounded. For wiring, connect the test line to the casing A, B and C of the pressure regulating side according to the yellow, green and red lines, and connect the black line to the neutral point of the side;

Transformer has load distribution

4) Connect the non-test side to three-phase short-circuit grounding respectively

5) After the power connection of the tester is correct, notify other personnel to evacuate the test

(6) After obtaining the consent of the person in charge of the test, pressure can be applied, and the power supply of the test instrument can be turned on to start the test. During the test, the voice should be shouted and the monitoring should be strengthened

(7) Switch on the power supply of the tester, check the starting state of the tester, set the instrument and options according to the requirements of the on-load tap switch parameters, and start the instrument into the measuring state after setting and options are completed;

(8) The value under the letter AB (or column) on the screen represents the resistance value of the corresponding test loop. During the test, the instrument automatically identifies the value (XXX indicates that the test line is in bad contact and should be re-connected). After the value is stable, press the "Execute" button and the screen will appear: "To be operated by electric or manual

(9) after the switch, the instrument measuring and waveform displayed on the screen, the operation instrument of single, dual function buttons on the transition resistance and dynamic resistance, is always switching time t2, t1 singular group resistance access time number of single and double bridge resistance time, access time, three-phase time t3 double array resistance and contact vibration bounce over the same time, to carry on the interpretation, According to the standard and manufacturer's regulations to judge, select the printing function for waveform printing and save

(10) For the combined on-load tap changer (M-type switch and M-type switch), the switching switch always moves back and forth between odd and even, so the test gear should be carried out from singular to even to singular, so as to measure the switching switch from singular to even and from even to singular. For the compound on-load tap changer, the switching between the moving contact and the static contact of each tap position is not repeated, and there is a difference between up and down contact, so the state is different. Therefore, all points should be continuously measured from 1 point ( plus N0), and then reversed to finish the process

5. Oil storage tank, breathing apparatus and oil level indicator shall be checked according to the requirements of their technical documents

Online oil filters should be checked according to the requirements of its technical documents; Open the electric mechanism box, check whether there is any loosening, rust; Check whether the heater is normal: record the number of actions if possible, check the function of the motor and counter by operating one step and then returning. Items checked every 3 years:

In the case of normal hand operation, local electric and remote operation of a cycle, no abnormality;

Check emergency stop function and limit device;

Check operation characteristics and measure switching time before winding resistance test; If possible, measure the transition resistance, the initial difference of resistance value should not exceed ±10 percent

Oil test: oil tolerance voltage Greater than or equal to 30kV; If equipped with an online oil filter, the voltage should be 240kV. If the requirements are not met, the oil needs to be filtered or replaced with a new oil.