Current transformer routine test

September 28, 2023

I. Management regulations

According to Q/GWD 168-2008 "Provisional Test Procedure for Power Transmission and Transformation Equipment Status", the routine test items, reference period and related requirements of Current Transformer are shown in Table 3-8-1.

Second, infrared thermal image detection

1. Judgment basis for current heating type equipment (see Table 3-8-2)

2. Judgment basis for voltage-induced equipment (see Table 3-8-3)

3. Judgment of comprehensive heating equipment

When the defect is caused by two or more factors, the nature of the defect should be comprehensively judged. The overheating caused by the magnetic field and magnetic flux leakage can be handled according to the criteria of the current heating type device.

Third, SF6 gas humidity detection (SF6 insulation)

(1) Preparation

Prepare one test instrument and related power lines, gas pipes, valves, etc., and one power supply shaft.

(ii) Test steps

(1) Turn on the power first, and the instrument will self-calibrate first. The measurement data and curve are displayed after self-calibration, as shown in Figure 3-8-3.

(2) When the instrument is self-calibrated, connect the test pipe of the instrument to the corresponding switch connector, and then connect the switch connector to the switch to be tested.

(3) When starting the measurement, open the flow control valve, adjust the flow rate to 0.5~0.6L/min, and do not exceed 0.8L/min at most. This will enter the measurement state, and the measurement time is about 5~7min. As shown in Figure 3-8-4.

(4) At the end of the measurement, record or save the measured data, close the flow regulating valve, remove the test tube from the instrument test port, and finally remove the switch connector.

(5) Turn off the power. Place the test tube inside the instrument.

(iii) Data analysis (see Table 3-8-4)

(four) matters needing attention

(1) The instrument should be placed in a safe position to stop the damage and avoid severe vibration.

(2) The probe should be cleaned and verified for a certain period of time. It is recommended that the calibration interval be preferably one year.

(3) When adjusting the gas flow rate, the control needle valve should be slowly opened to make the flow rate display at 0.5~0.6L/min.

(4) After using the instrument for a period of time (using the battery), charge it in time.

(5) Once the new operation is measured, if it is close to the attention value, it should be measured again after half a year.

(6) New charge (supplement) gas should be measured once within 48 hours to within 2 weeks.

(7) When the gas pressure drops significantly, the measured gas humidity should be tracked regularly.

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