25kVA wire and cable power frequency pressure tester operating procedures

This procedure is applicable to the soaking voltage test of round-sheathed cables (wires) and single-core cables (wires) for 25kVA wire and cable power frequency voltage testing machines and non-immersion voltage test between insulated cores with two or more cores.

1 Preparation

1.1 Ready to test the wire and cable, the cable to be tested must be cooled to room temperature before the high pressure test. Before the test, it is necessary to check the appearance quality, geometric dimensions, and whether the extruded core is eccentric or not.

1.2 The end of the wire and cable jacket is cut approximately 150mm long (The specific length can be determined by the number of insulated cores or the size of the cross-section, so as to ensure that the insulated cores can guarantee a certain distance when the voltage is applied. Conductive cores collide with each other as a principle.) Insulated cores are separated from each other, the pressure test ends are stripped of the insulating layer, and the cores are layered in layers, and the end of the test piezoelectric cable should be kept clean.

1.3 For the soaking test of single-core cables (wires), the length of the cable end shall be sufficient to ensure that when the cable is submerged in water, the length of the exposed end of the cable shall not be less than 200mm. Note that the thread must not be wet.

1.4 According to the test technical requirements, the rotary action current selects the knob and selects the operating current.

1.5 Turn on the power air switch to turn on the power according to the sample size and length.

1.6 Open the front door of the pressure tester, turn on the power air switch, and turn on the power.

1.7 Leave the high voltage lead unconnected, close the test area door, and turn on the door upper limit switch.

1.8 Turn on the control power switch. The power indicator is on, indicating that the control power is on.

1.9 Turn on the high voltage switch to increase the voltage and adjust the voltage knob so that the test voltage meets the test requirements.

1.10 After waiting for the test time, the voltage will automatically return to zero. After hearing (seeing) the “accepted” acousto-optic signal, press the reset switch to eliminate the audible and visual alarm signal and cut off the control power supply and the total power supply.

1.11 If the above test function is normal, you can prepare for normal test.

2 test steps

2.1 The wiring method for voltage test is carried out according to Table 6. It is required that all points of the insulated wire core can be subjected to voltage test.

2.2 After connecting the leads of the test sample, the test personnel left the test area and closed the door of the test area so that the on-gate travel switch was turned on.

2.3 Press the alert button to make the bell ring to alert the person in attendance.

2.4 Turn on the main power and control the power switch, the power indicator light.

2.5 Turn on the high voltage start switch, the high voltage indicator is high, adjust the voltage setting knob, so that the test voltage reaches the specified value.

2.6 The test time will automatically return to zero and cut off the high voltage, send out "accepted" acousto-optic signal, indicating that the sample is qualified, press the "reset" button to eliminate the signal until the test results.

2.7 If the test piece breaks down, the high voltage will be cut off immediately and a "breakdown" sound and light alarm will be issued. Pressing the "reset button" will eliminate the sound and light alarm.

2.8 re-wiring should disconnect the control power, cut off the total power.

2.9 During the test, if there is a cable breakdown, it should be recorded and the breakdown point should be found through the inverted disk for processing.

2.10 After the test is completed, open the front door of the pressure tester, turn off the power air switch, and turn off the power.

3 Precautions

3.1 This device is a high-voltage detection device. In order to ensure the personal safety of the test personnel, the power supply must be removed before the test sample can be replaced. During the operation, the floor plate must be covered with an insulating rubber pad, and the protective device must be worn. The operation must have a responsible supervision.

3.2 Before using the testing machine, it must be checked whether the testing machine and the fence are reliably grounded.

3.3 Press the high voltage start button to stay enough motor starting time, do not let go too fast.

3.4 The place where the test machine is to be placed should be ventilated and dry, and be dustproof.

Table 6 voltage test wiring
Test product
Number of cores
Test product structure diagram
Test product wiring (high voltage side to ground)
No metal sleeve, metal screen closure
No additional special electrode
Metal sleeve, metal shield, armor or additional special electrode
1
1
-
1→0
2
12
(1) 1→2
(1)1→2+0
(2) 2→1+0
3
123
(2)1→2+3
(3) 2→3+1
(1)1→2+3+0
(2) 2→1+3+0
4
1234
(1)1→2+3+4
(2) 2→3+4+1
(3) 3→4+2+1
(1) 1→2+3+4+0
(2) 2→3+4+1+0
(3) 3→4+2+1+0
5
12345
(1)1→2+3+4+5
(2) 2→3+4+5+1
(3) 3→4+5+2+1
(4) 4→5+3+2+1
(1)1→2+3+4+5+0
(2) 2→3+4+5+1+0
(3) 3→4+5+2+1+0
(4) 4→5+3+2+1+0

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