DS1106 Street Lamp Low Voltage Cable Fault Tester

DS1106 Street Lamp Low Voltage Cable Fault Tester

Overview
The low voltage cable fault tester is used for locating and testing the fault points of poor insulation of buried low voltage cables, buried high and low voltage cables, and optical cable metal conductors on the ground. Suitable for dead ground faults that cannot be located by discharge sound measurement of high-voltage cables, railway signal lines, low-voltage power and lighting buried cables that form circuits with the earth, and various cables with metal conductors (wire pairs, protective layers, shielding layers). Its main function is not only to locate and test points with poor ground insulation, but also to detect cable routing and the depth of cable burial.
This instrument uses a quartz crystal oscillator and a medium to large scale integrated circuit. Its characteristics are high receiving sensitivity, small static drift, strong anti-interference ability, stable operation, and high accuracy. Due to the use of small nickel cadmium batteries for power supply, the instrument has the advantages of small size, light weight, low power consumption, and easy portability, making it particularly suitable for field operations.

DS1106 Street Lamp Low Voltage Cable Fault Tester

technical performance
1. The distance for detecting routes and fault points: for low-voltage cables, it is ≥ 3km, and for high-voltage buried cables, it is ≤ 10Km.
2. Accurately locate the fault insulation resistance value: 0-5M Ω
3. Accuracy of positioning test: ≤± 10cm
4. Detection cable depth: ≤ 3m

working principle
1. Detecting the working principle of routing
When an alternating current passes through a linear conductor, a coaxial alternating electromagnetic field is generated around the conductor. Placing a coil in this magnetic field will induce an AC voltage of the same frequency within the coil, and the magnitude of the induced voltage depends on the position of the coil in the magnetic field. When the direction of magnetic field lines is parallel to the axis of the coil, the voltage induced by the coil will be higher (as shown in Figure 1); When the axis of the coil is perpendicular to the magnetic field lines, the voltage induced by the coil will be smaller (as shown in Figure 2). From this, the routing of the cable can be determined. The 45 ° method using a receiving coil can also measure the burial depth of underground cables.

2. Working principle of fault detection:

Send the DC pulse generated by the transmitter into the tested cable and ground it through poorly insulated points. At the entry point, a point electric field is formed, which forms an electric field on the ground surface as shown in Figure 2. The DC amplifier in the receiver obtains the potential difference before and after the fault point (along the cable route) through a potential difference probe. Due to the opposite sign of the potential difference before and after the fault point, when the sequence of the potential difference detection frame remains unchanged, the median meter head of the DC amplifier will swing in different directions, and there will be a directional change in the median meter head before and after crossing the fault point. By changing the direction of the header swing, the fault point of poor insulation of the cable to ground can be determined. According to the principle of electric field, the closer the potential difference probe of the receiver is to the fault point, the greater the potential difference obtained under equidistant conditions; The greater the swing of the median meter needle; Similarly, when the probe first leaves the fault point, the swing of the median meter needle is also relatively large (but in the opposite direction to the swing direction before passing the fault point). If the middle of the probe is exactly the fault point, due to the zero potential difference, the swing of the median meter head will also be zero.

Supporting components

1. One transmitter

2. One receiver
3. Inductive probe (component) 1 piece
4. One power cord
5. Two output lines [one test or ground extension line of about 18 meters]
6. Potential difference detection frame assembly [including two probes] 1 set
7. One grounding rod
8. One probe connecting wire
9. One manual
10. One charger
11. The above attachments are packed in two black boxes.