T-H200 SHEATH FAULT LOCATOR
The T-H200 provides an accurate fault location for cable sheath faults. It utilises the DC resistance method in conjunction with a high voltage DC source such as the T-100C. Control of the system is from an Android smart tablet PC with communication over a Bluetooth link. The tablet guides the user through on-site safety, correct wiring and step-by-step operation, to ensure the accuracy of the result. At the end of a session, a test summary report is produced to simplify user documentation.
Cable faults sheath faults occur when the outer insulation of a buried cable is damaged, exposing the metallic sheath to the earth. This cannot be detected by using a surge generator as there will not be a flashover and hence, the TDR prelocation will not identify the fault and there is no acoustic signal to use for pinpointing. Under these circumstances, alternative methods of fault detection and pinpointing are required.
As with fault location of high resistance faults on cables, the detection of external protective sheath faults and main insulation faults for the power cable can be divided in to prelocation and pinpointing. An effective method for the prelocation is the DC resistance method as used by the Kehui T-H200 device in conjunction with the T-100C High Voltage Generator.
The DC resistance method calculates the fault distance by measuring the DC resistance between the measuring point and the fault. Unlike the traditional DC bridge, this method is not affected by the resistance of the fault and the connection lead, leading to higher accuracy. The DC resistance method can be used to test the insulation resistance of the main insulation around each conductor and the protection layer. The T-H200, DC resistance is suitable to test high-voltage cable sheath faults; main insulation faults with low grounding resistance; and joint failures.
The suspect cable sheath is connected to a healthy core or to another healthy sheath at the remote end. Current is injected into the cable sheath from the T-100C, and the DC voltage is measured between the sheath and the core. There is no current flow from the fault point to the near end of the sheath where the voltage is measured, therefore they are of equal potential and so the measured voltage is effectively the voltage drop across the faulty section of the sheath.
The DC resistance (R) between the measured point and the fault can thus be calculated as: R = V/i
(where V is the measured voltage and i is the measured current)
Assuming the resistance per unit length is r (Ω/km), then the distance to fault (D) can be calculated as：
Users can perform safe, reliable and accurate testing using a high voltage generator, a signal acquisition unit together with an Android smart tablet. The exclusive tablet APP
- Accurate location of low and high resistance faults on single core cables
- Location of main insulation faults on three-core cables
- Suitable for unshielded cables
- Precise location of cable leakage current
- Avoids the influence of contact resistance and short circuit resistance
- Use of Android tablet App as the user interface
- Simplified operation with guided work flow
- Secure BluetoothTM communication with the tablet
|Maximum measurement distance||10km|
|Current measuring range||0 to 150mA|
|Voltage measuring range||0 to 50mV|
|Power source||Polymer Lithium Ion battery pack|
|Battery life||5 hours of continuous use|
|Charger||Input AC220V，50/60 Hz，Charging current 2A, Typical charging time from empty, 8 hours。|
|Dimensions：||216mm x 152mm x 95mm|
|Working temperature||-10℃ to +40℃|
|Relative humidity at 25℃||20 to 90%RH|
|Atmospheric pressure||86 to 106kPa|
- T-H200 Sheath Fault Locator
- Ruggedised tablet with T-H200 App
- Carrying Bag
- Test Lead