Mining Cable Fault Tester
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Product Introduction
It is a new generation of portable cable fault testing instrument carefully designed and manufactured by our company based on user requirements and field use considerations. It combines the fault testing part and path part of the original cable fault tester into one, reducing the size, adding DC power supply and USB communication interface. It can be used to detect various low-resistance, high-resistance, short-circuit, open-circuit, leakage faults, and flashover faults of various cables, and can accurately detect the fault point location, cable length, and burial path of underground cables. It adheres to our consistent high-tech, high-precision, high-quality purpose, elevating cable testing to a new level. It features accurate testing, high intelligence, wide adaptability, stable performance, and lightweight portability.
The instrument uses a Chinese character system, high-definition display, and user-friendly interface.
Features of the complete set of instruments:
The complete set combines fault testing and path detection into one, powered by lithium battery, with a lightweight main unit, easy to carry and convenient for testing.
It adopts a new large-screen LCD display with high brightness and strong anti-interference capability.
Built-in DC power supply facilitates on-site testing, field testing, and mine cable testing.
USB communication interface: currently only for professional production and technical personnel to debug and upgrade the host program.
Built-in micro printer can print fax waveforms, providing convenient technical services for users to accurately analyze and guide waveforms on-site.
The newly developed current sampler is a brand-new sampling method with simple wiring, intuitive and easy-to-analyze waveforms, complete isolation from high voltage, and absolute safety for the host and operators.
The key point is the pinpointing instrument part, which borrows German technology and adopts advanced acoustic-magnetic synchronous reception technology, completely isolating external noise interference, and can quickly determine the cable path and accurate fault point location. It is another innovation in domestic similar pinpointing technology, providing a strong guarantee for quickly and accurately finding cable faults and reducing power outage losses.
Dimensions: (length × width × height) 370×180×240mm.
This tester is used to roughly measure the actual underground distance of the fault point from one end of the cable, and also to measure cable length and determine the propagation speed of electrical waves in the cable.
Main Technical Performance Indicators
Tester Technical Specifications
Scope of application: Suitable for measuring various power cables, high-frequency coaxial cables, local telephone cables, and buried wires with two or more conductors laid evenly, with different cross-sections and media, for high and low resistance, short circuit, open circuit, broken wire, high-resistance leakage, and high-resistance flashover faults.
Testing distance: maximum not less than 40Km
Minimum testing distance (blind zone): 1～5m
Measurement error: rough measurement error ±1%, pinpointing error ±0.2m
Working modes: low-voltage pulse, DC high-voltage flash testing, and impulse high-voltage flash testing.
Sampling rate: 25MHz.
Internal transmitted pulse width and amplitude: 0.2us, 100～120V; 2us, 150～160V.
Storage capacity: 8Kbyte and can be divided into two storage areas to store and display two sampled waveforms for comparison measurement.
Display resolution: V/50m, V is propagation speed in m/us.
Display mode: 320×240 LCD with backlight.
Printing method: The main panel of the machine has a micro printer to record test date and test waveform data.
Power supply and consumption: AC 200V±10% or internal DC power supply, power consumption not greater than 10W; DC 6V (7AH) power consumption not greater than 6W.
Volume: 300×400×180mm (length × width × height).
Section 3: Cable Fault Testing Steps and Test Method Selection
Before measuring cable faults, test personnel must first determine the nature of the cable fault in order to adopt appropriate working methods and testing methods, in addition to mastering the performance and operation methods of this instrument.
First, use a megohmmeter or multimeter to measure the insulation resistance of each phase to ground and between phases at one end of the cable, and determine whether it is a low-resistance short circuit, broken wire open circuit, or high-resistance flashover fault based on the resistance value.
When the resistance is below 200-300 ohms, it is a low-resistance fault; 0 to tens of ohms is a short-circuit fault; extremely high resistance to infinity is an open circuit or broken wire fault. Whether it is a broken wire can also be confirmed by connecting the cable ends together and using a multimeter at the starting end to measure the resistance of the two phases that are shorted. Such faults can be directly measured using the low-voltage pulse method.
When the resistance is very high (hundreds of megohms to gigohms) and there is instantaneous discharge during high-voltage testing, such faults are generally called flashover faults and can be determined using the DC high-voltage flash testing method.
High-resistance faults: resistance higher than low-resistance faults, and determined by DC high-voltage flash testing during high-voltage testing.
After rough testing in a certain manner, pinpointing is then performed, and if necessary, the cable path is found and the cable length or distance is measured.
Chapter 2: Low-Voltage Pulse Testing Method
The low-voltage pulse testing method has the characteristics of simple operation, easy waveform recognition, and high accuracy. For short-circuit, low-resistance, and broken wire faults, this method can directly determine the fault distance. Even without such faults, before general high-voltage flash testing, the low-voltage pulse method can be used to measure the full length or speed of the cable, and comparing with the flash testing waveform usually facilitates waveform analysis and achieves the purpose of quickly determining the fault point.
Section 1: Basic Principles of Low-Voltage Pulse Testing
When measuring cable faults, the cable can be regarded as a uniformly distributed transmission line. When a pulse voltage is applied at one end of the cable, this pulse propagates along the line at a certain speed (determined by the dielectric constant and permeability of the cable medium). When the pulse encounters a fault point (or impedance discontinuity point), reflection occurs. The flash tester records the transmission time △T between the transmitted pulse and the reflected pulse, and then the fault distance Lx can be calculated based on the known transmission speed V: Lx=V·△T/2 |
