HZ-A10 Cable Fault Location Unit

I. Overview

1.1 Product Features
Through continuous development and innovation, the product possesses the following features:

Full-length testing of power cables: It can accurately measure the total length of power cables, providing important data for cable installation, maintenance, and management.

Wave velocity calibration: By calibrating the signal propagation speed in the cable, it improves the accuracy of fault location.

Embedded design with an English interface, stable operation, resistant to crashes and viruses.

Adopts distributed control bus technology, with high automation, simple operation, and convenient test wiring.

Equipped with a 12.1-inch large screen, touch mouse operation, high-brightness display, suitable for outdoor use under sunlight, lithium battery power supply for convenient on-site testing; engineered plastic case for shock and moisture resistance, achieving extreme stability.

The software enables automatic switching between the low-voltage pulse method and the impulse current method, with simple wiring and intuitive testing; automatic identification and search of waveform inflection points, automatic positioning of fault inflection points, and automatic reading and display of fault distances.

The waveform is displayed in three zones on the same screen, with ten measured waveforms randomly displayed for selection; simultaneously implements both automatic and manual processing modes for waveform positioning verification, and has the function of storing, playing back, and analyzing test waveforms.

1.2 Technical Specifications

Capable of testing various major insulation faults in power cables of different voltage levels, cross-sections, media, and materials, including: open circuits, short circuits, low-resistance, high-resistance leakage, and high-resistance flashover faults.

Display mode: 12.1-inch industrial-grade LCD screen

Storage space: Fixed 4G

Testing methods: TDR, ICE

Operation mode: Optoelectronic knob operation (touch screen function optional)

Pulse width/pulse amplitude (100ns ~ 10μs, 120V)

Gain adjustment (-20 ~ +40dB)

Output impedance matching (120Ω)

Testing distance: 5m ~ 100km (v/2=80m/μs)

Minimum testing distance (dead zone): 5 meters

Precise positioning error: ±0.2m

Testing error: System error less than ±1%

Resolution: (v/2)*f meters (v/2: half-wave velocity m/μs; f: sampling frequency MHz)

Sampling frequency: 3.125MHz, 6.25MHz, 12.5MHz, 25MHz, 50MHz, 100MHz, 200MHz, 250MHz

Power supply: DC12V

1.3 Operating Conditions
l Working temperature: -10℃ to +45℃
l Relative humidity: ≤90% (non-condensing)

II. Introduction to Cable Fault Location

2.1 Types of Cable Faults
■ Based on the cause of the fault:
● Externally induced faults (forced faults)
● Non-externally induced faults (non-forced faults)
☆ Joint faults
☆ Outer sheath faults
☆ Body faults

■ Based on the nature of the fault:
● High-resistance faults (insulation resistance above 1k ohms)
● Low-resistance faults (insulation resistance below 1k ohms)
● Dead ground faults (insulation resistance nearly zero)

2.2 Fault Location Process
The basic requirements for cable fault location are rapid location, safe operation, and accurate positioning, which greatly depend on the technical proficiency of the operators and the reliability of the equipment.
Before locating the fault, it is important to understand the basic information of the cable, such as its type, length, joint positions, laying method, etc. Additionally, it is essential to have some understanding of the nature of the fault before locating it.

Cable fault location is a highly specialized technical discipline that can be both challenging and straightforward. It is challenging because locating cable faults basically requires equipment; otherwise, it is very difficult. However, if one has the equipment and masters the knack, faults can be quickly located.

Tips for Cable Fault Location:
● Many cable faults are caused by external damage, and can be found by patrolling the line.
● When locating faults, it is best to have detailed cable information. If the information is not available, it is advisable to search for it yourself rather than relying solely on diagrams.
● Different test methods and instruments are required for different types of cable faults. Accurate pre-judgment can greatly improve efficiency.

Safe Operation

Great care must be taken when operating high-voltage equipment. Safety regulations must be strictly adhered to, and procedures must be followed. Before conducting fault testing, it is essential to strictly observe the following five safety rules:

During fault testing, prevent other personnel from approaching the site. It is advisable to isolate the fault testing area with warning signs to prevent electric shock accidents. After testing, discharge the tested cable. Safety first, prevent electric shock!

2.3 Safe Operation

Great care must be taken when operating high-voltage equipment. Safety regulations must be strictly adhered to, and procedures must be followed. Before conducting fault testing, it is essential to strictly observe the following five safety rules:

During fault testing, prevent other personnel from approaching the site. It is advisable to isolate the fault testing area with warning signs to prevent electric shock accidents. After testing, discharge the tested cable. Safety first, prevent electric shock!