What are the functions and faults of high voltage underground cables

Dude, are you asking about underground power cables? The biggest difference between this and the elevated cable is that, taking into account the needs of national defense, what if there is a war, the elevated cable is not the easiest to control and cut off, but the probability of the underground line being attacked is smaller, the interference by environmental factors is small, and the loss in the process of power transmission is also small

Features:1Transmission of electricity 2Passing on the message 3Conversion of electromagnetic energy.

Fault: short circuit; The cable is damaged by external forces; production quality problems of cables;

There are three main causes of cable ground faults.

First, the cable is manufactured with defects and is a non-qualified product;

second, the operating environment is harsh, natural aging, and damage by external forces;

Third, the installation is not standardized, and the wiring is rough. The root cause of the ground fault is only one --- the insulation of the cable.

In an underground power distribution system, the cables used are placed in the ground or in some form of duct. This makes the cable sturdy and has little chance of failure. As long as these cables fail, it is difficult to locate and repair the fault because the conductor is not visible.

Needless to say, detecting these faults is like looking for a needle in a haystack. There are many ways to locate faults, while also making the task easier and less time-consuming with the use of a new inspection device, the Cable Fault Tester (also known as the Fault Cable Tester). However, note that no single method or combination of methods is considered the "best" method.

For different faults, there are different types of methods that can safely and effectively locate faults without damaging the cables. However, the following are the faults that occur in underground cables:

Open-circuit faults. The breakage of the cable conductor is called an open-circuit fault. The equipment of the cable fault tester can check for this type of fault. In this type of fault, the 3 wires of the 3-conductor cable at the far end are shortened and then grounded.

Then, the resistance between each conductor and ground is read. If the resistance in the circuit indicating a conductor is 0, it means that it is not damaged. However, if an infinite resistance is measured, it means that the conductor is damaged and needs to be replaced.

Short-circuit faults. When an insulator fails, it is due to the fact that the 2 wires of a multi-core cable are in electrical contact with each other, which indicates that a short-circuit fault has occurred. Again use a megohmmeter for this. In this type, the 2 terminals of the cable fault tester are connected to any 2 conductors.

When a cable fault tester reads zero between electrical conductors, it indicates a fault. The other 2 conductors can be connected at a time, and the same process can be repeated.

Ground fault. If the conductor of the cable is in contact with the earth, it is called a ground fault. To identify this fault, the two terminals of the cable fault tester are connected to the conductor and the earth, respectively. If a zero reading is indicated, a ground fault can be investigated. Apply the same procedure to the other conductors of the cable.

Respondent: Huatian Power.

What are the common fault types of buried cables, because of its low cost and high safety. Thus it has been widely used. However, in the long-term operation of the buried cable, various types of faults will occur due to the influence of uncertain factors such as excessive transmission current or humidity in the surrounding environment.

So what are the common types of faults in buried cables?

Short-circuit faults. In general, the phenomenon that occurs when a short-circuit fault occurs in a buried cable is that the cable current instantly increases and the cable resistance becomes infinite. The main reason for the short-circuit fault of the cable is that the load rate of the cable is too large, which can make the conductor temperature rise rapidly and the insulation is damaged, resulting in the connection of multiple lines and sparks.

Low-resistance faults. When the insulation between the cable and the cable is damaged or the insulation of the cable to the ground is damaged, the cable insulation resistance will inevitably decrease, and in the case that the cable insulation resistance is less than ten times the characteristic impedance of the cable, we call this fault a low-resistance fault. When measuring low-impedance faults, the low-voltage pulse reflectometry method can be used.

High-impedance faults. When the insulation resistance between the cable and the cable or the cable to the ground is much lower than the normal value, but is greater than the characteristic impedance of the cable ten times, we call this kind of cable fault a high-impedance fault. According to the specific nature of high-impedance faults, the properties of high-impedance faults can be divided into leakage and flashover. At present, the most common types of faults in buried cables are the above, in addition, there are some other fault phenomena, such as open circuit faults, grounding faults.

The WD-A10 cable fault tester can be detected by this instrument, which is used for the testing of various faults of power cables, the search of cable paths, cable burial depths and the daily maintenance and management of cable archives, as well as the accurate testing of railway and airport signal control cables and street lamp cable faults.

1. It can test all kinds of faults of power cables with different voltage levels, different cross-sections, different media and various materials, including: open circuit, short circuit, low resistance, high resistance leakage, and high resistance flashover faults.

2. It can test all kinds of faults of railway communication control cables, street lamp cables and airport signal cables.

3. It can measure the speed of radio wave propagation in any cable whose length is known.

4. It can test the cable direction and burial depth.

Display: Inch industrial-grade LCD screen (XP operating platform) Storage capacity: 8 G

Test method: low-voltage pulse method, rushing lightning flow method, direct lightning flow method Operation mode: touch mouse operation.

Test distance: not less than 60km Minimum test distance (blind zone): 0-5 meters or no blind zone.

Accurate Fixed-Point Error: Test Error: Systematic error less than 1%.

Electricity can be found in the following ways.

Fault location underground cable faults can be a challenge, but modern fault location technology makes the process more efficient. The two basic techniques include:

TDR (Time Domain Reflectometer).

This tests underground cables using a low-energy signal without causing insulation damage, allowing faulty parts to be found. The TDR results are displayed as graphs, with a functioning cable sending a return signal (based on the set impedance settings) within a known time frame.

High-voltage radar method.

There are three types of high-voltage radar methods:

Arc Reflection - Filters, hammers, and TDR devices work together to provide an approximate distance to cable faults.

Surge Pulse Reflection - Stores oscilloscopes, hammers, and current couplers for ionizing faults over long distances or difficult to locate.

Voltage Impulse Reflection - This method uses a voltage coupler and analyzer equipped with a verification tester or dielectric test to locate voltage faults above 25kV.

Respondent: Huatian Power.