Power cable fault locator

one. use way

Cooperate with high-voltage signal generatorConducting acoustic magnetic synchronization testing can pinpoint high resistance and flashover type faults in power cables, while also detecting the path.

Combined with an audio signal generator, audio induction testing can quickly and accurately detect cable paths, locate low impedance faults, and perform cable identification and depth measurement.

two. special point

Fully functional, capable of pinpointing and determining cable paths for various cable faults.

High measurement accuracy, with errors in high resistance fault location and path detection not exceeding0.2Meter, low resistance fault location error not exceeding2m.

The instrument has two working modes: acoustic magnetic synchronization and audio induction, each using two different probes. After replacing the probe, the instrument automatically switches working modes.

Synchronize the sound and magnetic field signals generated by the discharge of cable fault points, with strong anti-interference ability.

The cursor can be used to determine the delay between sound and magnetic field signals, thereby determining the distance of the fault point.

The detection method mainly relies on waveform recognition, supplemented by headphone listening, to eliminate auditory errors and reduce fatigue during operation.

For different types of faults and fixed-point environments, the instrument provides two triggering and non triggering methods for the headphones to listen to faults during fixed-point, enabling operators to quickly and effectively determine the fault location and achieve accurate fixed-point.

The signal waveform is displayed on a large LCD screen, which is intuitive and easy to recognize.

It can be powered by rechargeable lithium-ion batteries or easily replaceable dry batteries.

Equipped with backlight, automatic shutdown, and charging protection circuit.

Easy to operate, aesthetically pleasing, and portable.

skill technique point mark

High resistance fault location accuracy ：≤0.2m

Path detection accuracy ：≤0.2m

Low impedance fault location accuracy ：≤2 m

merit consume ：1.5W

charger input voltage ：AC：220V±10%

Charger output voltage ：DC：9.1V

body accumulate(host)：200mm×90mm×165mm

quality quantity(host)：1Kg

Operating temperature ：-10～40℃

four. Structure of the instrument

1. Whole machine composition

host

Attachment, packed in backpack, including:

Acoustic magnetic probe

Lift the bar, handball

probe

earphones

charger

2. Composition and function of the panel

The input and output sockets, display devices, and adjustment knobs of the fixed-point instrument are mostly arranged on the panel, As shown in the figure4-1As shown.

image4-1 Panel of the fixed-point instrument

signal input Jack: Connect the probe output cable for signal input.

headphone jack Jack: Connect the headphone plug for listening purposes.

Magnetic field gain Knob: When conducting acoustic magnetic synchronization testingUsed to adjust the gain of the instrument's magnetic field amplifier, so that the instrument can be correctly triggered by the magnetic field signal emitted by the cable breakdown discharge.

Sound gain Knob: Used to adjust the gain of the instrument sound amplifier, so that the amplitude of the sound waveform displayed on the screen is large enough without distortion, and the headphone listening experience is clear without being harsh.

Synchronous indication LED: When conducting acoustic magnetic synchronization testingAt the same time as the instrument is triggered by a magnetic field signal, it emits light approximately0.2Seconds, indicating that the fault point has been discharged. If the detection point is within a few meters of the fault point, a discharge sound different from the ambient noise can be heard at this time.

LCD (Liquid Crystal Display) Used to display instrument waveforms and prompt information.

charging jack Used to connect a charger and charge the lithium-ion battery inside the instrument. When the indicator light on the charger is red during the charging process, it indicates that it is rapidly charging; When the indicator light turns green, it indicates that the charging is complete.

The functions of each button are as follows:

switch Key: Used to open/Turn off the power of the instrument.

backlight Key: When the surrounding environment is dark and the content displayed on the LCD is unclear, Press this button to turn on the LCD backlight and obtain a clear image. Press it again to turn off the backlight. After the backlight is turned on for half a minute, the instrument will automatically turn it off.

pause Key: It can pause the triggering of the instrument for careful observation and analysis of the waveform. At this time, the screen will displayThe word 'pause trigger' flashes, press it again to restore normal operation.

memory Key: Press this key to store the current waveform in the memory, while the last stored waveform will be flushed out.

compare Key: With Memory Use keys in conjunction. Press this button, and the instrument will display the memorized waveform on the screen, which can be compared with the current waveform after each screen update. Press the key again, and the waveform of the memory will disappear.

trigger Key: Used to switch the listening mode of headphone sound. The cable fault locator provides two types of sound listening modes: triggering mode and non triggering mode(default), to cope with different types of cable faults and adapt to different working environments. This makes it more convenient, fast, and accurate to locate cable faults.

< and>Keys: The left and right arrow keys of the cursor. Press it once, and the cursor will move left or right. If the hand does not leave after pressing the key, the cursor will continue to move rapidly. Lift the hand and the cursor will stop moving.

When conducting acoustic magnetic synchronization testingThe cursor key is used to calibrate the size of the acoustic magnetic delay. Move the cursor to the beginning of the discharge sound waveform at the fault point, and the acoustic magnetic delay value will be displayed in the upper right corner of the sound waveform box. The cursor is in another position, and the displayed time value is meaningless.

five.Acoustic magnetic synchronization test

(In conjunction with a high-voltage signal generator)

The acoustic magnetic synchronization test is suitable for detecting high resistance and flashover faults in power cables, and can detect the path of the cable at a fixed point.

This method requires the cooperation of a high-voltage signal generator.

1. Working principle

(1)Principle of Acoustic Magnetic Synchronous Path Detection

When high voltage causes a cable fault to click through, a strong instantaneous current will flow around the cable(Within the entire length range)Generate a magnetic field signal, as shown in the figure5-1As shown:

The initial direction (polarity) of the magnetic field generated by the pulse current on both sides of the cable is opposite. The instrument collects magnetic field signals at different positions and displays the waveform on the LCD screen. When it is determined that the initial direction has changed,The instrument probe has been moved to the other side of the cable,By repeatedly detecting with this method, the path of the cable can be determined.

(2)Principle of High Resistance Fault Location:

The high resistance fault point of the cable discharges under high voltage, generating a magnetic field around the cable

Signal, while generating vibration sound signals at the fault point. Directly above the fault point, the sound takes the least time to travel from the fault point to the ground, while the perceived sound intensity is the highest.

The instrument collects the magnetic field and sound signals generated when a cable fault occurs, displays the waveform on the LCD screen, and outputs the sound through headphones for listening. When receiving the discharge sound signal from the fault point, moving the cursor can calibrate the time difference between the sound and the magnetic field signal reaching the probe(Acoustic magnetic delay value)Due to the fact that the speed of magnetic field propagation is much higher than that of sound propagation, the propagation time of the magnetic field can be ignored, and the acoustic magnetic delay value is the propagation time required for the sound signal to travel from the fault point to the probe. According to the formula: distance=timeBy multiplying the speed, the distance of the fault point can be determined (as it is difficult to determine the propagation speed of sound in different media, the distance of the fault point cannot be accurately calculated based on the acoustic magnetic delay value). By listening to the sound and judging the amplitude of the sound waveform, the intensity of the sound can also be identified. The point with the smallest acoustic magnetic delay value and the highest sound intensity is the fault point.

2Preparatory work

(1)Fault location measurement

After a cable malfunction occurs,Please first use the power cable fault rangefinder to measure the fault distance. For detailed usage instructions, please refer to the rangefinder's operating manual.

(2)High voltage equipment wiring and use

In order to locate the fault, a high-voltage generating device should be connected to one end of the cable, and a high-voltage impulse pulse should be applied to the cable to cause the cable fault to click through and discharge. The grounding fault location of the core wire and the wiring of high-voltage equipment are the same as the flashing method used for fault location, as shown in the figure5-2As shown:

In the picture:

T1For the regulator;

T2For high-voltage test transformers;

DFor silicon stack;

GFor the ball gap

CFor capacitors, models with larger capacitance should be selected, especially when the fault distance is far away. Large capacity capacitors can generate strong sound signals at the fault point, making it easier to locate the fault. Generally, capacitors with larger capacitance are used1to4Micro method, rated voltage6Kilovolts or10kilovolt;

The above complete set of equipment can use our company's high-voltage signal generator for better results.

Adjust the interval of the ball gap, then connect the high-voltage equipment power supply, gradually increase the voltage until the ball gap discharges. If the discharge sound of the ball gap is loud, the fault point has generally been penetrated (at this time, a cable fault rangefinder can also be used to monitor whether the fault point has been discharged). If the fault point is not broken down, the discharge voltage needs to be increased. Firstly, stop the high-voltage equipment, discharge the charges on the capacitor and cable, increase the gap between the balls, and repeat the above process until the fault point can be broken down and discharged.

The larger the capacity of a capacitor, the higher the discharge voltage, and the stronger the sound signal emitted by the discharge at the fault point, making it easier to detect. However, the discharge time interval of high-voltage equipment will be extended, increasing the time required for fixed-point detection. It is necessary to select the capacitor capacity and adjust the discharge voltage reasonably according to the actual situation, in order to facilitate rapid positioning.

At the fault point, if the fault point is relatively close to the high-voltage equipment, the sound of ball gap discharge may be received by the probe and difficult to distinguish from the sound signal of the fault point discharge. In this case, the discharge equipment can be moved to the other end of the cable for further positioning.

For pure wire breakage faults, the ground wire should be short circuited to the fault at the far end of the cable;

If the wire is disconnected and grounded with a resistor, the diagram should be used as much as possible5-The wiring method allows discharge to occur between the core wire and the ground, making it easy for sound signals to be transmitted to the ground. For individual short-circuit faults (with low fault resistance close to zero), due to the inability to trigger discharge or the very weak sound signal emitted by discharge, audio induction method should be used for detection (see Chapter 6 "Audio Induction Method Testing").

3. On site installation of instruments

Insert the output cable plug of the acoustic magnetic probe into the signal input jack on the front panel of the instrument, place the probe flat on the ground, and use it to receive signals;

Insert the headphone plug into the headphone output jack on the front panel of the instrument for listening to sound;

Screw the lifting rod into the screw hole on the upper part of the probe for easy carrying;

If the ground on site is relatively soft, the probe can be screwed into the bottom of the probe and inserted vertically into the ground to improve detection sensitivity.

electricitysource

The instrument can be powered by rechargeable lithium-ion batteries or6 sectionsAAdry cell(AA battery)Power supply.

1. Lithium ion battery

When the battery symbol displayed on the screen is all white, it indicates that the battery is under voltage and the lithium-ion battery needs to be charged.

While charging,Connect the power plug of the charger to AC220Vsocket,Connect the output plug to the instrument host panelCharging port ", the charging indicator light on the charger indicates the charging status: red indicates fast charging, green indicates fully charged.

It takes about three hours to fully charge the battery from undervoltage. Charging is fully automatic and does not require human supervision. It can be charged at night and used during the day.

2. Dry battery

When the battery is under voltage and there is no condition to charge it in a timely manner, dry batteries can be used instead of lithium-ion rechargeable batteries.Remove the four screws on the lower left and right sides of the instrument, remove the bottom plate, and expose the battery compartment at the bottom of the instrument.Translate into English6 sectionsAAdry cell(No.5 dry battery)Place it in the dry battery compartment at the bottom of the instrument, and then switch the power switch above the dry battery compartment to the dry battery side.

Precautions

The probe of the instrument should avoid strong impact.

When the instrument exhibits the following phenomena, users can handle them themselves:

Turn on the instrument, there is no display on the screen

Reason: The internal battery voltage of the instrument is too low

Solution: Charging

Turn on the instrument, the screen displays, but it automatically shuts down after a few seconds

Reason: The internal battery voltage of the instrument is too low

Solution: Charging

crash

Reason: The instrument is strongly interfered with

Solution: Shut down and restart

When the malfunction of the instrument cannot be easily eliminated, please do not repair it yourself to avoid expanding the scope of the fault. Please contact our company for timely repair.