Understand Tester

An overview of tester

Studies in Language Testing (SiLT) is a series of academic books containing papers in the fields of education and applied linguistics related to language testing and assessment.

It has been published by Cambridge English Language Assessment and Cambridge University Press and Cambridge English Language Assessment since 1995. The Series Editors are Nick Saville (Cambridge English Language Assessment) and Cyril J Weir (University of Bedfordshire).

Although each volume has a variety of purposes, 10 broad themes characterise the series:

language testing terminology

language testing research methodology

test taker characteristics and language test performance

testing the four language skills

testing English for Academic Purposes: IELTS

test impact/washback

test comparability

test documenting

conference proceedings.

Understand  Tester 1

i just got a 55 gallon fish tank? of tester

Seachem Prime, Ammonia Tester, Nitrite Tester, Nitrate Tester, Ph Tester, Kh and Gh Tester

How does knowing the technology behind the system under test help in testing? of tester

There's two types of testing in the context of your question: black box testing and white box testing.General issueA black box tester doesn't know anything about the system. This allows the tester to uncover bugs that someone more familiar with the system might overlook.

A white box tester has more familiarity with the system. Based on knowledge of the application's internals, that a white box tester may always perform task X before performing task Y, whereas someone without familiarity might go straight to performing task Y in a system where task X must be completed before task Y, or both must be completed before the next task.Having both types of testers helps to uncover bugs where there are user interface issues, documentations issues, or missing validations.

Black box testerLet's use an e-commerce website for an example. The order form indicates which fields are required but also allows the user to skip around and leave some of them empty to come back to later. A white box tester might just omit the required shipping information, and just enter billing information followed by submit.

If they're then directed back to the missing fields for completion, then the design is likely fine. If not, and they land on a success page, they might not know that there's an issue.White box testerWith a white box tester performing the same test, they'll notice something is wrong after landing on a confirmation page.

The black box tester used the system and everything they saw indicated a success. The white box tester, on the other hand, knows the internals of the backend and knows that, without the required shipping fields, the application should not be accepting the submission. They'll know something is wrong despite no explicit error.

ConclusionThis is why it makes sense to have a balance of both types. A black box tester may be less likely to test this scenario. Maybe they just assume people know they need to put their shipping information into the form before hitting submit, so the test case never occurs to them.

A white box tester is more likely to test this case, but less likely to realize that there's an issue. When you have both doing quality assurance on your software, you're more likely to uncover the issue, either through coordination/communication with the two types of testers, or by an engineer seeing a backend failure triggered by the test that the white box tester may have never tested.AnecdoteThis happened frequently in the automated customer service speech recognition industry.

People familiar with a system (a white box tester) may be mis-recognized, try again, succeed, and chalk it up to a misrecognition. Someone less familiar with the system (a black box tester) would be more likely to report an issue. Usually it was just a misrecognition, but other times, it helped to uncover issues.

It sometimes turned out that the white box tester's misrecognition was actually caused by some bug in the system. If it weren't for the black box tester reporting the issue to be looked into, the bug might not be found.Alternatively, a black box tester might complete the speech recognition transaction with no issues, whereas a white box tester might realize that the transaction should have failed because a particular piece of information critical to the transaction was never collected.

Again, this is why it can be beneficial to have both types of quality assurance on a team.Edit: Apologies if this is confusing. I wrote this at around 3AM local time when I should have been working to meet a deadline

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Why CCTV Monitor Testers Is the Better of the Other
Why CCTV Monitor Testers Is the Better of the Other
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Another aspect of the functionality that should not be overlooked by a CCTV tester is the ability to work with analog and IP cameras.If you are a professional installer, you probably have heard of closed circuit television testers (also called LCD field monitors, CCTV video testers, CCTV camera testers or IP camera testers). The ability of CCTV testers to work with both analogue and IP cameras is particularly important as digital surveillance cameras become increasingly popular. A closed circuit TV tester is a handy tool for professional CCTV installers and do-it-yourselfers to set up and configure CCTV cameras from any source.NKTech's 3.5-inch CCTV Tester is a portable device designed to install and maintain existing on-site CCTV video surveillance systems. The 1920x1200 resolution allows the 5-inch touchscreen IP camera tester to display network HD cameras and high resolution analog cameras. 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The tester wakes up when the button is pressed. When the power switches are pressed and held down, the button selects the option Turn off to shut down the device.Brush - I could use two brass rods and a set of adapters for different brush sizes on a children's apron suitable for children 3-7 years. Bust 40, "Waist 38," Length 19 "(if you have smaller or larger sizes) Girl Nautical Miss Crab Fabric Personalized Crab.Note the handmade texture of the piece using hand stamping techniques using butterflies, butterfly cookie cutters, sunflowers and sugar. Hand cut and polished for participation in 2 Mineralogical exhibitions in Finland and Sweden, this is one favorite piece of ours that will be brought with you by Etsy if you wish a shipping offer for the purchase. The buyer of IP camera test equipment writes: "It is worth every penny.CCTV testers feature a colour LCD screen, video connection, rechargeable lithium batteries and several types of colour bars for signal output. A shopper who bought a CCTV camera tester used it to test his camera before he started installing it in his home.
The Basics of Using the CCTV Monitor Testers
The Basics of Using the CCTV Monitor Testers
Our security camera testers are designed to facilitate the installation, maintenance and testing of security cameras. All our CCTV test monitors are backed by a 1 year warranty from CCTV Camera Pro.CCV safety tester is a kind of multifunction test tool for CCTV security camera installation professionals. A CCTV tester (short for closed circuit television tester) is a tester and monitor that supports the installation and installation of CCTV security systems. It is used to check if the configured CCTV camera is in the right place, at the right angle, with free view and more.A CCTV tester can be used to display video, control the PTZ, generate images and acquire data from the RS485 test LAN cable. It also has a multi-meter feature to provide AC / DC voltage and resistance measurements to provide the installer with additional diagnostic capabilities to locate localized faults.The CCTV tester analyzes the video signal and displays peak, average video signal level, synchronization and pulse levels to determine the optimum level to display the best picture and synchronization to avoid cable loss. A multifunction tester can save you time and money on your next CCTV installation. In order to ensure accurate testing, it is important to study the CCTV system thoroughly and carry out a test with a tool that measures the performance of several indicators.Once the camera is set up in a separate area, the installer must run a video feed from the camera to refine the settings. Not only do you see the camera video and adjust the focus of the variofocal lens, you also have to supply the camera with its lithium-ion battery. This means a ride up and down the ladder to mount the camera, test the cables and adjust the settings.CCV testers, also known as LCD field monitors or CCTV field monitors, provide installers with an ideal solution that allows them to view, calibrate and correct the video feed of the camera in real time based on the additional features they provide. The basic features of a CCTV tester are an LCD screen (2.5 inch x 3.5 inch x 0.5 inch diagonal) that allows the installer to display a camera feed in place. Other features for video calibration include video test patterns, brightness, contrast and saturation adjustment, video test of signal intensity and support for PAL and NTSC video.The built-in 24-inch TFT LCD display enables the display and adjustment of camera settings and functions. The display monitor can also be connected to a DVR display to allow viewing of a CCTV camera with multiple cameras. The closed-circuit TV tester is a handy tool for professional installers of CCTV security systems and do-it-yourselfers to set up and configure a CCTV camera source.The NKTech 35-inch CCTV tester is a portable device designed to install and maintain existing on-site CCTV video surveillance systems. If you are a professional installer, you may have heard of closed circuit TV testing (also known as IP camera testers, CCTV video / LCD field monitors, CCTV camera testers or IP / CCTV camera testers ).The device can be used for TVI cameras as well as cameras in HD, SDI cameras and network IP cameras. IP cameras have the ability to record more than one camera and cover a wider angle, and can record multiple cameras so that the camera system is covered. The CCTV tester is handheld for good reason, it is for installation and convenience.Prisons use video surveillance to prevent drones from delivering drugs and other contraband to prisoners. Video encoders enable migration from an analog CCTV system to a network system, allowing users to take advantage of cheaper hardware with advanced features. There are three possibilities, which are used with high tendency: IP camera systems, digital video cameras or both.Perform real-time camera settings such as focus, zoom, optimization of advanced settings such as BLC, send-up, lighting adjustment, etc. Disaster management uses CCTV cameras for emergency services and responders to assess and monitor events in real time and report the situation to the disaster management team via video. City and community streets monitor cameras and traffic lights in cities to monitor people, collect traffic statistics, evidence and speed.A CCTV tester is a portable handheld service monitor that helps installers configure the camera at the touch of a finger. Market-buying reviewers looking for a video tester or an IP camera monitor kit can get an angle on where the camera is set up and how it should work. A shopper who bought a CCTV camera tester used it to test his camera before he started installing it in his home.The completion of the CAPTCHA proves that you are a human being and gives you temporary access to the web property. It takes 10-25 working days at best, and I cannot keep it in stock according to your order quantity. Your order has been put on hold for 14 days while we await the Woods trial.
Main Features of Cable Fault Tester
Main Features of Cable Fault Tester
Cable fault tester is a comprehensive cable fault detection instrument. It can test the cable flashover fault, low resistance grounding, short circuit, cable disconnection, poor contact and other faults. If equipped with an acoustic point detector, it can accurately determine the position of the fault point. It is especially suitable for testing power cables and communication cables of various models and different levels of voltage. The cable fault tester has the following remarkable characteristics: 1. It has complete functions and can test faults safely, quickly and accurately. The instrument adopts low-voltage pulse method and voltage flashover method for detection, which can test various faults of cables, and directly test the flashover and resistance faults of power cables without burning through. If equipped with a sound point meter, the position of the fault point can be measured accurately. 2. Test accuracy. The instrument adopts fast data sampling technology with a reading resolution of 1m. Degree of intelligence. The test results are automatically displayed on the large screen LCD with small and data, and the fault judgment is intuitive. It is also equipped with menu display operation function, without special training for operators. 3. It has the functions of wave opening, parameter storage and call out. Nonvolatile devices are adopted, and the waveform and data are not volatile after shutdown. 4. With dual trace display function. The test waveform of the faulty cable can be compared with the normal waveform, which is conducive to further judgment of the fault. 5. With waveform scaling function. By changing the waveform proportion, the waveform can be expanded for testing. 6. Control the measurement cursor to automatically search along the line and stop automatically at the inflection point of the fault waveform. 7. The position of the double cursor can be changed arbitrarily to directly display the direct distance or relative distance between the fault point and the test point. 8. With printing function. Print and archive the test results.
When Purchasing a Cable Fault Tester, Pay Attention to These Points to Avoid Entering the Pit
When Purchasing a Cable Fault Tester, Pay Attention to These Points to Avoid Entering the Pit
. the cable fault tester is an important tool for the power part to maintain the normal operation of the cable. It helps the power staff quickly reach the fault point and eliminate the fault in time, so as to ensure the normal operation and smoothness of the cable. Many people have introduced cable fault flashover and Gaozu fault, so pay attention to these points when buying to easily help you avoid stepping on the pit 1. You can't just look at the price, because what you need is an efficient and accurate testing equipment with perfect supporting after-sales service and pre-sales technical service guidance. These should be communicated and determined before purchase. It is worth paying attention to the details such as the list of accessories when the equipment leaves the factory, the use and installation after receiving, whether relevant technicians come to the site for guidance, or whether the use video is provided. The selection of cable fault detection equipment manufacturers is guaranteed. 2. Define your needs. This is to clarify the key parameters of the type and model of fault detection equipment you buy according to the scope of your use. The application scope of power cable fault test is relatively wide. It is compared with the communication cable fault tester, which is used to detect the fault point of communication cable. Many buyers, or purchasing departments, especially some power departments, are separated from the user department and the purchasing department. It is found that many remain unchanged in use, or even have no after-sales service at all. In fact, the basic principles of cable fault tester are almost the same, but the real competition is the service and product quality itself. I hope you can choose a cost-effective power fault detection equipment from the details when purchasing.
What Are the Common Faults and Discrimination Methods of Cable Fault Tester
What Are the Common Faults and Discrimination Methods of Cable Fault Tester
1、 Cable fault type power cable fault is mainly due to mechanical damage, insulation aging, low construction quality, overvoltage, etc. The commonly used cables are cross-linked ethylene, non dripping oil type, oil immersed paper type, polyvinyl chloride and unknown type. According to the nature of cable fault, they can be divided into low resistance grounding or short circuit fault, high resistance grounding or short circuit fault, disconnection fault, disconnection and grounding fault and flashover fault. 2、 Firstly, we need a megger to measure the insulation resistance of each phase, and judge the fault type according to different insulation resistance values. 1. When we measure that the insulation resistance of the cable to the ground is lower than 100k Ω, it is a low resistance grounding fault. 2. When we measure that the insulation resistance of the cable to the ground deviates from the normal value or is higher than 100k Ω, it is a high-voltage cable fault. 3. When the ground resistance of the measuring cable is high or normal, conduct multiple tests on the conductor to check whether there is a wire break. If there is a wire break fault. 4. When the conductor of each core or multiple cores of the measuring cable is discontinuous, and then after multiple core to ground measurement, judge which type of the above three faults. 5. Flashover fault basically occurs in preventive voltage withstand test, cable terminal and middle joint. Sometimes flashover occurs many times, but the interval is a few seconds or minutes. 3、 Cable fault tester to find out cable fault methods: 1. With high-voltage equipment, it has the traditional impact high-voltage flashover method and low-voltage pulse method. 2. 2. Any high resistance fault presents simple waveform characteristics similar to low voltage pulse short circuit fault, which is very easy to interpret. 3. The cable fault tester finds the fault point through four main parts: cable fault location host, locator, Pathfinder and high-voltage signal generator.
Advantage Analysis of Cable Fault Tester
Advantage Analysis of Cable Fault Tester
With the development of the market, cable fault tester is mainly divided into common and three pulses. What are the advantages and functions of these two kinds? Yuange will explain them to you. [functional advantages of common cable fault tester] 1. It can measure high and low resistance faults of all cables below 35KV, with wide adaptability. 2. It has user-friendly software and full Chinese menu. Key definition is simple and clear. The measurement method is simple and fast. 3. Excellent fault detection success rate, test accuracy and test convenience. As the display terminal, the 4.8-inch color LCD touch screen has strong data processing ability and friendly display interface. 5. Sampling high voltage protection measures are provided. The test instrument will not crash and damage in the impact high-pressure environment. 6. With computer communication interface, it is convenient to save data and graphics in the computer. 7. No test blind area. 8. The built-in power supply can test the open circuit and low resistance short circuit faults of the cable in the environment without power supply. [functional advantages of triple pulse cable fault tester] 1. It can measure high and low resistance faults of all cables of 35kV and below, and has a wide range of adaptability. 2. The "three-stage pulse method" and "three-stage multiple pulse method" are adopted. At the same time, it also has the traditional high-voltage flashover method and low-voltage pulse method. 3. Any high resistance fault presents simple waveform characteristics similar to low voltage pulse short circuit fault, which is very easy to interpret. 4. It has user-friendly software and full Chinese menu. Key definition is simple and clear. The measurement method is simple and fast. 5. The central control unit is used for one key control to trigger three levels of signal output in sequence to ensure safety and success rate. The central control unit can prompt the operation steps and monitor the work process. 6. It has the function of test waveform storage, which can easily store the waveforms tested on site in the instrument according to the specified sequence for call and observation at any time. A large number of field test waveforms can be stored. 7. The measured fault point waveform and good phase full-length open circuit waveform can be displayed on the screen at the same time for the same screen comparison and superposition comparison, and the fault distance can be judged automatically. 8. 11 inch bright color touch LCD display, with strong data processing ability and friendly display interface. 9. Sampling high voltage protection measures are provided. 10. With 232 computer communication interface and USB communication interface, it is convenient to save data and graphics in the computer. 11. The built-in power supply can test the open circuit and low resistance short circuit faults of the cable in the environment without power supply. [functional advantages of cable fault locator] 1. The data display part adopts a highlighted 4.3-inch OLED color LCD to make the display interface clearer. 2. The function and parameter adjustment part adopts a one key programmable pulse coding keyboard, which makes the operation panel more concise and the operation more convenient. 3. The instrument will collect and display the waveform of the audio part in real time. The distance of the fault point can be roughly observed by observing the repetitive waveform characteristics and distance axis, and the operator is not easy to be tired. 4. There are single and continuous modes in the acoustic magnetic fixed-point mode. If the discharge frequency is too fast and the gap time is too short, the user can select the single mode to carefully analyze the relevant data such as the primary discharge waveform, and the waveform page turning is supported in the single mode. 5. In the acoustic signal acquisition, four filter bands are adopted, including low frequency band, intermediate frequency band, high frequency band and full frequency band, which can be selected by the user according to the actual situation on site. 6. The step voltage part adopts waveform display to continuously sample and refresh the signal, so that the user can enhance the continuity analysis of the signal and the resolution of the jump signal. 7. The step voltage part is subdivided into multiple gears, and the large signal is automatically attenuated during the adjustment process to ensure that the display signal is not limited when the maximum voltage amplitude within the test range is input. 8. FIR digital filtering technology is adopted for audio filtering, which makes the characteristic frequency band more obvious and the filtering performance better. 9. Display the distance of the fault point. The distance of the fault point can be displayed within 0-25m. 10. In continuous mode, the compressed waveform within 15m can be displayed. In single mode, the waveform within 15m can be analyzed.
Instructions for Use of Cable Fault Tester
Instructions for Use of Cable Fault Tester
When using the cable fault tester, we should first look at some simple waveform diagrams to analyze different cable faults, and then find out the fault points through the corresponding methods. The following is our simple analysis and description. 1. Test the low resistance grounding, short circuit and open circuit faults of the cable with the low voltage pulse method. A. no other auxiliary equipment is needed at this time. A clip wire is directly connected to the input and output interface of the cable fault location host. Clamp the red clamp of the clamp wire on the faulty phase core wire of the faulty cable, and the Black clamp on the sheath ground wire of the cable. B. Start the power switch of the instrument, the screen saver picture will appear on the screen, and click to enter the interface automatically. At this time, the default state of the instrument is "low voltage pulse method". The use method shall be selected according to the type and length of the tested cable on site and the fault nature preliminarily judged. When it is set to "low voltage pulse method", wave velocity measurement can also be carried out on this interface, and historical files can be opened to view previous test results. C. After setting the equipment parameters, click the "sampling" button, and the instrument will automatically send out test pulses. This interface will display the (open circuit) full-length waveform of the cable (as shown in Figure 5) or the low resistance grounding (short circuit) fault waveform (as shown in Figure 6). If the waveform is not good, the operator shall adjust the "median" and "amplitude" and observe the collected echo until the operator thinks that the amplitude and position of the echo are suitable for analysis and positioning. Basic information such as instrument parameter setting is also displayed at the bottom of the screen. During operation, pay attention to the operation status at the bottom of the screen. D. Waveform positioning reading distance. It is easy to judge the distance of low-voltage pulse, as long as the cursor is positioned to the starting point of transmitted and reflected waves respectively. E. When "saving", the test results need to be retained or reserved for comparison. The "saving" function in the instrument should be used to save the measured waveform in the instrument database. If the tester thinks it is necessary to save the test results, he can click "save" and operate according to the prompt in the submenu. 2. The high resistance leakage fault (including high resistance flashover fault) of the cable is tested by the impact high voltage flashover method. The instrument can test the high resistance leakage fault of the cable by the impact high voltage flashover method. Impulse high voltage flashover method is a popular traditional detection method in China. Many users are used to this method. The external circuit is relatively simple, but the waveform analysis is more difficult. Only on the basis of a large number of tests and some experience can we master it skillfully, but it is still an effective test method. Connect the current sampler attached to the instrument with the host with the signal wire and place it next to the grounding wire between the cable and the high-voltage equipment. As long as the output voltage of the impulse high voltage generator is high enough, the fault point will be broken down under the impulse of this impulse high voltage, and the radio wave reflection will be generated in the cable. The current sampler transmits the induced reflected wave obtained from the current signal on the ground wire through magnetic coupling to the cable fault location host for a / D sampling and data processing, and displays the collected waveform on the screen for fault distance analysis. After the cable type and sampling frequency are determined, you can click the "sampling" button to wait for sampling. Once the high-voltage generator has impulse high-voltage flashover, the instrument will automatically carry out data acquisition and waveform display. The red waveform at the top of the screen is the waveform after local amplification, and the blue waveform at the bottom is the full picture of the test waveform. When the ideal waveform is collected, the "waveform scaling" and displacement and moving cursor can be operated to calibrate the fault distance. The operation method is consistent with the low-voltage pulse method. 3. Wave velocity measurement cables produced by different manufacturers, although the models are the same, the differences in process and medium formula will lead to the differences in radio wave propagation velocity. If the average wave propagation speed given by the instrument is directly used, it will cause a certain test error. In order to test the fault distance more accurately, it is often necessary to recheck (test) the radio wave propagation speed of the cable.
How to Find and Analyze the Fault Point of Buried Cable Fault Tester
How to Find and Analyze the Fault Point of Buried Cable Fault Tester
On site, the cable to be tested is high-voltage cable, and all three phases are short circuited. Usage when using the cable fault, first separate both ends of the cable from the system, and then connect the red and black clips of the instrument host to ab respectively. The measured short circuit distance between the two phases is 312m, and the total length of the cable is 639m. The same results are obtained when connecting to any other two phases. We determine that all three phases are short circuited. If the user knows the direct buried path of the cable, we can find it within 312 meters, and then use the transmitter red clip in the Pathfinder to connect phase A and the black clip to ground, and use the low-frequency high-grade loop resistance of 580 Ω. Because the cable is buried deeply before and after 312 meters, the depth measured by the 80% method is 3 meters, the gain 66db signal is about 675, and the signal is very stable without obvious attenuation. After the cable path is clear, boost and discharge phase a with high voltage, increase the voltage to 8Kv, fully discharge, start at a fixed point from 180m, and finally find the fault point. After communicating with the customer, excavate the fault point with an excavator for more than an hour. Host function of buried cable fault tester 1. It can measure high and low resistance faults of all cables below 35KV, with wide adaptability; 2. With user-friendly software and full Chinese menu, the key definition is simple and clear, and the measurement method is simple and fast; 3. Excellent fault detection success rate, test accuracy and test convenience; 4. 8-inch color LCD touch screen as the display terminal, the instrument has strong data processing ability and friendly display interface; 5. Sampling high voltage protection measures are provided. The test instrument will not crash and damage in the impact high-pressure environment; 6. The built-in power supply can test the open circuit and low resistance short circuit faults of the cable in the environment without power supply.
Correct Opening Method of Cable Fault Tester
Correct Opening Method of Cable Fault Tester
Why can't the fault point be found when using the cable fault tester? What is the correct opening method of cable fault tester? We need to understand some common problems of cable fault first, and then effectively solve the fault problems according to different problems. With the development of China's power system, the laying of high-voltage cables is becoming more and more common. Basically, the cables connected between distribution stations are very long. As long as the cables fail, it is very difficult to troubleshoot, and most of them are buried cables, which is difficult to judge. At this time, we need a cable fault tester to judge the correct fault point for us, So that we can quickly restore the power supply, we can analyze the problem according to several common cable faults. Cable faults are commonly divided into high resistance short circuit fault, phase to phase short circuit fault, low resistance fault, flashover fault and other common faults on site. 1. The low voltage pulse reflection method is applicable to low resistance (less than 10 times of wave impedance), grounding and open circuit faults, and can test the full length of the cable and the propagation speed of radio waves in the cable. In case of low resistance or grounding fault of the cable, the equivalent impedance at the cable fault point shall be the parallel connection of fault resistance and cable characteristic impedance. The smaller the cable fault resistance is, the more obvious the reflected waveform is. When the cable fault resistance is zero, it is total reflection. Because the equivalent impedance at the test end (input impedance of the test instrument) is greater than the characteristic impedance of the cable, the same polarity reflection pulse is generated at the test end. At the low resistance or ground fault, because the fault resistance is less than the cable characteristic impedance, the incident pulse generates the reverse polarity pulse after the fault point and transmits it to the test end. The falling edge of the received reverse polarity pulse corresponds to the reflected waveform of the cable fault point. In case of open circuit fault of cable, the equivalent impedance of cable fault is the series of fault resistance and cable characteristic impedance. Open circuit is equivalent to infinite fault resistance. In this case, the incident pulse will form total reflection, and the reflection pulse of the same polarity will be generated at the test end. The rising edge of the received pulse of the same polarity corresponds to the reflection waveform at the fault point. 2. First, use a certain voltage level The high voltage pulse with certain energy is applied to the faulty cable at the test end of the cable, causing breakdown and arcing at the high resistance fault point of the cable. At the same time, add the low-voltage pulse for measurement at the test end. When the measurement pulse reaches the high resistance fault point of the cable, it encounters an arc and reflects on the surface of the arc. When arcing, the high resistance fault becomes an instantaneous short-circuit fault, and the low-voltage measurement pulse will change obviously in impedance characteristics, so that the waveform of flashover measurement becomes a low-voltage pulse short-circuit waveform, making the waveform discrimination particularly simple and clear. This is what we call the "secondary pulse method". The received low-voltage pulse reflection waveform is equivalent to the waveform of a wire core completely short circuited to ground. Superimpose the low-voltage pulse waveform obtained when releasing the high-voltage pulse and when not releasing the high-voltage pulse. The two waveforms will have a divergence point, which is the reflected waveform point of the cable fault point. This method combines low-voltage pulse method with high-voltage flashover technology, which makes it easier for testers to judge the location of cable fault point. Compared with the traditional cable fault test method, the advantage of the secondary pulse method is to simplify the complex waveform in the impulse high-voltage flashover method into the low-voltage pulse short-circuit fault waveform, so the interpretation is very simple and the fault distance can be accurately calibrated. 3. The triple pulse method adopts the double impact method to prolong the arc burning time and stabilize the arc, which can easily locate the high resistance fault and flashover fault. The triple pulse method has advanced technology, simple operation, clear waveform and fast and accurate positioning. At present, it has become the mainstream positioning method of high resistance fault and flashover fault. The third pulse method is an upgrade of the second pulse method. The method is to first measure the reflected waveform of the low-voltage pulse without breaking through the fault point of the measured cable, then impact the fault point of the cable with the high-voltage pulse to generate an arc, trigger the medium voltage pulse when the arc voltage drops to a certain value to stabilize and prolong the arc time, and then send the low-voltage pulse, Thus, the reflected waveform of the fault point is obtained. After the superposition of the two waveforms, it can also be found that the divergence point is the corresponding position of the fault point. Because the medium voltage pulse is used to stabilize and prolong the arc time, it is easier to find the fault point waveform than the secondary pulse method. The cable fault tester often has to solve the following problems: 1. The diversity and complexity of cable faults determine that the cable fault tester needs complete functions and diverse test methods. 2. 2. To solve the fault, many instruments should be used together in order to achieve the result of solving the fault. 3. Different test methods are needed for cable insulation, fault location and different faults. 4. Sometimes the difficulty of cable fault test lies in the snow with a thickness of more than one meter and bad weather (the temperature is more than minus 20 degrees), which is also a test for underground cable detectors and testers to pass the above understanding. I believe you basically have some general and judgment on the cable fault problem and how to use the cable fault tester normally.
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During 15 years development, Noyafa has become the most famous brand in cable testing industry in China. With excellent production capability, reliable quality, good after-sales service, we get good reputation from customers all over the world.
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