Guide to Buy Internet Cable Tester in NOYAFA

Cable plays a very important role in daily life. If the cable fails, find the fault point in time and then repair it. Cable fault detector is the preferred tool for cable maintenance. It can accurately find the fault point, and then the construction personnel can carry out maintenance quickly, which is very effective in improving work efficiency. Today, we follow the cable fault tester manufacturer to understand what pulse method is. Working principle of power cable fault tester power cable fault tester consists of three main parts: power cable fault tester host, cable fault locator and cable path tester. The host of the cable fault tester is used to measure the nature and total length of the cable fault and the approximate position between the cable fault point and the test end. The cable fault locator determines the location of the cable fault point based on the approximate location of the cable fault point determined by the host of the cable fault tester. For buried cables with unknown direction, a pathfinder shall be used to determine the underground direction of the cable. The basic method of power cable fault test is to apply high-voltage pulse to the fault power cable to produce breakdown at the cable fault point. When the cable fault breakdown point discharges, it generates electromagnetic wave and sound at the same time. The working principle of the application of arc reflection method (secondary pulse method) in cable fault location: firstly, a high voltage pulse with a certain voltage level and energy is applied to the faulty cable at the test end of the cable to make the high resistance fault point of the cable break down and burn arc. 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 complete short circuit between the core and the 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 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 fault point. Compared with the traditional test methods, the advantage of the secondary pulse method is to simplify the complex waveform in the impulse high-voltage flashover method into a simple low-voltage pulse short-circuit fault waveform, so the interpretation is very simple and the fault distance can be accurately calibrated. The multiple 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. Cable fault tester manufacturers believe that the multiple 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 multiple pulse method is an upgrade of the secondary 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 obtain the fault point waveform than the secondary pulse method. Compared with the secondary pulse method, the triple pulse method does not need to select the synchronization time of arc burning, and the operation is also more simple. Cable fault tester is a comprehensive cable fault detection instrument. It can test the high resistance flashover fault, high and low resistance grounding, short circuit, cable disconnection, poor contact and other faults of the cable. If equipped with the acoustic method pointing instrument, 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 above is the introduction of the pulse method by the cable fault tester manufacturer, hoping to provide help to those in need.

How does the cable identifier judge whether the cable is live? First: why should we judge that the cable is live: as an important instrument of power cable detection instrument, cable identification instrument has been used more and more widely. When there are multiple cables in the cable trench, it is necessary to identify a specific power-off cable, calibrate, move or cut off the cable, and other cables in the cable trench operate live, so the cable identification instrument shall be used for cable identification. Second: easy to use: compared with the cable fault tester, the use of the cable identification instrument is relatively simple. It is easier to use it by reading the instructions. Third: test example: since the cable shielding layer is usually connected to the ground, if other cables are also connected to the public ground in the cable bundle, the black output jack on the generator can be connected to the public ground, The return current is distributed in several cable shielding layers, and the return current is divided into many tributaries, which means that the difference current of the identified cable is large and the useful signal is clear. "Difference" means that the output current and its divided return current are in the same channel. As shown in Figure 4, there are 5 cables in Figure 4. Cable 4 needs to be identified. The "output current" of the cables to be identified is 20A. Assuming that the return current is evenly distributed among the shielding layers of all cables, there should be a return current of 4A in the cable to be measured. The difference in the cable to be identified is: 20A (output) - 4a (return) = 16A (difference). How to use the cable identification instrument I. working method of the cable identification instrument: the transmitter (host) is powered by 220V AC power supply, which is used for the power-off The cable to be identified, plus a fixed period, unipolar DC pulse signal. The output line of the transmitter is connected to the cable core and the grounding point or ground nail. The armor of the cable is disconnected from the earth, and the core is connected to the grounding point or ground nail at the far end. The loop can conduct pulse current, which can be read out by the meter on the receiver of the identifier. The current is determined by the loop resistance, and the loop resistance should be as small as possible. The wiring diagram of the identifier is shown in Figure 2. Note: during field use, if the grounding resistance is too small, the output current of the transmitter will also be large when the output adjustment knob is turned back to zero, and the protection circuit in the transmitter will act (shown as a small fast swing of the meter). At this time, the randomly configured 1 ohm 20W high-power resistor can be connected in series in the transmitter circuit. After the transmitter and receiver start working normally, the voltage induced in the sensor coil is displayed in the receiver header. The pointer swing direction of the header can display the current direction, that is, only the cable with current flowing out, the pointer deflects and swings greatly. This is the cable to be found. For all other cables, only the return current flows, the pointer deflects in the opposite direction and the swing is very small. The output adjustment knob on the receiver can adjust the signal strength. 2、 Wiring mode: 1. Before the test, cut off the tested cable, and the surrounding environment shall be in a safe state. 2. The generator is connected with the tested cable, and the red clip is connected with one or several cores of the identified cable. Connect the black clip to the ground nail. 3. Connect the core wire at the far end of the cable to the ground nail. 4. Disconnect the armor at both ends of the cable from the ground wire. 5. Plug the power cord into the power outlet. 3、 Identify the cable through the loop test. 1. In order to ensure the normal use of the instrument, pay attention to setting the test loop. 2. Connect the red output jack to the core of the cable to be identified, connect the black output jack to the ground, and connect the cable core to the ground at the far end. As shown in Figure 3, 3. The output current flows to the far end in the direction of the arrow in the cable, and all cores of the identified cable can be connected together through the earth return generator to obtain a clearer signal.

Cable fault tester is a common cable fault detection equipment, and its accuracy and detection speed are guaranteed. We are used to evaluating this thing before we buy it, from its performance, value, price and other aspects. After that, we will decide whether to buy it. So, what evaluation should be done when purchasing a cable fault tester? When selecting the cable fault tester, the cable fault tester needs to understand its performance. Is its overall performance stable, or is it convenient in the whole operation? If there are problems in the operation and unstable performance of the cable fault tester you choose, it will certainly lead to more problems in the whole use, not to mention that the cable fault tester you choose is a test suitable for your own use, which can not highlight its whole use value. Therefore, when selecting the cable fault tester, we should pay attention to these two points: 1. How about the performance? Before choosing a cable fault tester, you'd better understand and test several different cable fault testers, that is, find some early tests to see if they really have high usability. 2. Quickly detect the fault point and find the problem of your own equipment in a very short time, If you can, it can show that it is a very good cable fault test. If you can't meet this standard, you will waste more time and money, and the selected cable fault tester will not be suitable for your own use. Therefore, we can understand how to select a more appropriate cable fault tester. After selecting an efficient and suitable cable fault tester, the next step is how to use it. What if you can better operate the cable fault tester to enable you to quickly detect the fault point? 1. Understand the instructions of the cable fault tester. After you get a cable fault tester, you need to understand its operating instructions before preparing for operation. Some people feel that they have a certain understanding of the cable, so it is not necessary to understand its operating instructions when using it. In fact, this is not the case, Most of the time, my knowledge is very different from professional operation, so I can understand the contents of the operation manual in advance before use, which naturally has a very good guarantee for the whole operation after use. 2. Check the circuit. When using the cable fault tester, do you need to test in advance or find out if there is a problem with its circuit connection? If there is a problem that needs troubleshooting, you also need to know whether the whole connection is normal in advance, so as to have higher detection efficiency in the whole detection, know the problem of cable fault, and find a good solution, so as to ensure the working performance of the whole power system. Generally speaking, after the carefully selected cable fault tester, the equipment performance of the cable fault tester is guaranteed. In the process of cable fault detection, the corresponding fault results can be obtained according to the fault performance in the operation manual.

Relays used in the circuits of relay protection devices and electrical automatic devices are generally made of electromagnetic, inductive, electrodynamic and magnetoelectric principles. In recent years, there have been magnetoelectric devices using rectified current, magnetic relays with saturated inductance coils and electronic relays, and relays using semiconductors are being studied. The purpose of studying and adopting these new principles of relays is to simplify the structure of relays, improve their reliability and improve their parameters. Use indirect methods to indicate that there is a fault or improper working state in the power system. For example, this kind of relay has the ability to react with the generation of gas, the generation of heat, the increase of pressure, etc. The relay protection device must have the function of correctly distinguishing whether the protected element is in normal operation state or has a fault, whether it is a fault in the protection area or a fault outside the protection area. In order to realize this function, the protection device needs to be composed based on the characteristics of changes in electrical physical quantities before and after power system failure. The three-phase / six phase relay protection tester is developed by using Zui new digital technology, high-precision electronic devices, microcomputer system and new structure of line and cable fault tester. It can independently complete the device test in professional fields such as microcomputer protection, relay protection, excitation, measurement, cable fault tester and fault recording. It is widely used in scientific research, production and electrical test sites in electric power, petrochemical, metallurgy, railway, aviation, military and other industries. After power system failure, the main characteristics of power frequency electrical quantity change are: (1) current increase. In case of short circuit, the current on the electrical equipment and transmission line between the fault point and the power supply will increase from the load current to greatly exceed the load current. (2) Voltage drop. In case of phase to phase short circuit and grounding short circuit faults, the phase to phase voltage or phase voltage value of each point of the system decreases, and the closer to the short circuit point, the lower the voltage. (3) The phase angle between current and voltage changes. During normal operation, the phase angle between current and voltage is the power factor angle of load, generally about 20. In case of three-phase short circuit, the phase angle between current and voltage of cable fault tester is determined by the impedance angle of the line, generally 60 85. In case of three-phase short circuit in the opposite direction of protection, the phase angle between current and voltage is 180 (60 85). (4) The measured impedance changes. Measuring impedance is the ratio of voltage and current at the measuring point (protection installation). During normal operation, the measured impedance is load impedance; In case of metal short circuit, the measured impedance changes to line impedance. After fault, the measured impedance decreases significantly and the impedance angle increases. Negative sequence current and negative sequence voltage components appear; In case of single-phase grounding, negative sequence and zero sequence current and voltage components appear. These components do not appear during normal operation. The relay protection of various principles can be formed by using the change of electrical quantity during short-circuit fault.

The emergence of electricity has broken people's original lighting mode and provided us with a convenient and comfortable living environment. Cable has the function of transmitting electric energy and plays a very important role in life. The demand for electricity is so great that sometimes the cable will inevitably have problems. Live cable identification instrument is one of the commonly used fault detection equipment. 1. The operator shall read the operation manual in advance, master the function, working method and work preparation of the instrument, and carry out correct test requirements. 2. Before the test, disconnect both ends of the tested wire with armored grounding, and ground the far end (one end) of the core wire. 3. The two output wires of the cable identifier shall be clamped in red on the core wire of the tested wire and grounded in black. 4. Before turning on the transmitter, the output adjustment knob must be turned counterclockwise to zero before starting. Slowly adjust the output adjustment knob to make the output reach 5a-15a (usually adjust the adjustment knob in the range of two-thirds). If the grounding resistance of the distribution station system is greater than 4 ohms, the output current is less than 8a, and the receiver instrument head can work normally, as long as it can deflect in the positive and negative directions. 5. Note: during field use, if the grounding resistance is too small and the output adjustment knob of the transmitter is zero in one clock cycle, the output current will be very large, and there is a protective circuit action in the transmitter (indicating a small swing of the plug). In Article 2, in the actual test, there are more than two connections between the two transformer chambers between the same cable conduit and other cables, The grounding resistance is connected because there are other armored cables in operation, and the change is very small, even close to zero. If the output current of the transmitter is too large and there is a protection circuit, the resistance can be tested in series in the transmitter loop test. After the test, the temperature of the test resistance is very high. Note that other 1-2 ohm resistors greater than 20W can also be used instead of the test resistance. 6. Before identifying the cable on site, please calibrate the receiver of the live cable identification instrument at the beginning of the wire according to the instrument calibration requirements in the instruction manual. 7. Standard for cable field identification: when the sensor is pasted on one of the cables for test, the header of the receiver will lean to one side and swing more. When testing on other cables (keeping the clamping direction of the sensor the same), the receiver instrument head will lean to the other side and swing less. The cable with the receiver instrument head leaning to one side and swinging sharply is the cable to be identified.

The 127th China Import and Export Fair, popularly known as Canton Fair, kicked off online on June 15, a first for the decades-old trade fair, in south China's Guangdong province. This year's online fair, which will last for 10 days, has attracted around 26,000 enterprises in 16 categories with 1.8 million products. The fair will provide round-the-clock services, including online exhibitions, promotion, business docking and negotiations. NOYAFA is a high-tech enterprise specialized in R&D, production and marketing of various professional measuring instruments, including LCD cable tester, Cable length tester, Optic multimeters, CCTV monitor tester, Network cable tester, GPS land meter, Thermal imager and Laser range finder etc.

This type of cable supplies power to the device in question and transmits the video signal to the output. The prefabricated Siamese cable is available in various lengths to keep most camera cables at a distance. The optical cable tester includes a plug for visible light sources that is compatible with the optical cable installation.A cable tester is a microcontroller that displays and automates the test process and displays the test results for multi-wire cables. It connects to the end of the cable separately with a display of the current source portion to allow the injection of test current from one end of a cable to detect the results from a remote end.To check a USB cable, you can perform simple USB tests by connecting the cable end to the appropriate port on the cable tester. You can also check your cloud services, data communications and data transmission by testing connection stability with network cable testers.There are a number of methods to test coaxial cables to obtain a reliable signal frequency. Following are the steps to test a coaxial cable with the help of a multimeter probe. This is a reliable method to test the coaxial cable without signal loss.A network cable tester is a revolutionary device designed to test the reliability and capability of cable connections. It is a necessity for network technicians, network testers, cable testers and other related work in this field. Cable network testers are not only reliable, but also able to fix problems and help you identify cable problems and connection problems.The coaxial cable RG-179 uses a 7.5 Ohm BNC connector and can be used in high temperatures. RG-6 coaxial cable is the "coaxial cable for the Internet" - it is used to transmit the signal over the Internet connection (the Internet signal runs at a higher frequency than traditional analog video). It can be operated up to a distance of RG-59 without loss of the video signal, but it is a thick and rigid cable that is not comfortable to work with.The RG-174 coaxial cable uses the 50 ohm BNC connector and is thin enough for wide applications such as GPS navigation antennas for cars and many vehicles. RG58 coaxial cables use the 50 ohm BNC connectors and are versatile due to their performance. The RG-59 coaxial cable is used to transmit video signals from a CCTV camera to a monitor in another room.Although 75 Ohm coax is likely the impedance found in most of today's applications, it is important to note that all components of a coaxial cabling system must have the same impedance to avoid internal reflections at connecting points that can cause signal loss and poor video quality. High-capacity cables can distort the transmission of digital signals by reducing the distinction between graduated peaks and sinks. 75 ohm coaxial cables are therefore of great benefit for digital transmission, and their lower capacity than 50 ohm cables ensures that all digital transmission passes through the wire with minimal losses or distortions.Digital Signal 3 signals (DS3 signals), which are used to transmit data traffic to the control panels, are called T3 lines and use coaxial cables comprising 7.5 ohms (type 735) and type 734. Type 735 cables are used for distances of up to 6.9 metres, while type 734 cables can be used for distances of up to 13.7 metres.There are various types of adapters for BNC connectors, including T connectors, cylinder connectors and terminators. They can be plugged into any type of connector or SDI signal transport connector.Choosing the right cable is a major problem that plagues most companies and teams. Choosing the right BNC connector for the cable for your project comes at a price. To avoid problems with your network, use BNC connectors instead of compressing or bolting cables.This guide to cabling security cameras provides a practical explanation of the cable types of surveillance cameras and termination cables for easy installation. Siamese cables for surveillance cameras are a two-wire solution with a cable assembly that enables easy video and power transmission to the BNC camera. Curveball Cat5E and Cat6 cables are used to send the video signal to the camera using a video balun adapter.When using a video balun network, the cable does not tip over and requires the lead wire to be exposed by removing the outer layer of the wire at each end.Connect one end of the coaxial cable tester to the socket and bring the other end to a point where several coaxial signal cables meet. The video signal and power supply are transmitted via a single network cable, similar to how Siamese cables work. Another method for network cables is to crimp the RJ45 connector and plug it into the socket of a video power baloon.When you touch the multimeter probe on the end of the right coaxial cable, the meter reads 0 but you will see different readings on the other cables.If your coaxial cable is on the wall, connect an end of the coaxial cable tester to the wall plate and point the other end to the tester to facilitate assembly of the entire cable. To find the right cable, touch the cable one way or the other and a beep will be generated. If it is the antenna on your roof, you can use a multimeter with an aluminum coil to track the right end of a particular coaxial cable.Once you traced and identified the coaxial signal of the cable that you want to test with a multimeter, the next step is to figure out how to perform the task. Touch the center of the conductor end of your coaxial cable with the multimeter probe.Confirm that the shielding patency at both ends of your coaxial cable is in good condition. A second test should be performed on the coaxial cable to determine the status of the screen continuity.

The introduction of wire trackerIn recent years, the use of wire trackers has increased due to their ease of use and effectiveness. For those who need to be in touch with their customers around the clock, this is a convenient way to stay connected.In recent years, there has been an increase in the use of wire trackers. For those who need to be in touch with their customers around the clock, this is a convenient way to stay connected.Tips for wire trackerWiretrackers are the unsung heroes of copywriting. They are in charge of making sure that all pieces of copy are correctly placed and that anything content is coherent and easy to understand.While there's no standard set of things that a wire tracker does, here are some tips to help you do your job better:1. Make sure to keep a clean layout- it is important for wire trackers to be able to easily read what they're working on. Keep spacing between paragraphs and between headlines and text clear so they don't have any trouble doing their job.2. Put yourself in the reader's shoes- while you're writing, think about what the reader would be looking at if they were reading this article in print.How to use wire tracker?Wire tracking is a writing tool used in copywriting that consists of a thin wire with a pen attached to it. The wire is used for creating the first draft, and then the pen is used to edit and refine the work.It can be helpful for writers to use wire trackers when they are stuck in creative block or need fresh ideas right away.The specifications of wire trackerWire trackers are used to connect the two wires of a circuit to one another. They are commonly made of copper, aluminum, or rarely steel.Cable wire trackers help you to make an easier and more efficient connection between two wires. It is also important to make sure that the wire connections will be strong enough and will not break easily.The very first step you should take is measuring the length of each wire before deciding which type of tracker you need for your project. The size usually depends on what type of connector and junction box you're using for your project.The product instructions of wire trackerWire trackers are an essential part of any electrician's toolkit - they're used to make electrical connections and can be found in a variety of shapes and sizes.Whether you're an electrician or not, we all use tools like wire trackers daily. When you pick up a new product from your favorite hardware store, just like the one shown in this article, you'll likely find that the instructions are missing. However, this is often intentional as the manufacturer doesn't want to ruin their product by giving away too many tips.Sometimes however, there isn't a manufacturer or distributor for a specific product. In those cases, it's up to us as customers to figure out how best to use our new purchase. And that's where our guide comes in!The application of wire trackerWire tracker is a device that helps to install new wires and cables in difficult to reach places. It has a rotating saw which can cut through steel, plastic, copper, and wood.Wire trackers have been made in different sizes from 8’ to 16’ in order to cover a variety of applications. Its main purpose is to enhance the efficiency of the workers by making it easier for them to install cables or wires.The most important reason why wire trackers are popular with people is because they provide an efficient means for people who need to make repairs on their home or when they are doing renovations.

In the whole process of application of high-voltage wires and cables, if a common fault occurs, it will lead to the final disconnection of the power supply system. It is necessary to carry out inspection immediately and quickly find the common fault point. The cable fault tester must be used. In this paper, we will briefly introduce in detail the functions of the cable fault tester. System software composition of cable fault tester: the cable fault tester is composed of test host, relative path signal generator, relative path signal receiver and detector. The cable fault tester includes integrated computer, bottom pressure single pulse generation and data processing methods to detect the spacing of common faults, and can also be used to accurately measure the length of cable and the rapid propagation of electromagnetic wave in cable. The relative path signal generator generates intermittent sinusoidal waveform data signals with a frequency of 30kHz and a force of 30V to find the relative path of the cable. The relative path signal receiver is used to receive the relative path data signal to search the cable route and estimate the depth of cable laying. The detector is used to accurately locate common fault points. Technical characteristics of cable fault tester: 1. Fault test system software: it can detect various common faults of various wires and cables, as well as the common faults of lead and short circuit faults of coaxial output power cables and local call cables. It can measure the propagation rate of electromagnetic waves in all known cable wires. The detection distance shall not be less than 16km 2. Relative path signal generator: output data signal frequency 30kHz, oscillation method, intermittent 3. Detector: detection sensitivity: 50 & omega; The video signal of the internal resistance outputs a 300Hz data signal, and the designated instrument inputs the data signal no more than 10&mu under the condition that the output remains 2V and the signal-to-noise ratio is better than 20:1; v. Input impedance: not less than 1.2k & omega;. Fault test method: the fault test is generally divided into the following processes: first find out the basic situation of common fault cable: measure the grounding resistance of common fault cable with megger and multimeter, and accurately measure the total length of cable with bottom voltage single pulse, whether there is disconnection, short circuit fault, etc. Second, according to the details of common faults, determine the appropriate detection methods and accurately measure the cable fault spacing. Generally, people set the common disconnection faults and resistance measurements at 100 & omega; The following cable faults are called low resistance (pilot) common faults, which are detected by bottom voltage single pulse method, and other common faults are detected by impulse flash method or direct flash method. Third, detect the relative path and depth of cable laying around common fault points. Identify the exact location of common fault points. Disconnect all connections between the cable head end and the terminal equipment head before testing. The control panel of the detection system software is equipped with two buttons for inputting amplitude and offset, which are respectively used to adjust the left and right parts of the input data signal strength and wave pattern for the next sampling.

Recently, many friends have consulted about the selection of cable fault detection equipment. Whether the matching of cable fault detection equipment is correct will directly affect the use effect of the equipment. It is only necessary to select the corresponding supporting equipment according to the cable condition of the unit to ensure the reliability and convenience of the test work. Now let the cable recognizer manufacturer introduce how to select the type. Generally, cable testing equipment can be selected according to the following principles: first, selecting perfect service is the primary factor; In recent years, due to the increasing popularity of cable test equipment faults among domestic users, domestic manufacturers and dealers are also increasing. Choosing reliable manufacturers and whether they can provide high-quality services should be the only correct choice for users to choose cable test equipment at present. 2、 Products with advanced performance are the best choice; Since it came out in the 1970s, the cable fault tester has undergone years of continuous improvement, especially the application of computer technology and high-speed sampling technology in the 1990s, which has revolutionized the performance of the instrument. By transforming analog test technology into digital test, the test waveform can be permanently saved or printed. Wave storage problem: due to the rapid development of microcomputer technology in recent years. Due to the adoption of new electronic components and new technologies, cable fault detection technology has developed greatly. The previous single waveform detection has been gradually replaced by a series of waveform processing technologies such as multi waveform display, waveform superposition and waveform comparison. Modern new cable fault tester generally has waveform storage function. Due to different models, the number of stored waveforms is also different. Generally, there should be at least two groups of waveform storage in use for comparison when analyzing waveforms. The advanced test instruments currently designed have on-site protection function. No matter when you start, you can reproduce the last test waveform. In this way, it plays an important role in summarizing and summarizing data in the office after the on-site test. In the design of old-fashioned instruments, the memory will be cleared after startup for test preparation. The test waveform will be lost and no data will be retained in the instrument. Automatic identification of waveform: the cable fault tester mainly collects and displays the waveform of cable fault discharge in the test process, and generally needs to analyze and judge the collected waveform manually. Therefore, the analysis level of the operator is required to be high, and the inexperienced operator is often unable to correctly judge the fault waveform, resulting in the query cable fault can not be handled correctly. And the existing new cable instrument has the function of automatic identification.