Hybrid Circuit Fault Diagnosis Based on Current Test

You are ready to start shopping now that you know a little more about what is involved in selecting a good voltage tester. Below are details of the best voltage testers on the market from trusted brands that manufacture high quality electrical tools. Trusted manufacturers in the power tool industry specialize in making electrical tools for professionals, and their products are top notch, with many professionals using gauges that they have purchased for decades.To help you find the best network cable tester for your use I have compiled a list of test products that work. I came across the Elegiant Network Cable Tester while working on establishing a LAN connection for a local company. With my extensive experience as an electrician, I can say that this is the best tool for testing cable connections.During the test, make sure you remove the cable from the computer, modem and router. Network cable testers are great for checking cable continuity and ensuring that the signal gets through. Klein Tools VDV501-823 and V DV Scout (r) Pro-2 test kits test voice (RJ11-12) and data (RJ45) via video-to-F connectors and coaxial connections.Platinum Tools TCB360K1 Cable Prowler (tm) Pro Test Kit - Full color cable length gauge with the ability to determine connection status, connectivity and POE detection. I love this type of cable tester because it provides accurate and accurate measurements of the integrity of cable connections. Make sure your cable and network connections are in top shape with this product.Network cable testers are sensitive products that are exposed to various extreme elements, so I suggest getting a tester with a longer warranty. A cable tester checks the electrical connection between signal and cable and confirms things like the wires at the end of the cable. With the HOSA CBT 500 you can test your cable gigging quickly and easily.Selecting, selecting and purchasing a suitable network cable tester can be a complicated and challenging task. In this article, a demanding effort is made to show you how you can test the continuity of circuits and how a good continuity tester will handle your situation. For example, suppose you are looking for a good Ethernet cable tester or an Ethernet cable speedometer.Continuity checks are indispensable for cable installation, cable marking, troubleshooting in the circuit and polarity testing. I have written this conclusion so that people can begin to make up their minds after reading this article. Here's a look at the best recommendations for the best continuity testers on the market.A continuity tester is an electrical test device that determines whether an electrical path has been established between two points where an electrical circuit can be produced [1]. The circuit is tested by activating and connecting the device. A voltage tester or plug analyzer detects the presence of electrical voltage.Voltage testers and socket analyzers indicate to which socket a device is connected. They are used for cables, wires, circuit breakers, lights, sockets and switches. A socket tester is the size of an electrical plug and works with any plug or socket.A fast, acoustic alarm test uses a digital multimeter to determine whether a circuit or line is complete or defective. A Fluke T6 1000 Pro electric tester with multimeter and field sensor not only detects the voltage, but also measures the voltage when disconnected from the outlet. During the sliding test of the fork wire, the tester reports the condition of the wire.The Fuke T6 1000 Pro electric tester also has other common settings that you would expect from a multimeter, including AC / DC resistance and Amperage measurements. One leads to the circuit breaker and fuse box, and the other conducts the current to other devices in the circuit. Using a multimeter, you can see whether the white or black cable is in the inverted socket and whether the earth cable inserted into the box is connected to the socket.When the receiver passes the correct circuit breaker, it emits a noise or light. To determine how hot the cable is, turn off the power, disconnect the socket and place a cap on the cable, usually one of the black ones. An electrician knows that with an electrical tester in his arsenal of tools, you never have to worry about getting a shock.It's the tester you want when you're constantly working with cables and circuits. If you work with coaxial cables, get a special tester, whether you are using a VDV512 or 007. Just like James Bond, they can spy on the cables and help you identify and label the right ones.

TCB360K1 Cable Prowler (tm) Pro Test Kit Full-color high-end cable length gauge with the ability to determine connection status and connectivity for POE detection. Klein Tools VDV501-823 VV Scout (r) Pro 2 Tester Kit Test Voice (RJ11-12) and Data (RJ45) via Video-to-F connector or coaxial connection. Before testing, make sure you remove the cable from your computer, modem or router.A cable tester checks the electrical connection between signal and cable and confirms that everything is wired correctly at both ends of the cable. With the HOSA CBT 500 you can test your cable gigging quickly and easily.Check that the cable connection you want to test is ready for analysis and that the tester is not electrocuted or that the device breaks. Test your network cables as with a network cable tester and run the test. If you connect both ends of the cable, a network cable tester will do the job for you and get an accurate reading of whether your cable is working or not.If you need to test voltage and current continuity, you should get an electric tester. With these testers you can test the cable against volts, current and ohms to check if the circuit is short-circuited through the cable. The testers can measure both AC and DC voltage and current in seconds.Continuity tests help to verify and reverse electrical circuit connections. For example, when two wires melt in a sheathed cable, a continuity detector lights up when you touch one probe with the black wire and the other with the white wire. Continuity testers are also excellent for checking if the wires are running smoothly and to see if the circuit is complete.Continuity checks can also be used to detect problems with cold soldering between wires or wire products. In addition, this type of electrical testing can also be used to check connection pads and traces on printed circuit boards (PCBs ).The most common and basic method to perform a continuity test with the help of a resistance tester is a simple multimeter function. Specialized continuity testers are available, but the most basic is an inexpensive light bulb that lights up when electricity is flowing. A digital multimeter continuity test can be used to test switches, switches, fuses, electrical connections, conductors and other components.A continuity tester consists of a battery, a housing, a probe connected to one end of the housing and a test wire connected to the other end with an Alligator clip. A continuity test on an electrical circuit is performed when it is not switched on by using a tester. To use a continuity tester, first pull the device off the connector and disassemble it to get to the component you want to test.Continuity testers are easy to understand: they consist of a battery housed in a housing, a cover, a probe for testing the wire, a tensed end of the battery in the housing and an alligator clip for the second end.A continuous tester is an electrical tester used to determine whether an electrical path has been created between two points [1] where an electrical circuit is produced. Its user-friendliness is determined by the fact that it is a power switch to determine whether an electrical device maintains a flowing current flow in its body. If this is not the case, it is used to find out the root of the problem within the device.Testers are excellent for checking whether a device is working properly, such as a single-pole switch, or for checking lamp wiring to see that electrical paths are intact. Make sure you turn off the power for the circuit or the device you are testing. These test tools allow network technicians to isolate cabling problems and network protocols to solve problems.This works with any coaxial cable with a special tester, whether you are using a VDV512 or 007. Like James Bond, the tester will spy on the cable and help you identify and label the right cable.A continuity tester is a special electrical device used to check the continuity of cables and wires in a circuit. A network tester calculates the signal and power transmitted from one end of a connection to the other in a twisted pair. If the cable is continuous, this means that all voltages applied to the cable are in the same place.If you want to check the quality of your cables, use a standard tester. Professional network testers are used in commercial environments and are used by certified professional cable installers to get the job done.Test tools do not provide bandwidth readiness information for high-speed data communication. Certification audits are a way for installers to ensure that the cable fed into the network meets TIA and ISO requirements. These tests are performed by professional network testers and certified installers.To help you find the best network and cable tester for your use, I have compiled a list of test products that work well. The LinkIQ cable network tester is easy to use as explains Eric Webb, Flukes Network Product Manager, in the video below. It shows the settings to use and how to use them to perform cable tests, save the results and upload them to linkware where they are available.I came across the Elegiant Network Cable Tester while working on establishing a LAN connection for a local company. With my extensive experience as an electrician, I can say that this is the best tool for testing cable connections.Selecting, selecting and purchasing a suitable network cable tester can be a complicated and challenging task. In this article, a great effort has been made to show you how to test the continuity of circuits and how a good continuity tester will handle your situation. This article examines which tools are best suited for normal cables, which are best suited for coaxial cables, which are to be used and which cable types are to be considered when measuring the limit values.

A voltage detector is a quick and inexpensive method to check the presence of voltage in an AC circuit, switch or socket without actually working with it. Also known as a voltage rod, rod, sniffer or pin, a voltage detector clings to a shirt pocket and beeps or glows when it detects voltage in a conductive part of the insulation.Voltage detectors are used to repair electrical circuits, detect live neutral wires and in other situations where you need to verify the presence of electric current. These types of voltage detectors are designed for the non-contact detection of electrical circuits in residential, commercial and industrial buildings. Random contact with live electrical conductors is no problem, and the detector evaluates the voltage level in the electrical safety category for which it is used.The voltage tester Klein Tools ET40 is ideal for checking regular electrical cables, door bell sockets, lights and other devices. It has functions for displaying positive and negative DC polarity and is able to detect DC voltage currents as low as 1.5 V. In addition to detecting standard voltages and low voltages, voltage detectors and LED testers can also detect rated voltages.A good voltage tester not only saves you time, but also gives you the certainty that your electricity prices are normal. The best voltage detector pins operate in a wide voltage range and are able to provide acoustic and acoustic feedback when detecting voltage. They are small enough to be transported and provide a precise reading that tells the user whether voltage is present or not.Reinforced electronic testers (also called electrical testers, pins and voltage detectors) rely on capacitive currents to detect changes in the electric field of an energy-charged object. Non-contact voltage testers (test pins, voltage sensors, voltage testers and pins they know) are the safest way to ensure that an electrical conductor has no voltage without touching it or suffering an electric shock. They work by detecting changes in an electric field surrounding an object conducting alternating or alternating current.Non-contact testers allow you to check the voltage of a wire or device without having to touch the wire or part. A voltage tester can be used to test the presence of voltage when a multimeter cannot detect it and to measure and display the exact amount of available voltage. These testers are designed to detect the main voltage and do not provide any indication of low voltage control circuits used in the bells or HVAC controls.A further limitation is that DC voltage can not be detected with this method because DC currents do not flow in a uniform state through capacitors and non-contact testers that detect electrical fields cannot be activated. You cannot detect voltage through shielded or armoured cables, and this is a basic limitation due to the Faraday cage effect. A TONG or AMmeter detects changes in magnetic fields, while a detector uses current flowing through the wire in question, and it senses alternating electric fields emitted by AC conductors.Given the variety of products in the contactless voltage tester category, you can expect different types of NCVTs, but you can imagine that there are more contactless DC voltage testers and contactless DC voltage testers than there are regular DC testers on the market. Remember to use a quality insulation resistance tester when you need to measure the insulation around your circuit. You want a non-contact voltage tester that comes with a hook so that you can put it in your shirt pocket.I call it the voltage sniffer, but the technical name for it is the capacitive voltage sensor. It is supplied with an alligator clip, which is interchangeable with test cables, and a holster to keep it handy. It uses black magic to determine whether wires are live or not, and it is 100% reliable at all times.

The tester is designed to detect the main voltage and does not provide any indication of low voltage control circuits as used in doorbells and HVAC controls. A voltage detector is used to detect sockets, power supplies and insulated wiring. Unlike a tonne or an ammeter, which detects changes in a magnetic field, a detector uses the current flowing through the wire in question as it detects alternating electric fields emitted by the AC conductors.In order to reduce the potential for false alarms on low voltage devices, I recommend inspectors to use a voltage tester starting at 90 volts. I don't buy voltage sniffers that run on button batteries because they're hard to find.It costs a little more than most other voltage sniffers, but it's worth the price. I've had it for three years and it's the most reliable and robust non-contact electrical tester I've ever owned. The non-contact voltage tester is a great voltage tester that can be called Fluke, and is characterized by a compact design that is easy to use.A good voltage tester should be small enough to carry and provide an accurate measurement that tells the user whether voltage is present or not. Each time you use the tester, voltage sniffer manufacturers recommend testing with a known power source to ensure proper function.To use a non-contact voltage tester, touch the tip of the tester with the wire you test with the socket and the tip must be placed with a small slot on the front panel. Manufacturers of voltage sniffers also recommend holding a tester with bare hands and keeping it close to the body. Fluke 1AC-II Non-Contact Voltage Test Tip: A bright red beep that sounds when voltage is detected.The invention of the non-contact voltage tester described above is a kind of voltage indicator that produces a signal of limited duration when the operator switches on to turn the tester on, which is operated by the user when no voltage at the probe tip is detected. The signal tells the operator that the battery is on, indicating that the device has a light or sound source at work. The use of voltage testers consists of touching one probe on a wire connection and the other probe on the opposite wire connection.Under certain circumstances, the voltage sniffer may not be able to detect the current if you do not hold it down, as shown in the following clip. In the United States, the Consumer Product Safety Commission states that the button can remain pressed during a power-to-power cycle, causing the tester to work incorrectly.Voltage is the potential difference between the two conductors and the ground. Measured as voltage in phase, a phase of zero volts indicates that the two energized conductors are in the same phase.The reading is the product of the current flowing through the circuit and is calibrated to read the voltage in kilovolts. The test lamp, the test light or the main test meter is an electronic tester used to determine the presence of electricity in the device under test. A test light is a simple but expensive measuring instrument, such as a multimeter, which is sufficient to check the presence of a voltage in a conductor.Choose a detector that displays the power level with an acoustic, visual or vibrating signal. Find a variety of Grainger voltage detectors to test battery and circuit integrity.CAP-40 houses the battery [41], which supplies the voltage detector circuit with energy (Fig. The additional energy from the lamp and the power amplifier is supplied by a small internal battery that does not flow through the user's body.The socket tester is about the size of an electrical plug and works by plugging it into the socket. They have grooves that hook into the surrounding wires and detect the voltage of the lead wire at the point where the tester checks the contact with the socket. The tester can test voltage and polarity and check the outlet wire, but it is not able to test the circuit directly at the outlet itself.Techineer is not responsible for any import duties or taxes, including VAT, that occur when a shipment reaches your destination country, and these are only your responsibility as a customer.We approach each case on a case-by-case basis and try our best to find a satisfactory solution. After talking to a 20-year veteran electrician and testing seven leading models for eight months we found that the Klein NCVT-3 was the best model.

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 camera's video feed in real time based on the additional features that they provide. The basic feature of a CCTV tester is an LCD display (25 inch x 3.5 inch diagonal) that allows the installer to view a camera feed on the spot. If the camera is set up in a separate area, the installer must run the feed to refine the settings.Other features of video calibration include video test patterns, the brightness, contrast and saturation adjustment, video signal intensity testing and support for PAL and NTSC video. 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. As with all our CCTV test monitors, we offer a one-year warranty of CCTV Camera Pro.All three options can be used together, but there is a higher tendency for IP camera systems than for digital video cameras. IP cameras have the ability to contain more cameras than one to cover wide angles captured by multiple cameras and camera systems to cover everything.The warranty does not cover operating system errors caused by third-party apps. On the Software Update screen, select Manual Updates and select Apps to Update. All features, including apps installed since the last factory reset, can be removed.Send your physical sample copy of your Dreiklang order to the address above. This allows you to store your videos in the cloud with EUFy's own subscription storage plan. For 10 days cloud video storage for a camera, you need to subscribe to a 200GB iCloud storage plan for $3 a month.Prisons use video surveillance to prevent drones from selling drugs and other contraband to prisoners. Disaster management uses CCTV cameras to allow emergency services and responders to assess and monitor events in real time and video the situation to the disaster management team.The CCV technology was first developed in 1942 by German scientists to monitor the launch of the V2 rocket. With road surveillance cameras and traffic lights, cities can monitor people, collect traffic statistics, evidence and speed. The legacy of the IoT (AOT) is the Chicago Initiative, which collects real-time weather and environmental data in Chicago.It is essential to constantly clean, pre-test and calibrate CCTV testers. To ensure accurate testing, it is important to study CCTV systems and conduct tests with tools that measure the performance of multiple indicators. A man on a ladder who manipulates a camera not only walks around, he measures the video signal and evaluates the running camera.This is a quick test for the effect of measuring the input and output video signal by examining a device. The same man who climbs a ladder and manipulates a camera can also do so with other video devices such as video splitters, disconnectors, switches, route switches, cable connectors, etc.With this connector we can connect the camera to its output and check the level of the video signal. It's a handy solution for men who have a ladder to manipulate the camera. You can connect the cable to the LED cable of the monitor to check the signal.Contrary to the impression, the 1.2V voltage causes many problems when we supply the camera with a long cable. The voltage loss caused by the greater resistance of the cable reduces the value of the camera clamp and interferes with proper operation.A tester with a USB port can charge mobile devices, but does not have a data interface. Android devices, mobile phones and tablets do not support hosting of USB sticks.As soon as the power switch is in position, press the power button to switch the tester to off mode and dim the backlight. 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.

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.

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.

The medical and pharmaceutical chamber of Commerce of the all China Federation of industry and Commerce established the medical device Professional Committee yesterday and issued the 2012 analysis statement of the medical device industry. The statement shows that the dependence of some domestic high-end medical equipment markets on imports has decreased slowly last year. According to the deployment of deepening medical reform and the spirit of the 2012 national health work conference, the statement implies that China's medical device industry achieved a total sales revenue of 68.7 billion yuan in the first half of 2012, a year-on-year increase of 20.27%, The overall requirements of this year's work are: closely focus on the central task of deepening medical reform. It is predicted that China's medical devices will maintain rapid growth in the next 5-10 years, and the industry as a whole will maintain a growth rate of more than 20%. Among them, the focus is on food safety, occupational disease prevention and drinking water safety. According to the statistics of the statement, at present, although the number of medical device enterprises across the country has reached more than 14000, the competition pattern of the medical device industry is relatively scattered. In 2012, the food safety and health supervision of the health system should pay close attention to the following aspects: first, do a good job in food safety, More than 80% of them are small and medium-sized enterprises. The scale of enterprises is small, and there are problems such as insufficient R & D investment and weak technical ability. Because of fierce competition and low profitability, enterprises can only produce medium and low-end products or provide spare parts for foreign enterprises. " The head of the association hinted.

1. Firstly, it is necessary to judge whether the cable fault is high resistance, low resistance or grounding. Different test methods can be adopted according to this condition. Two or three pulses can be used to measure the fault distance. Compared with the traditional test methods, the advantage of the two or three 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. Therefore, the interpretation is very simple and the fault distance can be accurately calibrated. 2. When finding the path, the manufacturer of the cable fault tester shall add a signal to the cable, then the receiver shall receive the signal, and walk along the path with the signal to determine the path of the cable. 3. Accurately locate according to the measured distance. When the cable fault tester manufacturer hears a loud sound from the headset of the pointing instrument, it is to find the location of the fault point.

1. Rough measurement of power cable fault (1) bridge method bridge method is a classical method of power cable fault location, which has a long history. Including DC resistance bridge method, DC high voltage resistance bridge method and capacitance bridge method. The resistance bridge method can only test some cable faults with low insulation resistance between single phase and ground or between two phases; High voltage bridge method is mainly used to test single-phase grounding fault or phase to phase and ground fault of main insulation with resistance greater than 10k Ω but less than megohm; The capacitance bridge method is mainly used to test the open circuit and broken wire fault of cables. The bridge method is relatively simple and convenient to operate, but it needs to know the original data such as the accurate length of the cable in advance. At the same time, it is not suitable for detecting high resistance faults. Most of the actual power cable faults are high resistance faults. Because the bridge current is very small when the fault resistance is very high, it is difficult for general sensitive instruments to detect. (2) Traveling wave method 1) low voltage pulse method low voltage pulse method is mainly used to measure the fault distance of open circuit, short circuit and low resistance faults of cables; At the same time, it can also be used to measure the cable length, wave velocity and identify and locate the middle head, T-joint and terminal head of the cable. Test principle: input a low-voltage pulse signal from the test end to the cable, and the pulse signal propagates along the cable. When encountering the impedance mismatch point in the cable, such as open circuit point, short circuit point, low resistance fault point, etc., a reflected pulse will be generated. The position of the fault point is calculated according to the round-trip time difference DT between the reflected pulse and the transmitted pulse and the pulse propagation speed v. 2) High voltage pulse method high voltage pulse method uses high voltage signal to turn cable fault into short circuit or low resistance fault instantly, so that the reflection coefficient of fault point is close to - 1, and the fault point almost produces total reflection. There are usually two basic flashover methods, namely direct flashover method and impulse flashover method. When testing cable fault by flashover method, the reflected wave formed at the cable fault point is high-voltage pulse wave, which cannot be displayed directly through the instrument. Generally, a sampler is needed to convert the high-voltage pulse formed at the fault point under the action of high voltage into the low-voltage pulse signal required by the instrument. According to different sampling methods, it is divided into voltage method, current method and voltage induction method. Wherein, R1 is the voltage dividing resistance, R2 is the sampling resistance, LP is the current sampler, C is the energy storage capacitor and B is the transformer. DC high voltage flashover method (direct flashover method): apply DC voltage to the fault cable to make the fault click through the room for discharge and flashover. Then, the fault distance can be calculated according to the transmission speed V of the traveling wave in the cable. The direct flash method is mainly used to test the flashover high resistance fault of power cable, and can also be used to test the leakage high resistance fault with particularly high resistance but lower resistance compared with the intact phase. Figure 6 shows the principle circuit of direct flash test. Impulse high voltage flashover method (impulse flashover method): due to the large equivalent internal resistance of DC high voltage power supply used in direct flashover method, the power output power is limited to a certain extent. For most leakage high resistance faults, direct flashover method cannot be tested. The impulse flashover method uses the high-capacity charging capacitor as the DC high-voltage power supply, which is connected to the fault cable to cause the flashover and discharge at the fault point to form an instantaneous short circuit. It is mainly used to test the leakage high resistance fault of power cable, and can also be used to test the low resistance, open circuit and flashover high resistance fault of power cable. The test principle circuit is basically the same as that of the direct flash method, except that a spherical gap is inserted between the energy storage capacitor and the cable, as shown in Figure 7. 2. Precise measurement of power cable fault point (1) acoustic measurement method uses the sound wave generated when the fault point is discharged for fixed point. The sound sensor detects the sound signal above the power cable. The place with loud sound is the location of the fault point. The farther away from the fault point, the smaller the vibration sound. (2) When the fault point flashover discharges under the action of impulse voltage, the acoustic magnetic synchronization method receives the electromagnetic wave and vibration sound wave generated by the discharge of the fault point at the same time, and judges whether the measured signal is generated by the discharge of the fault point to accurately judge the location of the fault point. (3) The audio induction method adds a certain power low-voltage audio signal to the fault of the cable at one end of the tested circuit. When the tested signal is transmitted to the short-circuit or disconnection point, it cannot continue to transmit along the cable, so there will be obvious signal size changes on both sides of the cable fault point. If the signal changes are detected through the receiver above the cable path, The location of the fault point can be determined. At the same time, the accuracy and integrity of various basic data of cables are also very important to improve the efficiency of fault point finding, such as cable laying direction, total cable length, distribution of cable intermediate joints, etc.