Cable Fault Finding Buying Guide

Cable Fault Finding Buying Guide

2021-11-03
NOYAFA
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SHENZHEN NOYAFA ELECTRONIC CO.,LIMITED puts great efforts into maintaining the highest level of material quality and product structure from the initial phase of Cable fault finding development. Although we don’t always seek certifications, many of the materials we use for this product are highly-certified. As a result of the effort, it meets the strictest performance criteria.Many new products and new brands flood the market daily, but NOYAFA still enjoy great popularity in the market, which should give the credit to our loyal and supportive customers. Our products have helped us earn a quite large number of loyal customers over these years. According to customer's feedback, not only the products themselves meets customer's expectation, but also the economic values of the products make customers greatly satisfied with. We always make customer's satisfaction our top priority.There is a variety of services tailored to customers' needs at Best Cable Tester Supplier in China _ Noyafa, such as product customization, sample, and shipment. Cable fault finding and other suchlike products are supplied with short lead time and adjustable MOQ.
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List of Fault Finding and Detection Methods for Low Voltage Cables
List of Fault Finding and Detection Methods for Low Voltage Cables
Generally, the radiation path of high-voltage cable is easy to determine, but the high-voltage cable needs to be filled with sand bricks to be deeply buried. Its fault point is difficult to find. The radiation length of low-voltage cable is short, the radiation is random and the path is unclear. The following small series will introduce the fault finding and detection methods of low-voltage cables. You can simply understand. In order to solve the problem of low-voltage cable fault, researchers have developed and produced a cable fault tester based on the principle of impulse flash method. In order to find and detect the fault of low-voltage cable, first measure the distance with rangefinder. In fact, first judge whether the cable fault is high resistance, low resistance or grounding, and adopt different test methods according to this condition. If it is a ground fault, the low-voltage pulse method of the rangefinder is directly used to measure the distance; If it is a high resistance fault, the high-voltage impulse discharge method should be used to measure the distance. When using the high-voltage impulse discharge method to measure the distance, there are many auxiliary equipment: such as high-voltage pulse capacitor, discharge ball, current limiting resistance, inductive coil and signal sampler. The operation is troublesome, unsafe and dangerous. What is more cumbersome is to analyze the sampling waveform, The knowledge requirements of testers are relatively high. The second step is to find the path (this step can be omitted if the path is clear). When finding the path, add a signal (path signal generator) to the cable, and then the receiver receives the signal. Walk along the path with the signal once to determine the path of the cable. However, the range of this path is about 1-2 meters, which is not particularly accurate. The third step is to accurately locate according to the measured distance. It is based on the sound generated by ignition and discharge. When a loud sound is heard from the headset of the pointing instrument, that is, the location of the fault point is found. Due to listening to the sound, it takes a lot of time to find it due to the influence of environmental noise. Sometimes it can't be found until the evening. When it comes to cross-linked cables, it takes more time. Generally, the sound of internal discharge of cross-linked cables is very small. After almost no hearing, it is only measured. Therefore, this method can solve most of the power cable faults with oil impregnated paper as insulating material. For the cable faults with crosslinked material and polyethylene material as insulating material in recent years, the test effect is not ideal, because the sound generated by ignition and discharge is often very small (the cable skin is not damaged, but the internal discharge of the cable), In this case, only other methods can be used to solve it. We know that the insulation requirements of low-voltage cables are low, and the current is large during operation, which has obvious characteristics after failure. It is specifically classified as follows: class I fault: the whole cable is burned out or a phase is burned out. This fault causes the current relay on the distribution cabinet to act, and the cable is seriously damaged at the fault. Class II fault: each phase of the cable is short circuited. Similarly, this kind of fault causes the current relay and voltage relay on the distribution cabinet to act, and the cable is seriously damaged at the fault point (possibly caused by external force). Class III fault: the cable has only one phase open circuit, the current relay acts, and the damage at the fault point is light but obvious. It may be that the phase current is too large or caused by the cable quality. Four types of faults: internal short circuit of cable, no trace can be seen on the surface. Such faults are generally caused by cable quality, which is relatively rare.
What Are the Fault Finding Methods for Rural Buried Cables
What Are the Fault Finding Methods for Rural Buried Cables
After a fault occurs in an underground cable, it is generally necessary to make a preliminary judgment on the nature of the fault. Then, according to the fault type, the appropriate fault location method is adopted to preliminarily locate the fault point; Finally, along the direction of the buried cable, carefully detect the fixed point before and after the position until the accurate position of the fault point is found, so as to realize the fault maintenance of the buried cable. Today, let's learn about the fault finding method of buried cables in rural areas. 1、 Analysis and judgment method before finding the fault of rural buried cable, it is generally necessary to understand the relevant situation of the fault, then conduct comprehensive analysis, find out the cause of the fault, and then find and eliminate it pertinently. For example, finding informed parties such as constructors, wire users and other relevant personnel to understand the situation in detail may often eliminate the fault in the shortest time at a small cost. The advantages of analysis and judgment are simple and easy, no complex instruments are required, and some faults can be eliminated in time. Therefore, it is difficult to eliminate it quickly by this method. For buried wires with a length of more than 100 meters, the fault can be found by human analysis and judgment without instruments. Sometimes, it takes more than a dozen times to excavate, and it is difficult to find the fault point in more than ten days. Sometimes, it will damage other wires in the same trench and cause new faults. This method is generally not used alone, but in combination with other instrument detection methods. The failure of buried wires is caused by the following reasons: 1. External force damage: it is the main cause of the failure. For example, repeated construction above buried lines, laying water pipes, building canals, planting trees, building buildings, etc. are often very easy to damage the buried wire insulation layer, resulting in wire breaking fault or grounding fault. 2. Joint failure: due to the nonstandard joint process during construction, it is very easy to cause mechanical damage at the joint. Or there are problems such as large contact resistance and poor insulation at the joint. After the wire runs under load for a period of time, the hidden danger at the joint often causes wire breakage or grounding fault 3. Nonstandard laying: there shall be strict process requirements when laying buried wires. However, due to the large workload, wide range and shortage of personnel in rural power network transformation, there are often some non-standard construction behaviors in some areas in the construction of buried lines. For example, when the trench is backfilled, the spinning soil is not used, and the soil block containing gravel is directly backfilled, which is very easy to damage the insulating layer. 2、 The simple ground fault tester is used to test faults. At present, many brands of ground fault testers on the market have similar working principles and test methods. Its working principle is: a fixed voltage signal is applied to the grounding wire, and an electric field is formed on the ground around the grounding point. The closer it is to the fault point, the greater the potential difference between the same distance, and vice versa. According to this principle, the ground fault point can be found. The market price of this kind of test instrument is hundreds to thousands of yuan. The buried wire fault with very small grounding resistance can achieve the test purpose. The fault finding method of rural buried cable is introduced here. I hope you can use it in your work.
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