How to Quickly Detect the Fault Point of Low Voltage Cable
In many years of specific work, people have found that there are many differences between the common faults of high-voltage cables and low-voltage cables. Most of the faults of high-voltage cables are dominated by common faults of operation, and most of them are common faults of high resistance, which can be divided into leakage and flashover; The common faults of cable can only be led, short circuit and open circuit (naturally, high-voltage cable also includes these three conditions). In addition, the cable also has the following characteristics in the whole process of specific application: 1. The laying is blind, and the relative path is not very clear. 2. When laying, it is not buried after filling sand and bricks like high-voltage cables. On the contrary, the buried depth is shallow, which is easy to be damaged by external forces and common faults occur. 3. Cables are generally short, ranging from tens of meters to 500 meters, unlike high-voltage cables, which are usually 500 meters to many kilometers. 4. The compressive strength of the insulating layer is low. When solving common faults and making connectors, the processing technology is relatively simple. 5. Most cables are often burnt and damaged at common fault points. The common fault point is that there is no mark on the surface of the cable, which is very rare. â the required load changes greatly, and the two colors are usually unbalanced, which is very easy to get hot, resulting in common faults. Considering the above characteristics of the cable and the proposals clearly put forward by many customers and the specific application status of people in each region, the scientific research staff has successfully developed and designed the DW cable fault test mobile phone positioning system: the system software includes two parts: rangefinder and detector. The range finder of hn-213x system software is a completely intelligent system and personalized design scheme. It automatically detects the cable fault point without manual service, analyzes the common fault wave type, and immediately gives the distance between common fault points and common fault characteristics. The rechargeable battery power supply system is selected, which is convenient for field work, small in size, light in weight, easy to use, and does not need all auxiliary machinery and equipment. The cable fault detector of hn-213x system software is an instrument and equipment for simultaneous and accurate positioning and detection of the laying relative path, buried depth and common fault points of directly buried cables. Because it is a mobile phone positioning system for common cable faults based on the magnetic effect of current and the basic principle of step voltage, it mostly considers all standards of cable fault test. This kind of detection system software has many advantages compared with the cable fault detector based on the impulse flash method: 1. A variety of test standards are integrated and the results are mutually certified to clarify the uniqueness of common fault points. 2. Small size, light weight, easy operation by one person, no auxiliary machinery and equipment. 3. The rechargeable battery power supply system is selected, which is suitable for field work without ignition, charge and discharge. 4. The relative path search of cable (which can be clearly in the middle of 30cm), buried depth detection and accurate positioning of common fault points are carried out in the same step with high efficiency. 5. Clarify the common fault points, and the instruments and equipment have visual display information without wave type analysis. â it will not be harmed by underground conditions (such as bifurcation of cable, bundling, distortion of connector, etc.). Like detecting bombs, it searches common fault points point by point, and the accurate positioning deviation is within more than ten centimeters, which is very accurate. â it will not be harmed by ground conditions, such as floor tiles, road greening, concrete ground, etc. 8. Check the safety on the spot, there is no risk to the inspector, and there is no secondary damage to the cable. â high quality and low price are acceptable to ordinary customers. We know that the insulation layer of cable is relatively low. In addition, the electric flow is very large in the whole process of operation, and there are significant characteristics after common faults. The actual classification is as follows: the first kind of common faults: a piece of cable is burned out or a phase is burned out. This kind of common faults lead to the posture of current relay on the distribution box, and the cable is seriously damaged at the common faults. The second type of common fault: short circuit fault of each phase of the cable. Similarly, this type of common fault causes the current relay and voltage relay on the distribution box to be in a bad position, and the cable is also seriously damaged at the common fault point (possibly caused by external force). The third type of common faults: the cable can only be short circuited in one phase, the current relay posture, and the common fault points are slightly damaged but significantly exposed. It may be due to the high voltage of this phase or the quality of the cable. The fourth type of common fault: internal short circuit fault of cable, no mark can be seen on the surface. This kind of common fault is generally caused by the quality of cable, which is relatively rare. Common faults of hn-213x cable can be easily detected by the fusion application of rangefinder and detector in mobile phone positioning system. In addition, the characteristics of different common faults and the length of cable can also be detected separately. The actual situation is as follows: the first type of common faults and the second type of common faults. If the cable is short (less than 500m), the common fault detector can be used to accurately locate the common faults immediately without the cooperation of the distance finder. The common fault points can be identified by stepping in the hand receiver along the relative path (the relative path can be measured while walking). The third type of common fault: because the cable is slightly damaged at the common fault point, the data signal sent by the transmitter leaks less here. When accurately locating the common fault with the detector, the marking scope is narrow. At this time, the distance between the common fault points can be measured with the distance meter, and then the accurate positioning with the detector is also very convenient. The fourth type of common fault: this type of common fault is the most difficult to predict among all cable faults at this stage. At this time, you can use a rangefinder to detect the cable on both sides of the cable, and then compare the detection results with the specific length, so that the common fault point can be defined in a small range (1-3m). At this time, dig the cable and find the problem, Or decisively cut off this section of cable (because the cable is very cheap, the insulation layer is low, and the connector is easy to do), or use a detector to select the audio frequency for accurate positioning in this section, which can also identify the common fault points. At this stage, the cable fault detector based on impulse flashover method, which is applied by many customers of cable fault detector in power engineering, generally can use a distance meter to roughly measure the distance between common fault points when dealing with common faults of low resistance of cable and common faults of dead grounding device (the distance detection of such common fault points does not need high-voltage charging and discharging machinery and equipment, and the bottom pressure single pulse method is used) However, ignition, charging and discharging and listening to sound are still used for accurate positioning of common fault points. In addition, the relative Pathfinder of such instruments and equipment is separated from the designated instrument, which makes it impossible to specify the relative path at the same time when selecting the correct relative path, and usually deviates from the relative path when specifying. Moreover, due to the limitation of the basic principle, the relative Pathfinder of such instruments and equipment finds the relative path of the cable It is impossible to find the exact relative path of the cable when the cable is in the middle of the total width of 1-2m. Considering the applicability, hn-213x cable fault detector just fills the shortcomings of the application. It can accurately locate the common fault points of the cable, detect the buried depth and the relative path smoothly. The instruments and equipment are very vivid in the marking of common faults, relative path and buried depth No need to do technical index analysis or rely on the working experience of the operator. It makes the original complex fault test work become a relaxed and interesting thing. Therefore, many customers of impulse lightning cable tester can form a set of extreme low-voltage cable fault tester if they have another DW cable fault detector and the original distance finder. In addition, the The common faults of low resistance and short circuit of external high-voltage cable can also be specified quickly to improve the efficiency many times.