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—— ABOUT US ——

Fujian Li'en Technology Co., Ltd. 「Li’en Cable」, founded in 2001, is guided by the business concept of leading by technology, innovation-driven, excellent quality and service foremost and commits to the research and development of cables. So far our company has been playing a leading role among business partners of the province.

—— NEWS ——

Mineral insulated fireproof cable model reference table

The continuous working temperature of the mineral cable is 250℃, and it can supply power continuously for 3 hours at 950℃-1000℃. It can work close to the melting point of copper at 1083℃ in a short or extraordinary period of time. Due to the excellent performance of mineral insulated cables, it is suitable for lines with rated voltages below 1000V. 　　 (1) Cable conductor: The conductor is made of metal copper with high conductivity. 　　(2) Insulation layer: Use high temperature resistant, non-combustible inorganic minerals as insulation material. 　　(3) Isolation layer: Use inorganic mineral material. 　　(4) Outer sheath: low-smoke non-toxic plastic material with good anti-corrosion properties. 　　Product display methodedit 　　(1) Fireproof cloth wire, rated voltage 450/750V, single core, 2.5mm, 　　 is expressed as: BTTEB-450/750V 1×2.5 　　(2) Fireproof power cable, rated voltage 0.6/1KV. 3-core, 120 mm, 　　 is expressed as: BTTE-0.6/1KV 3×120 　　(3) Fireproof control cable, rated power 450/750V, 6 cores, 2.5 mm 　　 is expressed as: BTTEK-450/750V 6×2.5 　　Using environmentedit 　　The continuous working temperature of the mineral cable is 250℃, and it can supply power continuously for 3 hours at 950-1000℃. It can work close to the melting point of copper at 1083℃ in a short time or in an extraordinary period. Due to the excellent performance of mineral insulated cables, it is suitable for lines with rated voltages below 1000V. 　　Main performance 　　(1) Fire performance 　　As all mineral cables are made of inorganic materials, they will not cause fire, cannot burn or support combustion, and will not produce toxic gas. Even if there is external flame burning, the cable can still work normally. After the fire is cleared, the cable does not need to be replaced. It is a true fire-resistant cable, which provides a foolproof guarantee for the fire-fighting line and has passed the test of the International Electrotechnical Commission IEC331. 　　(2) Large current carrying capacity 　　 Because the normal use temperature of mineral insulated cables can reach 250℃. IEC60702 stipulates that the continuous working temperature of mineral insulated cables is 105℃. This is to consider the terminal sealing material and safety requirements. Even so, its interception capacity is far more than other cables, because magnesium oxide powder has a better conductor coefficient than plastic, so the same operating temperature, the interception capacity is greater, for the line above 16mm, you can reduce a cross section, right Where people are not allowed to touch, two cross-sections can be lowered. 　　(3) Waterproof, explosion-proof, corrosion-resistant 　　Because the cable adopts low-smoke, halogen-free and high-flame retardant materials as the sheath, it has high corrosion resistance (plastic outer sheath is only needed in the occasion of certain chemical corrosion), and the conductor, insulation and sheath are densely compressed. As a result, it not only protects against water, moisture, oil and some chemical substances, it is practically used in places where there is a risk of explosion and the wiring of various explosion-proof equipment and equipment. 　　(4) Overload protection 　　 When the line is overloaded, the plastic cable will cause insulation heating or breakdown due to overcurrent or overvoltage. For mineral insulated cables, as long as the heat does not reach the melting point of copper, the cable will not be damaged. Even if the breakdown is instantaneous, the high temperature of the magnesium oxide at the breakdown point will not form carbides. After the overload is cleared, the performance of the cable will not change, and it can still be used normally. 　　(5) High working temperature 　　 Because the melting point of the insulating layer of magnesium oxide is much higher than that of copper, the maximum normal working temperature of the cable can reach 250°C, and it can continue to operate at a temperature close to the melting point of copper, 1083°C in the short term. 　　(6) Strong shielding performance 　　The copper sheath of the cable is the best shielding and protective layer, which can prevent the cable itself from interfering with other cables, and it can also prevent the external magnetic field from interfering with itself. 　　(7) Long life 　　Because the cable is composed of inorganic materials, it will not get old, and its service life shall be more than one hundred years at least. And the cable can be re-disassembled and reused with equipment shifting or line modification. 　　(8) Small outer diameter and light weight 　　 Compared with plastic cables with the same rules, the outer diameter of mineral insulated cables is reduced by 50%, and the weight is reduced by 30%, which can reduce the occupied space and facilitate installation. 　　(9) High radiation resistance 　　Since the cables are composed of inorganic materials, they have an effective neutron capture cross-section and maintain a high insulation resistance. Therefore, the electric

Testing method of power cable fault point

Testing method of power cable fault point 　　There are two types of cables commonly used in power systems, power cables and control cables. Power cables are used to transmit and distribute high-power electrical energy. According to the different insulation materials, it can be divided into oil-impregnated paper-insulated power cables, rubber-insulated power cables and PVC insulated cables. The most widely used in engineering is oil-impregnated paper-insulated power cables. Because the cables are being manufactured and laid The country has express regulations for wiring, ambient temperature, construction principles, etc., so I won't repeat them here. This article mainly introduces the possible points of power cables that are prone to failure and how to test several methods. 　　 Power cable fault point test method 　　 1. Types of cable faults and test methods After the cable fails, generally use a 1500V or higher shake meter or a high resistance meter to determine the type of fault, and then use different instruments and methods to first measure the fault, and finally use the fixed-point method to accurately determine the fault point. The precise measurement methods for the fault point include induction method and acoustic measurement. Two methods. The principle of the induction method is that when the audio current passes through the cable core, there are electromagnetic waves around the cable. Because some carry electromagnetic induction receivers, when walking along the line, you can hear the sound of the electromagnetic waves. When the audio current flows to the fault point , Sudden changes in current, sudden changes in the audio frequency of electromagnetic waves, this method is very convenient to find low-resistance short-circuit faults between disconnected phases, but it is not suitable for finding high-resistance short-circuits and single-phase grounding faults. The principle of 　　acoustic measurement is to use high-voltage pulses to prompt the discharge of the fault point to produce a discharge sound. The sensor is used to receive the discharge sound on the ground to measure the precise location of the fault point. 　　The specific fault types are tested according to the following methods. 　　1.1 Low resistance ground fault 　　 1.1.1 Single-phase low resistance ground fault 　　(1) Test of failure point. 　　 The single-phase low-resistance earth fault of the cable means that the insulation resistance of one core wire of the cable to the ground is less than 100kΩ, and the core wire has good continuity. This kind of fault is highly concealed, and we can use the principle of loop fixed-point method to test. The wiring diagram is shown in Figure 1a. The faulty core wire and another intact core wire form a measurement loop, measure with a bridge, one end is connected with a jumper, the other end is connected with a power supply, a bridge or a galvanometer, and the bridge resistance is adjusted. To balance the bridge, when the material and cross-section of the cable core wire are the same, it can be calculated according to the following formula If the damaged core and the good core are interchanged on the bridge, then there is the formula: Z——distance from the measuring end to the fault point in m; L——total cable length, m; R1, R2——electricity The resistance arm of the bridge. 　　Under normal circumstances, the measurement results of these two wirings should be the same, and the error is generally 0.1% to 0.2%. If it exceeds this range or X>L/2, the measuring instrument can be moved to the other end of the line for measurement. 　　 In addition, we can also use continuous scanning pulse oscilloscope method (MST-1A or LGS-1 digital tester) for testing. The reflected wave at the short-circuit or ground fault point will be negative reflection, as shown in Figure 1b on the oscilloscope screen. At this time, the distance to the fault point can be calculated according to the following formula: X-reflection time μs; V-wave speed, m/μs. 　　 (2) Matters needing attention during measurement. 　　A. The cross-section of the jumper should be close to the cross-section of the cable core, and the jumper should be as short as possible and kept well. 　　B. The measurement loop should bypass the branch box or substation or power distribution station as much as possible, the shorter the better. 　　C. The DC power supply voltage should not be less than 1500V. 　　D. The negative pole of the DC power supply should be connected to the cable conductor via an electric bridge, and the positive pole should be connected to the inner sheath of the cable and grounded. 　　E. The operator should stand on the insulating pad and place the bridge arm resistance, galvanometer, shunt, etc. on the insulating pad. 　　 1.1.2 Two-phase short circuit fault point test 　　 When a two-phase short-circuit fault occurs, the measurement wiring method is shown in Figure 2. When measuring, any faulty core wire can be used as a grounding wire, and the other faulty core wire ca

Analysis of Several Reasons for the Aging of Wires and Cables

—— PRODUCTS ——

NHV-YJV22 0.6/1KV 3X95+2X50mm²

YJV22 26/35KV 3X400mm²

ZBN-YJV-0.6/1KV 4X120mm²

WDZBV-YJV22 0.6/1KV 3X120+2X70n

—— CASE ——

Ningde Haojing Sunshine

Ningde Oriental Weiye Plaza

Fuding Zhonghui Square

Zhengxiang Group - Zhengxiang 1 Product New Building