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How to choose XLPE insulated power cables?


The commonly used insulating plastics for power cables in the market are polyethylene and polyvinyl chloride. Next, let me explain to you what is a cross-linked polyethylene insulated power cable? And how to choose XLPE insulated power cables?

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How to choose XLPE insulated power cables?

The commonly used insulating plastics for power cables in the market are polyethylene and polyvinyl chloride. Next, let me explain to you what is a cross-linked polyethylene insulated power cable? And how to choose XLPE insulated power cables?

一、 What is xlpe insulated power cable?  

XLPE insulated power cables use chemical methods or physical methods to change the cable insulation polyethylene molecules from a linear molecular structure to a main network molecular structure, that is, thermoplastic polyethylene is transformed into a thermosetting cross-linked polyethylene, thereby greatly improving Its heat resistance and mechanical properties reduce its shrinkage, so that it will not melt again after being heated, and can maintain excellent electrical properties.

 

二、The use characteristics of XLPE insulated power cables:

1. The maximum working temperature of the conductor of the cable is 90°C.
2. When short-circuited (the longest duration cannot exceed 5 seconds), the maximum operating temperature of the cable conductor is 250°C, and the overload temperature does not exceed 130°C.
3. The ambient temperature during laying is not lower than 0°C, and the laying temperature of polyethylene sheathed cables is not lower than -15°C.

 

三、Basic requirements for cross-section selection of XLPE power cable core

1. The temperature of the cable core under the action of the maximum operating current shall not exceed the specified allowable value. For the circuit of continuous operating current, the operating temperature of the cable core shall not exceed the allowable value, that is, the maximum rated temperature of the XLPE cable core is 90°C.

2. The thermal effect caused by the maximum short-circuit current action time should not damage the continuous use characteristics of the cable, so the maximum temperature of the XLPE power cable core is 250 °C.

3. The connected circuit is very long, and when it is required to limit the voltage drop, it should not exceed the allowable value.

4. For long-distance large circuit loops or high-voltage cables above 35KV, the induced voltage corresponding to the cable length cannot exceed the safe voltage.

 

四、Selection principles of XLPE power cables  

                                           
Insulation xlpe cable has excellent gas performance, the dielectric loss is smaller than that of paper insulation and PVC insulation, and the capacitance of XLPE cable is also small, which can also reduce charging current and ground fault current in systems without effective star grounding. Ease of laying is a major advantage of XLPE cables. Compared with other power cables, XLPE cables have a smaller bending radius, light weight, and simple terminal handling. Since XLPE cables do not contain oil, there is no need to consider the line requirements too much during laying. Therefore, The selection of XLPE power cables should be based on their suitable environmental conditions.


1.XLPE insulated copper tape shielded polyethylene sheathed power cables are suitable for overhead, indoor, tunnel, cable trench, pipeline and underground direct burial laying.

2. XLPE insulated copper tape armored PVC sheathed power cables are suitable for laying indoors, tunnels, cable trenches and underground direct burial. The cables can withstand external mechanical forces, but cannot withstand large tensile forces.

3. XLPE insulated copper tape/copper wire shielded steel tape armored PVC sheathed power cables are only suitable for underground direct burial, shaft and underwater laying. The cables can withstand external forces and can withstand considerable tension.

4. XLPE insulated copper tape/copper wire shielded thick steel wire armored PVC sheathed power cable is suitable for underground direct burial, vertical shaft and underwater laying. The cable can withstand mechanical external force and can withstand large tensile force.