Medium-voltage cables are mainly power cables for medium-voltage electrical equipment.
The working principle of the cable for medium-voltage electrical equipment is the use of power wire (cable) through the voltage control of high-voltage wire and cable insulation of a wire and cable.
Medium-voltage cables are applied in the field of power transmission and applied to the installation and use of voltage control and signal transmission cables within the power distribution system (hereinafter referred to as medium-voltage cables).
1. Medium-Voltage Electrical Equipment With Medium-Voltage Cable Applications
Power cables are mainly used in the field of power transmission, distribution, power, and lighting, and are also indispensable products in modern industry.
The selection of cables should be based on the materials selected for the cable and the installation method to determine the different roles and requirements of the cable in medium- and high-voltage electrical equipment. In the selection of medium-voltage cable should pay attention to the quality of the cable, its performance, and the use of environmental aspects to meet the requirements of the medium-voltage cable.
At present China’s medium-voltage electrical equipment is mainly used in three different structure modes: 1) single-core cable type. 2) double-core cable type. 3) composite cable type.
2. Medium-Voltage Electrical Equipment With Medium-Voltage Cable Quality Requirements
The current medium-voltage electrical equipment with power cables is mainly single-core and multi-core two.
Single-core cable usually refers to a single-core insulated power cable. Double-core cable is also known as intermediate-layer insulated cable.
As medium voltage cables are mainly used in medium and high voltage distribution systems, their technical requirements, performance requirements and weather resistance performance indicators are also higher than single-core cables.
Generally, medium-voltage cables have higher requirements in terms of weathering performance.
From the point of view of arc resistance performance – arc generation has a discharge time – to cable operation with a period (usually in about 10 minutes) as the standard.
From the insulation properties – should have good heat resistance (100 ℃), insulation layer good gloss (1000 ℃), and insulation layer good arc strength (10 s).
From the point of view of use – should meet the national regulations, product life (50 years) requirements, and power engineering standards.
Medium-voltage cable has good temperature and corrosion resistance, it is suitable for operation and uses in high-temperature conditions.
Medium-voltage cables have higher requirements for the noise generated during the operation of the equipment.
At the same time, the price of materials used in medium voltage cables is higher, so medium voltage cables are generally required to use shielding or other shielding materials made during design, which can reduce line impedance and reduce line losses.
At the same time, it reduces the thickness of the cable structure, making the cable better stable.