Cables are essential components in power systems. They are generally considered to be wires composed of one or more mutually insulated conductors surrounded by an insulating protective layer, used to transmit power or information from one point to another. Cables come in a variety of sizes and specifications based on different classification standards, and YJV cable is one such type.
1. What is YJV cable?
First, let's explain what YJV means. YJ stands for cross-linked polyethylene, and V stands for polyvinyl chloride. YJV designates the entire cable type—cross-linked polyethylene insulated and polyvinyl chloride sheathed power cable.
2. YJV Cable Usage Standards
The rated voltage range for YJV cables is primarily U0/U0.6/1kV to 26/35kV. During operation, the maximum temperature the cable's internal conductor can withstand is 90°C. In the event of a short circuit, the short circuit will not last more than 5 seconds. Furthermore, the maximum temperature of the YJV cable conductor must be maintained below 250°C.
III. YJV Cable Models and Specifications
YJV cable cores mainly include single-core, 2-core, 3-core, 4-core, 5-core, 3+1, 3+2, and 4+1. 3+1 represents 3 phase conductors + 1 ground conductor, 3+2 represents 3 phase conductors + 2 ground conductors, and 4+1 represents 4 phase conductors + 1 ground conductor.
Based on the standard model, specific sizes include: 1 square, 1.5 square, 2.5 square, 4 square, 6 square, 10 square, 16 square, 25 square, 35 square, 50 square, 70 square, 95 square, 120 square, 150 square, 185 square, 240 square, and 300 square. For example, a YJV 3*185+2*95 cable consists of three 185 square phase conductors and two 95 square ground conductors. Since the phase and ground conductor combinations are standardized, the 95 square at the end of the YJV 3*185+2*95 cable can be omitted.
YJV cables range in size from 1 square to 240 square (customization is available). They are used for transmitting and distributing electrical energy. They are most commonly used in urban underground power grids, outbound lines for power stations, internal power supplies for industrial and mining enterprises, and underwater transmission lines across rivers and seas. The proportion of cables in power lines is increasing. Power cables are used to transmit and distribute high-power electrical energy within the main lines of power systems. These cables include power cables with various voltage levels from 1 to 500 kV and above, and with various insulation options.
IV. YJV Cable Structure
From the inside out, YJV cables are categorized into the core, conductor insulation layer, filler layer, shielding layer, steel tape armor, and sheath. YJV cables primarily utilize copper cores, with aluminum being less common. The conductor insulation is PVC. The filler layer, designed to fill gaps between the cores and protect them, is typically made of a softer nylon material. Power cables 15 kV and above typically have both a conductor shield and an insulation shield. The steel tape armor is a protective steel layer wrapped around the core to prevent deformation. Armored YJV cables are primarily intended for underground use. The sheath, the outermost layer of YJV cables, is made of polyethylene and provides insulation and protection.
V. Advantages of YJV Cables: As cross-linked polyethylene insulated and PVC-sheathed power cables, YJV cables not only possess outstanding mechanical and thermal properties, but also superior electrical and corrosion resistance. Their simple internal structure and light weight also significantly enhance their ease of installation, making them suitable for installation over geographically varying heights. These advantages have led to their widespread use in urban power grids and many factories. It is worth mentioning that the superior electrical performance of the YJV cable is mainly maintained and improved by the cable's insulation - cross-linked polyethylene, which is converted into a three-dimensional network structure of polyethylene using chemical and physical methods.
