Cables come in a variety of sizes and specifications based on different classification standards. YJV cable is one such type. So what is YJV cable? What are its sizes and specifications?
Cables are essential components in power systems. Cables are generally considered to be wires that transmit power or information from one location to another, consisting of one or more mutually insulated conductors surrounded by an insulating protective layer. Cables come in a variety of models and specifications based on different classification standards. YJV cable is one such type. So what is YJV cable? What are its models and specifications? Let's take a look at it with Zhejiang Cable!
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 is a cross-linked polyethylene insulated and polyvinyl chloride sheathed cable. It is used for power transmission and distribution in power lines with a rated voltage (U0/U) of 0.6/1-26/35 kV. The maximum rated temperature of the cable conductor during operation is 90°C. In the event of a short circuit (maximum duration no more than 5 seconds), the maximum temperature of the cable conductor does not exceed 250°C. Its lightweight and simple structure make it widely used in urban power grids.
II. 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, available in sizes ranging from 1 square to 240 square (customizable), 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 voltages ranging from 1 to 500 kV and above, and with various insulation levels.
III. YJV Cable Structure
YJV cables are categorized from the inside out as follows: core, conductor insulation, filler layer, shielding layer, steel tape armor, and sheath. YJV cables primarily use copper as the core, with aluminum being less common. The conductor insulation is polyvinyl chloride (PVC). The filler layer fills the gaps between the cores and protects them, and is typically made of a softer nylon material. Power cables 15kV 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 outermost layer of the YJV cable is made of polyethylene and provides insulation and protection.
IV. YJV Cable Laying Methods
1. YJV and YJLV copper (aluminum) core cross-linked polyethylene insulated cables are laid indoors, in trenches and pipes, or buried in loose soil. They cannot withstand external forces. YJV22 and YJLV22 copper (aluminum) core cross-linked polyethylene insulated cables are laid underground. They can withstand mechanical forces but cannot withstand the greater tensile forces of steel-tape armored, PVC-sheathed power cables.
YJV wires and cables are used to transmit electromagnetic energy, information, and perform electromagnetic energy conversion. YJV cables are laid indoors, in trenches and pipes, or buried in loose soil. They cannot withstand external forces.
V. The Difference Between VV and YJV Wires and Cables
YJV cables have an operating temperature of 90°C, while VV cables only have an operating temperature of 70°C. YJV cables of the same cross-sectional area have a higher current carrying capacity.
1. YJV is superior to VV in the long run (longer service life, etc.), but more expensive than VV.
2. From a technical and economic perspective, three-core YJV cables have higher parameters than VV cables. For example, at 40°C in air, a 10-square-meter YJV cable has a current carrying capacity of 60 amps, while a VV cable has a current carrying capacity of 46 amps. However, some designs use 10-square-meter YJV cables for a 40A circuit breaker. Regarding operating temperatures, YJV is 90°C, while VV is 70°C. Regarding the maximum allowable short-circuit temperature, YJV is 250°C, while VV's are 160°C and 140°C, respectively.
3. There isn't much difference. To put it bluntly, YJV is for the nobility, while VV is for the common people. YJV's performance is slightly better than VV's, primarily in terms of insulation. YJV's insulation is better than VV's and has a higher degree of aging resistance. For example, a YJV can last 30 years, while a VV can last 28 years. That's the difference. 4. YJV is recommended for use in civil buildings. Its current carrying capacity is greater than that of VV. More importantly, in the event of an electrical fire, since its insulating material does not contain chlorine, it will not produce toxic gases when burned. Therefore, European countries have mandated the use of YJV in civil buildings.
