Power cables are mainly used for power transmission and distribution purpose. It is an assembly of one or more individually insulated electrical conductors, usually held together with an overall sheath. The assembly is used for transmission and distribution of electrical power. Electrical power cables may be installed as permanent wiring within buildings, buried in the ground and run overhead or exposed.……Including: rubber cable, welding cable, URD cable, XLPE insulated power calbe etc.
Bare Overhead Conductors are used in overhead transmission and distribution network applications.They are also used for un-insulated hook ups, jumpers, grounding conductors and other applications. Our Conductors conform to ASTM, IEC, BS, BS EN and DIN standards.…… Including: AAC conductor, AAAC conductor, ACSR conductor, ACAR conductor, AACSR conductor, etc.
Aerial bundled cables (also aerial bundled conductors or simply ABC) are overhead power lines using several insulated phase conductors bundled tightly together, usually with a bare neutral conductor. Our abc calbe conform to ASTM, IEC, SANS standards.……Including: abc cables, cvered line wire, service drop wire etc.
The relationship between the wire and the metal shield of the single core cable can be regarded as the primary winding of a transformer. When cable by alternating current, is formed around the part of the magnetic field lines will and shield hinge, makes the shielding layer induced voltage and induced voltage and the size of the cable line length and flows through a conductor current is proportional to the, with long cable, sheath on the induction of piezoelectric stack up to endanger the personal safety, in the line occurred short-circuit fault, suffer from operating over voltage and lightning impulse and shielding will form high induction voltage and may even breakdown sheath insulation. If at both ends of the shielding and grounding the shield line to form a closed path, the shielding will produce toroidal current, normal operation of the cable, shielding the circulation and conductor of the load current basically is the same order of magnitude, will produce great loss of circulation, make the heating cable, affect the electrical cable ampacity, shortening of the cable service life. Therefore, the cable shield should be reliable and reasonable grounding, the wire should be insulated from the outer sheath. The following is single core cable line several grounding methods:
1, shielding one end earthing directly, the other end through the protective layer to protect the ground:
When the length of the line is about 500-700m and below, the shield layer can be directly grounded at one end, and the other end is connected to the ground through the protective device. This grounding method should also be installed in a cable line parallel to the laying of the return line, both ends of the return line grounding. When laying the return line, it should make the distance between the cable and the middle one is 0.7s (s is the distance between the adjacent cables), and transposition in half of the line.
When the length of the line is about 1000-1400m, the neutral point grounding mode should be adopted.
In the middle position of the line, the shield is directly grounded, and the end of the cable ends of the cable is shielded by the shield of the protective layer. In the middle of the site is generally required to install straight connector.
Cable line is very long (about 1000-1400m or more), you can use the shield cross connection. This method is that the line into equal length of three short paragraphs or three multiples of the period, each piece is arranged between the insulating joint, insulating joints three-phase shield between with coaxial cable, through a cross connect box were transposed connection, cross connection box installed with a group of sheath protector, a group of the lines on each of the two groups of insulation connector clamp straight joint.
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