Problems with joints in high-voltage cables
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In the connection between cables and between the terminals and the powered equipment, some organizations do not use standard high-voltage cable terminations; instead, they rely on simple connections for the core wires, the shielding layer, and grounding. Cables with such terminations have not encountered any problems during operation. I would like to ask experts: does the relevant regulation permit such simplified connections for high-voltage cables? What potential problems might arise from this approach? Thank you.
When connecting high-voltage cables, direct connection is not allowed; special intermediate connectors must be used for the connection. Otherwise, the cable will not operate properly, and electrical losses at that connection point will increase. In practice, many organizations do use simple connection methods when linking cables to equipment, without employing specialized cable terminations. Generally, this does not cause any problems, as long as the connections and insulation are proper
Basic requirements for high-voltage cable terminations: Cable terminations are components that connect cables to other electrical devices, while cable splices are components used to connect two cables together. Cable terminations and splices are collectively referred to as cable accessories. Cable accessories should be able to operate safely for a long time just like the cable itself, and have the same service life as the cable. Good cable accessories should possess the following properties: proper connection of the conductors – mainly low connection resistance and stable connections, as well as the ability to withstand the impact of fault currents ； After long-term operation, its contact resistance should not be greater than 1.2 times the resistance of the cable core itself over the same length ； It should possess certain mechanical strength, vibration resistance, and corrosion resistance ； In addition, it should also be small in size, low in cost, and easy to install on-site. Good insulation performance: The insulation performance of cable accessories should be no lower than that of the cable itself. The dielectric loss of the insulating materials used must be low, and the structure of these accessories should enable effective handling of any sudden changes in the electric field, with measures in place to adjust the electric field distribution.
1. High-voltage cables must be connected using **special intermediate connectors that come with a legal production license**. 2. High-voltage cable terminals must be protected by specialized cable terminal fittings that possess **legal production permits** as shielding. 3. After the cable splices and cable terminals have been installed, a qualified unit must conduct high-voltage preventive tests; only those that pass these tests can be put into use.