What are electrical transmission cables?
Electrical tranmission cables are used to transmit and distribute from generation plants to users. It goes through various sections of low voltage which is below 1000 V. Meanwhile, the high voltage is more than 1000 V cables. Additionally, you use transmission cables to connect secondary outputs of current transformers. Those are located at both ends of the transmission stations.
In order to protect critical equipment and avoid the increase of faults that can impact the entire transmission network. Basically, the pilot cable’s purpose is to monitor any unbalances between the corresponding pairs of CT, which signify fault conditions. On the contrary, you only need one pair of wires to complete operations. These are the connections, operation, and redundancy planning calls for a minimum of three functional pairs of wires.
It is not possible to have a single cable that spans the distance between substations. This is because various joints are formed to connect different sections of cables together. These joints are the weakest links in the system. They are prone to failures caused by environmental factors such as thermal stress and moisture absorption. Basically, the failures will show up when current readings taken at the secondary of CT deviate from the proportional primary current readings
The utility team detected these failures and prevents them. They go through the sub-station from one end to another. This is done in order to isolate the affected CT and pilot cable located at the substation. Then they need to travel to the sub-station at the other end to check the insulation resistance of the pilot cable. Note that you must check the wires properly. This and including the remaining 4 or 9 pairs of wires in the same bunch of pilot cable and make sure at least three pairs are functional.
This is because some wires may have permanent damage, there are chances that different color wires are mixed in order to achieve a minimum of 3 functional pairs. Therefore, the team must verify the exact inter-connect pairs and they term this work as phasing. Meanwhile, you can replace faulty joints and replace them with shorter jumper cables. By doing this, you’ll be able to join two new cable joints.
Time is one of the most important things to consider when repairing. One of the main duties of maintenance people is troubleshooting. Additionally, they also need to repair in a short period of time. However, with Insulation resistance, as well as voltage measurements and continuity, checks Fluke 1587 Insulation Multimeter is the solution. Visit https://presidium.ph/ to learn more about our products.