Fault Analysis and Precontrol Measures for Power Cable ( III )
4. Measures to prevent cable failure
According to the cause analysis of insulation, accessories and outer sheath failure, it can be seen that cable line engineering is a systematic project. Only by managing the whole process from design, construction, operation and maintenance, can the maximum safety operation be ensured.
(1) From the beginning of design, the grounding system of cables is fully recognized, and the cable that meets its voltage level is selected to avoid the cable’s long-term overvoltage. The selection of outer sheath should be in line with the requirements of service environment and service life. At the same time, the selection of cable sheath protector should meet the principle of relative grounding, and the protector can reliably pass through the earth current without damage.
(2) Choosing cable path should avoid the influence of external environment such as overheating, corrosion and external force damage. At the same time, it also avoids the excessive concentration of cables, and causes the internal factors that heat can not spread in time and cause overheating. In addition, the cable route of double circuit power supply is not recommended to be laid in the same route, preventing the damage at the same time and causing a large area blackout accident.
(3) To strengthen the selection of cable and cable accessories, factory supervision and inspection, to ensure the quality of cable and cable accessories. In the field of inspection, the manufacturers, the construction party, the supervisor and the project supervisor should be present. According to the packing list to check one by one, to identify problems and timely record and make corrective recommendations, the multi signature recognition. For easy to damp parts, after inspection, it should be sealed in time so as to prevent the normal use of damp.
(4) To strengthen the personnel training work, carry out the necessary business qualification and technical evaluation to the cable head production personnel, and take the certificate for the job. After two consecutive failures in the period of the warranty period, the cable head production qualification is cancelled. After the retraining assessment is qualified, it can be put on post again.
(5) To strengthen the acceptance of concealed and intermediate links in all links of the cable engineering, and strictly check the quality acceptance. In the acceptance of civil and electrical engineering, the defects and hidden dangers should be rectified and rectified, and all the records should be done.
(6) Using the advanced on-line monitoring technology, such as outer sheath circulation online monitoring technology, online optical fiber temperature measurement technology and online partial discharge detection technology, to enhance cable real-time online operation monitoring, and detect hidden defects ahead of time, so as to avoid blackouts.