The 110 kV offshore power supply parallel line of the Shengli Oilfield adopts distance protection and zero-sequence protection.The Section Ⅰ instantaneous protection cannot cover the entire line,and fault at the line terminal can only be cleared by the Section Ⅱ and Section Ⅲ protections,with delayed fault clearing causing power grid fluctuation and widespread oil well shutdown.Therefore,the instantaneous fault clearing of short circuit at the terminal of 110 kV offshore power supply parallel line was investigated.By considering the special dual-circuit parallel supply mode of offshore power line and the protection function of the existing protection device,the application effectiveness of asymmetric successive fast-acting protection and dual-circuit successive fast-acting protection was discussed and verified.The principles of asymmetric successive fast-acting protection and dual-circuit successive fast-acting protection were elaborated,the protection action was analyzed,and the protection setting was introduced.The application of asymmetric successive fast-acting protection and dual-circuit successive fast-acting protection successfully achieves instantaneous fault clearing of short circuit at the terminal of dual-circuit power supply parallel line,preventing large-scale oil well shutdown caused by short circuit at the terminal of dual-circuit power supply parallel line,with almost no reconstruction cost.
Power Supply LineShort CircuitMicrocomputer ProtectionStudy
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