Petroleum Refinery Engineering ›› 2025, Vol. 55 ›› Issue (5): 21-24.

• PROCESS EQUIPMENT AND MACHINERY • Previous Articles     Next Articles

Analysis of Voltage Dip Factors in the Startup of Large Asynchronous Motors

Wang Meiwei, Qian Zhihong, Liu Weigong, Liu Xiaoduo, Tao Linan   

  1. Sinopec (Dalian) Petrochemical Research Institute Co., Ltd., Dalian, Liaoning 116045
  • Online:2025-05-15 Published:2025-05-22

大型异步电动机启动与电压暂降因素分析

王美威，钱志红，刘维功，刘小多，陶丽楠   

  1. 中石化（大连）石油化工研究院有限公司，辽宁省大连市 116045
  • 作者简介:王美威，助理研究员，硕士，2020 年毕业于大连理工大学电气工程专业，主要研究石化企业电力系统可靠性。联系电话：18342238375，E-mail：wangmeiwei.fshy@ sinopec.com。
  • 基金资助:
    大连市政府创新支持政策项目（2023RQ050）

PDF

Abstract:

The startup of large asynchronous motors can cause a sudden voltage drop at the motor terminals and busbars. This study analyzes the voltage dip during the startup process of electric motors in a petrochemical enterprise's 110 kV regional power grid, considering factors such as the capacity ratio of transformers to motors, reactive power of pre-connected loads, system operating modes, and startup circuit lines. Results show that when the rated power of the startup motor is close to 30% of the transformer's rated capacity and the startup circuit cable length is short, the minimum short-circuit capacity requirement for the busbar in the startup circuit is not less than 5.67 times the calculated capacity of the startup circuit if the reactive power of the pre-connected load is 0 or much less than the calculated capacity of the startup circuit. If the cable impedance in the startup circuit is large, there is a maximum limit value for the circuit length, which is related to the short-circuit capacity of the distribution busbar and the rated startup capacity of the motor.

异步电动机|区域电网|直接启动|电压暂降|变压器|预接负荷|配电母线电压|无功功率

Key words: asynchronous motor, regional power grid, direct startup, voltage dip, transformer, pre-connected load, distribution busbar voltage, reactive power

摘要：

石化企业电动机容量大，机泵等敏感负荷设备较多。大型异步电动机直接启动会引起机端及母线电压骤降。结合某石化企业 110 kV 电压等级区域电网，从变压器与电动机容量配比、预接负荷无功功率、系统运行方式、启动回路线路等方面开展电动机启动过程配电母线电压暂降分析。结果表明，启动电动机额定功率最大值接近于变压器额定容量的 30%，启动回路电缆长度较小时，预接负荷的无功功率为 0 或远小于启动回路的计算容量时，电动机直接启动对启动回路母线的最小短路容量要求为不低于 5.67 倍启动回路的计算容量。若电动机启动回路电缆阻抗较大，则满足线路长度要求存在一最大极限值，且与配电母线短路容量和电动机额定启动容量有关。

关键词: 异步电动机, 区域电网, 直接启动, 电压暂降, 变压器, 预接负荷, 配电母线电压, 无功功率