海上油田电网某平台35 kV侧PT高压保险熔断问题研究

Study on PT High Voltage Fuse on the 35 kV Side of a Platform in the Offshore Oilfield Grid

海上油田电网某平台在单机运行方式时频繁发生PT高压保险熔断事故,严重威胁着油田电网的安全稳定和正常运行。此类事故最常见的原因是发生了铁磁谐振和低频非线性振荡。首先,利用ATP-EMTP仿真手段分析了这两类振荡的典型特点;然后搭建了故障电路的仿真模型。仿真结果表明导致该平台PT保险熔断的原因是发生了低频非线性振荡,其冲击电流超出了保险的熔断电流而造成熔断;通过分析得出平台原有消谐措施无法避免该事故发生的结论。给出了避免此类事故发生的措施,并通过仿真验证了该措施的有效性。

A platform in the offshore oilfield power grid has frequent PT high-voltage insurance meltdown accidents during the stand-alone operation mode,which seriously affect the safety and stability of the oilfield power grid and the normal production.The most common causes of such accidents are usually the occurrence of ferro-resonance and low-frequency nonlinear oscillation.The article first analyzes the typical characteristics of these two types of oscillations by means of ATP-EMTP simulation;then builds a simulation model of the fault circuit.The simulation results show that the cause of the PT fuse meltdown of the platform is the occurrence of low-frequency nonlinear oscillation,whose inrush current exceeded the fusing current of the fuse and cause the meltdown.And it is concluded that the original harmonic eliminations measure of the platform cannot avoid the accident.The paper also gives the measures to avoid such accidents and verifies their effectiveness by simulation.