船舶综合电力系统绝缘电阻在线检测方法

On-line detection method of insulation resistance in marine integrated power system

当前采用中压直流供配电的船舶综合电力系统,在发电机端和负载端均存在接地电阻,对其电网绝缘电阻的在线检测产生较大影响。为此,提出一种改进注入法在线绝缘检测方案,通过外加电源和负载状态量获取的方式,排除系统接地电阻带来的影响。首先,在整流发电机接地电阻处,分别正向和反向并联直流电源,采用电源叠加法得到系统绝缘电阻解析表达式;然后,利用实时获取的变频器接地电阻柜的开关状态,折算直流母线实时的绝缘电阻值;最后,搭建了全系统仿真模型并进行了验证。研究结果表明:所提方案测量精度满足工程需求,为综合电力系统母线绝缘的在线检测提供了理论基础。

At present,the marine integrated power system using medium-voltage DC power supply and distribution has grounding resistance at both the generator end and the load end,which has a great impact on the online detection of the insulation resistance of its power grid.Therefore,an improved injection method online insulation detection scheme was proposed to eliminate the influence of system grounding resistance through the acquisition of external power supply and load status.Firstly,at the grounding resistance of the rectifier generator,the forward and reverse parallel DC power supplies were respectively connected,and the analytical expression of the system insulation resistance was obtained by using the power superposition method.And then,the real-time insulation resistance value of the DC bus was converted by using the real-time acquisition of the switch status of the inverter grounding resistance cabinet.Finally,the whole system simulation model was built to verify that the measurement accuracy of the proposed scheme meets the engineering requirements,which provides a theoretical basis for the online detection of bus insulation in the integrated power system.