基于开关状态组合的直流接地故障检测方法

提出了一种高精度检测电力系统直流接地电阻的新方法,利用两个可控开关,控制产生3种有效电路状态,利用3种状态下的电量关系,无须高精度电流、电压传感器,只使用一个模拟输入通道和几个廉价的电阻元件,即可实现直流接地电阻的低成本、高精度检测,克服了使用非线性检测元件造成的每台仪器必须单独编程、元件不能互换、仪器维护困难、难以批量生产等问题,进一步提高了检测精度,大大简化了生产过程。基于新检测方法的直流接地故障检测仪,具有对直流系统无任何不良影响、检测结果不受分布电容的影响、检测电路简单、检测精度高、仪器一致性好、价格低廉等显著优点。

Method for Measuring Insulating Resistance Based on Switch State Combination in Power Systems

A novel method for precise measurement of resistance between ground and direct current (DC) power supply in power systems is proposed. Three valid circuit states can be achieved by means of two controllable switches. And then three equations describing the relationship of circuit parameters in the three states can be obtained in terms of theorem of electric circuits. Further more, the resistances between ground and negative and/or positive bus can be obtained by solving the equations. In particular, only several resistors and one analog input channel are needed for the precise measurement of the resistances. Apparatus based on the above method has the advantages of simplicity, high precision, low cost and fine consistency, etc.