Patent ID: 11892495
Assignee: LS ELECTRIC CO., LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G  H

Claim 22:
23. A method for controlling an insulation monitoring device comprising insulation resistance disposed between an electric line of a system and a ground, the method comprising:
applying a pulse signal having a voltage of a predetermined magnitude to the electric line;
determining an initial sampling interval;
performing primary tuning of calculating a sampling interval based on the initial sampling interval and a first time multiple, calculating an average voltage as a first average voltage during a sampling period according to the calculated sampling interval, and comparing the calculated first average voltage and a second average voltage calculated before the first average voltage;
repeatedly performing the primary tuning when a difference between the first average voltage and the second average voltage exceeds a preset first error range as a result of the primary tuning;
determining at least one reference point when the difference between the first average voltage and the second average voltage is within the first error range as the result of the primary tuning, and calculating a slope ratio based on voltage slopes according to a voltage difference between voltages according to the at least one reference point;
calculating a time constant based on the calculated slope ratio;
switching an operation state of the insulation monitoring device to an idle state for an idle time determined according to the calculated time constant;
checking whether the idle time has elapsed, to switch the operation state to an active state according to a result of the check;
performing a secondary tuning of calculating a sampling interval based on a reset initial sampling interval and a second time multiple when the operation state is switched to the active state, calculating an average voltage as a third average voltage during a sampling period according to the calculated sampling interval, and comparing the calculated third average voltage and a fourth average voltage calculated before the third average voltage;
detecting the third average voltage as a steady-state voltage according to the applied pulse signal when the difference between the third average voltage and the fourth average voltage is within a steady voltage error range as a result of the secondary tuning; and
repeatedly performing the secondary tuning when the difference between the third average voltage and the fourth average voltage exceeds the steady voltage error range as the result of the secondary tuning.