US 12,436,181 B2
Electric insulation monitoring arrangement
Mats Nyström, Torslanda (SE)
Assigned to VOLVO TRUCK CORPORATION, Gothenburg (SE)
Filed by VOLVO TRUCK CORPORATION, Gothenburg (SE)
Filed on Jun. 17, 2021, as Appl. No. 17/350,347.
Claims priority of application No. 20181727 (EP), filed on Jun. 23, 2020.
Prior Publication US 2021/0396800 A1, Dec. 23, 2021
Int. Cl. G01R 31/12 (2020.01); G01R 31/00 (2006.01)
CPC G01R 31/1272 (2013.01) [G01R 31/007 (2013.01)] 9 Claims
OG exemplary drawing
 
1. An electric insulation monitoring arrangement for monitoring electric insulation in an electric system comprising a first conductor and a second conductor, the electric insulation monitoring arrangement comprising:
an insulation monitoring device comprising a primary measuring unit configured to, when and while an initial test voltage is applied between at least one of the first and second conductors and ground, measure, as a function of time, a voltage response comprising a first voltage between the first conductor and the ground, and a second voltage between the second conductor and ground, the insulation monitoring device being configured to determine an electric insulation resistance of the electric system based on measurement data relating to the first voltage and the second voltage from the primary measuring unit, and
at least one secondary measuring unit configured to:
measure, independently from the primary measuring unit, a set of voltage values of the first voltage with respect to the ground and a set of voltage values of the second voltage with respect to the ground, and
communicate to the insulation monitoring device the measured set of voltage values of the first voltage with respect to the ground and the measured set of voltage values of the second voltage with respect to the ground;
wherein the at least one secondary measuring unit is provided separately from the insulation monitoring device, and wherein the insulation monitoring device is configured to use the measured set of voltage values of the first voltage with respect to the ground and the measured set of voltage values of the second voltage with respect to the ground received from the at least one secondary measuring unit to verify the determined electric insulation resistance,
wherein the at least one secondary measuring unit is configured to monitor measure the set of voltage values of the first voltage and the set of voltage values of the second voltage at secondary measuring different positions that are physically separated from primary measuring positions at which the primary measuring unit is configured to measure the first voltage and the second voltage,
wherein the insulation monitoring device is configured to determine that an electric insulation fault is present between the at least one of the first and second conductors and the ground given that at least one insulation fault criterion fulfilled if one of the primary and secondary measuring units measures a voltage drop that corresponds to a calculated insulation resistance being below a predetermined threshold value being a safe electric insulation level, and
wherein the insulation monitoring device is configured to, in response to the determination of the electric insulation fault, generate a signal and/or disconnect a power supply of the electric system.