A ground fault detection device includes: a detection capacitor; a switch group for switching between a first charging path connecting the battery and the detection capacitor, a second charging path connecting the battery, a negative side insulation resistance and the detection capacitor, a third charging path connecting the battery, a positive side insulation resistance and the detection capacitor, and a measurement path for measuring a charging voltage of the detection capacitor; and a controller configured to calculate the insulation resistance based on a charging voltage measured value of the detection capacitor which exists after charging each of the charging paths, wherein after measurement of the charging voltage of the second charging path, the controller is configured to cause the switch group to switch to the third charging path before switching to the first charging path.

An apparatus for diagnosing an insulation condition between a battery pack and the ground includes a first resistor element electrically connected between a positive terminal of the battery pack and the ground, and a control circuit. The control circuit records a current flowing through the first test port as a first test current, while a high-level voltage is being applied between the positive terminal and the ground. The controller diagnoses the insulation condition between the battery pack and the ground, based on the first test current.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun and sending the perforating gun to a wellbore site with at least one of an electrical property and a dimension that has been previously verified. The perforating gun may be received in a perforating gun holder positioned between a first connecting portion and second connecting portion. The first connecting portion may be moved from a first position to a second position at which the at least one of the electrical property and the dimension is measured. Upon verification that the at least one of the electrical property and the dimension is within a predetermined specification, the perforating gun may be sent to the wellbore site.

An inspection tool and associated methods for testing physical and electrical properties of a perforating gun and sending the perforating gun to a wellbore site with at least one of an electrical property and a dimension that has been previously verified. The perforating gun may be received in a perforating gun holder positioned between a first connecting portion and second connecting portion. The first connecting portion may be moved from a first position to a second position at which the at least one of the electrical property and the dimension is measured. Upon verification that the at least one of the electrical property and the dimension is within a predetermined specification, the perforating gun may be sent to the wellbore site.

The present disclosure provides a method and system for ground fault detection. The method may include obtaining an input voltage and a null-ground voltage; determining whether the null-ground voltage is less than a voltage threshold; if yes, further determining whether the null-ground voltage is less than a preset voltage; if yes, determining that the grounding state is normal; if the null-ground voltage is greater than or equal to the preset voltage, determining that the grounding state is abnormal; if the null-ground voltage is greater than or equal to the voltage threshold, determining that the live wire and the null wire are reversed; in the case that the live wire and the null wire are reversed, determining whether the difference between the input voltage and the null-ground voltage is less than the preset voltage; if yes, determining that the grounding state is normal; if no, determining that the grounding state is abnormal.

A power converting device includes a DC-DC converting circuit, a DC-AC converting circuit, and an insulation detecting circuit. The DC-DC converting circuit is configured to convert a DC input voltage to a DC bus voltage. The DC-AC converting circuit is electrically coupled to the DC-DC converting circuit and configured to convert the DC bus voltage to an AC voltage. The insulation detecting circuit is electrically coupled between the DC-DC converting circuit and the DC-AC converting circuit. The insulation detecting circuit is configured to detect a ground impedance value of the power converting device according to the DC bus voltage.

Some aspects of this disclosure are directed to an automated method to check electrostatic discharge (ESD) effect on a victim device. For example, some aspects of this disclosure relate to a method, including determining a probe point, in a circuit design, for determining effective resistance between the probe point and ground, where the probe point is on an ESD path of in the circuit design. The method includes determining voltage between the probe point and the ground. The method further includes comparing, by a processing device, a resistance value of the ESD path determined based a predefined electric current value at a source point and the measured voltage with a target resistance value range. The method further includes reporting a violation upon determining that the determined resistance value of the ESD path is outside the target resistance value range.

Some aspects of this disclosure are directed to an automated method to check electrostatic discharge (ESD) effect on a victim device. For example, some aspects of this disclosure relate to a method, including determining a probe point, in a circuit design, for determining effective resistance between the probe point and ground, where the probe point is on an ESD path of in the circuit design. The method includes determining voltage between the probe point and the ground. The method further includes comparing, by a processing device, a resistance value of the ESD path determined based a predefined electric current value at a source point and the measured voltage with a target resistance value range. The method further includes reporting a violation upon determining that the determined resistance value of the ESD path is outside the target resistance value range.

A method for discharging a vehicle high-voltage electrical system, which is galvanically isolated from a ground potential, in the presence of a residual current makes provision for the following step: determining whether a residual current flows between a first HV potential of the vehicle high-voltage electrical system and the ground potential or a residual current flows between a second HV potential of the vehicle high-voltage electrical system and the ground potential. The method furthermore makes provision to discharge only that Cy capacitance which exists between the ground potential and that HV potential from which or to which the residual current flows. The discharging is triggered by determining the existence of a residual current. Furthermore, an on-board vehicle electrical system and an insulation monitoring device which are designed for performing the method are described. In addition, a corresponding charging-station high-voltage electrical system is described.

The invention relates to a method, electrical circuit arrangements and insulation monitoring devices for an interference-resistant insulation monitoring of an ungrounded power supply system having a converter. Switching-frequent interfering signals, which are caused by operating the converter, are identified and assessed in a measured displacement voltage independently of the detection of a measuring signal in order to derive a switching (off) signal if required. Complementary thereto, an interfering resistance with respect to low-frequency interfering portions generated by the converter is attained by these low-frequency interfering portions being generated from a replica of a pulse width modulation signal of the converter and being suppressed sufficiently via subtraction that a monitoring without gaps (frequency) of the insulation resistance becomes possible.