The present invention discloses an insulation detection circuit and a detection method thereof for a two-way on-board charger. The detection circuit comprises an inverter circuit, a first Y capacitor connected between an output live line and a ground line of the inverter circuit, a second Y capacitor connected between an output neutral line and the ground line of the inverter circuit, a live line sampling circuit and a neutral line sampling circuit which are connected with the output live line and the output neutral line of the inverter circuit, and a controller. The controller determines an insulation state of the two-way on-board charger according to two sampling voltages.

It is disclosed an insulation impedance detection circuit and detection method of a photovoltaic inverter system. The photovoltaic inverter system includes one or more input circuits and an inverter circuit, each of the input circuit electrically coupled to the inverter circuit through a positive bus and a negative bus, with a first equivalent impedance R.sub.p between the positive bus and a protective earth point and a second equivalent impedance R.sub.n between the negative bus and the protective earth point. The detection circuit includes: a bus voltage sampling circuit coupled to the positive bus and the negative bus for generating a first bus voltage and a second bus voltage; a protective earth voltage sampling circuit coupled to the protective earth point for generating a first protective earth voltage and a second protective earth voltage; and a controller for calculating an equivalent insulation impedance.

It is disclosed an insulation impedance detection circuit and detection method of a photovoltaic inverter system. The photovoltaic inverter system includes one or more input circuits and an inverter circuit, each of the input circuit electrically coupled to the inverter circuit through a positive bus and a negative bus, with a first equivalent impedance R.sub.p between the positive bus and a protective earth point and a second equivalent impedance R.sub.n between the negative bus and the protective earth point. The detection circuit includes: a bus voltage sampling circuit coupled to the positive bus and the negative bus for generating a first bus voltage and a second bus voltage; a protective earth voltage sampling circuit coupled to the protective earth point for generating a first protective earth voltage and a second protective earth voltage; and a controller for calculating an equivalent insulation impedance.

A method for determining the resistive component of the leakage current impedance (R.sub.i50) of a downstream branch to an alternating current network having a live phase (L), a neutral conductor (N), and a protective conductor (PE) conducted by: (a) measuring a differential current I.sub.LN between the live phase (L) and the neutral conductor (N); (b) measuring a voltage U between the live phase (L) and the neutral conductor (N) or between the live phase (L) and the protective conductor (PE); (c) correcting a phase shift between the differential current I.sub.LN and the voltage U; (d) determining several individual differential current values I.sub.LN,i and several individual voltage values U.sub.i, the differential current values I.sub.LN,i being phase-corrected with respect to the voltage values U.sub.i; (e) determining the effective power P from the several individual differential current values I.sub.LN,I and the several individual voltage values U.sub.i; (f) determining the effective voltage U.sub.Eff by the voltage values U.sub.i; and (g) determining the resistive component of the leakage current impedance (R.sub.i50).

A method for determining the resistive component of the leakage current impedance (R.sub.i50) of a downstream branch to an alternating current network having a live phase (L), a neutral conductor (N), and a protective conductor (PE) conducted by: (a) measuring a differential current I.sub.LN between the live phase (L) and the neutral conductor (N); (b) measuring a voltage U between the live phase (L) and the neutral conductor (N) or between the live phase (L) and the protective conductor (PE); (c) correcting a phase shift between the differential current I.sub.LN and the voltage U; (d) determining several individual differential current values I.sub.LN,i and several individual voltage values U.sub.i, the differential current values I.sub.LN,i being phase-corrected with respect to the voltage values U.sub.i; (e) determining the effective power P from the several individual differential current values I.sub.LN,I and the several individual voltage values U.sub.i; (f) determining the effective voltage U.sub.Eff by the voltage values U.sub.i; and (g) determining the resistive component of the leakage current impedance (R.sub.i50).

In leakage detecting device (10) that detects an electric leakage from a high-voltage unit in which power storage unit (20) and a load are connected by a power supply line in a state of being insulated from an earth, Y capacitor (CY) is connected between the earth and a current path between power storage unit (20) and the load. Drive unit (11) of leakage detecting device (10) outputs a rectangular wave voltage to the current path between power storage unit (20) and the load via driving coupling capacitor (Cd1) to charge or discharge Y capacitor (CY). Leakage detector (12) determines presence or absence of the electric leakage between the current path and the earth according to a time transition in which the voltage at the measurement point of the current path changed according to charging or discharging of Y capacitor (CY) converges to an original voltage.

In leakage detecting device (10) that detects an electric leakage from a high-voltage unit in which power storage unit (20) and a load are connected by a power supply line in a state of being insulated from an earth, Y capacitor (CY) is connected between the earth and a current path between power storage unit (20) and the load. Drive unit (11) of leakage detecting device (10) outputs a rectangular wave voltage to the current path between power storage unit (20) and the load via driving coupling capacitor (Cd1) to charge or discharge Y capacitor (CY). Leakage detector (12) determines presence or absence of the electric leakage between the current path and the earth according to a time transition in which the voltage at the measurement point of the current path changed according to charging or discharging of Y capacitor (CY) converges to an original voltage.

A measurement individual difference correction system for measuring voltage to ground includes a cable comprising a conductor, a floor panel provided on a floor and comprising a conductor, an oscillation circuit connected between the cable and the floor panel, and configured to output a signal, a voltage-to-ground measurement device comprising an upper electrode and a lower electrode positioned apart from each other, and configured to measure voltage between the upper electrode and the lower electrode, and a computation device in communication with the voltage-to-ground measurement device, in which the computation device calculates combined impedance of electrostatic capacity between the user and the cable, impedance of the user, and electrostatic capacity between the user and the upper electrode, by using voltage of the signal output from the oscillation circuit and the voltage between the upper electrode and the lower electrode measured by the voltage-to-ground measurement device.

A measurement individual difference correction system for measuring voltage to ground includes a cable comprising a conductor, a floor panel provided on a floor and comprising a conductor, an oscillation circuit connected between the cable and the floor panel, and configured to output a signal, a voltage-to-ground measurement device comprising an upper electrode and a lower electrode positioned apart from each other, and configured to measure voltage between the upper electrode and the lower electrode, and a computation device in communication with the voltage-to-ground measurement device, in which the computation device calculates combined impedance of electrostatic capacity between the user and the cable, impedance of the user, and electrostatic capacity between the user and the upper electrode, by using voltage of the signal output from the oscillation circuit and the voltage between the upper electrode and the lower electrode measured by the voltage-to-ground measurement device.

Apparatus, assembly and method for investigating the integrity of a seal and sealant contained in a sealing fitting used in hazardous locations. The apparatus/assembly can include signal transmitters and signal receivers provided on a conduit system on either side of a sealing fitting. The apparatus/assembly can include probes placed on either side of a sealant within a sealing fitting, the probes placed in probe ports provided through the wall of the sealing fitting.