A method (200) and a connection test device (100; 300) for checking an intermittent impedance variation in a first and/or a second line (110; 302, 334) are described. The connection test device (100; 300) comprises a transmitter (102; 308) having a test signal generator (106) for generating a test signal and a first test point (108; 304) for connecting the first (110; 302) or the second line (334), wherein the test signal generator (106) supplies the test signal to the first (110; 302) or the second line (334) via the first test point (108; 304). The connection test device (100; 300) further comprises a first receiver (104; 310) having a second test point (112; 306, 336) for connecting the first (110; 302) or second line (334) and a receiver front end (114; 326, 328) which receives an incoming signal from the first (110; 302) or second line (334) via the second test point (112; 306, 336). The connection test device (100; 300) has, in addition, an evaluation logic (116), which is connected to the receiver front end (114; 326, 328) and which compares the input signal to a threshold value in order to identify an intermittent impedance variation in the first (110; 302) and/or the second line (334).

A method (200) and a connection test device (100; 300) for checking an intermittent impedance variation in a first and/or a second line (110; 302, 334) are described. The connection test device (100; 300) comprises a transmitter (102; 308) having a test signal generator (106) for generating a test signal and a first test point (108; 304) for connecting the first (110; 302) or the second line (334), wherein the test signal generator (106) supplies the test signal to the first (110; 302) or the second line (334) via the first test point (108; 304). The connection test device (100; 300) further comprises a first receiver (104; 310) having a second test point (112; 306, 336) for connecting the first (110; 302) or second line (334) and a receiver front end (114; 326, 328) which receives an incoming signal from the first (110; 302) or second line (334) via the second test point (112; 306, 336). The connection test device (100; 300) has, in addition, an evaluation logic (116), which is connected to the receiver front end (114; 326, 328) and which compares the input signal to a threshold value in order to identify an intermittent impedance variation in the first (110; 302) and/or the second line (334).

During measuring an insulation resistance for an inverter having at least one half-bridge including two active switching elements for driving an output current, and a DC link voltage, a center point of the half-bridge positioned between the switching elements is connected to a grounding point by closing a grounding switch, and the center point connected to the grounding point is connected, one after the other, to a first ungrounded terminal and a second ungrounded terminal of the DC link voltage of the inverter present at the half-bridge by means of the two active switching elements of the half-bridge to establish a connection between the first and second ungrounded terminals, respectively, and the grounding point. A current flowing via the connection to the grounding point is measured using a measuring device.

During measuring an insulation resistance for an inverter having at least one half-bridge including two active switching elements for driving an output current, and a DC link voltage, a center point of the half-bridge positioned between the switching elements is connected to a grounding point by closing a grounding switch, and the center point connected to the grounding point is connected, one after the other, to a first ungrounded terminal and a second ungrounded terminal of the DC link voltage of the inverter present at the half-bridge by means of the two active switching elements of the half-bridge to establish a connection between the first and second ungrounded terminals, respectively, and the grounding point. A current flowing via the connection to the grounding point is measured using a measuring device.

The invention relates to a battery system (100) with a battery (20), which is designed to supply a high voltage network (70) with electric energy, and a measuring device (130) for measuring at least one insulation resistance provided between the battery (20) and a housing of the battery (20). The measuring device (130) is equipped with two measuring paths (140, 150), each of which is paired with one of two high-voltage connections (21, 22) of the battery (20), each of which comprises a series circuit that comprises a first resistor (142, 152) and a relay (145, 155), and each of which is connected between the paired high-voltage connection (21, 22) and a point (25) that has a housing potential. Furthermore, each series circuit has a semiconductor switch (147, 157). The measuring device (130) also has two functional modes in which the relays (145, 155) of the measuring paths (140, 150) are closed. When switched to a passive functional mode of the two functional modes, the measuring device (130) is designed to open each semiconductor switch (147, 157) or to keep the semiconductor switch in an open state. When switched to an active functional mode of the two functional modes, the measuring device (130) is additionally designed to alternately open and close the semiconductor switches (147, 157), to measure a first voltage which drops over the first resistor (142, 152) of each measuring path (140, 150) when the semiconductor switch (147, 157) of the corresponding measuring path (140, 150) is closed, and to determine a corresponding insulation resistance of the battery (20) using each measured first voltage.

The invention relates to a battery system (100) with a battery (20), which is designed to supply a high voltage network (70) with electric energy, and a measuring device (130) for measuring at least one insulation resistance provided between the battery (20) and a housing of the battery (20). The measuring device (130) is equipped with two measuring paths (140, 150), each of which is paired with one of two high-voltage connections (21, 22) of the battery (20), each of which comprises a series circuit that comprises a first resistor (142, 152) and a relay (145, 155), and each of which is connected between the paired high-voltage connection (21, 22) and a point (25) that has a housing potential. Furthermore, each series circuit has a semiconductor switch (147, 157). The measuring device (130) also has two functional modes in which the relays (145, 155) of the measuring paths (140, 150) are closed. When switched to a passive functional mode of the two functional modes, the measuring device (130) is designed to open each semiconductor switch (147, 157) or to keep the semiconductor switch in an open state. When switched to an active functional mode of the two functional modes, the measuring device (130) is additionally designed to alternately open and close the semiconductor switches (147, 157), to measure a first voltage which drops over the first resistor (142, 152) of each measuring path (140, 150) when the semiconductor switch (147, 157) of the corresponding measuring path (140, 150) is closed, and to determine a corresponding insulation resistance of the battery (20) using each measured first voltage.

An electricity meter includes at least one phase conductor and a neutral conductor, an internal cut-off device includes at least one phase cut-off member connected in series with the phase conductor, and at least one detector circuit for acting when the internal cut-off device is open to detect whether a circuit breaker of the installation is open or closed. The electricity meter includes coupling components connected, downstream from the internal cut-off device, to an injection conductor selected from the phase conductor and the neutral conductor, and an injection component arranged to apply a reference voltage to the injection conductor via the coupling capacitor; and connection components connected to a measurement conductor selected from the phase conductor and the neutral conductor, and a measurement component arranged to measure a measurement voltage across the terminals of one of the connection components, the measurement voltage being representative of an impedance of the installation.

An autonomous breaker can apply a current through a high impedance source to a bus coupled to either end of a breaker in order to measure an impedance of the bus. The status of the bus can be determined from the measurement. Based on the determined status, a fault detection procedure can be selected and implemented to determine if a fault exists on the bus. When the fault detection procedure has been implemented and no fault has been detected, the breaker can close, and thus couple the bus to another bus.

The present invention monitors an electric power system using a time-series measurement value including abnormality. An electric power system monitoring device is provided with: a storage unit that stores facility information indicating a position relationship of a plurality of measurement sites in an electric power system; a reception unit that receives time-series measurement information measured by a measurement device disposed at each of the plurality of measurement sites; and a computation unit that acquires an electrical distance between the plurality of measurement sites on the basis of the facility information, classifies the plurality of measurement sites into at least one measurement site group on the basis of the electrical distance, extracts, with respect to each of the measurement sites in the measurement site group, a frequency component of electric power fluctuation from the measurement information, selects, with respect to a first frequency component which is a frequency component of a first measurement site in the measurement site group, a second frequency component which is a frequency component of a second measurement site in the measurement site group, and calculates a similarity between the first frequency component and the second frequency component.

The present invention monitors an electric power system using a time-series measurement value including abnormality. An electric power system monitoring device is provided with: a storage unit that stores facility information indicating a position relationship of a plurality of measurement sites in an electric power system; a reception unit that receives time-series measurement information measured by a measurement device disposed at each of the plurality of measurement sites; and a computation unit that acquires an electrical distance between the plurality of measurement sites on the basis of the facility information, classifies the plurality of measurement sites into at least one measurement site group on the basis of the electrical distance, extracts, with respect to each of the measurement sites in the measurement site group, a frequency component of electric power fluctuation from the measurement information, selects, with respect to a first frequency component which is a frequency component of a first measurement site in the measurement site group, a second frequency component which is a frequency component of a second measurement site in the measurement site group, and calculates a similarity between the first frequency component and the second frequency component.