Abstract: The invention relates to a method and a device for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system, the method comprising the steps: detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit to be monitored and displaying the temporal progression of the differential current via a differential current signal by means of a differential current sensor; providing a processing signal which temporally describes a process sequence of a process taking place in the consumer; correlating the differential current signal with the processing signal in a computing unit in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal; signaling the momentary insulation fault via the computing unit by means of a signaling signal if the correlation signal shows the temporal match.

Abstract: The invention relates to an electric circuit arrangement (2) for standard insulation monitoring with emergency shut-down for an ungrounded power supply system (4) upon detection of a ground fault, having a standard insulation monitoring device (10) which is coupled to an active conductor (L1, L2, L3) of the power supply system (4) on the network side via a coupling branch (12) each or to a neutral point (S) of the power supply system (4) via a coupling branch (12) and is connected to ground (PE) on the ground side via a ground connection branch (14).

Abstract: Methods and electric circuit arrangements for protecting metallic components in an electrolytic medium from corrosion due to direct-current (DC) stray current (Is) from a power supply system. The DC stray current may be jointly registered as a total sum current across all active conductors together with the protective conductor of the power supply system by a DC total differential-current sensor. Alternatively, a combined DC differential-current sensor is switchable by a switching device, a differential current being registered across all active conductors or the DC stray current being registered as a total differential current across all active conductors and the protective conductor.

Abstract: A method and a measuring device for detecting a leakage current in an ungrounded, single-phase alternating-current power supply system. A variable test resistance is switched between one of the outer conductors and ground and starting from a minimally admissible test-resistance value, at least one of three support test-resistance values is determined as support locations. In an equivalent circuit of the modeled alternating-current power supply system, an equations system is set up for describing the dependency of currents and voltages. An extrapolation on the test-resistance value zero leads to a calculated test current which corresponds to the leakage current to be detected. Consequently, a ground fault situation may be simulated without actually causing a dangerous ground fault.

Abstract: A method for automatically creating installation-specific measuring profiles for an insulation monitoring system, includes: assisting in a computer-controlled manner by means of an assist system via guided instructions for acquiring installation data; and executing the instructions by means of one more sensor devices. The method further includes pre-selecting, assisting, recording, evaluating, detecting, and optimizing steps.

Abstract: 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.

Abstract: The invention relates to a method and a device for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system, the method comprising the steps: detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit to be monitored and displaying the temporal progression of the differential current via a differential current signal by means of a differential current sensor; providing a processing signal which temporally describes a process sequence of a process taking place in the consumer; correlating the differential current signal with the processing signal in a computing unit in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal; signaling the momentary insulation fault via the computing unit by means of a signaling signal if the correlation signal shows the temporal match.

Abstract: The invention relates to an electric circuit arrangement (2) for standard insulation monitoring with emergency shut-down for an ungrounded power supply system (4) upon detection of a ground fault, having a standard insulation monitoring device (10) which is coupled to an active conductor (L1, L2, L3) of the power supply system (4) on the network side via a coupling branch (12) each or to a neutral point (S) of the power supply system (4) via a coupling branch (12) and is connected to ground (PE) on the ground side via a ground connection branch (14).

Abstract: An electric measuring assembly and a method for continuously monitoring a protective-conductor resistance of a protective-conductor connection in a power supply system having a supply station, a supply line, and an electric installation, grounded via the connection. A signal generator generates a signal alternating voltage having a measuring frequency; a first transformer encircles the connection and a first winding inductively couples the voltage into the connection so a loop current flows via first and second leakage capacitors, the active conductors, and the connection, and a second winding for the second measurement of a protective-conductor voltage; a second transformer encircles the connection and has a secondary winding capturing a protective-conductor current flowing in the connection; an evaluation unit determines a loop impedance from the protective-conductor voltage and the protective-conductor current for evaluating the real part of the loop impedance.

Abstract: A method and a measuring device for detecting a leakage current in an ungrounded, single-phase alternating-current power supply system. A variable test resistance is switched between one of the outer conductors and ground and starting from a minimally admissible test-resistance value, at least one of three support test-resistance values is determined as support locations. In an equivalent circuit of the modeled alternating-current power supply system, an equations system is set up for describing the dependency of currents and voltages. An extrapolation on the test-resistance value zero leads to a calculated test current which corresponds to the leakage current to be detected. Consequently, a ground fault situation may be simulated without actually causing a dangerous ground fault.

Abstract: Methods and devices for insulation monitoring of an ungrounded IT power supply system having at least two phase conductors includes determining an insulation resistance separately for each phase conductor using a separate response value. In one embodiment of the invention, relevant current and voltage distributions are calculated. In another embodiment, a change time window is set within which a second response value is activated. In yet another embodiment, an option of shutting down/continuing operation of the IT power supply system is offered.

Abstract: The present invention relates to a method for determining an insulation resistance and for locating insulation faults in a power supply system whose active parts are ungrounded and which is supplied via a converter operated grounded and equipped with controlled power semiconductor switches. A common-mode voltage against ground is generated at the output of the converter and is superimposed on the ungrounded network as an active measuring voltage in order to measure the insulation resistance. The direct integration of the generation of the common-mode measuring voltage in the converter allows cost-effective implementation including similarly comprehensive insulation monitoring functions as those possible in fully ungrounded power supply systems. Furthermore, the method for determining the insulation resistance can be expanded into a method for locating insulation faults and thus for locating faulty system branches.

Abstract: A monitoring device and a method for monitoring an insulation resistance for an ungrounded electric system includes a liquid cooling operated to ground and having refrigerant flowing in tubes. For this purpose, the measuring signal is supplied in series in the tube system via the refrigerant resistance. The monitoring device is realized having a current measurement or a voltage measurement at the tube sections in order to detect the insulation resistance and can be enhanced for monitoring a shared insulation resistance of several ungrounded electric subsystems fed by a shared transformer.

Abstract: An electric measuring assembly and a method for continuously monitoring a protective-conductor resistance of a protective-conductor connection in a power supply system having a supply station, a supply line, and an electric installation, grounded via the connection. A signal generator generates a signal alternating voltage having a measuring frequency; a first transformer encircles the connection and a first winding inductively couples the voltage into the connection so a loop current flows via first and second leakage capacitors, the active conductors, and the connection, and a second winding for the second measurement of a protective-conductor voltage; a second transformer encircles the connection and has a secondary winding capturing a protective-conductor current flowing in the connection; an evaluation unit determines a loop impedance from the protective-conductor voltage and the protective-conductor current for evaluating the real part of the loop impedance.

Abstract: The invention relates to a method and a device for identifying arc faults in an ungrounded power supply system. This object is attained by detecting a displacement voltage to ground at an active conductor or at a neutral point of the ungrounded power supply system; by providing a value of an operating frequency occurring in the power supply system; and by analyzing a frequency spectrum of the detected displacement voltage by calculating and assessing Fourier coefficients at the locations of the operating frequency and its harmonics. Due to the broadband detection of the displacement voltage interacting with the “quick” generation of the basic functions by means of a DDS generator, arc faults can be identified reliably in an ungrounded power supply system.

Abstract: The invention relates to a magnetic field measuring device and a method for detecting a localization current in a branched AC power supply system. Furthermore, the invention relates to a use of the magnetic field measuring device according to the invention as a device for detecting a test current for an insulation fault localization system. By combining two current sensors having a different magnetic field measuring sensitivity and a different magnetic field measuring range, it can be achieved that a reliable detection of localization currents in insulation fault localization systems is possible by means of a constructionally easy and cost-effective realization, in particular as retrofitting in existing systems.

Abstract: A method and a device for protecting a person from electric shock includes detecting a physical-medical factor by means of a sensor device (6) carried on the body (4) of the person; evaluating the physical medial factor, which has been detected by the sensor device (6) as sensor data (20), by means of an evaluation device (8) to discover whether a risk from a body current (IB) is to be anticipated; and switching off a power supply (12), which is allocated to the person and causes the possible body current (IB), by means of a switch-off device (10) if this risk exists.

Abstract: A method and a monitoring device for selectively determining a partial system leakage capacitance in an ungrounded power supply system having a main system and at least one partial system. An extended insulation monitoring system is configured for determining an overall system leakage capacitance of the power supply system; an extended insulation fault location system for determining an ohmic and a capacitive partial test-current portion of a partial test current captured in the respective partial system; and an impedance evaluation system for determining a partial insulation resistance and a partial system leakage capacitance for each partial system to be monitored are provided. For preventing the entire ungrounded power supply system from being switched off, the fundamental idea of the present invention is advantageously based on identifying in which partial system a critical increase of a partial system leakage capacitance has taken place.

Abstract: A monitoring device and a method for monitoring an insulation resistance for an ungrounded electric system includes a liquid cooling operated to ground and having refrigerant flowing in tubes. For this purpose, the measuring signal is supplied in series in the tube system via the refrigerant resistance. The monitoring device is realized having a current measurement or a voltage measurement at the tube sections in order to detect the insulation resistance and can be enhanced for monitoring a shared insulation resistance of several ungrounded electric subsystems fed by a shared transformer.

Abstract: A method and device for determining a division of a total insulation resistance and of a total system leakage capacitance in an ungrounded power supply system. The basic idea is to determine how the total insulation resistance is divided into partial insulation resistances and how the total system leakage capacitance is divided into partial system leakage capacitances between the active conductors of the ungrounded power supply system from displacement voltages measured between each of the active conductors of the ungrounded power supply system based on values determined in advance for the total insulation resistance and for the total system leakage capacitance of the ungrounded power supply system. By evaluating the displacement voltages in terms of their changes in amplitude, their frequency and their phasing, conclusions can be drawn as to the division of the total insulation resistance and of the total system leakage capacitance between the individual active conductors.