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: Methods and devices for minimizing a possibly corroding DC protective-conductor current for a DC system grounded via a protective conductor designed as a foundation ground electrode with connected SK 1-operating equipment. Balancing includes feeding a balancing current to a casing of the class I operating equipment at a ground terminal via an output circuit between a fault-free active conductor and ground terminal, a balancing-current polarity and amplitude set such that the DC protective-conductor current is minimized in the foundation ground electrode. In contrast to DC balancing, DC compensation means a compensating current is fed to the casing at the ground terminal of the class I operating equipment via an output current between the faulty active conductor and the ground terminal. Regarding the polarity and the amplitude, the compensating current is such that the DC protective-conductor current is minimized in the foundation ground terminal.

Abstract: A method and devices for testing and monitoring the continuity of a PEN conductor for a three-phase TN-C-S power supply system to which operating equipment is connected via a single or three phases. As intended by the invention, a voltage is measured for this purpose at a virtual star point set up according to the invention at operating equipment using three-phase machine terminals, and the measured star-point voltage is evaluated. Should the star-point voltage exceed a critical voltage, the operating equipment is disconnected. The invention therefore does not require a constructively difficult installation of a local reference ground. For operating equipment with single-phase machine terminals, a load voltage is measured in a first and a second load case along with a computation of a loop impedance from the voltage change and a residual-current change. The thus determined loop impedance value allows drawing a conclusion on whether a functional PEN conductor is present.

Abstract: The present disclosure relates to protective devices and methods for protection against electric shock in an AC, 3AC or DC power supply system, which has a main supply and additional power sources. In a first embodiment, a voltage measuring device is switched at each of the additional power sources. A signaling device disposed at the additional power sources signals when a voltage is exceeded by means of a disconnect signal should the measured voltage exceed a voltage threshold at the corresponding additional power source. A second embodiment comprises a residual current device disposed at each of the additional power sources and intended for identifying a corresponding residual differential current, and a measuring impedance switched at the additional power sources and intended for generating the residual differential current.

Abstract: A method and insulation monitoring arrangement for insulation monitoring of an electric installation operated using a supply direct voltage and has a first insulation resistance between the positive active conductor and ground and a second insulation resistance between the negative active conductor and ground as well as a functional grounding between the negative active conductor and ground by a ground resistance. The method involves measuring a ground current, which flows in the path of the functional grounding, by means of a DC measuring device; measuring the supply direct voltage by means of a voltage measuring device; computing the first insulation resistance from the supply direct voltage divided by the ground current by means of a computing unit; the condition is valid during operation of the electric installation that the second insulation resistance being at least 100 times greater than the ground resistance.

Abstract: A method and an electrical circuit arrangement is for determining an insulation resistance of an ungrounded power supply system, which feeds electrical energy to the water-electrolysis installation. The fundamental idea of the method is based on predicting the insulation resistance of the ungrounded power supply system during an initial booting of the water-electrolysis installation and thus keeping the delay caused by the demineralization process as short as possible until the electrolysis process for subsequent booting processes of the electrolysis installation has been actually cleared. In a variation of the method, the electric conductance value and the temperature of the process water are additionally provided and recorded depending on the specific installation by the demineralization installation during the demineralization process.

Abstract: The invention relates to a method (1) and to an electric circuit arrangement (2) for selective insulation monitoring in a power supply system (10) having isolable subsystems (20) which each has an integrated energy storage (22). In this context, the subsystem to be monitored (20) is cyclically and temporarily isolated (S1) for the duration of a measuring interval (?T) with all-pole semiconductor disconnectors (SW); operation of the isolated subsystem (20) to be monitored is continued (S2) by means of its integrated energy storage (22) during the measuring interval (?T); and an insulation resistance (Rf) of the subsystem (20) is measured (S3) during the measuring interval (?T) by means of a standard insulation monitoring device (IMD).

Abstract: A method and insulation monitoring arrangement for insulation monitoring of an electric installation operated using a supply direct voltage and has a first insulation resistance between the positive active conductor and ground and a second insulation resistance between the negative active conductor and ground as well as a functional grounding between the negative active conductor and ground by a ground resistance. The method involves measuring a ground current, which flows in the path of the functional grounding, by means of a DC measuring device; measuring the supply direct voltage by means of a voltage measuring device; computing the first insulation resistance from the supply direct voltage divided by the ground current by means of a computing unit; the condition is valid during operation of the electric installation that the second insulation resistance being at least 100 times greater than the ground resistance.

Abstract: A method and an electrical circuit arrangement is for determining an insulation resistance of an ungrounded power supply system, which feeds electrical energy to the water-electrolysis installation. The fundamental idea of the method is based on predicting the insulation resistance of the ungrounded power supply system during an initial booting of the water-electrolysis installation and thus keeping the delay caused by the demineralization process as short as possible until the electrolysis process for subsequent booting processes of the electrolysis installation has been actually cleared. In a variation of the method, the electric conductance value and the temperature of the process water are additionally provided and recorded depending on the specific installation by the demineralization installation during the demineralization process.

Abstract: The invention relates to a method (1) and to an electric circuit arrangement (2) for selective insulation monitoring in a power supply system (10) having isolable subsystems (20) which each has an integrated energy storage (22). In this context, the subsystem to be monitored (20) is cyclically and temporarily isolated (S1) for the duration of a measuring interval (?T) with all-pole semiconductor disconnectors (SW); operation of the isolated subsystem (20) to be monitored is continued (S2) by means of its integrated energy storage (22) during the measuring interval (?T); and an insulation resistance (Rf) of the subsystem (20) is measured (S3) during the measuring interval (?T) by means of a standard insulation monitoring device (IMD).

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 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.