Bender Gmbh & Co Kg

Julian Reitz

Eckhard Broeckmann

Karl Schepp

Dieter Hackl

Eckhard BRÖCKMANN

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.

Method and measuring device for detecting a leakage current in an ungrounded, single-phase alternating-current power supply system

An extinguishing-agent discharge device includes a casing having a guide channel for an extinguishing agent, a metallic handle, a hose connection, an adjustment means for regulating an extinguishing-agent supply using a manual control unit and a discharge nozzle. A measuring-current transformer generates a current signal proportional to the electric current flowing in the extinguishing agent; an insulator section divides the casing into a discharge area having the discharge nozzle and an inlet area having the manual control unit, the measuring-current transformer disposed in the insulator section; a first electrode disposed in the discharge area in the extinguishing-agent flow and serves for detecting an extinguishing-agent potential; a second electrode disposed at the handle for detecting a ground potential in the inlet area; and a controller for evaluating the current signal for a potential difference occurring between the extinguishing-agent and ground and having a drive element acting on the adjustment means.

Device for discharging extinguishing agent

The invention relates to an electric circuit arrangement () for the functional testing of a monitoring device () for a power supply system (), the electric circuit arrangement () having a test resistance (R, R) which is switched between an active conductor (L, L) of the power supply system () and ground (PE) and has a settable actual resistance value (R). In this context, a bidirectional cascade () consisting of field-effect transistors as test resistances (R, R) and an analog control () for the continuous-value setting of the actual resistance value (R) to a predefined target resistance value (R) are provided. Furthermore, the invention relates to a modular circuit arrangement () consisting of several electric circuit arrangements () according to the invention, each of the electric circuit arrangements () being assigned a different active conductor (L, L) of the electric power supply system (), and a central control unit () being implemented for controlling and monitoring the electric circuit arrangements ().

Electric circuit arrangement and a method for the functional testing of a monitoring device for an electric power supply system

The invention relates to an electric circuit arrangement and a method for coupling an insulation monitoring device to an ungrounded power supply system via a coupling impedance, which is realized to be operant for each active conductor of the power supply system and which is formed as an ohmic resistance circuit, the ohmic resistance circuit having a settable resistance value which is changeable and a switching-off function for decoupling the insulation monitoring device from the network and being realized as a bidirectional cascade comprising a series circuit of two transistors provided in a mirror-inverted manner, each having a diode connected in parallel, a controlled change in resistance of the transistors for setting the changeable resistance value being effected by a control circuit and the switching-off function for decoupling from the grid being realized by setting a maximum resistance value.

Electric circuit arrangement and method for coupling an insulation monitoring device to an ungrounded power supply system

A method and a test apparatus for determining the elements of a dielectric equivalent circuit diagram for an insulation of an electric system and to an insulation monitoring device. All data points of the system's step response are stored for a measuring period T, and fault resistance Rand an initial value Cof leakage capacitance Care calculated. After this determination of fault resistance Rand initial value C, the elements of absorption element Rand Cand leakage capacitance Care determined by numeric signal processing by using an approximation algorithm which continuously simulates the recorded step response. For simulating the step response, a transfer function G(s) modelled by the equivalent circuit diagram having equivalent circuit diagram elements R, C, R, Cand measurement resistance Ris formed analytically and the output signal is calculated, which is described using transfer function G(s), by means of the step function.

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Gruenberg, Germany

Julian Reitz