Siemens Aktiengesellschaft

Reinhard Schmid

Manfred Kleemeier

Reinhard Solleder

Stefan Gies

Fritz Pohl

Bernhard Bauer

Dirk Graupner

Gerald Lehner

Markus Huber

A protective switching device is disclosed for monitoring the electrical current flow to an electrical user, including a switching functionality, an excess current triggering functionality and a short circuit triggering functionality. In at least one embodiment, the protective switching device includes a first microcontroller with a first input signal filter, wherein the first microcontroller is configured for monitoring the excess current triggering functionality and wherein a second microcontroller is provided with a second input signal filter that is configured for monitoring the short circuit triggering functionality, wherein the two input signal filters are designed differently, and wherein the switching functionality is provided in one of the two microcontrollers. A method is further disclosed for monitoring the electrical current flow to an electrical user by way of a protective switching device.

Protective switching device for monitoring the electrical current flow to an electrical user and method for monitoring the electrical current flow to an electrical user by way of a protective switching device

A protective switching device, such as a differential-current circuit breaker, having a corebalance transformer which monitors a line network and which, via a tripping circuit and an actuation circuit, actuates a release which is coupled to a switching mechanism in order to operate a power breaker. The invention provides that a tripping circuit, which can be tripped by means of a remote tripping signal, is connected to a transformer which can be actuated on the secondary side and whose primary side is connected to an actuation circuit of the release for remote tripping of the protective switching device.

Power circuit-breaker

A fault current detection system is provided. The detection system detects a fault current generated on a conductive path supplying power to an electric device and prevents the fault current from being supplied to the electric device. In particular, the detection system contains a detector, a switch, and a controller. The detector detects a fault current generated on the conductive path and outputs a corresponding detection signal. The controller inputs the detection signal and determines predetermined characteristics of the fault current based on said detection signal. Then, the controller identifies the fault current as a first type of fault current based on the predetermined characteristics and sets a trigger current to a first trigger current value when the fault current is identified as the first type of fault current. Also, the controller outputs a control signal to the switch to instruct the switch to isolate the electric device from the conductive network when the fault current is greater than the trigger current. In addition, a software program performed by the fault current detection system is also provided.

Software-controlled evaluation of fault currents for protection and monitoring systems

Two detection systems are provided for a protective device, in particular an FI protective device, having a core balance transformer whose secondary winding is followed by a tripping relay for operating a switching mechanism, which switches a conductor network. In this case, a first detection system carries out the tripping function for fault currents at a fault current frequency below a changeover frequency. The second detection system carries out the tripping function for fault currents above the changeover frequency. The changeover frequency is in this case preferably not less than 1 kHz.

Protective device, in particular a fault current protective device

A fault or differential current detection system is provided. The detection system detects a fault or differential current generated on a conductive path supplying power to an electric device and prevents the fault or differential current from being supplied to the electric device. The detection system comprises a detector, a switch, and a controller. The detector detects a detected current generated on the conductive path and outputs a corresponding detection signal. The controller inputs the detection signal and determines if the detected current is greater than or equal to a first predetermined current threshold based on the detection signal. Then, the controller refrains from outputting a control signal to the switch for a predetermined delay period after the detected current becomes greater than or equal to the first predetermined current threshold. Then, the controller determines if the detected current is greater than or equal to a second predetermined current threshold when the predetermined delay period is over. After the detected current becomes greater than or equal to the second predetermined current threshold, the controller determines if the detected current is a fault or differential current. When the detected current is a fault or differential current, the controller outputs the control signal to the switch to instruct the switch to isolate the fault or differential current from the electric device. A software program executed by the controller is also provided.

Fault current and differential current detection system capable of preventing spurious triggering of a protection system due to transient interference pulses

A protective device against fault currents includes a triggering arrangement for performing at least the functions of detecting a fault current and/or triggering power-down of the network to be protected. The triggering arrangement, outside the most strict quartic curve (A), corresponds to the protection of persons in case of indirect contact, and below the triggering quartic curve (B), corresponds to protection against fire. The triggering quartic curve (B) satisfies the relationship: I (f)/I &equals;F(f)&equals;B&equals;const., wherein I (f)&equals;W /U . In the relationships, I (f) represents the limit fault current permissible for the corresponding frequency, where there is still no risk of fire; I represents the nominal triggering fault current at the frequency of the network taking into consideration the protection of persons; W represents the power limit in watt required for protection against fire; U represents the network voltage to be protected and F(f) represents what is called the frequency factor.

Protective device against fault currents for protection against fire

A residual current device includes a residual current tripping circuit for actuating a release, and an additional monitoring device for checking the release, in which case a device is provided for electrically decoupling the residual current tripping circuit from the monitoring device.

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Wuppertal, Germany

Reinhard Schmid