Switching device for safely disconnecting an electrical load from a power supply network and a safety switching system

Patent metadata

Field	Value
Publication number	US-2022006291-A1
Application number	US-201917279470-A
Country	US
Kind code	A1
Filing date	Sep 25, 2019
Priority date	Sep 28, 2018
Publication date	Jan 6, 2022
Grant date	—

Abstract

A switching apparatus for safely disconnecting an electrical load from a power supply network and to facilitate safe disconnection in the event of failure of a supply voltage thereof, includes an energy storage device which, in the event of failure of the supply voltage of a control unit, provides the energy for generating switching signals for a first electromechanical switch, a second electromechanical switch and a semiconductor switch. In order to be able to detect the failure of the supply voltage, a detector and signaling device is provided which is configured to detect discharging of the energy storage device and to supply a notification signal to the control unit signaling the discharging of the energy storage device to the control unit. In response to the notification signal, the control unit causes the electrical load to be disconnected from the power supply network in a safe and terminal-friendly manner.

First claim

1 . A switching apparatus for safely disconnecting an electrical load from a power supply network, comprising:
a first connection device to which a power supply network for providing a supply voltage for an electrical load can be connected; a second connection device to which an electrical load can be connected; a third connection device to which a power supply source for providing a supply voltage for the switching apparatus can be connected; at least one current path connected between the first and second connection devices, the at least one current path including a first electromechanical switch and, connected in series with the first electromechanical switch, a parallel circuit of a second electromechanical switch connected in parallel to a semiconductor switch; a power supply unit electrically connected to the third connection device; an energy storage device electrically connected to the third connection device in such a way that the energy storage device can be charged by a supply voltage that can be applied to the third connection device; a control unit electrically connected to the power supply unit; wherein: the control unit is configured to output a respective switching signal for the first electromechanical switch, the second electromechanical switch, and the semiconductor switch, wherein the control unit receives power for generating the switching signals via the power supply unit; a detector and signaling device configured to detect discharging of the energy storage device and to supply a notification signal to the control unit signaling the control unit that the energy storage device is discharging, wherein the control unit is configured to be responsive to said notification signal by using the energy stored in the energy storage device to: first switch the semiconductor switch to an electrically conductive state, then to open the second electromechanical switch, then to switch the semiconductor switch to an electrically non-conductive state, and then to open the first electromechanical switch.

2 . The switching apparatus of claim 1 , further comprising:
a voltage limiting device connected to the energy storage device, configured to limit the voltage applied to the energy storage device to a predetermined voltage value, wherein the energy storage device discharges when a supply voltage applied to the third connection device drops below the predetermined voltage value applied to the energy storage device.

3 . The switching apparatus of claim 2 , wherein:
the first connection device comprises a ground terminal and an operating potential terminal; the voltage limiting device comprise a Zener diode and an electrical resistor, the Zener diode being connected in parallel to the energy storage device, wherein the anode terminal of the Zener diode is connected to the ground terminal and the cathode terminal is connected to a terminal of the electrical resistor, while the other terminal of the electrical resistor is associated with the operating potential terminal.

4 . The switching apparatus as claimed in claim 1 , wherein:
the detector and signaling device includes a coupling element connected to the energy storage device, to an input of the control unit, and to an input of the power supply unit, wherein the detector and signaling device supplies a binary notification signal.

5 . The switching apparatus of claim 4 , wherein:
the coupling element is an optocoupler comprising an optical transmitter connected between the energy storage device and the input of the power supply unit, and an optical receiver connected to the input of the control unit.

6 . The switching apparatus as claimed in claim 1 , further comprising:
a further current path connected between the first and second connection devices, which includes a first electromechanical switch and, connected in series with the first electromechanical switch, a parallel circuit of a second electromechanical switch connected in parallel to a semiconductor switch; wherein the control unit is configured to output a respective switching signal for the first electromechanical switch, the second electromechanical switch, and the semiconductor switch of the further current path, wherein the control unit is furthermore configured, in relation to the further current path, to be responsive to said notification signal from the detector and signaling device by using the energy stored in the energy storage device to first switch the semiconductor switch to an electrically conductive state, then to open the second electromechanical switch, then to switch the semiconductor switch to an electrically non-conductive state, and then to open the first electromechanical switch.

7 . A safety switching system for safely disconnecting an electrical load from a power supply network, comprising:
at least one switching apparatus according to claim 1 ; and an external power supply source which can be connected to the third connection device of the at least one switching apparatus via an external switching device or can be disconnected from the third connection device of the at least one switching apparatus.

8 . A safety switching system for safely disconnecting an electrical load from a power supply network, comprising:
a plurality of the switching apparatus according to claim 1 , which can be connected in parallel to a power supply source via an external switching device, wherein each switching apparatus includes a decoupling diode, with an anode terminal thereof connected to the operating potential terminal of the third connection device and with a cathode terminal thereof connected to the power supply unit of the respective switching apparatus.

Assignees

• Phoenix Contact Gmbh & Co

Inventors

• Schaper Elmar
• Schulz Bernd

Classifications

• Y04S20/222

  Demand response systems, e.g. load shedding, peak shaving · CPC title

• H01H9/542 Primary

  Contacts shunted by static switch means · CPC title

• Y02B70/3225

  Demand response systems, e.g. load shedding, peak shaving · CPC title

• H02H7/26

  Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured (locating faults in cables G01R31/08) · CPC title

• H02J3/14 Primary

  by switching loads on to, or off from, the networks, e.g. progressively balanced loading · CPC title