Capacitive energy storage device for switchgear, a drive with such an energy storage device and a switchgear with such a drive

Abstract

The invention relates to an energy storage device (10) for an electromagnetic drive of a low-, medium- or high-voltage switch, wherein the energy storage device (10) has one or more capacitors (201, 202, 203, 204, 205) of a first capacitor type and one or more further capacitors (301, 302, 303, 304, 305) of a second capacitor type, wherein the first capacitor type comprises ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor (301, 302, 303, 304, 305), and wherein the at least one capacitor (201, 202, 203, 204, 205) of the first capacitor type and the at least one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in parallel to one another. are interconnected.

Description

[0001] The invention relates to a capacitive energy storage device for switchgear, a drive with such an energy storage device and a switchgear with such a drive.

[0002] Switching devices for low, medium or high voltage systems, such as circuit breakers, with electrical drives, for example magnetic drives, require a quantity of energy for a switching operation, which is usually stored in capacitors, since the auxiliary voltage supply of the switching device cannot provide the high power required for a switching operation, i.e. the amount of energy in a very short time.

[0003] Furthermore, the requirement must be met on a regular basis that in the event of an auxiliary voltage failure, i.e. a failure of the auxiliary voltage supply, a switching operation to the safe switching position OPEN, i.e. open or opened, must be guaranteed for at least 5 minutes after the auxiliary voltage supply failure.

[0004] These two requirements result in the need to design the energy storage device in such a way that, on the one hand, a low electrical internal resistance for the switching energy and, on the other hand, a high storage capacity for the bridging time in the event of an auxiliary power supply failure is provided.

[0005] Electrolytic capacitors are known from the state of the art as energy storage devices for electromagnetic drives. These are used because, when appropriately dimensioned, electrolytic capacitors can meet both requirements: low internal resistance for high short-term power for switching operation, as well as sufficient specific capacitance for the required bridging times in the event of an auxiliary power supply failure.

[0006] Since a correspondingly high number of electrolytic capacitors must be provided to ensure a sufficiently long bridging time in the event of an auxiliary power supply failure, the costs for such an electrolytic capacitor assembly are high, as is the required installation space.

[0007] The object of the invention is to provide an alternative design of the energy storage device which eliminates the disadvantages of the prior art.

[0008] The problem is solved by independent claim 1 and the claims dependent thereon.

[0009] One embodiment relates to an energy storage device for an electromagnetic drive of a low-, medium- or high-voltage switch, wherein the energy storage device has one or more capacitors of a first capacitor type and one or more further capacitors of a second capacitor type, wherein the first capacitor type comprises ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor, and wherein the at least one capacitor of the first capacitor type and the at least one further capacitor of the second capacitor type are connected in parallel to one another.

[0010] In other words, the energy storage device for an electromagnetic drive is a hybrid energy storage device consisting of capacitors and supercapacitors. The capacitors are designed for rapid energy delivery, i.e., high power output, to the electromagnetic drive to operate the drive, and the supercapacitors serve as energy storage devices if the auxiliary power supply of a switchgear fails. In the event of a failure of the auxiliary power supply, the supercapacitors are designed to take over the function of the auxiliary power supply and provide sufficient operating voltage to charge the capacitors, thus switching a switching device, for a period of at least 5 minutes, thus enabling at least one opening operation.

[0011] Supercapacitors are also called electrochemical capacitors or ultracapacitors and are characterized by the fact that they generally do not have a dielectric in the conventional sense, but rather the energy is stored in double layers on the electrodes, with storage taking place both in the form of charge separation in the double layers and in the form of electrochemical storage.

[0012] It is preferred that the first capacitor type is an electrolytic capacitor.

[0013] It is also preferred that the first capacitor type has an energy density of at most 0.5 Wh / l and the second capacitor type has a power density of at least 3 Wh / l, and / or that the second capacitor type has an energy density that is at least 5 times higher than that of the first capacitor type, and wherein the first capacitor type has a lower internal resistance than the second capacitor type.

[0014] It is further preferred that more than one capacitor of the first capacitor type are connected in parallel.

[0015] It is preferred that more than one further capacitor of the second capacitor type are connected in series with each other.

[0016] In particular, it is preferred that the energy storage device further comprises a charge balancing circuit, wherein the charge balancing circuit is configured to transfer excess charge from higher-voltage supercapacitors to lower-voltage supercapacitors and / or to prevent the excess charge and / or to dissipate the excess charge. The charge balancing circuit is also referred to as a voltage balancing device. The charge balancing circuit prevents overcharging, and thus damage to the individual supercapacitors, especially when the cell voltages of the individual supercapacitors differ.

[0017] An active charge balancing circuit is particularly preferred.

[0018] Furthermore, it is particularly preferred that each supercapacitor is connected in parallel to the charge balancing device.

[0019] It is also particularly preferred that the charge balancing circuit of the energy storage device be constructed without highly integrated, inductive or capacitive components, in particular without coils and capacitors. Such a construction can be implemented, for example, by means of a series connection of one or more Zener diodes and one or more resistors. Alternatively, such a construction can be implemented using a resistor network in combination with operational amplifiers as voltage followers.

[0020] A further embodiment relates to an electromagnetic drive for a vacuum interrupter of a low-, medium- or high-voltage switchgear, wherein the electromagnetic drive has an energy storage device according to one or more of the above embodiments.

[0021] Another embodiment relates to a low-, medium- or high-voltage switchgear, wherein the low-, medium- or high-voltage switchgear has an electromagnetic drive according to the preceding embodiments.

[0022] It is preferred that the one or more further capacitors of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for the one or more capacitors of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source.

[0023] It is also preferred that the one or more further capacitors of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for the one or more capacitors of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source and to enable a switching cycle of opening - closing - and reopening.

[0024] A further embodiment relates to a method for operating a low-, medium- or high-voltage switchgear, wherein the low-, medium- or high-voltage switchgear has an electromagnetic drive according to one of the preceding embodiments, and the one or more capacitors of the first capacitor type serve as an energy source for carrying out switching operations, and the one or more further capacitors of the second capacitor type replace the failed auxiliary voltage source for 5 minutes or more in the event of a failure of an auxiliary voltage source.

[0025] With regard to the device according to the invention, all statements made above and below regarding the method according to the invention apply accordingly, and vice versa. In particular, the device according to the invention is designed to carry out the method according to the invention in any desired embodiment or a combination of desired embodiments. With regard to the advantages of the device according to the invention, reference is also made to the advantages described for the method according to the invention.

[0026] The invention is explained in more detail below using an exemplary embodiment. The specific embodiment of the exemplary embodiment is in no way intended to limit the general design of the method and device according to the invention; rather, individual design features of the exemplary embodiment can be freely combined with one another and with the features described above in any way. Regardless of the grammatical gender of a particular term, this includes persons with male, female, or other gender identities.

[0027] The invention is explained in more detail below with reference to figures. Fig. 1: Schematic representation of a switchgear; Fig. 2: Exemplary equivalent circuit diagram of an energy storage device according to the invention; Fig. 3: Example equivalent circuit of a charge balancing circuit.

[0028] The Fig. 1 shows a schematic representation of a switchgear 1 with a display 4 and a user interface 6. The displays 4 and the user interface 6 are analog and / or digital.

[0029] The Fig. 2 shows an exemplary equivalent circuit diagram of an energy storage device 10 according to the invention. The energy storage device 10 has a system 100 for connecting the energy storage device 10 to an electromagnetic drive and an auxiliary voltage source of a switchgear 1.

[0030] Furthermore, the Fig. Two capacitors of a first capacitor type 201, 202, 203, 204, 205, connected in parallel, here five electrolytic capacitors, which are designed to supply the electromagnetic drive with electrical energy for at least one switching operation. Several further capacitors 301, 302, 303, 304, 305 of the second capacitor type, here supercapacitors 301, 302, 303, 304, 305, here five supercapacitors, are connected in parallel to the last electrolytic capacitor 205, with the supercapacitors 301, 302, 303, 304, 305 being connected in series with one another. A charge balancing circuit 400 is optionally arranged in parallel with each additional capacitor 301, 302, 303, 304, 305.

[0031] The Fig. 3 shows an exemplary equivalent circuit diagram of a charge balancing circuit 400 for, here, five supercapacitors 301, 302, 303, 304, 305.

[0032] The charge equalization circuit 400 has a voltage divider, here for example a resistor network with five resistors 410, 420, 430, 440, 450 as a voltage divider between a first potential 401, here for example a ground potential, and a second potential 402, here for example a positive voltage V +,. Furthermore, the charge balancing circuit 400 has, for example, four operational amplifiers 415, 425, 435, 445. The voltage difference between the first potential 401 and the second potential 402 corresponds to the theoretical charging voltage of the supercapacitors 301, 302, 303, 304, 305. However, since the actual capacitances of capacitors can deviate from the nominal capacitances, deviations in the range of ±5% to ±20% are possible, the charge balancing circuit 400 is constructed in such a way that the theoretical charge voltage is divided by means of the resistor network of resistors 410, 420, 430, 440, 450 as a voltage divider and, in the case of deviating capacitances of the supercapacitors 301, 302, 303, 304, 305, the operational amplifiers 415, 425, 435, 445 act as voltage followers to achieve a voltage compensation corresponding to the respective capacitances of the respective supercapacitors 301, 302, 303, 304, 305.For this purpose, the inverting input of each operational amplifier 415, 425, 435, 445 is directly connected to the output of the respective operational amplifier 415, 425, 435, 445. The operational amplifiers 415, 425, 435, 445 are each supplied with voltage by two cells, here supercapacitors 301, 302, 303, 304, 305.

[0033] The operational amplifier 445, referred to here as the lowest operational amplifier 445, is supplied with voltage through the ground contact 401 and the cell above it, i.e. at the output of the operational amplifier 435, here supercapacitor 302.

[0034] The operational amplifier 435 located above is supplied with voltage by the cell with the output of the operational amplifier 445, here supercapacitor 301, and the cell with the output of the operational amplifier 425, here supercapacitor 303.

[0035] The operational amplifier 425 is powered by the cell containing the output of the operational amplifier 435, here supercapacitor 302, and the cell containing the output of the operational amplifier 415, here supercapacitor 304. The top operational amplifier 415 is powered by the cell containing the output of the operational amplifier 425, here 303, and the cell containing the input voltage 402, here supercapacitor 305.

[0036] If one or more supercapacitors 301, 302, 303, 304, 305 have a lower voltage than the desired capacitor voltage, the respective operational amplifier 415, 425, 435, 445 acts as a current source and charges the respective supercapacitor 301, 302, 303, 304, 305. The charge required for this is then taken from one of the neighboring supercapacitors 301, 302, 303, 304, 305.

[0037] If one or more supercapacitors 301, 302, 303, 304, 305 have a higher voltage than the desired capacitor voltage, the operational amplifier 415, 425, 435, 445 acts as a current sink and discharges the respective supercapacitor 301, 302, 303, 304, 305. The excess charge is then absorbed by one of the neighboring supercapacitors 301, 302, 303, 304, 305.

[0038] The charge balancing circuit 400 thus reduces the voltages of the supercapacitors 301, 302, 303, 304, 305 with excessively high voltages and increases the voltages of the supercapacitors 301, 302, 303, 304, 305 with excessively low voltages. This achieves charge balancing. In particular, such a charge balancing circuit 400 does not have any highly integrated, inductive, or capacitive components, in particular, no coils or other capacitors. List of reference symbols 1 switchgear; 4 Display on switchgear 1; 6 User interface of switchgear 1; 10 energy storage units; 100 System for connecting the energy storage device 10 to an electromagnetic drive and an auxiliary voltage source of a switchgear 1 201 capacitor of a first capacitor type, e.g. electrolytic capacitor; 202 Capacitor of a first capacitor type, e.g. electrolytic capacitor; 203 Capacitor of a first capacitor type, e.g. electrolytic capacitor; 204 Capacitor of a first capacitor type, e.g. electrolytic capacitor; 205 Capacitor of a first capacitor type, e.g. electrolytic capacitor; 301 capacitor of a second capacitor type, a supercapacitor; 302 Capacitor of a second capacitor type, a supercapacitor; 303 Capacitor of a second capacitor type, a supercapacitor; 304 Capacitor of a second capacitor type, a supercapacitor; 305 Capacitor of a second capacitor type, a supercapacitor; 400 charge balancing circuit 401 first potential, for example earth potential; 402 second potential, for example positive voltage V + ; 410 resistance of the voltage divider; 415 operational amplifiers; 420 resistance of the voltage divider; 425 operational amplifiers; 430 resistance of the voltage divider; 435 operational amplifiers; 440 resistance of the voltage divider; 445 operational amplifiers; 450 resistance of the voltage divider.

Claims

[1] Energy storage device (10) for an electromagnetic drive of a low, medium or high voltage switch, characterized by that the energy store (10) has one or more capacitors (201, 202, 203, 204, 205) of a first capacitor type and one or more further capacitors (301, 302, 303, 304, 305) of a second capacitor type, wherein the first capacitor type comprises ceramic, film and / or electrolytic capacitors and the second capacitor type is a supercapacitor, and wherein the at least one capacitor (201, 202, 203, 204, 205) of the first capacitor type and the at least one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in parallel to one another. [2] Energy storage device (10) according to claim 1, characterized by that the first type of capacitor is an electrolytic capacitor. [3] Energy storage device (10) according to one of the preceding claims, characterized bythat the first capacitor type (201, 202, 203, 204, 205) has an energy density of at most 0.5 Wh / l and the second capacitor type (301, 302, 303, 304, 305) has a power density of at least 3 Wh / l, and / or that the second capacitor type (301, 302, 303, 304, 305) has an energy density that is at least 5 times higher than that of the first capacitor type (201, 202, 203, 204, 205), and wherein the first capacitor type (201, 202, 203, 204, 205) has a lower internal resistance than the second capacitor type (301, 302, 303, 304, 305). [4] Energy storage device (10) according to one of the preceding claims, characterized by that more than one capacitor (201, 202, 203, 204, 205) of the first capacitor type are connected in parallel. [5] Energy storage device (10) according to one of the preceding claims, characterized by that more than one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected in series with each other. [6] Energy storage device (10) according to claim 5, characterized by in that the energy storage device (10) further comprises a charge balancing circuit (400), wherein the charge balancing circuit (400) is designed to transfer excess charges from higher voltage supercapacitors to lower voltage supercapacitors and / or to prevent the excess charge and / or to dissipate the excess charge. [7] Energy storage device (10) according to claim 6, characterized by that the charge equalization circuit (400) of the energy storage device (10) is constructed without highly integrated, inductive or capacitive components, in particular without coils and capacitors. [8] Electromagnetic actuator for a vacuum interrupter of a low, medium or high voltage switchgear (1), characterized by that the electromagnetic drive has an energy store (10) according to one of the preceding claims. [9] Low, medium or high voltage switchgear (1), characterized by that the low-, medium- or high-voltage switchgear (1) has an electromagnetic drive according to the preceding claim. [10] Low, medium or high voltage switchgear (1) according to claim 9, characterized by that the one or more further capacitors (301, 302, 303, 304, 305) of the second capacitor type of the energy storage device (10) store sufficient energy to serve as an auxiliary voltage source for the one or more capacitors (201, 202, 203, 204, 205) of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source. [11] Low, medium or high voltage switchgear (1) according to claim 9, characterized bythat the one or more further capacitors (301, 302, 303, 304, 305) of the second capacitor type of the energy storage device store sufficient energy to serve as an auxiliary voltage source for the one or more capacitors (201, 202, 203, 204, 205) of the first capacitor type for 5 minutes or more after a failure of an auxiliary voltage source and to enable a switching cycle of the vacuum interrupter from opening - closing - and reopening. [12] Method for operating a low-, medium- or high-voltage switchgear (1), characterized bythat the low-, medium- or high-voltage switchgear (1) has an electromagnetic drive according to one of the preceding claims, and the one or more capacitors (201, 202, 203, 204, 205) of the first capacitor type serve as an energy source for carrying out switching operations, and the one or more further capacitors (301, 302, 303, 304, 305) of the second capacitor type replace the failed auxiliary voltage source for 5 minutes or more in the event of a failure of an auxiliary voltage source.

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