Apparatus and method for capacitive determination of hybrid capacitor energy stores and switching device with such capacitive determination

Abstract

An energy store (10) for an electromagnetic drive of a low-, medium- or high-voltage switch, wherein the energy store (10) has one or more capacitors (201, 202, 203) 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 capacitors, film capacitors and / or electrolytic capacitors and the second capacitor type are supercapacitors, and wherein at least one capacitor (201, 202, 203) of the first capacitor type and at least one further capacitor (301, 302, 303, 304, 305) of the second capacitor type are connected to each other in parallel by an energy flow regulating device (100).

Description

Technical Field

[0001] The present invention relates to an apparatus and method for determining the capacitance of a hybrid capacitor energy storage device in a hybrid capacitor energy storage device, and a switching device having such capacitance determination. Background Technology

[0002] A hybrid energy storage device is an energy storage device composed of at least two different types of energy storage devices. Therefore, a hybrid capacitor energy storage device is an energy storage device formed using at least two different types of capacitors. Such a hybrid capacitor energy storage device is meaningful when the electrical characteristics of the storage medium have significant differences in at least one parameter, i.e., for example, energy density and / or internal resistance.

[0003] In the case of a hybrid capacitor energy storage system consisting of electrolytic capacitors and supercapacitors, the differences in basic electrical parameters are as follows:

[0004] Electrolytic capacitors have low internal resistance with relatively small capacitance, thus enabling them to carry large currents.

[0005] Supercapacitors have a large internal resistance and a large capacitance, which results in a high amount of usable energy at moderate discharge currents.

[0006] Switching devices used in low-voltage, medium-voltage, or high-voltage equipment, such as circuit breakers with electrical drives, i.e., magnetic drives, require a certain amount of energy to be consumed during the switching process. This amount of energy is usually stored in capacitors because it may not be possible to provide the high power, i.e. the required amount of energy, required for the switching process from the auxiliary voltage supply of the switching device in a very short time.

[0007] In addition, the following requirement must generally be met: in the event of auxiliary voltage failure, i.e., auxiliary voltage supply failure, the switching process must still be switched to the safe switching position OPEN, i.e., interrupted or disconnected, within at least 5 minutes after the auxiliary voltage supply failure.

[0008] Because of these two requirements, the energy storage device must be designed to provide low internal resistance for switching energy and high storage capacitance for the transition time in the event of auxiliary voltage supply failure.

[0009] Hybrid capacitor energy storage systems meet these requirements.

[0010] Furthermore, for the long-term safe operation of capacitor banks, such as those used in circuit breakers, cyclic capacitance measurements and monitoring are essential to detect aging and sudden failures promptly and to enable timely responses. This also applies to hybrid capacitor banks. For this purpose, the capacitance of the entire capacitor bank is determined. This is done by increasing the charging voltage to a small amount above the normal operating voltage, followed by controlled discharge to the normal operating voltage, and measuring the current, voltage, and discharge time to determine the capacitance. In the case of hybrid capacitor banks, this capacitance determination is not possible because the capacitance of electrolytic capacitors is much smaller than that of supercapacitors, making capacitance degradation / reduction in electrolytic capacitors difficult to detect.

[0011] In the prior art, electrolytic capacitors are known as energy storage devices for electromagnetic drive devices, such as load switches and circuit breakers, particularly in medium-voltage switchgear. Electrolytic capacitors are used because they can meet both requirements given their corresponding dimensions. This is due to their low internal resistance for the high, short-term power requirements of switch operation, and sufficient specific capacitance for the required transition time in the event of auxiliary voltage supply failure. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide an alternative design for determining the capacitance of a hybrid capacitor energy storage device, which eliminates the disadvantages of the prior art.

[0013] The aforementioned technical problem is solved by independent claims 1 and 14 and the claims dependent thereto.

[0014] One embodiment relates to a capacitance determination device for a hybrid capacitor energy storage device, wherein,

[0015] • A hybrid capacitor energy storage device has one or more capacitors of a first capacitor type and one or more capacitors of another second capacitor type.

[0016] • Wherein, the first capacitor type includes ceramic capacitors, film capacitors, and / or electrolytic capacitors, and the second capacitor type is a supercapacitor, and wherein,

[0017] • At least one capacitor of a first capacitor type and at least one other capacitor of a second capacitor type are connected in parallel with each other via a capacitance determining device, and wherein,

[0018] • Capacitance determination device

[0019] The device includes an energy flow regulating device that allows for selective charging of a capacitor of the first capacitor type, or charging of a capacitor of the first capacitor type together with another capacitor of the second capacitor type.

[0020] The device has a control element arranged between a first capacitor type and a second capacitor type connected in parallel, such that the discharge process of the second capacitor type is controlled by the control element, and the current flow from the first capacitor type to the second capacitor type is blocked.

[0021] o has a capacitance determination unit that determines the capacitance based on the charging current, the generated voltage, and a preferred discharge time.

[0022] This arrangement avoids the need for the first capacitor type to operate in parallel with another second capacitor type via conventional switching elements, which reduces installation space and costs.

[0023] Here, the energy storage device, particularly the energy storage device for the electromagnetic drive of vacuum switching tubes in low-voltage, medium-voltage, or high-voltage switchgear, is a hybrid energy storage device composed of capacitors and supercapacitors, wherein the capacitors are connected to the supercapacitors via an energy flow regulating device. The capacitors are configured to provide rapid energy output, i.e., high-power output, to the electromagnetic drive to operate the drive; while the supercapacitors function as energy storage devices when the auxiliary voltage supply to the switchgear fails. In the event of an auxiliary voltage supply failure, the supercapacitors are designed to take over the function of the auxiliary voltage supply and preferably provide sufficient operating voltage for at least 5 minutes to charge the first type of capacitor, thereby switching the switchgear and thus enabling at least one disconnection process.

[0024] The energy flow regulating device is designed to regulate the energy flow between a first capacitor type and a second capacitor type, and preferably also an auxiliary voltage supply.

[0025] With this energy flow regulation device, the charging time of the first capacitor type is reduced relative to the total charging time of the hybrid energy storage device, especially because the first capacitor type capacitor can be charged first, and the second capacitor type capacitor is charged later in time.

[0026] Supercapacitors, also known as electrochemical capacitors or ultracapacitors, are characterized by the fact that they typically do not have a dielectric in the traditional sense, but instead store energy in a double-layer manner on electrodes. This storage occurs not only in a double-layer manner through charge separation, but also in an electrochemical manner.

[0027] In particular, by first charging the capacitor of the first capacitor type, a short charging time is achieved before functionally preparing it for switching operation, and then the capacitor of the second capacitor type is charged. That is, after charging the capacitor of the first capacitor type and after a short waiting period, a transition time is achieved in case of auxiliary voltage failure, but this does not adversely affect the operation guidance.

[0028] Additionally, by using a supercapacitor, a longer transition time is guaranteed in the event of auxiliary voltage failure without increasing the charging time of the first type of capacitor.

[0029] At the same time, with the same installation space, a longer transition time was also achieved in the event of auxiliary voltage failure.

[0030] The preferred type of capacitor is an electrolytic capacitor.

[0031] Preferably, the first capacitor type has a maximum energy density of 0.5 Wh / L, while the second capacitor type has an energy density of at least 3 Wh / L, and / or the second capacitor type has an energy density 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.

[0032] Furthermore, it is preferable that more than one of the first capacitor type capacitors be connected in parallel with each other.

[0033] Preferably, more than one capacitor of the second capacitor type is connected in series with each other.

[0034] In particular, the hybrid capacitor energy storage device preferably also has a charge balancing circuit, which is designed to transfer excess charge from a higher-voltage supercapacitor to a lower-voltage supercapacitor.

[0035] Preferably, the control element is a diode. The diode is arranged such that it blocks the flow of current from the first type of capacitor to another second type of capacitor, while allowing current to flow from the second type of capacitor to the first type of capacitor.

[0036] It is also preferred that the energy flow regulation device is formed by one or more bidirectional DC-DC converters.

[0037] It is particularly preferred that at least one of the bidirectional DC-DC converters is configured to further perform the functions of the control element.

[0038] It is also preferred that the energy flow regulating device is formed using at least one bidirectional DC-DC converter in each flow direction.

[0039] It is particularly preferred that at least one of the bidirectional DC-DC converters is configured to further perform the functions of the control element.

[0040] Another embodiment relates to an electromagnetic drive device for a vacuum switch tube in a low-voltage, medium-voltage, or high-voltage switchgear, wherein the electromagnetic drive device has a capacitance determination device for a hybrid capacitor energy storage device according to one or more of the foregoing embodiments.

[0041] Another embodiment relates to a low-voltage, medium-voltage, or high-voltage switchgear, wherein the low-voltage, medium-voltage, or high-voltage switchgear has an electromagnetic drive device according to the foregoing embodiments.

[0042] Another embodiment relates to a method for determining the capacitance in a hybrid capacitor energy storage device for a low-voltage, medium-voltage, or high-voltage switchgear according to a previous embodiment, wherein,

[0043] To determine the capacitance of the hybrid capacitor energy storage device,

[0044] a) Determine the first capacitance of a capacitor of the first capacitor type by charging the capacitor of the first capacitor type to the voltage required for capacitance measurement, wherein the other capacitor of the second capacitor type, i.e., the supercapacitor, is not charged, such that the voltage of the other capacitor of the second capacitor type is lower than the voltage of the capacitor of the first capacitor type, and thus the current flow from the other capacitor of the second capacitor type to the capacitor of the first capacitor type is blocked, and thus the capacitance determination unit determines the capacitance of the capacitor of the first capacitor type.

[0045] b) The capacitance determination unit determines the capacitors of the first capacitor type and the capacitors of the second capacitor type, i.e., the total capacitance of the entire hybrid capacitor energy storage device; and

[0046] c) Calculate the additional capacitance of the capacitor of the second capacitor type based on the determined first capacitance and the determined total capacitance.

[0047] Preferably,

[0048] - Execute step a) before step b), or execute step b) before step a), and

[0049] - Step c) is performed after steps a) and b).

[0050] Regarding the apparatus according to the invention, all embodiments above and below concerning the method according to the invention apply, and vice versa. In particular, the apparatus according to the invention is configured to perform the method according to the invention in any embodiment or combination of embodiments. For advantages of the apparatus according to the invention, please refer to the advantages described regarding the method according to the invention.

[0051] The present invention will now be described in more detail with the aid of embodiments. The specific design schemes of the embodiments should not be construed as limiting the general design schemes of the method and apparatus according to the present invention; rather, the various design features of the embodiments can be freely combined with each other in any manner, and can be combined with the features described above.

[0052] Regardless of the grammatical gender of a particular term, people with either male or female gender identity are included. Attached Figure Description

[0053] The invention will now be described in more detail with the aid of the accompanying drawings.

[0054] Figure 1 A schematic diagram of the switching equipment is shown;

[0055] Figure 2 An exemplary equivalent circuit diagram of the hybrid capacitor energy storage device according to the present invention is shown;

[0056] Figure 3 A flowchart for executing the method is shown;

[0057] Figure 4 An exemplary equivalent circuit diagram of a charge balance circuit is shown. Detailed Implementation

[0058] Figure 1 A schematic diagram of a switching device 1 is shown, which has an indicator 4 and a user interface 6. Here, the indicator 4 and the user interface 6 are implemented in an analog and / or digital manner.

[0059] Figure 2An exemplary equivalent circuit diagram of a hybrid capacitor energy storage device 10 according to the present invention is shown. Here, the hybrid capacitor energy storage device 10 has a capacitance determination device 100, which has an energy flow regulation device, optionally an energy supply device, and a control element for connecting the hybrid capacitor energy storage device 10 to an electromagnetic drive device and an auxiliary voltage source of a switching device 1. The energy flow regulation device and the control element are also configured to regulate, i.e., control, the energy flow between capacitors 201, 202, 203 of a first capacitor type and capacitors 301, 302, 303, 304, 305 of another second capacitor type.

[0060] also, Figure 2 Capacitors 201, 202, and 203, of the first capacitor type, are shown connected in parallel; here, three electrolytic capacitors are exemplarily provided. These are designed to supply electrical energy to an electromagnetic drive device for at least one switching operation. A capacitance determining device 100, having energy flow regulation and control elements, is connected at the last electrolytic capacitor 203, and is connected in parallel with supercapacitors 301, 302, 303, 304, and 305; here, five supercapacitors are exemplarily provided. These supercapacitors are connected in series with each other. Optionally, a charge balancing circuit 400 is arranged in parallel with each capacitor.

[0061] Figure 3 A flowchart for performing the method is shown. In the first step 1000, the capacitance determination of the hybrid capacitor energy storage 10 is initiated, and the capacitors 201, 202, and 203 of the first capacitor type are charged to the voltage required for capacitance measurement, for example, 3% to 5% higher than the predetermined operating voltage of the first capacitor type capacitors 201, 202, and 203. The other capacitors 301, 302, 303, 304, and 305 of the second capacitor type, i.e., supercapacitors, are not charged here. This is achieved by a control element, such as a diode or a DC-DC regulator. Therefore, the voltages of the other second-type capacitors 301, 302, 303, 304, and 305 are lower than the voltages of the first-type capacitors 201, 202, and 203, and the current flowing from the other second-type capacitors 301, 302, 303, 304, and 305 to the first-type capacitors 201, 202, and 203 is blocked. Thus, the subsequent capacitance measurements of the first-type capacitors 201, 202, and 203 are not affected by the other second-type capacitors 301, 302, 303, 304, and 305.

[0062] In the second step 1100, the capacitance of the entire system is measured, wherein only capacitors 201, 202, and 203 of the first capacitor type contribute to the measurement.

[0063] In the third step 1200, capacitors 201, 202, and 203 of the first capacitor type are discharged again to the predetermined operating voltage.

[0064] Then, in the fourth step 1300, the capacitors 201, 202, 203 of the first capacitor type and the other capacitors 301, 302, 303, 304, 305 of the second capacitor type are charged to the voltage required for capacitance measurement, for example, recharged to 3% to 5% higher than the predetermined operating voltage of the capacitors 201, 202, 203 of the first capacitor type and / or the other capacitors 301, 302, 303, 304, 305 of the second capacitor type.

[0065] Then, in the fifth step 1400, the total capacitance of the entire system is measured, wherein capacitors 201, 202, and 203 of the first capacitor type and capacitors 301, 302, 303, 304, and 305 of the other second capacitor type all contribute to the measurement.

[0066] In the sixth step 1500, the capacitors 201, 202, and 203 of the first capacitor type and the other capacitors 301, 302, 303, 304, and 305 of the second capacitor type are discharged again to the predetermined operating voltage.

[0067] In the seventh step, the capacitances of capacitors 201, 202, and 203 of the first capacitor type and the determined total capacitance are used to determine the capacitances of capacitors 301, 302, 303, 304, and 305 of the other second capacitor type.

[0068] Figure 4 An exemplary equivalent circuit diagram is shown for a charge balancing circuit 400 used for five supercapacitors 301, 302, 303, 304, and 305, which are exemplary herein.

[0069] The charge balancing circuit 400 has a voltage divider, exemplarily a resistor network with five resistors 410, 420, 430, 440, and 450, serving as a first potential 401, exemplarily ground potential, and a second potential 402, exemplarily a positive voltage. A voltage divider between them. Furthermore, the charge balancing circuit 400 exemplarily has four operational amplifiers 415, 425, 435, and 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, and 305. However, because in the case of capacitors, the actual capacitance may deviate from the nominal capacitance, and this deviation may... to Within the specified range, the charge balancing circuit 400 is therefore constructed to divide the theoretical charging voltage using a resistor network consisting of resistors 410, 420, 430, 440, and 450 as a voltage divider. When there is a capacitance deviation in the supercapacitors 301, 302, 303, 304, and 305, operational amplifiers 415, 425, 435, and 445 act as voltage followers to balance the voltage corresponding to the capacitance of the respective supercapacitors 301, 302, 303, 304, and 305. For this purpose, the corresponding inverting inputs of operational amplifiers 415, 425, 435, and 445 are directly connected to their respective outputs. Operational amplifiers 415, 425, 435, and 445 are respectively supplied with voltage by two units, here supercapacitors 301, 302, 303, 304, and 305.

[0070] Here, the operational amplifier 445, referred to here as the lowest operational amplifier 445, is supplied with voltage by the ground contact 401 and the unit located above it, namely at the output terminal of the operational amplifier 435, which is the supercapacitor 302.

[0071] The operational amplifier 435 located above it is supplied with voltage by a unit having the output terminal of operational amplifier 445, here supercapacitor 301, and a unit having the output terminal of operational amplifier 425, here supercapacitor 303.

[0072] Operational amplifier 425 is supplied with voltage by a unit having the output terminal of operational amplifier 435, here supercapacitor 302, and a unit having the output terminal of operational amplifier 415, here supercapacitor 304.

[0073] The top operational amplifier 415 consists of a unit with the output terminal of operational amplifier 425, here supercapacitor 303, and a unit with input voltage 402, here supercapacitor 305 supplying voltage.

[0074] If one or more supercapacitors 301, 302, 303, 304, 305 are required to have a voltage lower than the desired capacitor voltage, then the corresponding operational amplifiers 415, 425, 435, 445 act as current sources to charge the respective supercapacitors 301, 302, 303, 304, 305. The required charge is then absorbed from one of the adjacent supercapacitors 301, 302, 303, 304, 305.

[0075] If one or more supercapacitors 301, 302, 303, 304, and 305 are required to have a voltage higher than the desired capacitor voltage, operational amplifiers 415, 425, 435, and 445 will act as current sinks, discharging the corresponding supercapacitors 301, 302, 303, 304, and 305. This allows excess charge to be absorbed from one of the adjacent supercapacitors 301, 302, 303, 304, and 305.

[0076] The charge balancing circuit 400 thus reduces the voltage of supercapacitors 301, 302, 303, 304, and 305 that are overvoltaged, and thus increases the voltage of supercapacitors 301, 302, 303, 304, and 305 that are undervoltaged. Therefore, charge balance is achieved. In particular, this charge balancing circuit 400 does not contain any highly integrated inductive or capacitive components, especially no coils or additional capacitors.

[0077] List of reference numerals

[0078] 1. Switchgear;

[0079] 4. Indicators on switchgear 1;

[0080] 6. User interface of switchgear 1;

[0081] 10 energy storage devices;

[0082] 100 A capacitor determining device having an energy flow regulating device and a control element;

[0083] 201. Capacitors of the first capacitor type, such as electrolytic capacitors;

[0084] 202 Capacitors of the first type, such as electrolytic capacitors;

[0085] 203. Capacitors of the first capacitor type, such as electrolytic capacitors;

[0086] 301 Second type of capacitor, such as supercapacitor;

[0087] 302 Second type of capacitor, such as supercapacitor;

[0088] 303 Second type of capacitor, such as supercapacitor;

[0089] 304 capacitors are second-type capacitors, such as supercapacitors;

[0090] 305 Second type capacitors, such as supercapacitors;

[0091] 400 charge balance circuit

[0092] 401 First potential, such as ground potential;

[0093] 402 Second potential, for example, positive voltage ;

[0094] The resistor of the 410 voltage divider;

[0095] 415 operational amplifier;

[0096] The resistor of the 420 voltage divider;

[0097] 425 operational amplifier;

[0098] The resistor of the 430 voltage divider;

[0099] 435 operational amplifier;

[0100] The resistor of the 440 voltage divider;

[0101] 445 operational amplifier;

[0102] The resistor of a 450V voltage divider.

Claims

1. A capacitance determination device (100) for a hybrid capacitor energy storage device (10) in a hybrid capacitor energy storage device (10). Its features are, - The hybrid capacitor energy storage device (10) has one or more capacitors of a first capacitor type (201, 202, 203) and one or more capacitors of another second capacitor type (301, 302, 303, 304, 305). Wherein, the first capacitor type includes ceramic capacitors, film capacitors, and / or electrolytic capacitors, and the second capacitor type is a supercapacitor, and wherein, - At least one capacitor of a first capacitor type (201, 202, 203) and at least one other capacitor of a second capacitor type (301, 302, 303, 304, 305) are connected in parallel with each other via a capacitance determining device (100), and wherein, - The capacitance determination device (100) The device includes an energy flow regulating device that selectively charges capacitors of the first capacitor type (201, 202, 203), or charges capacitors of the first capacitor type (201, 202, 203) together with the other capacitors of the second capacitor type (301, 302, 303, 304, 305). The device includes a control element arranged between capacitors of a first capacitor type (201, 202, 203) and capacitors of a second capacitor type (301, 302, 303, 304, 305) connected in parallel. The control element controls the discharge process of the second capacitor type capacitors (301, 302, 303, 304, 305), blocking the current flow from the first capacitor type capacitors (201, 202, 203) to the second capacitor type capacitors (301, 302, 303, 304, 305). o has a capacitance determination unit, which determines the capacitance based on the charging current and the resulting voltage.

2. The capacitance determining device (100) according to claim 1. Its features are, The first type of capacitor is an electrolytic capacitor.

3. The capacitance determining device (100) according to any one of the preceding claims. Its features are, The first capacitor type has a maximum energy density of 0.5 Wh / L, while the second capacitor type has an energy density of at least 3 Wh / L, and / or the second capacitor type has an energy density 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.

4. The capacitance determining device (100) according to any one of the preceding claims. Its features are, More than one capacitor of the first capacitor type (201, 202, 203) are connected in parallel with each other.

5. The capacitance determining device (100) according to any one of the preceding claims. Its features are, More than one capacitor of the second capacitor type (301, 302, 303, 304, 305) are connected in series with each other.

6. The capacitance determining device (100) according to claim 5. Its features are, The energy storage device (10) also has a charge balancing circuit (400), wherein the charge balancing circuit (400) is designed to transfer excess charge from a higher voltage supercapacitor to a lower voltage supercapacitor.

7. The capacitance determining device (100) according to any one of the preceding claims. Its features are, The control element is a diode.

8. The capacitance determining device (100) according to any one of the preceding claims. Its features are, The energy flow regulation device is formed using one or more bidirectional DC-DC converters.

9. The capacitance determining device (100) according to claim 8. Its features are, At least one of the bidirectional DC-DC converters is configured to further perform the functions of the control element.

10. The capacitance determining device (100) according to any one of claims 1 to 7. Its features are, The energy flow regulating device is formed using at least one bidirectional DC-DC converter in each flow direction.

11. The capacitance determining device (100) according to claim 10. Its features are, At least one of the bidirectional DC-DC converters is configured to further perform the functions of the control element.

12. An electromagnetic drive device for a vacuum switch tube in a low-voltage, medium-voltage, or high-voltage switchgear (1), Its features are, The electromagnetic drive device has a capacitance determination device (100) for the hybrid capacitor energy storage (10) in the hybrid capacitor energy storage (10) according to any one of the preceding claims.

13. A low-voltage, medium-voltage or high-voltage switchgear (1). Its features are, The low-voltage, medium-voltage, or high-voltage switchgear (1) has an electromagnetic drive device according to the previous claim.

14. A method for determining the capacitance in a hybrid capacitor energy storage (10) for a low-voltage, medium-voltage, or high-voltage switchgear (1) according to claim 13, Its features are, In order to determine the capacitance of the hybrid capacitor energy storage device (10), a) Determine the first capacitance of a capacitor of the first capacitor type (201, 202, 203) by charging the capacitor of the first capacitor type (201, 202, 203) to the voltage required for capacitance measurement, wherein the other capacitor of the second capacitor type (301, 302, 303, 304, 305), i.e., the supercapacitor, is not charged, such that the voltage of the other capacitor of the second capacitor type (301, 302, 303, 304, 305) is lower than the voltage of the capacitor of the first capacitor type (201, 202, 203), and therefore the current flow from the other capacitor of the second capacitor type (301, 302, 303, 304, 305) to the capacitor of the first capacitor type (201, 202, 203) is blocked, and thus the capacitance determination unit determines the capacitance of the capacitor of the first capacitor type (201, 202, 203); b) The capacitance determining unit determines the capacitors of the first capacitor type (201, 202, 203) and the other capacitors of the second capacitor type (301, 302, 303, 304, 305), i.e., the total capacitance of the entire hybrid capacitor energy storage device (10); and c) Calculate the additional capacitance of the capacitors (301, 302, 303, 304, 305) of the other second capacitor type from the determined first capacitance and the determined total capacitance.

15. A method for operating low-voltage, medium-voltage, or high-voltage switchgear according to claim 14. Its features are, - Execute step a) before step b), or execute step b) before step a), and - Step c) is performed after steps a) and b).

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