Current measurement system for switching devices arranged in matrix configuration
By arranging current sensors near the electrical switching device and processing the measured values of multiple sensors using mathematical matrix calculations, the problem of magnetic field interference in the matrix-configured electrical switching device is solved, and accurate current measurement is achieved.
Patent Information
- Application Number
- CN202380086208.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-01-03
- Filing Date
- 2023-12-28
- Publication Date
- 2025-07-11
AI Technical Summary
In electrical switching devices arranged in matrix configurations, the contactless current measurement system is disturbed by magnetic fields generated by adjacent conductors, resulting in a decrease in measurement accuracy, and it is difficult to achieve accurate current measurements in a compact arrangement.
By arranging current sensors near each switching device, the original measured values of multiple current sensors are calculated, combined with mathematical matrix operations and weighting processing, the influence of adjacent magnetic fields is reduced and accurate current measurement is achieved.
Even without magnetic shielding, accurate current measurement of electrical switching devices is provided, improving the accuracy and computational efficiency of the measurement system.
Smart Images
Figure CN120303568A_ABST
Abstract
Description
Field of the Invention
[0001] The present invention relates to a measurement system for determining the current through electrical switching devices arranged in a matrix configuration, the measurement system comprising a plurality of current sensors and a measurement unit designed to receive raw measurement values from the current sensors. Each of the current sensors is associated with one of the switching devices and is arranged in the vicinity of the switching device, but neither surrounds the switching device nor any electrical conductor leading to or from the switching device. Furthermore, the present invention relates to a device comprising electrical switching devices arranged in a matrix configuration and a measurement system of the above type, wherein each of the current sensors is associated with one of the switching devices and is arranged in the vicinity of the switching device, but neither surrounds the switching device nor any electrical conductor leading to or from the switching device. Background Art
[0002] Current measurement systems for switching devices and devices of the above type are well known in the prior art. The main purpose of a switching device is to connect a load to the electrical grid or disconnect it from the electrical grid. For example, such a switching device may comprise a base body with fixed contacts and a switch cap with movable contacts. If the switch cap is placed on the base body, the switch is closed, and if the switch cap is removed, the switch is open. Such switching devices are particularly used for medium voltages (1 to 52 kV).
[0003] In a variety of applications, in addition to the switching function of the switching devices, attention is also paid to the current flowing through these switching devices. Therefore, current sensors can be arranged in the current path of such switching devices. In some applications, a plurality of electrical switching devices are arranged in a matrix configuration and a rather compact configuration. When current measurement is based on a non-contact principle and non-contact sensors forming a loop surrounding the electrical conductor leading to or from the said switching device cannot be applied, the magnetic field generated by the adjacent conductors may interfere with and corrupt the current measurement values. Therefore, accurate current measurement is required even under the above conditions. Summary of the Invention
[0004] Accordingly, it is an object of the present invention to provide an improved measurement system and an improved device. Specifically, it is necessary to provide accurate current measurement values for a switching device arrangement that is retrofitted with non-contact current sensors, arranged in a matrix configuration and configured rather compactly. More specifically, it is necessary to provide accurate current measurement values for a switching device having a switch cap and arranged in a matrix configuration.
[0005] The object of the invention is solved by a measuring system of the type disclosed in the first paragraph, wherein the measuring unit is additionally designed to calculate the current through an electrical switching device based on the raw measurement values, wherein the current through one of the plurality of electrical switching devices is calculated based on the raw measurement values received from a current sensor associated with and arranged closest to the switching device and based on the raw measurement values received from at least one other current sensor of the plurality of current sensors.
[0006] The object of the invention is also solved by a device comprising electrical switching devices arranged in a matrix configuration and a measuring system of the above type, wherein each of the plurality of current sensors is associated with one of the plurality of switching devices and arranged in the vicinity of the switching device, without enclosing the switching device and also without enclosing any electrical conductor leading to or from the switching device.
[0007] By utilizing these measurement values and taking into account the magnetic fields generated by adjacent switching devices, the accuracy of the current measurement is improved. Specifically, accurate current measurement values can be provided for a device of switching devices that is retrofitted with (non-contact) current sensors, arranged in a matrix configuration and configured quite compactly. Specifically, the proposed solution provides accurate results even if the electrical switching devices and / or the electrical conductors leading to or from said switching devices are not magnetically shielded. Specifically, each of the plurality of electrical switching devices can have an associated current sensor. Specifically, the measuring system can have the same number of current sensors as the number of switching devices. However, the measuring system can also have fewer current sensors than the number of switching devices.
[0008] For example, the current sensors can be implemented as pick-up coils with or without a ferromagnetic core, or can be implemented as Hall sensors. These techniques are known per se and provide a non-contact measurement of the current through the electrical switching device by using established means.
[0009] Advantageously, each of the plurality of current sensors can be arranged in or on a protective cap or switching cap of one of the plurality of electrical switching devices. In this way, the device of switching devices can be easily retrofitted with current sensors, which are additionally well protected by the cap against adverse environmental conditions. As mentioned above, the switching device can comprise a base body with fixed contacts and a switching cap with movable contacts. In this case, by placing the current sensor in the switching cap of the switching device, the retrofit can be carried out in a very easy way and without worrying about a decrease in measurement accuracy. Generally, it is advantageous if the protective cap or switching cap is made of a solid insulator / plastic. In this way, an undesired shielding of the magnetic field emitted by the switching device can be avoided.
[0010] Further advantageous embodiments are disclosed in the claims, the description and the drawings.
[0011] Advantageously, the measuring unit can be designed to calculate the current through one of a plurality of electrical switching devices based on: the raw measurement value received from the current sensor arranged closest to the switching device minus the weighted raw measurement value received from at least one other current sensor. Tests have shown that even in the case of alternating current and taking into account the phase shift of the current in other conductors, the magnetic field influence radiated by the adjacent switching device can be considered to be proportional to the current in the target switching device. In this way, other raw measurement values can be taken into account by simple mathematical operations.
[0012] The measuring unit can be designed to calculate the current through one of a plurality of electrical switching devices based on: the raw measurement value received from the current sensor arranged closest to the switching device; and:
[0013] a) the raw measurement values received from all other current sensors or
[0014] b) the raw measurement values received from all directly adjacent current sensors.
[0015] Specifically, the measuring unit can be designed to calculate the current through one of a plurality of electrical switching devices based on the following: using the raw measurement value received from the current sensor arranged closest to the switching device, minus:
[0016] a) the weighted raw measurement values received from all other current sensors or
[0017] b) the weighted raw measurement values received from all directly adjacent current sensors.
[0018] In case a), very accurate current measurement values can be achieved, while in case b), the computational effort can be reduced.
[0019] In a very advantageous embodiment of the measurement system, the measuring unit can be designed to calculate the current based on the following mathematical matrix operation
[0020] I = M · K
[0021] where I is a 1×n matrix of the current through the electrical switching device, M is a 1×n matrix of the raw measurement values received from the current sensors, K is an n×n matrix of weighting factors, and n is the number of current sensors.
[0022] Alternatively, the measuring unit can be designed to calculate the current based on the following mathematical matrix operation
[0023] I’ = K’·M’
[0024] Wherein, I’ is an n×1 matrix of the current passing through the electrical switching device, M’ is an n×1 matrix of the original measurement values received from the current sensor, K’ is an n×n matrix of weighting factors, and n is the number of current sensors.
[0025] In both cases, the current passing through the electrical switching device can be calculated by mathematical matrix operations and thus in a very efficient manner. For example, in a test device, the weighting factors can be measured according to different conductor layouts.
[0026] Advantageously, before calculating the current passing through the electrical switching device, the original measurement values received from the current sensor can be linearized. In this way, the non-linear characteristics of the current sensor can be taken into account. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The present invention will now be described in more detail with reference to the specific embodiments. However, the present invention is not limited thereto.
[0028] Figure 1 An example of a switching device having a frame and a plurality of switching devices in a matrix configuration is shown;
[0029] Figure 2 An exemplary cross-sectional schematic diagram of a switching unit having three single-pole switching devices is shown;
[0030] Figure 3 A detailed cross-section of the switching device in the closed position is shown;
[0031] Figure 4 A detailed cross-section of the switching device in the open position is shown;
[0032] Figure 5 An exploded view of the switching device having a current sensor in the switch cap is shown, and
[0033] Figure 6 A schematic diagram of an example of a measurement system having a measurement unit is shown. DETAILED DESCRIPTION OF THE INVENTION
[0034] Generally, the same or similar components are denoted by the same / similar names and reference numerals. The features disclosed in the description apply to the components having the same / similar names and the same / similar reference numerals respectively. The indications of orientation and relative position are related to the associated drawings, and the indications of orientation and / or relative position need to be modified according to the corresponding situation in different drawings.
[0035] Figure 1An example of a switching device 1 with a frame 2 and a plurality of switching devices 3 arranged in a matrix configuration in the frame 2 is shown. The switching devices 3 are arranged in three rows L1..L3 and three columns C1..C3. However, other arrangements can also be used in principle. In addition, the switching device 1 includes an optional fuse 4 and a cable box 5, which are provided to connect the power grid to the switching device 1.
[0036] Figure 2 An exemplary cross-sectional schematic view of a switching unit 6 is shown, which has three switching devices 3a..3c in one of the three columns of switching devices C1..C3. The switching unit 6 includes a base body 7 having terminals 8 for connecting cables to the switching unit 6. Each of the switching devices 3a..3c includes a fixed contact 9 and a switching cap 10, which includes a switching cap body 11 in which a contact bridge 12 is arranged. When the switching cap 10 is pulled away from the fixed contact 9, the switching devices 3a..3c are opened (see Figure 2 switching device 3a in Figure), and when the switching cap 10 is located on the fixed contact 9, the switching devices 3a..3c are closed (see Figure 2 switching devices 3b, 3c in Figure) and currents i1..i3 can flow through the switching devices.
[0037] Figure 3 and Figure 4 Now a more detailed cross-section of the switching device 3 is shown, which is in the closed position in Figure 3 Figure and in the open position in Figure 4 Figure. Specifically, a fixed main contact 13 having a fixed arc contact 14 and an arc chamber 15 is arranged in the base body 7 of the switching device 3. A movable main contact 16 having a movable arc contact 17 and an opening spring 18 is arranged in the switching cap body 11. In addition, a handle 19 is fixed to the switching cap body 11. When the switching cap 10 moves on the base body 7, the switching device 3 is closed and current i can flow through the switching device, and when the switching cap 10 is moved away from the base body 7 by using the handle 19, the switching device 3 is opened. The switching devices 3, 3a..3c and their functions themselves are known and will not be explained in detail here.
[0038] Figure 5 Now an exploded view of a specific embodiment of the switching device 3 is shown. The switching device 3 includes a switching cap having a switching cap base 20, a switching cap cover 21, a current sensor 22, a battery holder 23 and a battery 24. As Figure 5 can be seen in Figure, the current sensor 22 is arranged in the hollow space formed by the switching cap base 20 and the switching cap cover 21. The current sensor 22 is powered by the battery 24, which is fixed to the switching cap cover 21 by using the battery holder 23. It should be noted thatFigure 5 Only an exemplary embodiment for arranging the current sensor 22 near the switching device 3 is shown, and other arrangements can also be adopted. For example, the battery 24 can also be arranged within the switch cap cover 21, etc. Specifically, the switch cap base 20 and the switch cap cover 21 can be made of a solid insulator (such as epoxy resin or plastic).
[0039] Generally, the current sensor 22 can be implemented as a pick-up coil with or without a ferromagnetic core, or can be implemented as a Hall sensor. These techniques perform non-contact measurement of the currents i, i1..i3 passing through the electrical switching device 3.
[0040] Figure 6 A schematic diagram of an example of the measurement system 25 is now shown, which includes a plurality of current sensors 22a..22i arranged in a matrix formed by three rows L1..L3 and three columns C1..C3, and the measurement system relates to Figure 1 the devices of the electrical switching devices 3a..3c depicted in. The measurement system 25 also includes a measurement unit 26 designed to receive raw measurement values from the current sensors 22a..22i.
[0041] Accordingly, a device is proposed that includes a plurality of electrical switching devices 3, 3a..3c arranged in a matrix configuration and the measurement system 25 as outlined above. The measurement system 25 includes a plurality of current sensors 22, 22a..22i, each current sensor being associated with and arranged near one of the switching devices 3, 3a..3c. The current sensors 22, 22a..22i neither surround the switching devices 3, 3a..3c nor any electrical conductors leading to or from the switching devices 3, 3a..3c. Specifically, the electrical switching devices 3, 3a..3c may not be magnetically shielded. Specifically, the electrical conductors leading to or from the switching devices 3, 3a..3c may also not be magnetically shielded.
[0042] Generally, it is possible that only some of the switching devices 3, 3a..3c have associated current sensors 22, 22a..22i. However, it is beneficial that each electrical switching device 3, 3a..3c can have an associated current sensor 22, 22a..22i. Specifically, the measurement system 25 can have the same number of current sensors 22, 22a..22i as the number of switching devices 3, 3a..3c.
[0043] The measuring unit 26 is designed to calculate the currents i, i1..i3 through the electrical switching devices 3, 3a..3c based on raw measurement values, wherein the currents i, i1...i3 through the electrical switching devices 3, 3a..3c are calculated based on: the raw measurement values received from the current sensors 22, 22a..22i associated with and closest to the switching devices 3, 3a..3c; and the raw measurement values received from at least one other current sensor 22, 22a..22i. In this way, the magnetic fields generated by adjacent switching devices 3, 3a..3c can be taken into account.
[0044] Specifically, the current can be calculated based on the raw measurement values received from all other current sensors 22, 22a..22i or from all directly adjacent current sensors 22, 22a..22i. Thus, in a case where, for example, it is necessary to calculate the current through the switching device 3a associated with a current sensor 22a, in addition to the raw measurement value from this current sensor 22a, in the first case the raw measurement values of all other current sensors 22b..22i are also taken into account, or in the second case the raw measurement values of all directly adjacent current sensors 22b, 22d, 22e are also taken into account. In the first case, a very precise current measurement can be achieved, while in the second case, the computational effort can be reduced.
[0045] Generally, the consideration of other raw measurement values can be achieved by subtracting the weighted raw measurement values received by other current sensors among the current sensors 22, 22a..22i from the raw measurement values associated with the target switching devices 3, 3a..3c. In this way, advantageously, other raw measurement values can be taken into account by simple mathematical operations.
[0046] Generally, before calculating the currents i, i1..i3 through the electrical switching devices 3, 3a..3c, the raw measurement values received from the current sensors 22, 22a..22i can be linearized. In this way, the non-linear characteristics of the current sensors 22, 22a..22i can be taken into account.
[0047] In a very advantageous embodiment, the measuring unit 26 is designed to perform calculations based on mathematical matrix operations. Specifically, the measuring unit 26 can be designed to calculate the currents i, i1..i3 based on the following mathematical matrix operation
[0048] I = M·K
[0049] Wherein, I is a 1×n matrix of currents i, i1..i3 passing through electrical switching devices 3, 3a..3c. M is a 1×n matrix of raw measurement values received from current sensors 22, 22a..22i, K is an n×n matrix of weighting factors, and n is the number of current sensors 22, 22a..22i.
[0050] Alternatively, the measuring unit 26 can be designed to calculate the currents i, i1..i3 based on the following mathematical matrix operation
[0051] I’ = K’·M’
[0052] Wherein, I’ is an n×1 matrix of currents i, i1..i3 passing through electrical switching devices 3, 3a..3c. M’ is an n×1 matrix of raw measurement values received from current sensors 22, 22a..22i, K’ is an n×n matrix of weighting factors, and n is the number of current sensors 22, 22a..22i.
[0053] In fact, the switching device 1, the electrical switching devices 3, 3a..3c, and other components shown in the figures may be more or less than those shown in the figures. In addition, the description may include the subject matter of other independent inventions.
[0054] It should also be noted that the term "comprising" does not exclude other elements and the use of the article "a" or "an" does not exclude a plurality. Elements described in connection with different embodiments may also be combined. It should also be noted that the reference signs in the claims should not be construed as limiting the scope of the claims.
[0055] List of reference signs
[0056] 1 Switching device
[0057] 2 Frame
[0058] 3, 3a..3c Electrical switching devices
[0059] 4 Fuse
[0060] 5 Cable box
[0061] 6 Switching unit
[0062] 7 Substrate
[0063] 8 Terminal
[0064] 9 Fixed contact
[0065] 10 Switch cap
[0066] 11 Switch cap body
[0067] 12 Contact bridge
[0068] 13 Fixed main contact
[0069] 14 Fixed arcing contact
[0070] 15 Arc chamber
[0071] 16 Moving main contact
[0072] 17 Moving arcing contact
[0073] 18 Opening spring
[0074] 19 Handle
[0075] 20 Switch cap base
[0076] 21 Switch cap cover
[0077] 22, 22a..22i Current sensor
[0078] 23 Battery holder
[0079] 24 Battery
[0080] 25 Measurement system
[0081] 26 Measurement unit
[0082] Columns C1..C3
[0083] Rows L1..L3
[0084] Currents i, i1..i3
Claims
1. A measurement system (25) for determining currents (i, i1..i3) through a plurality of electrical switching devices (3, 3a..3c) arranged in a matrix configuration, the measurement system comprising: - a plurality of current sensors (22, 22a..22i), wherein each current sensor (22, 22a..22i) of the plurality of current sensors (22, 22a..22i) is associated with one of the plurality of electrical switching devices (3, 3a..3c) and is arranged in the vicinity of that electrical switching device without surrounding the electrical switching device (3, 3a..3c) and without surrounding any electrical conductor leading to or from the electrical switching device (3, 3a..3c), and - a measurement unit (26), the measurement unit being designed to receive raw measurement values from the plurality of current sensors (22, 22a..22i), characterized in that - the measurement unit (26) is additionally designed to calculate the currents (i, i1..i3) through the electrical switching devices (3, 3a..3c) based on the raw measurement values, wherein the current (i, i1..i3) through one of the plurality of electrical switching devices (3, 3a..3c) is calculated based on: the raw measurement value received from the current sensor (22, 22a..22i) associated with and arranged closest to that electrical switching device; and the raw measurement values received from at least one other current sensor of the plurality of current sensors (22, 22a..22i).
2. The measurement system (25) according to claim 1, characterized in that, Each of the plurality of electrical switching devices (3, 3a..3c) has an associated current sensor (22, 22a..22i) of the plurality of current sensors (22, 22a..22i).
3. The measurement system (25) according to claim 1 or 2, characterized in that, The measurement unit (26) is designed to calculate the current (i, i1..i3) through one of the plurality of electrical switching devices (3, 3a..3c) based on: subtracting the weighted raw measurement values received from at least one other current sensor of the plurality of current sensors (22, 22a..22i) from the raw measurement value received from the current sensor (22, 22a..22i) arranged closest to that electrical switching device (3, 3a..3c).
4. The measurement system (25) according to any one of claims 1 to 3, characterized in that The measurement unit (26) is designed to calculate the current (i, i1..i3) through one of the plurality of electrical switching devices (3, 3a..3c) based on: the raw measurement value received from the current sensor (22, 22a..22i) arranged closest to that electrical switching device (3, 3a..3c); and a) the raw measurement values received from all other current sensors (22, 22a..22i) or b) The raw measurement values received from all directly adjacent current sensors (22, 22a..22i).
5. The measurement system (25) according to any one of claims 1 to 4, characterized in that, The measurement unit (26) is designed to calculate the current (i, i1..i3) through one of the plurality of electrical switching devices (3, 3a..3c) based on the following: subtracting from the raw measurement value received from the current sensor (22, 22a..22i) arranged closest to the electrical switching device (3, 3a..3c): a) The weighted raw measurement values received from all other current sensors (22, 22a..22i) or b) The weighted raw measurement values received from all directly adjacent current sensors (22, 22a..22i).
6. The measurement system (25) according to claim 5, characterized in that, The measurement unit (26) is designed to calculate the current (i, i1..i3) based on the following mathematical matrix operation I = M·K where I is a 1×n matrix of the currents (i, i1..i3) through the plurality of electrical switching devices (3, 3a..3c), M is a 1×n matrix of the raw measurement values received from the plurality of current sensors (22, 22a..22i), K is an n×n matrix of weighting factors, and n is the number of current sensors (22, 22a..22i), or the measurement unit is designed to calculate the current based on the following mathematical matrix operation I’ = K’·M’ where I’ is an n×1 matrix of the currents (i, i1..i3) through the plurality of electrical switching devices (3, 3a..3c), M’ is an n×1 matrix of the raw measurement values received from the plurality of current sensors (22, 22a..22i), K’ is an n×n matrix of weighting factors, and n is the number of current sensors (22, 22a..22i).
7. The measurement system (25) according to any one of claims 1 to 6, characterized in that, Before calculating the current (i, i1..i3) through the plurality of electrical switching devices (3, 3a..3c), the raw measurement values received from the plurality of current sensors (22, 22a..22i) are linearized.
8. The measurement system (25) according to any one of claims 1 to 7, characterized in that, The plurality of current sensors (22, 22a..22i) are implemented as pick-up coils with or without ferromagnetic cores, or as Hall sensors.
9. A device comprising a plurality of electrical switching devices (3, 3a..3c) arranged in a matrix configuration, characterized in that a measurement system (25) according to any one of claims 1 to 8, wherein each current sensor (22, 22a..22i) of the plurality of current sensors (22, 22a..22i) is associated with one of the plurality of electrical switching devices (3, 3a..3c) and is arranged in the vicinity of the electrical switching device without surrounding the electrical switching device (3, 3a..3c) and without surrounding any electrical conductor leading to or from the electrical switching device (3, 3a..3c).
10. The device according to claim 9, characterized in that, Each of the plurality of current sensors (22, 22a..22i) is arranged in or on a protective cap or switch cap (10) of one of the plurality of electrical switching devices (3, 3a..3c).
11. The device according to claim 10, wherein The protective cap or switch cap (10) is made of plastic.
12. The device according to any one of claims 9 to 11, characterized in that, The plurality of electrical switching devices (3, 3a..3c) are not magnetically shielded.
13. The device according to any one of claims 9 to 12, characterized in that, The plurality of electrical conductors leading to or from the plurality of electrical switching devices (3, 3a..3c) are not magnetically shielded.