Method, measuring device and system

Abstract

Method for obtaining information about a transformer (100), wherein the transformer (100) comprises: - a magnetic section (10) with a magnetic core (11) for guiding and focusing a magnetic flux of the transformer (100), - a first coil section (20) with three input coils (21, 22, 23), wherein the three input coils (21, 22, 23) are connected in a delta configuration, and wherein the three input coils (21, 22, 23) are arranged on the magnetic core (11), - a contacting section (40) with three contacting elements (41, 42, 43), wherein each contacting element of the three contacting elements (41, 42, 43) is electrically connected to each of the three delta-connected input coils (21, 22, 23), - a second coil section (30) for transferring energy between the first coil section (20) and the second coil section (30), and wherein the method comprises: - Applying (320) at least one detection signal to the three contacting elements (41, 42, 43) of the contacting section (40) for at least one first combination possibility of three combination possibilities (K1, K2, K3) such that two input coils of the three input coils (21, 22, 23) of the first coil section (20) are electrically connected in parallel and a third input coil of the three input coils (21, 22, 23) is electrically short-circuited, wherein in particular the at least one detection signal has a changing polarity, - Capture (340) at least one investigation signal response of the transformer (100) to the at least one applied investigation signal at least for at least one first combination possibility (K1, K2, K3) of the three combination possibilities (K1, K2, K3), - Determining (360) information about the transformer (100) based on at least one applied detection signal and at least one detected detection signal response, - wherein at least for recording (340) the investigation signal response and for determining (360) information about the transformer (100) a measuring device (200) is used, comprising: i. a signal source unit (220) for generating at least one detection signal, in particular the detection signal with a changing polarity, ii. a connecting device (240) for connecting the signal source unit (220) to three contacting elements (41, 42, 43) of a contacting section (40) of a transformer (100), and wherein the connecting device (240) is configured and / or the signal source unit (220) is configured such that the at least one detection signal is applied to the three contacting elements (41, 42, 43) for at least one first combination of three combinations (K1, K2, K3) such that two input coils of the three input coils (21, 22, 23) of the first coil section (20) are electrically connected in parallel and a third input coil of the three input coils (21, 22, 23) is electrically short-circuited, iii. a detection unit (260) for detecting at least one detection signal response of the transformer (100) to the at least one applied detection signal, iv. wherein the connecting device (240) has at least two connecting lines (241, 242, 243) for connecting the signal source unit (220) to the three contacting elements (41, 42, 43) of the contacting section (40) of the transformer (100), v. wherein a connecting line of the at least two connecting lines (241, 242, 243) for contacting two contacting elements of the three contacting elements (41, 42, 43) of the contacting section (40) of the transformer (100) forms at least section by section a common connecting line (249) and / or is at least section by section split into a first connecting line part (247) and a second connecting line part (248).

Description

[0001] The present invention relates to a method, a measuring device and a system.

[0002] Power grids for the transmission and distribution of electrical energy comprise electrical lines such as overhead lines and underground cables, as well as associated equipment such as switching stations and substations, especially power transformers. Furthermore, power grids are modeled and simulated to identify undesirable conditions, for example during operation, and to initiate appropriate measures.

[0003] To model a power transformer in a power grid, transformer manuals or datasheets are used, for example. However, these provide only limited and imprecise information about the physical properties of a power transformer, especially the physical properties of a power transformer core or a power grid. Furthermore, changes in a power transformer over time usually cannot be accounted for using data from transformer manuals or datasheets. A power transformer's hysteresis curve, for example, can be used to infer damage to the power transformer. WO 2016 113 072 A1 and EP 3 391 063 B1 are known for this purpose.

[0004] It is an object of the present invention to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to provide a method, a measuring device, or a system by which information about a transformer, especially information about the magnetic hysteresis behavior of a transformer, can be determined particularly easily and / or which is particularly realistic and / or closely reflects operational requirements.

[0005] Furthermore, it is a particular object of the invention to provide a method or measuring device or system by which information about a transformer in which the delta connection of (input) coils of the transformer is accessible with considerable effort and / or can be separated with considerable effort can be determined particularly easily and / or which is particularly practical or realistic.

[0006] The foregoing problem is solved by a method having the features of claim 1, a measuring device having the features of claim 10, and a system having the features of claim 15. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the measuring device and / or the system according to the invention, and vice versa, so that the disclosure relating to the individual aspects of the invention always makes, or can make, reciprocal references.

[0007] According to a first aspect, the present invention discloses a method for obtaining information about a transformer. The transformer comprises a magnetic section with a magnetic core for guiding and focusing the transformer's magnetic flux. The transformer further comprises a first coil section with three input coils, the three input coils being connected in a delta configuration and arranged on the magnetic core. The transformer also comprises a contact section with three contact elements, each contact element being electrically connected to a vertex of the three delta-connected input coils. Finally, the transformer includes a second coil section for transferring energy between the first coil section and the second coil section.The method comprises, as a step, applying at least one detection signal to the three contact elements of the contact section for at least one first combination of three possible combinations, such that two input coils of the three input coils of the first coil section are electrically connected in parallel and a third input coil of the three input coils is electrically short-circuited, wherein, in particular, the at least one detection signal has an alternating polarity. The application of the at least one detection signal can be effected, in particular, by means of a signal source unit of a measuring device. Furthermore, the method comprises, as a step, acquiring at least one detection signal response from the transformer (as a reaction) to the at least one applied detection signal for at least one first combination of the three possible combinations.In particular, the acquisition of at least one transformer detection signal response can be carried out using a detection unit of a measuring device. Furthermore, the method comprises, as a step, the determination of information about the transformer based on at least one applied detection signal and at least one acquired detection signal response. In particular, the determination of information about the transformer can be carried out using a detection unit of a measuring device.

[0008] The process steps described above and below can be carried out individually, together, simply, multiple times, in parallel and / or sequentially in any order, provided it is technically feasible.

[0009] In particular, the transformer is a three-phase transformer, specifically a three-phase transformer of connection group Dy(n) or Dz(n). The three-phase transformer can also be understood as a three-phase transformer. For example, the transformer can be a transformer for converting a medium voltage to a low voltage, with the medium-voltage side of the transformer having the three input coils connected in a delta configuration.

[0010] The magnetic core can also be understood as an iron core. Specifically, the magnetic core of the magnetic section comprises three magnetic arms, with each of the three input coils of the first coil section arranged on one of the three magnetic arms. The three input coils can also be understood as input windings.

[0011] In particular, the second coil section of the transformer has three output coils, the three output coils being connected in a delta, star, or zigzag configuration. Furthermore, the three output coils are also arranged on the magnetic core.

[0012] The expression "where the three input coils are connected in a delta configuration" is intended to express that the three input coils are connected in a delta configuration. In particular, the three delta-connected input coils of the first coil section have (exactly) three vertices, wherein each of the three vertices is (directly) connected to exactly one (different) contact element of the three contact elements of the contact section.

[0013] In particular, the three contact elements of the contact section are each externally accessible and / or serve for the (electrical) connection of the transformer. For example, the three contact elements of the contact section can each be an externally accessible terminal. The term "externally accessible" can also be understood as accessible from outside the transformer.

[0014] The at least one applied detection signal can exhibit a changing polarity, at least temporarily. For example, the at least one detection signal with changing polarity can be an alternating current, in particular a pulsed direct current. Specifically, such an alternating current is applied as the detection signal, such that the magnetic core of the magnetic section saturates for both polarities, with a polarity change preferably occurring only after saturation. As a response of the transformer to the alternating current as the applied detection signal, a voltage drop across two parallel-connected input coils of the three input coils of the first coil section can be detected as the at least one detection signal response. In particular, the detection of the voltage drop across two parallel-connected input coils of the three input coils of the first coil section can be carried out using a voltmeter.The alternating current (or alternating current intensity) as an applied or impressed detection signal can be measured using an ammeter. Advantageously, the measured alternating current intensity (as at least one detection signal) is a measure of the magnetic field strength of the transformer, in particular a measure of the magnetic field strength of the two parallel-connected input coils of the three input coils of the first coil section. Advantageously, a time integral over the measured voltage (as at least one detection signal response) is a measure of the magnetic flux density of the transformer. Furthermore, it is conceivable that, prior to integration over the measured voltage, the (impressed or applied) current intensity or the current with known or determined characteristic values, e.g., R, could be used. streu and / or X streu The leakage inductance is taken into account and, in particular, subtracted. R streucan be understood as stray resistance and / or X streu This can be understood as the leakage reactance of a leakage inductance. This allows the determination, preferably approximation, of a "core voltage" of the main inductance, for example, in or for a transformer equivalent circuit. In particular, the detection unit of a measuring device can be configured to integrate the detected voltage over time. The detection unit of the measuring device can include the voltmeter and / or the ammeter.

[0015] It is also conceivable that at least one of the detection signals with alternating polarity is an alternating voltage, in particular a pulsed alternating voltage. As a response of the transformer to the alternating voltage as the applied detection signal, a current flowing through two parallel-connected input coils of the three input coils of the first coil section can be detected as the at least one detection signal response. Specifically, the current flowing through two parallel-connected input coils of the three input coils of the first coil section can be detected using an ammeter. The alternating voltage as the applied detection signal can be detected using a voltmeter. Advantageously, a time integral of the detected alternating voltage (as the at least one detection signal) is a measure of the magnetic flux density of the transformer.Furthermore, it is also conceivable that, prior to integration via the applied or manufactured voltage, the measured current (as at least one detection signal response) could be compared with known or determined characteristic values, e.g., R. streu and / or X streu The leakage inductance is taken into account and, in particular, subtracted. This allows an approximate determination of the main inductance's "Xern voltage," for example, in a transformer equivalent circuit. Advantageously, the measured current (as at least one of the signal responses) is a measure of the transformer's magnetic field strength, specifically a measure of the magnetic field strength of the two parallel-connected input coils of the three input coils in the first coil section. The measuring device's detection unit can include an ammeter and / or a voltmeter.

[0016] In particular, magnetic hysteresis behavior can be determined as information about the transformer based on at least one applied detection signal and at least one detected detection signal response. Specifically, a detection unit of a measuring device can be configured to determine magnetic hysteresis behavior as information about the transformer based on at least one applied detection signal and at least one detected detection signal response. In particular, the magnetic hysteresis behavior can be represented by at least one magnetic hysteresis characteristic curve.

[0017] The magnetic hysteresis characteristic can be determined based on a measured AC current as at least one detection signal (measure of the transformer's magnetic field strength) and a time integral over a measured voltage as at least one detection signal response (measure of the transformer's magnetic flux density). It is also conceivable to first integrate the (impressed or applied) current with known or determined parameters, e.g., R, over the measured voltage. streu and / or X streuThe leakage inductance is taken into account and, in particular, subtracted. This allows a "core voltage" of the main inductance, e.g., in or for a transformer equivalent circuit, to be determined, preferably approximately. Alternatively or additionally, the magnetic hysteresis characteristic can be determined based on a time integral over a measured AC voltage as the at least one detection signal (measure of the magnetic flux density of the transformer) and a measured current as the at least one detection signal response (measure of the magnetic field strength of the transformer). Furthermore, it is conceivable that, prior to integration over the impressed or applied voltage, the measured current (as the at least one detection signal response) is integrated using known or determined characteristic values, e.g., R. streu and / or X streuThe leakage inductance is factored in and, in particular, subtracted. This allows for the approximate determination of a "core voltage" of the main inductance, for example, in a transformer equivalent circuit. Advantageously, parameterization data, such as (heat) loss and / or magnetic saturation and / or remanence and / or coercive field strength, can be derived from a determined hysteresis characteristic curve for a model representing the magnetic hysteresis behavior of the transformer. In particular, the determination of the parameterization data can be carried out by a parameterization unit of a measuring device.

[0018] The three possible combinations are, in particular, the three (different) ways or wiring configurations in which the three input coils of the first coil section can be connected via the three contact elements, such that two of the three input coils of the first coil section are electrically connected in parallel and a third input coil is electrically short-circuited. Specifically, a measurement is performed for at least two of the three possible combinations, or for each of the three possible combinations, wherein each measurement preferably includes the (detected) applied detection signal and the detection signal response.

[0019] Advantageously, by applying at least one detection signal to the three contact elements of the contact section in such a way that two of the three input coils of the first coil section are electrically connected in parallel and a third input coil is electrically short-circuited, particularly realistic information, such as magnetic hysteresis behavior or a magnetic hysteresis characteristic curve, can be determined in a very simple manner. By electrically short-circuiting one of the three input coils (while the other two input coils are electrically connected in parallel), it can be ensured that current flows only, or essentially only, through the two parallel-connected input coils.Advantageously, the three input coils of the first coil section of the transformer are identical or substantially identical (due to technical tolerances), so that the current is divided equally, or substantially equally, between the two parallel-connected input coils of the first coil section. In other words, the current is divided into two equal or substantially equal current components. This allows magnetic fluxes to be impressed into the magnetic core of the magnetic section, which are particularly similar to the magnetic fluxes that could be impressed into the magnetic core by individually energizing the two parallel-connected input coils of the first coil section if the delta connection of the three input coils of the first coil section could be removed and the three coils individually energized. Furthermore, induced circulating currents can be kept particularly low.This avoids unnecessary complications. Thus, particularly operationally relevant or realistic information about the transformer, such as its magnetic hysteresis behavior, can be obtained. Advantageously, information about a transformer in which the delta connection of the (input) coils of the transformer is accessible and / or can only be separated with considerable effort (in order to obtain information about the transformer) can be determined with particularly low effort using a method, measuring device, or system according to the invention. The term "determined with particularly low effort" refers in particular to obtaining information about the transformer without opening the (main) housing of the transformer and / or without compromising the integrity of the electrical insulation (e.g., by removing the transformer).(an oil insulation) of the transformer and / or without manipulating a wiring configuration, in particular a wiring configuration of the three input coils of the first coil section. Advantageously, information about a transformer can thus be determined or obtained with particularly little effort and / or while maintaining the transformer's operating state and / or avoiding the effort required to restore the transformer to a proper operating state by means of a method or measuring device or system according to the invention.

[0020] It can be advantageous if, in a method according to the invention, at least one detection signal is applied to the three contacting elements of the contacting section for at least two different combinations of the three possible combinations, particularly successively, wherein a detection signal response is recorded for each of these two combinations. Thus, magnetic fluxes are advantageously impressed in different regions of the magnetic core of the magnetic section, particularly in different magnetic legs of the magnetic core of the magnetic section, and the detection signal response of the second or further combination (as a reaction to the at least one applied detection signal) of the three possible combinations can provide additional information about the transformer.In particular, information about the transformer can be determined based on at least one applied detection signal and the respective detection signal response for the two different combinations of the three possible combinations. For example, a magnetic hysteresis curve can be determined for each of the two different combinations, and the two determined magnetic hysteresis curves can be combined to obtain an overall magnetic hysteresis curve. Information about the effect of a structural asymmetry of the transformer's magnetic section, particularly its magnetic core, can also be obtained from the at least two determined magnetic hysteresis curves.Ideally, at least one detection signal could be applied to the three contact elements of the contact section for the three different combinations of the three possible combinations, particularly sequentially, with a detection signal response being recorded for each of the three different combinations. This would allow for the determination of particularly accurate and operationally relevant information about the transformer. For example, a magnetic hysteresis curve could be determined for each of the three different combinations, and the three determined magnetic hysteresis curves could then be combined to obtain an overall magnetic hysteresis curve.From the three determined magnetic hysteresis curves, information about the effect of a structural asymmetry of the magnetic section, in particular of the magnetic core of the magnetic section, of the transformer can also be determined or obtained as information about the transformer. In particular, a measurement unit of a measuring device can be configured to calculate several magnetic hysteresis curves together to form a total magnetic hysteresis curve.

[0021] It can be advantageous if, in a method according to the invention, two different detection signals, particularly sequentially, are applied to the three contacting elements for at least one of the three possible combinations, with a detection signal response being recorded for each of the two different detection signals. The at least two different detection signals can differ with respect to frequency and / or amplitude and / or duration. Thus, for example, magnetic fluxes of different strengths can be impressed into the magnetic core of the magnetic section for the first possible combination, and the (further) detection signal response in reaction to the second or further detection signal (in addition to the at least one detection signal) can provide additional information about the transformer.In particular, information about the transformer can be determined based on at least the different detection signals and the respective detection signal response for at least one of the three possible combinations. For example, at least for the first possible combination, a magnetic hysteresis characteristic can be determined for each of the two different detection signals, and in particular, the two determined magnetic hysteresis characteristics can be combined to obtain an overall magnetic hysteresis characteristic. It is also conceivable that, in a method according to the invention, at least two different detection signals, in particular sequentially, are applied to each of the three contact elements for the three possible combinations, and that a detection signal response is recorded for each of the two different detection signals.Similarly, these can also be combined to form a common magnetic hysteresis characteristic curve.

[0022] It can be advantageous if, in a method according to the invention, the determination of information about the transformer is based on at least one (applied) detection signal and / or several (applied) detection signals, as well as the at least one (captured) detection signal response and / or several (captured) detection signal responses. This allows for the determination of particularly realistic information, such as the magnetic hysteresis behavior or magnetic hysteresis characteristic curve of the transformer. For example, the at least one (applied) detection signal and / or the several (applied) detection signals, as well as the at least one (captured) detection signal response and / or the several (captured) detection signal responses, can be combined to form a substitute signal, e.g.Using a measuring device's detection unit, a magnetic hysteresis characteristic of the transformer is determined or obtained from the substitute signal. The calculation can, for example, involve averaging the results.

[0023] It can be advantageous if, in a method according to the invention, for acquiring (the at least one detection signal response of the transformer) and / or after acquiring the at least one detection signal response of the transformer to the at least one applied detection signal for the at least one first combination of the three possible combinations, at least the magnetic core of the magnetic section is brought into a defined state. This allows particularly realistic information, such as the magnetic hysteresis behavior or magnetic hysteresis characteristic curve, of the transformer to be determined, since in particular distortions are improved or prevented. For example,For the acquisition of at least one detection signal response from the transformer and / or after the acquisition of at least one detection signal response from the transformer to the at least one applied detection signal for at least one first combination of the three possible combinations, the magnetic core of the magnetic section may be demagnetized or already demagnetized. The demagnetization of at least the magnetic core of the magnetic section can be carried out, for example, by means of a demagnetizing unit of a measuring device, in particular by an electrical method.Alternatively or additionally, it is also conceivable that when applying, especially when applying in succession, at least one detection signal to the three contacting elements of the contacting section for two different combination possibilities or three different combination possibilities, the magnetic core of the magnetic section is brought to the defined state, e.g., demagnetized, at least between two different successive combination possibilities.

[0024] It can be advantageous if, in a method according to the invention, the at least one detection signal applied to the three contacting elements is a current signal with alternating polarity. Thus, a magnetic hysteresis characteristic can be determined particularly easily based on the current signal with alternating polarity (alternating current) as the at least one detection signal (measure of the magnetic field strength of the transformer) and a time integral over a detected voltage as the at least one detection signal response (measure of the magnetic flux density of the transformer). Furthermore, it is also conceivable that, for integration over the detected voltage, the (impressed or applied) current or the current with known or determined characteristic values, e.g., R, could be used beforehand. streu and / or X streuThe leakage inductance is taken into account and subtracted. This allows a "core voltage" of the main inductance, e.g., in or for a transformer equivalent circuit, to be determined, preferably approximately. The current signal can, for example, have an amplitude of 1 to 5 A (amperes). In particular, a signal source unit of a measuring device can include a voltage-limited DC current source for generating the current signal with alternating polarity as the detection signal.

[0025] It can be advantageous if, in a method according to the invention, the second coil section of the transformer is in no-load mode at least during the application of the at least one detection signal to the three contacting elements and / or during the acquisition of the at least one detection signal response of the transformer to the at least one applied detection signal. This allows for the determination of particularly realistic information, such as the magnetic hysteresis behavior or magnetic hysteresis characteristic curve of the transformer. The term "in no-load mode" is intended to express that the second coil section is (electrically) "open".

[0026] It can be advantageous if, in a method according to the invention, the three input coils of the first coil section are arranged in the same orientation, particularly on the magnetic core of the magnetic section. Because the three input coils of the first coil section are arranged in the same orientation, the current, or a respective current component, flows in opposite directions through the two electrically parallel-connected input coils for each of the three possible combinations. Thus, the magnetic fluxes of these two input coils can close in the magnetic core, particularly in the two associated magnetic legs, largely bypassing one of the magnetic legs belonging to the short-circuited input coil.Thus, magnetic fluxes can be impressed into the magnetic core of the magnetic section, which are particularly similar to magnetic fluxes that can be impressed into the magnetic core when each of the two parallel-connected input coils of the first coil section is individually energized. The expression, "whereby the three input coils of the first coil section are arranged in the same orientation, in particular on the magnetic core of the magnetic section," is intended to express that the three input windings are arranged in the same orientation on the magnetic core, in particular on a respective leg of the magnetic core, preferably wound on top of each other.

[0027] It can be advantageous if, in a method according to the invention, a hysteresis characteristic, in particular a magnetic hysteresis characteristic, of the transformer is determined based on the at least one applied detection signal and the at least one acquired detection signal response. Advantageously, parameterization data, e.g., a (heat) loss and / or a magnetic saturation and / or a remanence and / or a coercive field strength, can thus be obtained or determined particularly easily for a model to represent the magnetic hysteresis behavior of the transformer. The determination of the hysteresis characteristic can be carried out, for example, by means of a detection unit of a measuring device.

[0028] According to a second aspect, the present invention discloses a measuring device for at least acquiring a detection signal response of a transformer for determining information about the transformer. In particular, the transformer is a transformer designed according to the invention or a transformer as described in relation to the method according to the invention. The measuring device comprises a signal source unit for generating at least one detection signal, in particular a detection signal with alternating polarity. Furthermore, the measuring device comprises a connection device for (electrically) connecting the signal source unit to three contact elements of a contact section of a transformer, wherein, in particular, each of the three contact elements is electrically connected to a corner point of three delta-connected input coils of a first coil section of the transformer.The connection device and / or the signal source unit is configured such that the at least one detection signal is applied to the three contact elements for at least one first combination of three possible combinations in such a way that two input coils of the three input coils of the first coil section are electrically connected in parallel and a third input coil of the three input coils is electrically short-circuited. Furthermore, the measuring device includes a detection unit for detecting at least one detection signal response of the transformer to the at least one applied detection signal.

[0029] The measuring device is, in particular, a mobile measuring device. Therefore, information about existing transformers can also be obtained using the measuring device.

[0030] The measuring device may also include a demagnetizing unit for moving the magnetic core of the magnetic section into a defined state.

[0031] In particular, the measuring device may have a housing, wherein at least the signal source unit of the measuring device and / or the detection unit of the measuring device and / or the determination unit of the measuring device and / or the parameterization unit of the measuring device and / or the demagnetization unit are arranged in the housing.

[0032] Furthermore, the measuring device, in particular the mobile measuring device, may include a computing unit for data processing and / or a memory, in particular a non-volatile memory, for storing data, e.g. information about the transformer.

[0033] The signal source unit can have at least one first connection for contacting a connection device, in particular a connection line of the connection device, and a second connection for contacting the connection device, in particular a connection line or a further connection line of the connection device.

[0034] According to the invention, the connecting device of a measuring device according to the invention has at least two connecting leads for connecting the signal source unit to the three contact elements of the contact section of the transformer. This makes connecting the signal source unit to the three contact elements of the contact section of the transformer particularly easy. In particular, the connecting device can have exactly two connecting leads, i.e., a first connecting lead and a second connecting lead, for connecting the signal source unit to the three contact elements of the contact section of the transformer.Furthermore, the first connecting line is connected, or connectable, in particular detachably, to a (first) connection of the signal source unit at one end of its two ends, and to a second contact element of the three contact elements of the transformer at an intermediate section, and to a third contact element of the three contact elements of the transformer at a second end of its two ends, and to the first contact element of the three contact elements of the transformer at a second end of its two ends. In particular, the second connecting line is connected, or connectable, in particular detachably, to a second connection of the signal source unit at one end of its two ends, and to a third contact element of the three contact elements of the contact section of the transformer at a second end of its two ends.

[0035] It is also conceivable that an (electrical) contact bridge is arranged between two of the three contact elements. This would make connecting the signal source unit to the three contact elements of the transformer's contact section particularly easy.

[0036] According to the invention, in a measuring device according to the invention, a connecting line of the at least two connecting lines for contacting two contacting elements of the three contacting elements of the transformer's contacting section forms a common connecting line at least partially and / or is at least partially divided into a first connecting line part and a second connecting line part. Thus, a contact bridge arranged between two contacting elements of the contacting section can be dispensed with.Preferably, one of the at least two connecting lines for contacting two of the three contact elements of the transformer's contact section forms a common connecting line at least section by section and is furthermore divided at least section by section into a first connecting line part and a second connecting line part. The common connecting line is, in particular, connected or connectable at one end to a terminal of the signal source unit, and especially detachably connected or connectable. Furthermore, the common connecting line can form a node at one end to a first end of the first connecting line part and at the first end of the second connecting line part.Furthermore, the first connecting line section is connected at one end to a (first) contact element of the three contact elements of the transformer's contact section, in particular detachably, and the second connecting line section is connected at one end to a second (or further) contact element of the three contact elements of the transformer's contact section, in particular detachably. In other words, one of the connecting lines can be Y-shaped. The first connecting line section and the second connecting line section can, in particular, have the same length or substantially the same length. Thus, an impedance symmetry between a detection measurement point for detecting a detection signal or...to ensure or substantially ensure the recording of an investigation signal response and to determine information about the transformer in a particularly unadulterated or particularly accurate manner.

[0037] It can be advantageous if, in a measuring device according to the invention, the connecting lines for connecting the signal source unit to the three contacting elements of the transformer's contacting section have a symmetrical or substantially symmetrical impedance. This ensures, or substantially ensures, impedance symmetry between a detection point for acquiring a detection signal or for acquiring a detection signal response, and allows for particularly accurate and unadulterated information about the transformer.

[0038] It can be advantageous if a measuring device according to the invention includes a detection unit for determining information about the transformer based on the at least one applied detection signal and the at least one detected detection signal response. Determining information about the transformer can be done, for example, with the aid of a computing unit. In particular, the determination of information about the transformer is carried out automatically.

[0039] It can be advantageous if, in a measuring device according to the invention, the measuring device includes a parameterization unit for determining parameterization data based on the information obtained about the transformer. This allows the magnetic hysteresis behavior of the transformer to be modeled. In particular, the parameterization data is determined based on at least one (determined) magnetic hysteresis characteristic of the transformer. The hysteresis characteristic of the transformer describes, in particular, the magnetic flux density as a function of the magnetic field strength.

[0040] It can be advantageous if a measuring device according to the invention is set up to carry out a method according to the invention for determining information about a transformer.

[0041] The measuring device according to the second aspect of the invention thus has the same advantages as those already described for the method according to the first aspect of the invention.

[0042] According to a third aspect, the present invention discloses a system. The system comprises a measuring device designed according to the invention. Furthermore, the system comprises a transformer. In particular, the transformer is a transformer designed according to the invention or a transformer as described for the method according to the invention. Furthermore, the signal source unit of the measuring device is connected to three contacting elements of a contacting section of the transformer by means of the connection device of the measuring device.

[0043] In particular, the signal source unit of the measuring device is connected to the three contacting elements of the contacting section of the transformer by means of the connecting device of the measuring device in such a way that the at least one detection signal of the signal source unit can be applied to the three contacting elements for at least one first combination possibility of three combination possibilities such that two input coils of the three input coils of the first coil section are electrically connected in parallel and a third input coil of the three input coils is electrically short-circuited.

[0044] The system according to the third aspect of the invention thus has the same advantages as those already described for the method according to the first aspect of the invention or the measuring device according to the second aspect of the invention.

[0045] Further improvements to the invention will become apparent from the following description of some exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages arising from the claims, the description, or the drawings, including design details, spatial arrangements, and process steps, can be essential to the invention, both individually and in various combinations. It should be noted that the figures are for descriptive purposes only and are not intended to limit the invention in any way.

[0046] They show schematically: Fig. 1 a system comprising a measuring device and a transformer, Fig. 2 a system with a measuring device and a transformer, Fig. 3 a part of a system, Fig. 4 an equivalent circuit diagram, Fig. 5 a procedure, Fig. 6 a procedure, and Fig. 7 a procedure.

[0047] In the following figures, identical reference numerals are used for the same technical features even for different embodiments.

[0048] Fig. 1 and Fig. Figure 2 each schematically discloses a system 400 with a measuring device 200, in particular a portable measuring device 200, and with a transformer 100, in particular a transformer 100 as it is used in Fig. 3 and / or Fig. 4 is described. A signal source unit 220 of the measuring device 200 is connected to three contacting elements 41, 42, 43 of a contacting section 40 of the transformer 100 by means of a connecting device 240, in particular by means of a first connecting line 241 and a second connecting line 242 of the measuring device 200. The measuring device 200 is at least for acquiring a detection signal response of the transformer 100 for determining information about the transformer 100. The measuring device 200 comprises the signal source unit 220 for generating at least one detection signal, in particular a detection signal with a changing polarity, e.g. an alternating current i(t) (see e.g. Fig. 3) Furthermore, the measuring device 200 comprises a detection unit 260 for detecting at least one detection signal response of the transformer 100 to the at least one applied detection signal, e.g. a voltage u(t) (see e.g. Fig. 3) It is additionally, i.e., optionally, conceivable that the measuring device 200 has a detection unit 270 for determining information about the transformer 100 based on the at least one applied detection signal and the at least one detected detection signal response. Furthermore, it is additionally, i.e., optionally, conceivable that the measuring device 200 has a parameterization unit 280 for determining parameterization data based on the determined information about the transformer 100.

[0049] Furthermore, in Fig. 1. The first connecting line 241 is connected, in particular detachably, to a first end of two ends with a (first) terminal 221 of the signal source unit 220, and with an intermediate section with a second contacting element 42 of the three contacting elements 41, 42, 43 of the transformer 100, and with a second end of the two ends with a first contacting element 41 of the three contacting elements 41, 42, 43 of the transformer 100. Furthermore, the second connecting line 242 is electrically connected, in particular, to a second terminal 222 of the signal source unit 220, and with a second end of the two ends of the second connecting line 242 to a third contacting element 43 of the three contacting elements 41, 42, 43 of the contacting section 40 of the transformer 100.It is also conceivable that the first contacting element 41 and the second contacting element 42 are electrically connected by means of a contact bridge 243. Through such an electrical connection using the connecting device 240, at least one detection signal can be applied to the three contacting elements 41, 42, 43 for at least one first combination possibility K1 of three combination possibilities K1, K2, K3 such that two input coils 21, 23 of the three input coils 21, 22, 23 of the first coil section 20 are electrically connected in parallel and a third input coil 22 of the three input coils 21, 22, 23 is electrically short-circuited (see, for example, [reference]). Fig. 3).

[0050] As opposed to Fig. 1 forms in Fig. 2. The first connecting line 241 of the at least two connecting lines 241, 242 forms a common connecting line 249 at least section by section and is furthermore divided at least section by section into a first connecting line part 247 and a second connecting line part 248. The common connecting line 249 is connected at one end of two to a first connection 221 of the signal source unit 220, in particular detachably. Furthermore, the common connecting line 249 forms a node at one end of two to a first end of the first connecting line part 247 and at one end of the second connecting line part 248.Furthermore, the first connecting line part 247 is connected with a second end of the two ends to the first contacting element 41 of the three contacting elements 41, 42, 43 of the contacting section 40 of the transformer 100, in particular detachably connected, and the second connecting line part 248 is connected with a second end of the two ends to the second contacting element 42 of the three contacting elements 41, 42, 43 of the contacting section 40 of the transformer 100, in particular detachably connected.By such an electrical connection using the connecting device 240, at least one detection signal can be applied to the three contacting elements 41, 42, 43 for at least one first combination possibility K1 of three combination possibilities K1, K2, K3 such that two input coils 21, 23 of the three input coils 21, 22, 23 of the first coil section 20 are electrically connected in parallel and a third input coil 22 of the three input coils 21, 22, 23 is electrically short-circuited (see, for example, . Fig. 3) The first connecting line section 247 and the second connecting line section 248 can, in particular, have the same length or substantially the same length. Thus, impedance symmetry between a detection measurement point for detecting a voltage u(t) as a detection signal or for detecting a voltage u(t) as a detection signal response can be ensured or substantially ensured.

[0051] Fig. Figure 3 discloses a transformer 100, e.g. a three-phase transformer, such as is already known in particular to Fig. 1 and / or Fig. The transformer 100 comprises a magnetic section 10 with a magnetic core 11, in particular a magnetic core 11 with three magnetic legs, for guiding and focusing a magnetic flux of the transformer 100. The transformer 100 further comprises a first coil section 20 with three input coils 21, 22, 23, wherein the three input coils 21, 22, 23 are connected in a delta configuration, and wherein the three input coils 21, 22, 23 are arranged on the magnetic core 11. The transformer 100 further comprises a contacting section 40 with three contacting elements 41, 42, 43, wherein each of the three contacting elements 41, 42, 43 is electrically connected to one vertex of each of the three delta-connected input coils 21, 22, 23. Furthermore, the transformer 100 includes a second coil section 30 for transferring energy between the first coil section 20 and the second coil section 30.The second coil section 30 also has, in particular, three output coils, wherein the three output coils are connected in a delta or star configuration. Furthermore, the three output coils of the second coil section 30 are also arranged on the magnetic core 11. Furthermore, the three input coils 21, 22, 23 of the first coil section 20 are arranged on the magnetic core 11, in particular with the same orientation. Because the three input coils 21, 22, 23 of the first coil section 20 are arranged with the same orientation, for this combination K1, the current or a respective current component of the current i(t) flows in opposite directions through the two outer, electrically parallel-connected input coils 21 and 23.Thus, the magnetic fluxes of these two input coils 21, 23 (see respective north pole N and south pole S) can close in the magnetic core 11, in particular in the two associated magnetic legs of the magnetic core 11, largely bypassing one of the short-circuited input coils 21, 23 ("middle magnetic legs").

[0052] Fig. Figure 4 schematically reveals an equivalent circuit diagram for the circuit in Fig. 3 Transformer 100 shown.

[0053] Fig. 5 discloses a method for determining information about a transformer 100, as described in particular in the preceding Fig. 1 to 4 is described, or for determining parameterization data for a model to represent the magnetic hysteresis behavior of the transformer 100, as it is used in particular in the preceding Fig. The method is described in sections 1 to 4. As a step, the method comprises applying at least one detection signal 320 to the three contacting elements 41, 42, 43 of the contacting section 40 for at least one first combination possibility K1 of three combination possibilities K1, K2, K3, such that two input coils 21, 23 of the three input coils 21, 22, 23 of the first coil section 20 are electrically connected in parallel and a third input coil 22 of the three input coils 21, 22, 23 is electrically short-circuited, wherein, in particular, the at least one detection signal has a changing polarity. Furthermore, the method comprises, as a step, acquiring at least one detection signal response of the transformer 100 to the at least one applied detection signal, at least for the at least one first combination possibility K1 of the three combination possibilities K1, K2, K3.Furthermore, the method comprises, as a step, the determination of information about the transformer 100 based on at least one applied detection signal and at least one recorded detection signal response. Furthermore, the method may include, as an additional step, the determination of parameterization data based on the determined information about the transformer 100 for a model to represent the magnetic hysteresis behavior of the transformer 100.

[0054] Fig. 6 discloses a method such as has already been used in particular for Fig. 5 is described. In the case of the Fig. In the method described in section 6, at least one detection signal is applied to the three contacting elements 41, 42, 43 of the contacting section 40 for at least two different combination possibilities K1, K2 of the three combination possibilities K1, K2, K3, in particular successively 320, wherein a detection signal response is recorded for each of the two combination possibilities K1, K2 340.The procedure can optionally include a further step in which, for the acquisition 340 of the at least one detection signal response of the transformer 100 to the at least one applied detection signal for the first combination possibility K1 and / or after the acquisition 340 of the at least one detection signal response of the transformer 100 to the at least one applied detection signal for the second combination possibility K2, at least the magnetic core 11 of the magnetic section 10 is put into a defined state, in particular the same defined state 350, e.g. demagnetized.

[0055] Fig. 7 discloses a method such as has already been used in particular for Fig. 5 and / or Fig.6 is described, wherein at least for the first combination K1 of the three combinations K1, K2, K3, two different detection signals, in particular successive in time, are applied to the three contacting elements 41, 42, 43, and wherein for each of the two different detection signals, a detection signal response is recorded 341, 342. Based on the two different detection signals and the two recorded detection signal responses, a hysteresis characteristic, in particular a magnetic hysteresis characteristic, of the transformer 100 can also be determined 361. Reference symbol list 10 Magnetic section 11 Magnetic core 20 first coil section 21, 22, 23 Input coils 30 second coil section 40 Contact section 41, 42, 43 Contact elements 100 transformer 200 measuring device 220 signal source unit 221, 222 Connections Signal source unit 240 Connecting device 241, 242 Connecting lines 243 Contact bridge 247 first connecting line section 248 second connecting line section 249 common connecting line 260 recording units 270 Investigation Unit 280 parameterization unit 320, 321, 322 Creating an investigation signal 340, 341, 342 Recording an investigation signal response 360° gathering information about the transformer 361 Determining a hysteresis curve K1, K2, K3 combination possibilities 400 System North Pole South Pole i(t) current u(t) voltage

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