Capacitive voltage sensor arrangement with tuning circuit and voltage sensor system

Abstract

The disclosure relates to a capacitive voltage sensor arrangement for an electrical energy distribution network. The capacitive voltage sensor arrangement includes a first input terminal, a second input terminal, a first sensor output terminal, and a second sensor output terminal. Further, the capacitive voltage sensor arrangement comprises a capacitive voltage divider comprising a primary capacitor arranged between the first input terminal and the first node and a secondary capacitor arranged between the first node and the second input terminal and electrically connected in series to the primary capacitor. The voltage sensor arrangement further includes a tuning circuit arranged between the first node, the second node, the third node, and the fourth node. The second node is connected to the first sensor output terminal, the third node is connected to the second input terminal, and the fourth node is connected to the second sensor output terminal. In addition, the tuning circuit includes only one or more passive components.

Description

Technical Field

[0001] The present disclosure relates to a capacitive voltage sensor arrangement with a tuning circuit and a voltage sensor system for an electrical energy distribution network. Background Art

[0002] In large energy distribution networks operating at high voltage, this high voltage must be converted to medium or low voltage levels to bring the voltage into a measurable range. Traditionally, large transformers have been used for this conversion. Transformers enable high power to be supplied on the transformed secondary side. However, transformers have the disadvantages of high cost and the large size of the overall system.

[0003] In recent years, the use of transformers has continued to decline, and transformers have been replaced by voltage dividers. Furthermore, the need to gain more detailed insight into distribution networks has recently become stronger. As distribution networks become increasingly complex, the number of voltage measurement systems required and implemented in the network has increased. Voltage dividers offer an easier and cost-effective solution for converting voltage into a measurable range. Voltage dividers can be incorporated into voltage sensors, which are typically available in the form of plug sensors, bushings, post insulators, or detachable connectors. The most common types of voltage dividers are resistive and capacitive. These sensors provide accurate voltage measurements over a wide voltage range. To perform measurements in the system, the sensor is connected to a measuring device, an intelligent electronic device (IED), which is included in a switching station as part of the energy distribution network.

[0004] In theory, the measured transformed voltage at the output of a voltage sensor depends solely on the voltage divider factor. However, in practice, the measured components can influence the measurement result. This can be due to the cable connecting the sensor to the measuring device or the measuring device itself. These components can affect the signal parameters of the measured signal, making the transformed low- or medium-voltage signal no longer a perfect representation of the original high-voltage signal.

[0005] The influence on the signal parameters results in a phase shift in the measured signal, which then results in a deviation, or more precisely, an error, between the ideal amplitude and phase of the signal and the actual measured amplitude and phase of the signal. Limits for such deviations or errors that occur when using capacitive voltage dividers are defined in international standards.

[0006] International standards define the maximum permissible error, and thus the required accuracy, of voltage dividers. For example, the international standards IEC 61869-1 / 6 / 11 (DIN EN 61869-6:20 17-06; DIN EN 61869-1:2010-04; DIN EN 61869-11:2019-01) define the accuracy requirements for so-called low-power passive voltage transformers (LVPTs). An LVPT in this context typically refers to a voltage divider. These requirements take into account various parameters, such as the voltage amplitude, frequency, and temperature. Depending on these parameters, different values ​​for the maximum permissible error are defined.

[0007] To meet the stringent requirements of capacitive voltage dividers, the primary capacitance of the primary capacitor is typically chosen to be very high. However, this high capacitance has the disadvantage of making the primary capacitor very large. This is due to the fact that the achievable permittivity of the capacitor dielectric and the distance between the capacitor electrodes are limited. A large primary capacitor further impacts the overall size of the voltage sensor. Manufacturing and handling these large sensors becomes inconvenient and difficult.

[0008] To overcome these issues, correction circuits have been used to correct the amplitude and phase errors of the measured signal to within defined tolerances. For both amplitude and phase, corresponding calibration or correction factors are measured and then fed into the system to correct the signal. Because the calibration factors are specific to each sensor and measurement setup, correction measurements must be made individually for each sensor when setting up the system. This creates a significant installation workload for the workers and is time-consuming for large switching stations containing numerous voltage sensors. Summary of the Invention

[0009] It is therefore an object of the present disclosure to provide an improved voltage sensor arrangement and a corresponding voltage sensor system, which enable voltage measurements within defined tolerances and which overcome the disadvantages of existing solutions.

[0010] This problem is solved by the subject matter of the independent claims. Advantageous examples of the disclosure are subject matter of the dependent claims.

[0011] The present disclosure is based on the idea that a tuning circuit is provided together with a capacitive voltage divider to provide an easy plug-and-play solution in a voltage measurement setup.

[0012] In particular, the present disclosure relates to a capacitive voltage sensor arrangement for an electrical energy distribution network. The capacitive voltage sensor arrangement includes a first input terminal, a second input terminal, a first sensor output terminal, and a second sensor output terminal. In addition, the capacitive voltage sensor arrangement includes a capacitive voltage divider, which includes a primary capacitor arranged between the first input terminal and a first node, and a secondary capacitor arranged between the first node and the second input terminal and electrically connected in series to the primary capacitor. In addition, the capacitive voltage sensor arrangement includes a tuning circuit arranged between a first node, a second node, a third node, and a fourth node. The second node is connected to the first sensor output terminal, the third node is connected to the second input terminal, and the fourth node is connected to the second sensor output terminal. In addition, the tuning circuit includes only one or more passive components.

[0013] The capacitive voltage sensor arrangement advantageously allows for tuning of signal characteristics to meet defined voltage measurement requirements. In particular, the tuning circuit advantageously influences the transformation ratio of the capacitive voltage divider, enabling accuracy requirements for phase and amplitude errors to be met for lower values ​​of the primary capacitor. This is advantageously achieved by the tuning circuit modifying the capacitance of the secondary capacitor. Therefore, the tuning circuit advantageously comprises only one or more passive components. This means that no active components are required in the tuning circuit according to the present disclosure. This not only simplifies the circuit design and reduces complexity, but is also more cost-effective.

[0014] According to an advantageous further development of the disclosure, the tuning circuit of the capacitive voltage sensor comprises a first resistor arranged between the first node and the second node and has a third node of the tuning circuit directly connected to the fourth node.

[0015] This advantageous embodiment of the tuning circuit comprises only at least one resistor and still enables the signal characteristics to be influenced in order to meet the accuracy requirements of the voltage measurement.

[0016] According to an advantageous further development of the present disclosure, the tuning circuit further comprises a first capacitor arranged in parallel with the first resistor between the first node and the second node, and the tuning circuit comprises a second capacitor arranged between the second node and the third node. In an advantageous example of the invention, the second capacitor represents the input capacitance of a measuring device connected to the tuning circuit and preferably has a value of approximately 50 pF.

[0017] This further embodiment comprises further passive components and advantageously enables accuracy requirements to be met over a wider frequency range, in particular high frequencies.

[0018] According to an advantageous further development of the disclosure, the tuning circuit comprises an inductor arranged between the first node and the second node and has a third node of the tuning circuit directly connected to the fourth node.

[0019] Advantageously, the tuning circuit according to the present disclosure may also comprise at least one inductor, which leads to the same advantageous effects as described with respect to the previous embodiments of the tuning circuit. This shows the adaptability and flexibility of the present solution.

[0020] According to an advantageous further development of the disclosure, the primary capacitor is formed by an electrode arrangement and a dielectric material or by at least one discrete capacitor. Advantageously, the secondary capacitor is formed by an electrode arrangement and a dielectric material or by at least one discrete capacitor.

[0021] According to an advantageous further development of the disclosure, the primary capacitor comprises a capacitance of 10 pF - 30 pF. Advantageously, the secondary capacitor comprises a capacitance of 30 nF - 300 nF.

[0022] According to an advantageous further development of the disclosure, the first resistor comprises a resistance of 500 kΩ - 2 MΩ. Preferably, the first capacitor comprises a capacitance of 1 pF - 50 pF and / or the second capacitor comprises a capacitance of 1 pF - 500 pF.

[0023] According to an advantageous further development of the disclosure, the inductor comprises an inductance of 0.1 H - 5 H.

[0024] The choice of values ​​for the capacitors, inductors, and resistors of the tuning circuit and capacitive voltage divider naturally depends on the application. The given values ​​merely illustrate that the idea and concept are applicable to a wide variety of settings and applications and are not limited to a specific type of voltage measurement setup. Depending on the capacitive voltage divider used, the values ​​of the components of the tuning circuit can be adjusted so that the positive effects of the tuning circuit are also achieved.

[0025] According to an advantageous further development of the disclosure, the second input terminal is connected to ground.

[0026] The present disclosure also relates to a voltage sensor system comprising a first measurement output terminal, a second measurement output terminal, and a capacitive voltage sensor arrangement according to the present disclosure. The first sensor output terminal is connected to the first measurement output terminal, and the second sensor output terminal is connected to the second measurement output terminal. The voltage sensor system further comprises a measuring device having a load capacitor arranged between the first measurement output terminal and the second measurement output terminal, and a load resistor arranged in parallel with the load capacitor.

[0027] Advantageously, the proposed capacitive voltage sensor arrangement can be integrated into a system having a measuring device that performs the actual voltage measurement. The measuring device is advantageously represented by a load resistor and a load capacitor. As will be described in detail below, the location of the tuning circuit within the sensor system can be varied and flexibly adapted as needed.

[0028] According to an advantageous further development of the disclosure, the voltage sensor system comprises a signal cable having a signal cable capacitance arranged between the first measurement output terminal and the second measurement output terminal.

[0029] In this advantageous embodiment of the present disclosure, the tuning circuit is arranged closer to the capacitive voltage divider. The tuning circuit is preferably arranged either directly at the voltage sensor or closer to the sensor at the beginning or in the middle of a signal cable connecting the voltage sensor and in particular the capacitive voltage divider to the measuring device.

[0030] According to an advantageous further development of the disclosure, the voltage sensor system comprises a signal cable having a signal cable capacitance arranged between the first node and the third node.

[0031] In this advantageous embodiment of the present disclosure, the tuning circuit is arranged closer to the measuring device.The tuning circuit can also be arranged directly at the measuring device.

[0032] It is important to note that the beneficial effects of the tuning circuit, such as adjusting the signal characteristics to compensate for the impedance present due to the voltage measurement and meeting the accuracy requirements of such voltage measurements, can be achieved by placing the tuning circuit in a variety of different locations within the sensor system. The same positive effects can be achieved by placing the tuning circuit directly at the capacitive voltage divider, either as part of the voltage sensor or somewhere between the voltage divider and the measurement device. This demonstrates the high flexibility of this solution.

[0033] According to an advantageous further development of the disclosure, the signal cable capacitance is in the range of 2 pF - 1600 pF. Alternatively, the value of the signal capacitance can be described as being in the range of 15 pF / m - 160 pF / m. Thus, the preferred length of the signal cable is up to 10 m.

[0034] According to an advantageous further development of the disclosure, the load capacitance is in the range of 0 pF - 5000 pF and / or the load resistance is in the range of 2 kΩ - 10 MΩ.

[0035] Of course, the values ​​for the signal cables and the measuring device are only exemplary, and the exact values ​​depend on the cables and measuring device used. As mentioned above, the exact components and values ​​of the tuning circuit can be adapted according to the capacitive voltage divider used, and of course also depend on the cables and measuring device used, in order to provide the best tuning result.

[0036] According to an advantageous further development of the disclosure, the tuning circuit is adapted to compensate for the impedance of a load caused by a measuring device arranged at the first measurement output terminal and the second measurement output terminal.

[0037] Performing voltage measurements using a measuring device affects the signal characteristics of the voltage signal, resulting in small errors in the phase and amplitude of the measured signal compared to the ideal signal. The present disclosure, and in particular the concept of providing a proposed tuning circuit, advantageously aims to compensate for these effects. Advantageously, the tuning circuit compensates for effects caused by the measuring device, such as the impedance of the load.

[0038] The proposed capacitive voltage sensor arrangement is preferably used in medium-voltage or high-voltage distribution networks. The maximum system voltage between conductors is exemplarily between 7.2 kV and 42 kV for medium-voltage networks and between 52 kV and 145 kV for high-voltage networks. However, the present disclosure is not limited to applications with a specific voltage or voltage range. The term "low voltage" refers to voltages exemplarily below 1 kV. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] For a better understanding of the present disclosure, the present disclosure is explained in more detail using the examples depicted in the following figures. Therefore, identical components have identical reference numerals and identical component names. Furthermore, some features or combinations of features from the various examples shown and described may also represent independent solutions, inventive solutions, or solutions according to the present disclosure. In the figures:

[0040] Figure 1 shows a voltage sensor arrangement according to the present disclosure,

[0041] Figure 2 shows a tuning circuit according to a first embodiment of the present disclosure,

[0042] Figure 3 Another tuning circuit according to a second embodiment of the present disclosure is shown.

[0043] Figure 4 Another tuning circuit according to a third embodiment of the present disclosure is shown.

[0044] Figure 5 shows a voltage sensor system according to the present disclosure,

[0045] Figure 6FIG. 4 shows a voltage sensor system according to another embodiment of the present disclosure.

[0046] Figure 7 A voltage sensor system according to the present disclosure is shown. DETAILED DESCRIPTION

[0047] The present disclosure is explained in more detail with reference to the accompanying drawings. Figure 1 A capacitive voltage sensor arrangement 100 according to the present disclosure is shown. Capacitive voltage sensor arrangement 100 includes a capacitive voltage divider 111 to convert a high voltage into a measurable medium or low voltage. Advantageously, capacitive voltage divider 111 can also convert the medium voltage into a low voltage level. Capacitive voltage divider 111 is advantageously part of a capacitive voltage sensor. Capacitive voltage divider 111 includes at least one primary capacitor 110 and at least one secondary capacitor 112 arranged in series and electrically connected to each other. Primary capacitor 110 is arranged between a first input terminal 102 of voltage sensor arrangement 100 and a first node 131. Secondary capacitor 112 is arranged between first node 131 and second input terminal 104. Primary capacitor 110 is exemplarily selected as a high-voltage capacitor having a capacitance in the range of 10-20 pF. Secondary capacitor 112 is exemplarily selected as a low-voltage capacitor having a capacitance in the range of 41-82 nF.

[0048] Advantageously, primary capacitor 110 and secondary capacitor 112 are each formed from an electrode arrangement. Specifically, each capacitor includes two sensing electrodes. These sensing electrodes are preferably configured as disc capacitors or as a coaxial electrode arrangement. A conductive paste is preferably applied to the disc-shaped material forming the capacitor. The capacitor preferably consists of a conductive layer applied to a dielectric component, such as ceramic, which provides high accuracy and stability over a wide temperature range.

[0049] The original high input voltage 120 to be measured is applied between the first input terminal 102 and the second input terminal 104. The actual voltage measured is typically the voltage tapped from the node between the second input terminal and the two capacitors. This actual measured voltage is defined by the voltage divider factor and provides a voltage representation of the high voltage applied between the two input terminals 102, 104 of the voltage sensor arrangement 100. Due to the technical implementation of the capacitive voltage divider and the connection to the measurement device, errors may occur in the amplitude and phase of the signal between the actual measured voltage and the original voltage. This means that the measured signal is not a perfect representation of the original high voltage and is affected not only by the voltage divider factor but also by small deviations. As a result, the measured phase and amplitude of the signal deviate from the ideal phase and amplitude.

[0050] The maximum permissible levels of amplitude and phase errors are defined in the international standards IEC 61869-1 / 6 / 11 (DIN EN 61869-6:2017-06; DIN EN 61869-1:2010-04; DIN EN 61869-11:2019-01). This standard includes requirements, in particular, error ranges for different values ​​of various parameters, such as voltage magnitude, frequency, and temperature. For example, different maximum values ​​are defined for different voltage levels and frequency ranges. By way of example, in accuracy class 0.5, for a nominal frequency of 50 Hz and for a voltage amplitude in the range of 0.8 to 1.2 times the rated voltage at the primary capacitor of the capacitive voltage divider, the permissible amplitude error is 0.5%, and the permissible phase error is 0.33 degrees. Other frequency ranges and / or accuracy classes may have different error rates.

[0051] In order to address the high accuracy requirements, the voltage sensor arrangement 100 of the present disclosure further comprises a tuning circuit 130, 230, 330. Different embodiments of the tuning circuit 130, 230, 330 can be implemented and will be exemplarily explained below.

[0052] The tuning circuit 130 , 230 , 330 according to the present disclosure is arranged between a first node 131 , a second node 132 , a third node 133 and a fourth node 134 .

[0053] The second node 132 is connected to the first sensor output terminal 105 of the voltage sensor arrangement 100. The fourth node 134 is connected to the second sensor output terminal 107 of the voltage sensor arrangement 100. Between the two sensor output terminals 105, 107, a sensor output voltage 124 can be tapped, which is defined by the original voltage applied at the inputs 102, 104 of the sensor arrangement, the voltage division factor of the tuning circuit 130, 230, 330, and the tuning factor.

[0054] Furthermore, the third node 133 is connected to the second input terminal 104. The second input terminal 104 is exemplarily connected to ground.

[0055] The sensor arrangement 100 disclosed herein includes a capacitive voltage divider 111 and a tuning circuit 130, 230, 330. The capacitive voltage divider can be in the form of a capacitive voltage sensor having one of the commonly known shapes of these sensors. Common implementations of such sensors are post-insulators, bushings, or switchgear connectors. Preferably, the sensor is implemented as a plug for use with a switchgear connector. Therefore, the tuning circuit 130, 230, 330 can be included in the capacitive voltage sensor or be a separate component. Therefore, the capacitive voltage sensor arrangement 100 can include the capacitive voltage sensor and the tuning circuit 130, 230, 330, whereby the capacitive voltage sensor includes the capacitive voltage divider 111. In another embodiment, the capacitive voltage sensor arrangement 100 can include a capacitive voltage sensor that includes both the capacitive voltage divider 111 and the tuning circuit 130, 230, 330.

[0056] The tuning circuits 130, 230, and 330 according to the present disclosure include only one or more passive components. This means that the tuning circuits 130, 230, and 330 according to the present disclosure can meet the accuracy requirements for the measured voltage with respect to amplitude and phase errors without requiring active components. Therefore, the tuning circuits 130, 230, and 330 advantageously lack active components. This simplifies the design and complexity of the tuning circuit while still meeting accuracy requirements.

[0057] The term "passive component" as used herein refers to a component that does not have a gain or control function for voltage or current. Therefore, the control function of a passive component is linear. In other words, a passive component has no amplification effect and no control function. Furthermore, passive components can have linear or nonlinear electrical characteristics. Examples of passive components are resistors, capacitors, inductors, or memristors. In contrast, "active components" have a gain or control function, so that the control of a parameter is not linear. Active components enable a circuit to output an electrical signal in some form that has a higher power than the power provided by the signal source. Furthermore, active components allow a type of control, meaning that auxiliary energy is drawn from an additional power source or they generate energy themselves. Examples of active components are transistors or amplifiers.

[0058] exist Figures 2 to 3 An advantageous example of a tuning circuit 130, 230, 330 according to the present disclosure is shown in Briefly, the tuning circuit is adapted to adjust the signal characteristics in a system to handle the loads that occur due to the technical implementation using the measuring device.

[0059] Figure 2, a first embodiment of a tuning circuit according to the present disclosure is shown in FIG. The tuning circuit 130 according to this embodiment includes at least one first resistor 116 arranged between a first node 131 and a second node 132. Furthermore, a third node 133 is connected to a fourth node 134. The inclusion of resistor 116 influences the voltage division factor of the primary capacitor 110 and the secondary capacitor 112 of the capacitive voltage divider. This positively influences the phase and amplitude of the signal, so that the deviation between the actual measured signal and the ideal measured signal meets the requirements of international standards over a wide frequency range. In particular, the described tuning circuit 130 reduces the phase and amplitude errors of the measured signal. Specifically, the inclusion of resistor 116 reduces the phase error, but may introduce a voltage drop across resistor 116. This voltage drop can advantageously be compensated for by adjusting the voltage division ratio of the primary capacitor 110 and the secondary capacitor 112, so that the desired output signal at the sensor output terminals 105 and 107 can be achieved.

[0060] Figure 3 , a second embodiment of a tuning circuit according to the present disclosure is shown. Tuning circuit 230 according to this embodiment includes a first resistor 116 arranged between a first node 131 and a second node 132. Furthermore, tuning circuit 230 includes at least one capacitor. Exemplarily, tuning circuit 230 includes a first capacitor 117 arranged in parallel with first resistor 116 between first node 131 and second node 132. Furthermore, a second capacitor 118 is exemplarily arranged between second node 132 and a third node 133. Second capacitor 118 can also advantageously represent the input capacitance of a measurement device connected to the tuning circuit (see description below) and preferably has a value of approximately 50 pF. Third node 133 is connected to fourth node 134.

[0061] This further advantageous embodiment of the tuning circuit 230 allows for meeting the phase and amplitude error requirements defined in international standards over a wide frequency range. In particular, requirements for accuracy at high frequencies can be met. For example, accuracy can be met for frequencies in the range of 1 Hz to 650 Hz.

[0062] Figure 4 A third embodiment of a tuning circuit 330 is shown in FIG. In this embodiment, tuning circuit 330 includes an inductor 119 arranged between a first node 131 and a second node 132. Furthermore, a third node 133 is connected to a fourth node 134. This embodiment demonstrates that, in addition to using resistors and capacitors, inductors can also be used to influence the impedance of a system. The inductor preferably has an inductance in the range of 4 Henrys (H). In another preferred embodiment (not shown), inductor 119 is arranged in series with a resistor between first node 131 and second node 132. This arrangement has the further advantage of preventing or reducing potential oscillations.

[0063] It is clear that modifications and different arrangements of the components within the presented tuning circuit are also feasible and within the scope of the present disclosure. The exact arrangement of the resistors, capacitors and / or inductors can vary depending on the specific requirements for phase and amplitude errors. Furthermore, it is clear that the exact arrangement and design of the components of the tuning circuit also depends on the voltage level at which the sensor arrangement operates, and the selection of the primary capacitor 110 and the secondary capacitor 112 also depends on this voltage level. In other words, the design and arrangement of the components of the tuning circuit may be affected by the voltage level to be achieved for the voltage at the primary capacitor 110 and the secondary capacitor 112. This voltage level to be achieved is advantageously defined by the desired voltage divider ratio of the capacitive voltage divider. Furthermore, the choice of the measuring device also affects the phase and amplitude errors that occur, which then affects the design of the capacitive voltage divider and the tuning circuit.

[0064] When using the capacitive voltage sensor arrangement 100 as described above to transform and measure the voltage in a system, the first sensor output terminal 105 and the second sensor output terminal 107 are connected to a measuring device, where the actual measured signal is obtained. As already indicated above, the connection of the capacitive voltage divider and thus the implementation of the capacitive voltage divider causes a deviation between the original high-voltage signal and the actual measured signal, which is referred to as an error in the measured signal.

[0065] Specifically, the connection to the measuring device can be understood as a finite resistance value that is applied to the output of the capacitive voltage divider. This finite resistance causes a phase shift in the signal, which then leads to a phase error between the original and measured voltage signals. The amplitude error is primarily influenced by parameters such as component tolerances.

[0066] The capacitive voltage sensor arrangement with the proposed tuning circuit provides an easy-to-implement and cost-effective solution for compensating errors caused by the technical implementation of the system. With this solution, high requirements for voltage measurement accuracy can be met.

[0067] Figure 5 The described voltage sensor arrangement is shown in a system having a measuring device, an intelligent electronic device (IED). In the illustrated system 1000, a first sensor output terminal 105 is connected to a first measurement output terminal 106. A second sensor output terminal 107 is connected to a second measurement output terminal 108. The measurement output terminals 106, 108, and in particular the voltage tapped from these terminals, represent the technical implementation of the output voltage of the voltage sensor arrangement and depict the actual voltage being measured.

[0068] Illustratively, the sensor output terminals are connected to the measurement device via a signal cable. The length of the signal cable and its exact location within the system can vary depending on the implementation of the sensor system. Illustratively, the signal cable is depicted as including cable capacitance 113 and is illustratively arranged between the first measurement output terminal 106 and the second measurement output terminal 108.

[0069] The value of the capacitance of the signal cable depends on the parameters of the cable, but is exemplarily described as being between [100-500] pF.

[0070] Furthermore, the properties of the measuring device are depicted as resistance and capacitance. A load resistor 115 of the measuring device is arranged in parallel with the cable capacitance 113 between the first measurement output terminal 106 and the second measurement output terminal 108. A load capacitance 114 of the measuring device is again arranged in parallel with the signal cable capacitance 113 and also in parallel with the load resistor 115.

[0071] The impact on the signal varies depending on the load value and the type of measuring device. Load values ​​are defined in international standards. IEC 61869-1 / 6 / 11 (DIN EN 61869-6:2017-06; DIN EN 61869-1:2010-04; DIN EN 61869-11:2019-01) defines loads in such systems as 2 kΩ to 2.1 MΩ and [0-5000] pF, specifically 2 MΩ and 50 pF. However, the exact values ​​of IEDs available on the market may deviate from these defined values.

[0072] As mentioned above, when measuring the transformed signal, phase and amplitude errors occur between the original voltage and the transformed measured voltage. To address this issue, the present disclosure focuses on a voltage sensor arrangement that includes a tuning circuit that corrects for these errors, thereby meeting the accuracy requirements defined in the aforementioned international standards. The tuning circuits 130, 230, and 330 are intended to compensate for the impedance of the load caused by the measurement device arranged at the first and second measurement output terminals.

[0073] As mentioned above, also within the present disclosure, the tuning circuit is not provided directly at the sensor arrangement, but can also be provided at the beginning or end of the cable connecting the sensor arrangement to the measuring device. Alternatively, the tuning circuit can be provided within the measuring device. In particular, the described advantageous effects can be achieved by arranging the tuning circuit somewhere between the original voltage applied to the capacitive voltage divider and the measured voltage at the measuring device. The exact location of the tuning circuit can be selected based on the specific application and site requirements.

[0074] In this disclosure Figure 6exemplarily illustrates a system with a tuning circuit positioned closer to the measurement device. This demonstrates the flexibility and adaptability of the proposed solution, particularly with regard to the exact placement of the tuning circuit. Depending on the application and the installation in the field, the tuning circuit can be positioned wherever space or safety requirements permit, while still providing an easy and effective solution for correcting any phase and amplitude errors that occur.

[0075] like Figure 6 As shown, voltage sensor system 1000 includes a capacitive voltage sensor arrangement 100 having a capacitive voltage divider 111 as described above. Furthermore, the tuning circuits 130, 230, and 330 of capacitive voltage sensor arrangement 100 are advantageously positioned closer to the measuring device. This is illustrated by the signal cable capacitance 113 arranged between a first node 131 and a third node 133, and the load capacitance 114 and load resistance 115 arranged between a second node 132 and a fourth node 134. Because second node 132 is connected to first measurement output terminal 106 and fourth node 134 is connected to second measurement output terminal 108, the positions of load capacitance 114 and load resistance 115 can also be described relative to output terminals 106 and 108.

[0076] like Figure 5 and Figure 6 As shown, the capacitive voltage sensor arrangement may or may not include a signal cable. This depends solely on the choice of arrangement of the tuning circuit, but different options are within the scope of the present disclosure and lead to advantageous effects as described above.

[0077] With the proposed solution, the accuracy requirements for the phase and amplitude errors of the voltage measurement system can be met for lower values ​​of the capacitance of the primary capacitor of the capacitive voltage divider. In particular, without a tuning circuit as presented, a transformation ratio of 6135.85 / 1 as defined in the international standards IEC 61869-1 / 6 / 11 (DIN EN 61869-6:2017-06; DIN EN 61869-1:2010-04; DIN EN 61869-11:2019-01) requires a primary capacitor with a capacitance higher than 40 pF.

[0078] With the proposed solution including the tuning circuit, the standard requirement of a transformation ratio of 6135.85 / 1 can be met for a primary capacitor with a capacitance of approximately 20 pF or even less. This shows that with the proposed solution the required value of the capacitance needed to meet the standard has been halved.

[0079] Since the value of the capacitance of the capacitor has a direct influence on the size of the capacitor, the size of the capacitor and thus the size of the sensor arrangement can be drastically reduced with the proposed solution.

[0080] Figure 7 A voltage sensor system 1000 according to the present disclosure and its installation in the field is shown. A capacitive voltage sensor arrangement 100 is exemplarily depicted in the form of switchgear connectors 150. Multiple switchgear connectors 150 are connected to an IED 160 in the switchgear, where voltage measurements are taken. IED 160 is preferably an electronics device mounted on the front of the switchgear. Each switchgear connector 150 includes a capacitor voltage sensor arrangement 100 with a capacitive voltage divider 111.

[0081] Reference Signs List

[0082] Description of Reference Numerals

[0083] 100 Capacitive voltage sensor arrangement

[0084] 102 First input terminal

[0085] 104 Second input terminal

[0086] 105 First sensor output terminal

[0087] 106 First measurement output terminal

[0088] 107 Second sensor output terminal

[0089] 108 Second measurement output terminal

[0090] 110 Primary capacitor

[0091] 111 Capacitive Voltage Divider

[0092] 112 Secondary capacitor

[0093] 113 Signal cable capacitance

[0094] 114 Load Capacitor

[0095] 115 load resistor

[0096] 116 First resistor

[0097] 117 First Capacitor

[0098] 118 Second capacitor

[0099] 119 Inductor

[0100] 120 Sensor input voltage

[0101] 122 Measure output voltage

[0102] 124 Sensor output voltage

[0103] 130, 230, 330 tuned circuits

[0104] 131 First Node

[0105] 132 Second Node

[0106] 133 Third Node

[0107] 134 Fourth Node

[0108] 150 Switchgear Connector

[0109] 160 IED

[0110] 1000 Voltage Sensor System

Claims

1. A capacitive voltage sensor arrangement (100) for use in an electrical energy distribution network, the capacitive voltage sensor arrangement (100) comprising: A first input terminal (102), a second input terminal (104), a first sensor output terminal (105), and a second sensor output terminal (107); A capacitive voltage divider (111), the capacitive voltage divider (111) comprising: a primary capacitor (110) arranged between the first input terminal (102) and the first node (131), and a secondary capacitor (112) disposed between the first node (131) and the second input terminal (104) and electrically connected in series to the primary capacitor (110); The voltage sensor arrangement (100) further comprises: A tuning circuit (130, 230, 330) is arranged between the first node (131), the second node (132), the third node (133) and the fourth node (134); wherein the second node (132) is connected to the first sensor output terminal (105), the third node (133) is connected to the second input terminal (104), and the fourth node (134) is connected to the second sensor output terminal (107); Wherein, the tuning circuit (130, 230, 330) only includes one or more passive components.

2. The capacitive voltage sensor arrangement (100) according to claim 1, wherein The tuning circuit (130, 230) comprises a first resistor (116) arranged between the first node (131) and the second node (132), and wherein the third node (133) of the tuning circuit (130) is directly connected to the fourth node (134).

3. The capacitive voltage sensor arrangement (100) according to claim 2, wherein The tuning circuit (230) further includes: a first capacitor (117) arranged in parallel with the first resistor (116) between the first node (131) and the second node (132); and A second capacitor (118) is arranged between the second node (132) and the third node (133).

4. The capacitive voltage sensor arrangement (100) according to claim 1, wherein The tuning circuit (330) comprises an inductor (119) arranged between the first node (131) and the second node (132), and wherein the third node (133) and the fourth node (134) of the tuning circuit (130) are directly connected.

5. The capacitive voltage sensor arrangement (100) according to any one of the preceding claims, wherein The primary capacitor (110) is formed by an electrode arrangement and a dielectric material, or by at least one discrete capacitor; and / or wherein The secondary capacitor (112) is formed by an electrode arrangement and a dielectric material, or by at least one discrete capacitor.

6. The capacitive voltage sensor arrangement (100) according to any one of the preceding claims, wherein The primary capacitor (110) comprises a capacitance of 10 pF - 30 pF, and / or wherein, The secondary capacitor (112) comprises a capacitance of 30 nF - 300 nF.

7. The capacitive voltage sensor arrangement (100) according to claim 2 or 3, wherein The first resistor (116) comprises a resistance of 500 kΩ - 2 MΩ, and / or wherein, The first capacitor (117) comprises a capacitance of 1 pF - 50 pF, and / or wherein, The second capacitor (118) comprises a capacitance of 1 pF - 500 pF.

8. The capacitive voltage sensor arrangement (100) according to claim 4, wherein The inductor (119) includes an inductance of 0.1 H - 5 H.

9. The capacitive voltage sensor arrangement (100) according to any one of the preceding claims, wherein The second input terminal (104) is connected to ground.

10. A voltage sensor system (1000), the system (1000) comprising: A first measurement output terminal (106) and a second measurement output terminal (108); A capacitive voltage sensor arrangement (100) according to any one of the preceding claims; wherein the first sensor output terminal (105) is connected to the first measurement output terminal (106), and the second sensor output terminal (107) is connected to the second measurement output terminal (108); and A measuring device comprising a load capacitor (114) arranged between the first measurement output terminal (106) and the second measurement output terminal (108), and comprising a load resistor (115) arranged in parallel with the load capacitor (114).

11. The voltage sensor system (1000) according to claim 10, further comprising: A signal cable comprising a signal cable capacitor (113) arranged between the first measurement output terminal (106) and the second measurement output terminal (108).

12. The voltage sensor system (1000) according to claim 10, further comprising: A signal cable comprising a signal cable capacitor (113) arranged between the first node (131) and the third node (133).

13. The voltage sensor system (1000) according to claim 11 or 12, wherein: The signal cable capacitance (113) is in the range of 2 pF to 1600 pF.

14. The voltage sensor system (1000) according to any one of claims 10 to 13, wherein: The load capacitance (114) is in the range of 1 pF – 5000 pF, and / or wherein, The load resistor (115) is in the range of 2 kΩ - 10 MΩ.

15. The voltage sensor system (1000) according to any one of claims 10 to 14, wherein The tuning circuit (130, 230, 330) is adapted to compensate for the impedance of a load caused by the measuring device arranged at the first measurement output terminal (106) and the second measurement output terminal (108).

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