Measurement circuits for measuring voltage pulses, shaping systems, and methods for measuring discharge arcs in vacuum circuit breakers.

Abstract

This invention relates to a measuring circuit (10) for measuring voltage pulses (14) in the voltage-carrying conductors of a line branch (6, 6') in a high-voltage forming system insulated with SF6, an SF6-N2 gas mixture, or clean air gas (1); and also to a corresponding method for processing the surface of electrical contacts (2) in an electro-vacuum circuit breaker (3). The line branch (6, 6') is configured to conduct high voltage from a self-operating voltage source (4) to the vacuum circuit breaker (3). A partial discharge measuring unit (8) is configured to measure voltage pulses (14) in the voltage-carrying conductors caused by a discharge arc (21) in the vacuum circuit breaker (3). For this purpose, the partial discharge measuring unit (8) is electrically connected to the capacitive cladding (9) of the line branch (6, 6') via a resistor (11) at a low voltage potential, and particularly to a component of the line branch (6, 6') electrically coupled to the voltage-carrying conductor through the electric field of the voltage-carrying conductor.

Description

Technical Field

[0001] This invention relates to a measuring circuit for measuring voltage pulses in the voltage-carrying conductors of a line branch in a molding system, wherein the molding system is a gas-isolated molding system, preferably insulated with SF6, an SF6-N2 gas mixture, and / or clean air; the invention also relates to a method for measuring discharge arcs in a vacuum circuit breaker. Background Technology

[0002] To achieve higher withstand voltage performance in circuit breakers, especially vacuum circuit breakers, high-voltage conditioning is typically used to "polish" the surfaces of the contacts or shielding. Specifically, this involves applying high voltage to the circuit breaker contacts until a discharge arc is generated. During this arc, electrons escape from the anode and collide with the cathode. Through this collision, the surface gradually becomes finer. A crucial parameter for production monitoring during this process is the frequency of the circuit breaker's discharge arc.

[0003] Detecting discharge arcs requires a robust and rapid measurement technique. Typically, a high voltage is applied to one or both sides of the circuit breaker, and current pulses are measured either within the current path of the high-voltage transformer or via an antenna mounted near the circuit breaker. However, these methods are not very accurate or highly susceptible to interference. On one hand, measurements within the current path of the high-voltage transformer are severely limited, weakened, and filtered due to the large attenuation impedance. On the other hand, measurements via an antenna are prone to interference, which can not only count discharge arcs between the circuit breaker contacts but also incorrectly record external interference as discharge arcs. Summary of the Invention

[0004] Based on known prior art, the purpose of this invention is to provide an improved measurement technique for pulse counting or discharge arc counting in a molding system.

[0005] This invention relates to the molding system itself, which uses SF6, SF6-N2 gas mixtures, and / or clean air for insulation, and a pulse counting measurement circuit for use in a vacuum circuit breaker molding system. This also includes adapting the measurement circuit so that the molding pulses measured by the circuit can be acquired via the input of a partial discharge measuring instrument conforming to IEC 60270. The pulse count can be transmitted to the process control device (e.g., PLC) of the molding system through the interface of the measuring instrument. The necessary software for equipment control and stored in the so-called molding scheme is not part of this invention.

[0006] This objective is achieved by a measuring circuit having the features of claim 1, which can be particularly installed in a molding system. Advantageous further improvements can be derived from the dependent claims, the description, and the drawings.

[0007] Accordingly, a measurement circuit is proposed for measuring voltage pulses in the voltage-carrying conductor of a line branch configured to conduct high voltage, particularly from a working voltage source to a vacuum circuit breaker. The measurement circuit includes a partial discharge measurement unit configured to measure voltage pulses in the voltage-carrying conductor caused by a discharge arc in the vacuum circuit breaker.

[0008] According to the present invention, the partial discharge measurement unit is electrically connected to the capacitive coating of the line branch via a resistor at a low voltage potential.

[0009] In other words, the capacitive cladding can be electrically coupled to the voltage-carrying conductor of the line branch via the electric field of that conductor. Here, "electrical coupling" can mean "current coupling" and / or "capacitive coupling," thereby transmitting the electrical effects caused by changes in current and / or voltage in the current-carrying conductor of the line branch to the capacitive cladding. High voltage can be, in particular, high voltage or ultra-high voltage, while low voltage can be below 1. kV The voltage. Alternatively, the partial discharge measurement unit can also be configured to measure current pulses in the current-carrying conductors of a line branch.

[0010] Impedance can have both resistance and inductance, especially inductance connected in parallel with a resistance. For example, the resistance of the impedance can be 50 Ω. The impedance can be configured to attenuate voltage pulses from a capacitive coating. The impedance can be electrically connected between the capacitive coating of a line branch and the partial discharge measurement unit. The capacitive coating and the impedance here can form a voltage divider that steps down high voltages, especially reducing them by at least a thousand times.

[0011] The advantage of this is that it reduces the impact of external interference on the measurement of the discharge arc frequency and lowers signal noise. Therefore, measurements performed through the capacitive coating can be more accurate than measurements performed directly in the grounding path of the power transformer and / or with the aid of an antenna / probe positioned near the vacuum circuit breaker.

[0012] The measurement circuit also includes implementation methods that can bring further advantages.

[0013] One embodiment proposes a capacitive cladding comprising a component of a line branch electrically coupled to a voltage-carrying conductor via the electric field of the voltage-carrying conductor, wherein the component is particularly ungrounded. In other words, particularly a metallic component, coupled to the voltage-carrying conductor of the line branch via the electric field of the voltage-carrying conductor, or capacitively coupled to the voltage-carrying conductor, and may be connected in series with the impedance at a low voltage potential. The component can be arranged within the inductively influenced region around the voltage-carrying conductor of the line branch, so that when a voltage pulse occurs in the voltage-carrying conductor, the charge state in the component changes through the electrical coupling effect via its electric field. For this purpose, the component can be ungrounded and / or electrically insulated. The advantage of this is that voltage pulses in the voltage-carrying conductor can be coupled out with relatively small signal distortion.

[0014] One embodiment proposes that the line branch is constructed as gas-isolated, wherein the component is particularly arranged in the gas-isolated region of the line branch. In other words, the voltage-carrying conductor of the line branch may be metal-encapsulated and optionally gas-isolated. The capacitive coating and / or the component may be arranged inside the metal encapsulation of the line branch, within which a gas-isolated region may be provided, and the capacitive coating and / or the component is arranged around the voltage-carrying conductor.

[0015] For example, a line branch can be constructed as a tubular conductor, particularly a gas-isolated tubular conductor. Here, the component can be, for example, a current-carrying, ungrounded or electrically insulated, particularly metallic inner tube of the tubular conductor, which surrounds the voltage-carrying conductor and is also capacitively coupled to it. The component can also be a bent component, particularly metallic, surrounding the voltage-carrying conductor. The inner tube can be electrically insulated relative to the outer tube of the tubular conductor. Thus, the voltage pulse generated in the current-carrying conductor of the line branch when a discharge arc occurs in the vacuum circuit breaker is transmitted to the capacitive cladding, particularly the component, through the electrical coupling of the voltage-carrying conductor's electric field, thereby changing the charge state of the capacitive cladding, particularly the components constituting the capacitive cladding. The advantage of this is that the spatial size of the line branch can be reduced and / or the line branch can be arranged indoors.

[0016] One embodiment proposes that the component forms a capacitor, particularly with a current-carrying conductor. In other words, the component can form a coaxial capacitor with a voltage-carrying conductor, which can be capacitively coupled to the voltage-carrying conductor of the line branch via the electric field of the voltage-carrying conductor. The component can be non-current-carrying. The capacitor can be configured as the upper arm capacitor of a high-voltage divider and connected in series with the impedance at a low voltage potential. This achieves a voltage division ratio on the order of thousands, thereby reducing the signal level to a measurable / reasonable level.

[0017] One embodiment proposes that the capacitor be configured as a high-voltage capacitor, and that this high-voltage capacitor is particularly suitable for high-frequency applications. In other words, the high-voltage capacitor can be constructed as a robust, low-loss capacitor suitable for high frequencies. The capacitor should not have a solid or liquid dielectric. The advantage of this is that the capacitor is stable to sudden current or voltage changes in the high-voltage and ultra-high-voltage ranges, and can couple its output without distortion.

[0018] One embodiment proposes that an attenuator and / or frequency filter, particularly a high-pass or band-pass filter, is electrically connected between the impedance and the partial discharge measurement unit. In other words, the attenuator can be electrically connected between the partial discharge measurement unit of the line branch and the impedance, and can optionally be configured to further attenuate voltage and / or current pulses with little or no signal distortion. Through the series connection of the impedance and the attenuator, voltage pulses from the capacitive coating, particularly from the capacitor, can thus be attenuated with relatively little signal distortion.

[0019] Additionally, a frequency filter can be electrically connected between the partial discharge measurement unit and the attenuator. This frequency filter can be configured as a high-pass filter or a band-pass filter. The frequency filter can be configured to filter out the frequency components of the alternating current from the voltage pulse.

[0020] The advantage of this is that the voltage pulse from the capacitor can be attenuated to a size with relatively small signal distortion, so as not to damage the partial discharge measuring instrument.

[0021] One embodiment proposes that a partial discharge measurement unit is configured to determine the presence of a discharge arc between the contacts of a vacuum circuit breaker based on measured voltage pulses. In other words, the partial discharge measurement unit can be configured as a voltage and / or current measuring instrument, particularly configured to measure the current and / or voltage of voltage pulses from a capacitive coating relative to a reference potential. The reference potential can be at a low voltage potential or electrically grounded. For example, the partial discharge measurement unit can be configured to determine the presence of a discharge arc in the vacuum circuit breaker when a voltage pulse from the capacitive coating exceeds a voltage threshold, and optionally count the voltage pulses, especially the discharge arcs.

[0022] Additionally, the partial discharge measurement unit can be configured to measure at least two voltage pulses at a given time, particularly the voltage pulses of the capacitive coatings of at least two line branches. For example, the partial discharge measurement unit can be configured to determine the presence of a discharge arc in the vacuum circuit breaker when voltage pulses with the same timestamp are measured at at least two input terminals of the partial discharge measurement unit. Additionally, the partial discharge measurement unit can also be configured to perform a plausibility check on the voltage pulses measured at a given time. Here, the partial discharge measurement unit and / or the control device data-coupled with the partial discharge measurement unit can be configured to determine the presence of a current discharge arc only if the plausibility check passes. Additionally, the plausibility check can include signal comparison, particularly amplitude comparison, and / or timestamp comparison. For example, when the amplitudes and / or timestamps of two signals are the same, and / or their difference is less than a voltage threshold, a discharge arc can be determined to exist in the vacuum circuit breaker.

[0023] The advantages of this are that the discharge arc frequency in the vacuum circuit breaker can be determined more accurately, and the influence of external interference factors on the discharge arc frequency measurement can be reduced, while signal noise is decreased. Therefore, measurements performed through the capacitive coating can be more accurate than measurements performed directly in the grounding path of the power transformer and / or measurements performed using an antenna / probe placed near the circuit breaker.

[0024] The aforementioned objective is also achieved by a molding system, which preferably uses SF6, an SF6-N2 gas mixture, and / or clean air gas for insulation, and has the features of claim 8. Advantageous further improvements to this molding system can be derived from the dependent claims of the aforementioned measuring circuit, as well as from this specification and the accompanying drawings.

[0025] The aforementioned measuring circuit, particularly the line branch, can be incorporated into a molding system, preferably insulated with SF6 and / or an SF6-N2 gas mixture or clean air, for machining the surfaces of the electrical contacts in the vacuum circuit breaker. This molding system can be arranged within or mounted on the molding system. The molding system can be gas-isolated and / or metal-encapsulated, and is particularly configured as a high-voltage molding system. The molding system may include a working voltage source for providing a working voltage to a receiving device configured to make electrical contact with at least one contact of the vacuum circuit breaker and to supplementarily adjust the contact spacing of the vacuum circuit breaker, wherein the corresponding contact of the vacuum circuit breaker is electrically connected to the working voltage source via the line branch between the receiving device and the working voltage source. According to the invention, a partial discharge measuring unit for measuring voltage pulses in the voltage-carrying conductor of a line branch is electrically connected to the capacitive coating of the line branch via a low-voltage impedance due to the discharge arc caused by the working voltage occurring between the contacts of the vacuum circuit breaker. In other words, the capacitive cladding of the line branch is coupled to the voltage-carrying conductor of the device through the electric field of the voltage-carrying conductor, and can be connected in series with the partial discharge measurement unit through an impedance at a low voltage potential. The clean air gas can be dry air or synthetic air (a mixture of pure oxygen and pure nitrogen).

[0026] The molding system can also include the above-described measurement circuit implementation, or vice versa.

[0027] The above objective is also achieved by a method for processing the surface of electrical contacts in an electrovacuum circuit breaker, particularly by means of a forming system having the features of claim 9. Advantageous further improvements can be derived from the dependent claims, this specification, and the accompanying drawings.

[0028] Accordingly, a method is proposed for machining the surface of electrical contacts in a vacuum circuit breaker using the discharge arc induced by the operating voltage between the contacts. The operating voltage is provided by an operating voltage source, which is electrically connected to a receiving device for the vacuum circuit breaker via a line branch to make electrical contact with the contacts of the vacuum circuit breaker. To count the discharge arcs in the vacuum circuit breaker, a partial discharge measurement unit is used to measure the voltage pulses in the voltage-carrying conductor of the line branch.

[0029] According to the present invention, the partial discharge measurement unit is electrically connected to the capacitive coating of the line branch through a resistor at a low voltage potential.

[0030] In other words, partial discharge measurements can be performed at a measurement tap using a partial discharge measurement unit, which is electrically connected to the capacitive cladding of the line branch, particularly to a capacitor formed by the capacitive cladding. The capacitive cladding may include an ungrounded, particularly metallic component of the line branch, which is capacitively coupled to the voltage-carrying conductor of the line branch, thereby forming a capacitor. Therefore, the capacitive cladding may be or include an ungrounded component of the line branch and capacitively coupled to the current-carrying conductor of the line branch, which is further uncharged or non-current-carrying. This component can be configured to withstand the inductive effect of the current-carrying conductor of the line branch. For example, this component may be a non-current-carrying and electrically insulating inner tube of a metal-encapsulated and / or gas-isolated line branch, which surrounds a voltage-carrying conductor and is further electrically insulated relative to a grounded outer tube.

[0031] The current discharge arcs between circuit breaker contacts can be counted based on measurements of partial discharge on the capacitive coating, particularly the components and / or capacitors. Voltage pulses and / or current pulses on the output side of the capacitive coating, particularly the capacitors, facing the partial discharge measurement unit, can be correlated with voltage pulses in the voltage-carrying conductors when a discharge arc occurs between the contacts of the vacuum circuit breaker.

[0032] The advantage of this is that by measuring the partial discharge on the capacitive coating, the discharge arc between the contacts of a vacuum circuit breaker can be determined more accurately and with less interference. This can improve the manufacturing process of vacuum circuit breakers, especially the processes for machining or polishing the contact surfaces.

[0033] The method also includes implementations that can bring further advantages.

[0034] One implementation proposes determining whether a discharge arc exists between the contacts of a vacuum circuit breaker based on voltage pulses measured using a partial discharge measurement unit. In other words, the presence of a current discharge arc between the circuit breaker contacts is recorded by measuring partial discharges, particularly voltage pulses. For example, when partial discharges, particularly voltage pulses, with the same timestamp are measured or recorded at at least two inputs of the partial discharge measurement unit, the presence of a current discharge arc can be determined or recorded. The advantage of this is that the number of discharge arcs can be determined more accurately, thereby improving the setting of the optimal operating point, especially the setting of the operating voltage and / or the circuit breaker contact spacing.

[0035] For example, the discharge arcs between the contacts of a vacuum circuit breaker can be counted by a control device and / or a partial discharge measuring unit, and the operating voltage can be adjusted by means of an operating voltage source and / or the spacing between the vacuum circuit breaker contacts can be adjusted by means of a receiving device of the forming system, based on the number of discharge arcs per unit time, especially per second. The discharge arc frequency is determined by counting the number of discharge arcs, especially per unit time, using the partial discharge measuring unit and / or control device. The time unit can be, for example, one second, one-tenth of a second, or one-hundredth of a second. For example, the partial discharge measuring unit and / or control device can determine the discharge arc frequency as the number of discharge arcs per second, and further set, especially adjust, the operating voltage and / or contact spacing based on this. The advantage of this is that the setting of the required operating voltage and / or contact spacing in the vacuum circuit breaker by the forming system can be improved, especially its control or adjustment. For this purpose, the control system connected to the partial discharge measuring instrument can read these signals and send them to further process control via an interface. Thus, the number of discharge arcs used for surface treatment can be determined more accurately, thereby improving the overall surface treatment process.

[0036] The method may have the structural features of the measurement circuit and / or molding system described above, or vice versa. To avoid repetition, please refer to the descriptions in the corresponding sections above for method features corresponding to the measurement circuit and / or molding system.

[0037] The present invention also includes implementations that incorporate a combination of features from the above-described embodiments. Attached Figure Description

[0038] Preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Wherein: Figure 1 A schematic diagram showing the relationship between voltage and / or current pulses in a line branch and the discharge arc occurring between contacts in a vacuum circuit breaker is shown. Figure 2 A circuit diagram is shown for a forming system used to process the contacts of a vacuum circuit breaker by generating a discharge arc between the contacts; and Figure 3 A circuit diagram is shown for a measurement circuit used to measure and count discharge arcs by means of voltage pulses or current pulses in the voltage-carrying conductor of a line branch. Detailed Implementation

[0039] The preferred embodiments are described below with reference to the accompanying drawings. In different drawings, elements that are the same, similar, or have the same function are denoted by the same reference numerals, and to avoid repetition, repeated descriptions of these elements are omitted.

[0040] Figure 1 The diagram schematically shows the operating voltage. U A Current I And the time curve of the discharge arc 21 between the contacts in the vacuum circuit breaker. Vacuum circuit breakers are commonly used as medium-voltage, high-voltage, and ultra-high-voltage circuit breakers. To improve electrical breaking capacity, the contact surface of the vacuum circuit breaker is processed by means of the discharge arc 21, thereby melting the uneven structure of the surface and achieving smoothness. The discharge arc 21 is the electrical discharge that occurs between the contacts in the vacuum circuit breaker, especially the metal vapor arc discharge.

[0041] Therefore, a vacuum circuit breaker is incorporated into a molding system, which in... Figure 2 The details are shown in more detail below, and the molding system utilizes the operating voltage. U A An electric discharge arc 21 is generated at the contacts of the vacuum circuit breaker when applied. A voltage pulse 14 occurs each time the discharge arc 21 occurs. Similar to the voltage pulse 14, a current pulse 15 also occurs simultaneously between the operating voltage source and the vacuum circuit breaker. The discharge arc 21 and the operating voltage... U A The voltage pulse 14 and / or the current pulse 15 are recorded synchronously. The number of discharge arcs 21... N These are important parameters in the contact surface treatment process. Among them, the discharge arc frequency is the number of discharge arcs per unit time. N For example, the number of discharge arcs per second is an important standard for processing, especially polishing, the contact surfaces in vacuum circuit breakers.

[0042] Figure 2 A circuit diagram of a forming system 1 for processing contacts 2 in a vacuum circuit breaker 3 is shown. The forming system 1 has an operating voltage source 4 for providing operating voltage at the receiving device 5. U A The operating voltage source 4 is electrically connected to the receiving device via line branches 6 and 6'. The operating voltage source 4 can be configured as an interface for connection to the power grid, and each line branch 6 and 6' includes a transformer 18, particularly a power transformer, and a damping impedance 18 for current and voltage conversion relative to the power grid. The operating voltage... U A It is for high voltage, especially ultra-high voltage.

[0043] The receiving device 5 is configured to receive the vacuum circuit breaker 3 to be processed, and to electrically contact each contact 2 with the operating voltage source 4 via corresponding line branches 6 and 6', thereby ensuring that both contacts 2 of the vacuum circuit breaker 3 are electrically connected to the operating voltage source 4 via the receiving device 5 and corresponding line branches 6 and 6'. Additionally, the receiving device 5 is also configured to adjust the spacing between the contacts 2. For this purpose, the receiving device 5 may include a corresponding actuator (not shown).

[0044] The molding system may also have a control device 16, which is configured based on the operating voltage. U A and / or the spacing between contact 2 d Set the number of discharge arcs per unit time 21 N , for use in machining the surface of contact 2.

[0045] To detect the discharge arc 21 between the contacts 2 of the vacuum circuit breaker 3, partial discharge, particularly voltage pulses 14 and / or current pulses 15, can be measured by means of a partial discharge measurement unit 8 in at least one line branch 6 and / or 6'. Because high voltage, especially ultra-high voltage, exists in line branches 6 and 6', the measuring taps 7 of the partial discharge measurement unit 8 cannot be directly electrically connected to the current-carrying components in the corresponding line branches 6 and 6'.

[0046] For this purpose, the measuring tap 7 of the partial discharge measuring unit 8 is electrically connected to the capacitive cladding 9 of the corresponding line branch 6, 6' via an impedance 11 at a low voltage potential, particularly to the ungrounded component of line branch 6, 6', which is electrically coupled to the voltage-carrying conductor of line branch 6, 6' through the electric field of the voltage-carrying conductor. For example, the capacitive cladding 9, especially the component, can form a capacitor with the voltage-carrying conductor. Therefore, the component is capacitively coupled to the current-carrying conductor and is neither grounded nor electrically insulated. The component also does not carry current. For example, line branches 6, 6' can be constructed as tubular conductors with a charged inner conductor, wherein the component can be an ungrounded inner tube surrounding the current-carrying inner conductor and further electrically insulated relative to a grounded outer tube.

[0047] Therefore, the measuring tap 7 of the partial discharge measuring unit 8 is electrically connected to the capacitor. In particular, the capacitor, consisting of this component and the voltage-carrying conductor, is constructed as a high-voltage capacitor and is further configured to withstand high-voltage pulses. For example, capacitors insulated with oil paper should not be used.

[0048] Furthermore, a measurement circuit 10 is provided between the capacitor and the partial discharge measurement unit 8, particularly between the measurement tap 7 and the partial discharge measurement unit 8. This measurement circuit 10 is configured to attenuate the partial discharge from the capacitive coating 9, particularly the resulting voltage pulses 14 and / or current pulses 15, without altering the signal characteristics of the partial discharge, particularly the voltage pulses 14 and / or current pulses 15. This measurement circuit 10... Figure 3 The details are shown in more detail below.

[0049] Partial discharge measurement unit 8 is configured to measure partial discharge at the capacitive coating 9, particularly voltage pulses 14 and / or current pulses 15 at the voltage-carrying conductors of line branches 6 and 6', thereby recording the discharge arc 21 between the contacts 2 of the vacuum circuit breaker 3. Additionally, the partial discharge measurement unit and / or control device 16 can be configured to determine the presence of a discharge arc 21 when partial discharge, particularly voltage pulses 14 and / or current pulses 15, is measured or recorded by the partial discharge measurement unit 8. Furthermore, the partial discharge measurement unit 8 and / or control device 16 can also be configured to count the discharge arcs 21 and determine the discharge arc frequency as the number of discharge arcs 21 per unit time. N Additionally, the control device 16 can also be configured to adjust based on the number of discharge arcs 21. N , operating voltage U A and / or the spacing between contact 2 d Adjust to the set value, especially perform closed-loop adjustment. For this purpose, the partial discharge measurement unit 8 can be configured to transmit signals to the control device 16 via a data connection, the signals including the occurrence of the discharge arc 21 and / or the number of discharge arcs 21 per unit time. N .

[0050] Figure 3 A circuit diagram of the measurement circuit 10 located between the capacitive coating 9 and the partial discharge measurement unit 8 is shown. The partial discharge measurement unit 8 is electrically connected to the capacitive coatings 9 of the line branches 6 and 6' at the contacts 2 on both sides of the vacuum circuit breaker 3 via a plug 19 and a branch connection 20. Thus, the partial discharge measurement unit 8 measures voltage pulses 14 and / or current pulses 15 on the capacitive coatings 9 of each line branch 6 and 6' at the contacts 2 on both sides of the vacuum circuit breaker 3. Alternatively, the partial discharge measurement unit 8 can also be electrically connected to only one capacitive coating 9 on the line branch 6 or 6' via the measurement circuit 10, which is located between the operating voltage source 4 and the receiving device 5.

[0051] The measurement circuit 10 includes an impedance 11, an attenuator 12, and an optional frequency filter 13. The impedance 11 may include a resistor. Rand inductor L Conversely, attenuator 12 is configured to attenuate voltage pulse 14 and / or current pulse 15, and further maintain the signal shape of voltage pulse 14 and / or current pulse 15, or cause only relatively small distortion. Impedance 11 is electrically connected between attenuator 12 and capacitive cladding 9, particularly a capacitor. Furthermore, attenuator 12 and optional frequency filter 13 are electrically connected between impedance 11 and partial discharge measurement unit 8. Thus, while ensuring that the measurement signal is attenuated to produce only relatively small distortion, the partial discharge measurement unit 8 is protected from damage by voltage pulse 14 and / or current pulse 15.

[0052] The partial discharge measurement unit 8 and / or control device 16 can be configured to measure partial discharges from two line branches 6, 6', particularly voltage pulses 14 and / or current pulses 15, and further compare the corresponding measurements of the two line branches 6, 6' with each other for reasonable verification in order to record the discharge arc 21. For example, the discharge arc 21 can be detected when partial discharges, particularly voltage pulses 14 and / or current pulses 15, are measured in parallel at at least two input terminals.

[0053] Additionally, partial discharges at the input, particularly voltage pulse 14 and / or current pulse 15, can have the same amplitude and / or the same timestamp, or their amplitude difference and / or timestamp difference can be below a threshold.

[0054] The partial discharge measurement unit 8 and / or control device 16 are configured to record and count each recorded discharge arc 21, and to determine the discharge arc frequency as the number of discharge arcs 21 per unit time. N For example, the number of electric arcs per second.

[0055] Figure 4 A schematic method for controlling or regulating the molding system 1, performed by the partial discharge measurement unit 8 and / or control device 16, is shown.

[0056] In the first step S1, the partial discharge of the capacitive coating 9 and / or the capacitor is measured, especially the voltage pulse 14 and / or current pulse 15 relative to a reference potential.

[0057] In the second step S2, based on the measured partial discharge, particularly based on the measured voltage pulse 14 and / or the measured current pulse 15, and especially with the aid of the aforementioned measurement circuit 10, it is determined whether a discharge arc 21 exists between the contacts 2 of the vacuum circuit breaker 3. Additionally, the occurrence of the discharge arc 21 is also determined based on a plausibility check. This plausibility check can include amplitude comparison and / or timestamp comparison of the received measurement signals. For example, when partial discharge is measured at at least two input terminals of the partial discharge measurement unit 8, particularly voltage pulse 14 and / or current pulse 15, and their timestamps are the same and / or their amplitudes are the same, and / or the timestamp difference and / or amplitude difference between the input terminals of the partial discharge measurement unit 8 is less than a threshold, it can be determined that a discharge arc 21 exists.

[0058] In the third step S3, the counter containing the number of discharge arcs 21, especially the number of discharge arcs 21 per unit time, is used. N The counter is incremented, and the frequency of the discharge arc is determined as the number of discharge arcs 21 within that time unit. N In the fourth step S4, the deviation of the discharge arc frequency from the target frequency is determined.

[0059] In the fifth step S5, based on the aforementioned deviation, the operating voltage in the vacuum circuit breaker 3 is calculated. U A and / or the spacing between contact 2 d Adjust to the target operating voltage U soll and / or target spacing d soll The control and regulation signals are output to the working voltage source 4 and / or the housing device 5.

[0060] Where applicable, all individual features shown in the various embodiments may be combined with and / or substituted for one another without departing from the scope of the invention.

[0061] Reference number list

[0062] 1 Molding System

[0063] 2 contacts

[0064] 3 Circuit Breakers

[0065] 4. Working voltage source

[0066] 5. Containing device

[0067] d Spacing

[0068] 6. Branch lines

[0069] 7. Measuring taps

[0070] 8 Partial Discharge Measurement Unit

[0071] 9. Capacitive coating

[0072] 10 Measurement Circuit

[0073] 11 Impedance

[0074] 12 Attenuators

[0075] 13 Frequency Filter

[0076] 14 Voltage Pulse

[0077] 15 Current pulses

[0078] 16. Control device

[0079] 17 Transformers

[0080] 18 Damping resistor

[0081] 19 plugs

[0082] 20 Branch Connection Section

[0083] 21 Discharge Arc

[0084] N quantity

[0085] U A Operating voltage

[0086] t time

[0087] d spacing

[0088] U soll Target operating voltage

[0089] d soll Target Spacing

[0090] S1 First Step

[0091] S2 Second Step

[0092] S3 Third Step

[0093] S4 Fourth Step

[0094] S5 Fifth Step

Claims

1. A measuring circuit (10) for measuring voltage pulses (14) in the voltage-carrying conductor of a line branch (6, 6'), said line branch being configured to conduct high voltage, particularly from a working voltage source (4) to a vacuum circuit breaker (3), said measuring circuit comprising a partial discharge measuring unit (8) configured to measure voltage pulses (14) in the voltage-carrying conductor caused by a discharge arc (21) in said vacuum circuit breaker (3), characterized in that, The partial discharge measurement unit (8) is electrically connected to the capacitive coating (9) of the line branch (6, 6') via a resistor (11) at a low voltage potential.

2. The measurement circuit (10) according to claim 1, characterized in that, The capacitive cladding (9) includes components of the line branch (6, 6'), which are electrically coupled to the voltage carrier via the electric field of the voltage carrier, wherein the components are, in particular, electrically ungrounded.

3. The measurement circuit (10) according to any one of the preceding claims, characterized in that, The line branch (6, 6') is configured to be gas-isolated, wherein the component is particularly arranged in the gas-isolated region of the line branch (6, 6').

4. The measurement circuit (10) according to any one of the preceding claims, characterized in that, The component, in particular, utilizes the current-carrying conductor to form a capacitor.

5. The measurement circuit (10) according to claim 4, characterized in that, The capacitor is designed as a high-voltage capacitor, which is particularly suitable for high-frequency applications.

6. The measurement circuit (10) according to any one of the preceding claims, characterized in that, An attenuator (12) and / or a frequency filter (13), especially a high-pass filter or a band-pass filter, are electrically connected between the impedance (11) and the partial discharge measurement unit (8).

7. The measurement circuit (10) according to any one of the preceding claims, characterized in that, The partial discharge measurement unit (8) is configured to determine the presence of a discharge arc (21) between the contacts (2) of the vacuum circuit breaker (3) based on the measured voltage pulse (14).

8. A molding system (1), preferably insulated with an SF6 and / or SF6-N2 gas mixture or clean air gas, said molding system being particularly a high-voltage molding system, said molding system being used by means of a working voltage ( U A The discharge arc (21) between the contacts (2) of the vacuum circuit breaker (3) caused by the discharge arc (21) processes the surface of the electrical contacts (2) in the vacuum circuit breaker (3), and the forming system includes a measuring circuit (10) according to any one of claims 1 to 7.

9. A method for using a working voltage ( U A A method for processing the surface of the electrical contacts (2) in a vacuum circuit breaker (3) by using the discharge arc (21) between the contacts (2) of the vacuum circuit breaker (3) caused by the discharge arc (21). The operating voltage is provided by the operating voltage source (4). U A The operating voltage source is electrically connected to the receiving device (5) for the vacuum circuit breaker (3) via the line branch (6, 6') to electrically contact the contacts (2) of the vacuum circuit breaker (3), wherein, in order to count the discharge arc (21) in the vacuum circuit breaker (3), the voltage pulse (14) in the voltage carrier conductor of the line branch (6, 6') is measured by means of a partial discharge measuring unit (8), characterized in that the partial discharge measuring unit (8) is electrically connected to the capacitive coating (9) of the line branch (6, 6') via a resistor (11) at a low voltage potential.

10. The method according to claim 9, characterized in that, The capacitive cladding (9) includes components of the line branch (6, 6'), which are electrically coupled to the voltage carrier via the electric field of the voltage carrier, wherein the components are, in particular, electrically ungrounded.

11. The method according to claim 9 or 10, characterized in that, The line branch (6, 6') is configured to be gas-isolated, wherein the component is particularly arranged in the gas-isolated region of the line branch (6, 6').

12. The method according to any one of claims 9 to 11, characterized in that, The component, in particular, utilizes the current-carrying conductor to form a capacitor.

13. The method according to any one of claims 9 to 12, characterized in that, The capacitor is designed as a high-voltage capacitor, which is particularly suitable for high-frequency applications.

14. The method according to any one of claims 9 to 13, characterized in that, An attenuator (12) and / or a frequency filter (13), especially a high-pass filter or a band-pass filter, are electrically connected between the impedance (11) and the partial discharge measurement unit (8).

15. The method according to any one of claims 9 to 14, characterized in that, The presence of a discharge arc (21) between the contacts (2) of the vacuum circuit breaker (3) is determined based on the voltage pulse (14) measured by the partial discharge measurement unit (8).

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