Broadband current and voltage sensor

Abstract

The invention relates to a broadband current and voltage sensor. The broadband current and voltage sensor comprises a sensing module, a signal isolation module and a signal collection module. The sensing module is connected with three phases of the power distribution network and is used for detecting a broadband current signal and a broadband voltage signal of the power distribution network; the input end of the signal isolation module is connected with the output end of the sensing module, and the signal isolation module is used for isolating the primary side and the secondary side of the broadband current signal and the broadband voltage signal; and the input end of the signal collection module is connected with the output end of the signal isolation module, and the signal collection module is used for transmitting the broadband current signal and the broadband voltage signal to a power distribution terminal. The sensor can be matched with a primary and secondary fusion circuit breaker, is high in anti-interference capability, and achieves the high-precision collection of signals of a power distribution network.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a broadband current and voltage sensor. Background Art

[0002] The fault location technology of the distribution network and the line insulation status detection technology are effective means to improve the power supply reliability management level. In the process of signal acquisition, the primary and secondary fusion pole-mounted circuit breakers widely use electronic current and voltage sensors for signal acquisition, converting the primary side voltage and current signals into analog signals that can be directly processed and analyzed by the secondary equipment, which is the development trend of digitalization, miniaturization and intelligence of new distribution equipment.

[0003] However, the traditional positioning and detection technology has poor high-frequency response characteristics and poor high-frequency signal acquisition accuracy. At the same time, the sensor's small signal acquisition accuracy is easily interfered with and has weak anti-interference ability, which cannot meet the requirements for accurate acquisition of high-frequency weak signals. Summary of the invention

[0004] Based on this, it is necessary to provide a high-precision wide-band current and voltage sensor that can be adapted to primary and secondary fusion circuit breakers.

[0005] In a first aspect, the present application provides a broadband current and voltage sensor, comprising:

[0006] A sensor module is connected to the three phases of the distribution network and is used to detect broadband current signals and broadband voltage signals of the distribution network;

[0007] A signal isolation module, the input end of the signal isolation module is connected to the output end of the sensor module, and is used to isolate the primary side and the secondary side of the broadband current signal and the broadband voltage signal;

[0008] A signal collection module, the input end of the signal collection module is connected to the output end of the signal isolation module, and is used to transmit the broadband current signal and the broadband voltage signal to the power distribution terminal.

[0009] In one embodiment, the sensor module includes:

[0010] A current measuring unit, the output end of which is connected to the input end of the signal isolation module, and is used to adjust the internal structure and electrical parameters of the current measuring unit to detect the broadband current signal of the power distribution network;

[0011] A voltage measuring unit, the output end of which is connected to the input end of the signal isolation module, is used to adjust the electromagnetic parameters of the voltage measuring unit to detect the broadband voltage signal of the distribution network.

[0012] In one of the embodiments, the current measurement unit is also used to obtain a first transfer function of the primary and secondary side signals of the distribution network; based on the first transfer function, the first amplitude-frequency characteristic and the first phase-frequency characteristic of the primary and secondary side signals are calculated; based on the first amplitude-frequency characteristic and the first phase-frequency characteristic, a numerical solution model of the current measurement unit is established; based on the numerical solution model of the current measurement unit, electrical optimization parameters are obtained; based on the electrical optimization parameters, the internal structure and electrical parameters of the current measurement unit are adjusted to obtain a wideband current signal.

[0013] In one of the embodiments, the voltage measurement unit is also used to obtain a second transfer function of the primary and secondary side signals of the distribution network; based on the second transfer function, the second amplitude-frequency characteristic and the second phase-frequency characteristic of the primary and secondary side signals are calculated; based on the second amplitude-frequency characteristic and the second phase-frequency characteristic, a numerical solution model of the voltage measurement unit is established; based on the numerical solution model of the voltage measurement unit, electromagnetic optimization parameters are obtained; based on the electromagnetic optimization parameters, the electromagnetic parameters of the voltage measurement unit are adjusted to obtain a wide-band voltage signal.

[0014] In one embodiment, the current measuring unit comprises:

[0015] An induction coil, used to convert the current on the primary side of the induction coil into an output voltage on the secondary side of the induction coil;

[0016] The first resistor is connected in parallel with the induction coil and is used to convert the output voltage of the secondary side of the induction coil into a broadband current signal.

[0017] In one of the embodiments, the voltage measuring unit comprises:

[0018] A first capacitor, the first capacitor is a voltage transformer equivalent capacitor;

[0019] The RC voltage divider structure includes a second capacitor and a second resistor. The second resistor is connected in parallel with the second capacitor. The RC voltage divider structure is connected in series with the first capacitor and is used to reduce the voltage of a broadband voltage signal for measurement.

[0020] In one embodiment, the signal isolation module includes:

[0021] A current isolation unit, used to isolate the primary side from the secondary side of the broadband current signal;

[0022] The voltage isolation unit is used to isolate the primary side from the secondary side of the broadband voltage signal.

[0023] In one embodiment, the current isolation unit includes a phase a current isolation transformer, a phase b current isolation transformer, a phase c current isolation transformer, a zero-sequence current isolation transformer, and a sampling resistor corresponding to each current isolation transformer;

[0024] The primary side of each current isolation transformer is connected to the input end of the sensor module, and the secondary side of each current isolation transformer is connected to the input end of the signal collection module, so as to isolate the three-phase input current of the primary side from the current output signal of the secondary side.

[0025] In one of the embodiments, the voltage isolation unit includes a phase a voltage isolation transformer, a phase b voltage isolation transformer, and a phase c voltage isolation transformer;

[0026] The primary side of each voltage isolation transformer is connected to the output end of the sensor module, and the secondary side of each voltage isolation transformer is connected to the input end of the signal collection module, which is used to isolate the three-phase input voltage on the primary side from the three-phase voltage signal and zero-sequence voltage signal on the secondary side.

[0027] In one embodiment, the signal collection module includes:

[0028] The current signal input terminal is connected to the fully shielded aviation plug interface and is used to collect the broadband current signal to the fully shielded aviation plug interface by differential transmission;

[0029] The voltage signal input terminal is connected to the fully shielded aviation plug interface and is used to collect the broadband voltage signal to the fully shielded aviation plug interface by differential transmission;

[0030] The fully shielded aviation plug interface is connected to the power distribution terminal to shield interference signals and transmit broadband current signals and broadband voltage signals to the power distribution terminal.

[0031] In a second aspect, the present application provides a control method for a broadband current and voltage sensor, which is used to control the broadband current and voltage sensor in any of the above embodiments.

[0032] In a third aspect, the present application provides a broadband current and voltage sensor system, comprising the broadband current and voltage sensor in any of the above embodiments.

[0033] This application proposes a high-precision broadband current and voltage sensor that can be adapted to a primary and secondary integrated circuit breaker. The broadband voltage and current signals of the distribution network are obtained through a sensing module, and the broadband voltage and current signals are transmitted to the distribution terminal through a signal collection module, so as to realize high-precision acquisition of the power frequency current, power frequency voltage, high-frequency current, and high-frequency voltage signals of the distribution network, and provide high-precision data support for intelligent operation and maintenance in multiple scenarios such as fault traveling wave positioning, line insulation detection, and high-resistance fault detection in the distribution network. At the same time, the broadband current and voltage sensor of this application isolates the primary side from the secondary side through a built-in signal isolation module, which can reduce the interference of the primary side line induced electromagnetic field and the external stray magnetic field on the secondary side signal acquisition, improve the sensor's anti-interference ability, and ensure the measurement accuracy of power frequency and high-frequency small signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 A module structure of a broadband current and voltage sensor according to an embodiment;

[0036] Figure 2 for Figure 1 A module structure of the sensor module 100;

[0037] Figure 3 for Figure 1 A module structure of the signal isolation module 200;

[0038] Figure 4 for Figure 3 A module structure of the current isolation unit 210;

[0039] Figure 5 for Figure 3 A module structure of the medium voltage isolation unit 220;

[0040] Figure 6 for Figure 1 A module structure of the signal collection module 300.

[0041] Description of reference numerals:

[0042] 100, sensing module; 110, current measuring unit; 120, voltage measuring unit; 200, signal isolation module; 210, current signal isolation unit; 211, a-phase current isolation transformer; 212, b-phase current isolation transformer; 213, c-phase current isolation transformer; 214, zero-sequence current isolation transformer; 220, voltage signal isolation unit; 221, a-phase voltage isolation transformer; 222, b-phase voltage isolation transformer; 223, c-phase voltage isolation transformer; 300, signal collection module; 310, current signal input terminal; 320, voltage signal input terminal; 330, fully shielded aviation plug interface; L, induction coil; R1, first resistor; R2, second resistor; C1, first capacitor; C2, second capacitor; Ra, sampling resistor; Rb, sampling resistor; Rc, sampling resistor; Rd, sampling resistor. DETAILED DESCRIPTION

[0043] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0046] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0047] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0048] Broadband voltage and current signals refer to voltage or current signals with a wide frequency band within a certain frequency range, and are usually used in the fields of communication, radar, wireless transmission, signal processing, and test and measurement. In the distribution network signal acquisition method, the primary and secondary fusion pole-mounted circuit breakers widely use electronic voltage sensors and electronic current sensors to collect distribution network voltage and current signals. The primary side voltage and current signals are converted into analog signals that can be directly processed and analyzed by secondary equipment through capacitive voltage divider sensing units and weak-feed coils. This is a trend in the development of digitalization, miniaturization, and intelligence of new distribution equipment.

[0049] The fault traveling wave location technology of the distribution network and the line insulation status detection technology are effective means to improve the power supply reliability management level. However, due to the sampling frequency band limitation, the high-frequency response characteristics of the electronic sensors used in conjunction with the primary and secondary fusion pole-mounted circuit breakers of the traditional technology are not good, and the high-frequency signals such as fault traveling waves and line hidden dangers are poorly collected, and cannot provide multi-dimensional high-precision data support for fault location and line insulation detection scenarios. At the same time, the small signal acquisition accuracy of traditional current and voltage sensors is easily affected by the induced electromagnetic field on the high-voltage side and the external stray magnetic field, and the anti-interference ability is weak, which cannot meet the requirements for accurate collection of high-frequency weak signals in the high-resistance grounding scenario of the distribution network line.

[0050] Therefore, the present application proposes a broadband current and voltage sensor to solve the above problems.

[0051] In an exemplary embodiment, Figure 1 As shown, a broadband current and voltage sensor is provided, including a sensing module 100 , a signal isolation module 200 and a signal collection module 300 .

[0052] The sensor module 100 is connected to the three phases of the power distribution network and is used to detect the broadband current signal and broadband voltage signal of the power distribution network.

[0053] The signal isolation module 200 has an input end connected to the output end of the sensor module and is used to isolate the primary side and the secondary side of the broadband current signal and the broadband voltage signal.

[0054] The signal collection module 300 has an input end connected to an output end of the signal isolation module, and is used to transmit a broadband current signal and a broadband voltage signal to a power distribution terminal.

[0055] Exemplarily, the input end of the sensor module 100 is connected to the three phases a, b, and c of the power distribution network, and is used to collect and detect the broadband current signal and broadband voltage signal of the power distribution network.

[0056] Exemplarily, the input end of the isolation module 200 is connected to the output end signal of the sensor module 100, isolating the primary side and secondary side of the broadband current signal and broadband voltage signal to improve the acquisition and measurement accuracy. The primary side is the high-voltage side signal of the broadband current and voltage signal, and the secondary side is the broadband current and voltage signal to be measured after the voltage reduction process.

[0057] Exemplarily, the input end of the signal collection module 300 is connected to the output end of the signal isolation module 200, and the output end of the signal collection module 300 is connected to the distribution terminal through a fully shielded cable to transmit the broadband current and voltage signal to the distribution terminal for subsequent processing.

[0058] The above-mentioned broadband current and voltage sensor obtains the broadband current and voltage signal of the distribution network through the sensing module, and transmits the broadband current and voltage signal to the distribution terminal through the signal collection module, so as to realize high-precision collection of the current and voltage signal of the distribution network, and provide high-precision data support for intelligent operation and maintenance of multiple scenarios such as fault traveling wave positioning of the distribution network, line insulation detection, and high-resistance fault detection. At the same time, the broadband current and voltage sensor of the present application isolates the primary side from the secondary side of the broadband current and voltage sensor through a built-in signal isolation module, thereby improving the anti-interference ability of the current and voltage sensor and ensuring the measurement accuracy of the broadband current and voltage signal.

[0059] The following is a detailed introduction to the solution of the present application for realizing broadband current and voltage acquisition and measurement.

[0060] In an exemplary embodiment, Figure 2 As shown, the sensing module 100 includes a current measuring unit 110 and a voltage measuring unit 120 .

[0061] The current measuring unit 110 has an output end connected to an input end of the signal isolation module 200 and is used to adjust the internal structure and electrical parameters of the current measuring unit 110 to detect a broadband current signal of the power distribution network.

[0062] The voltage measuring unit 120 has an output end connected to an input end of the signal isolation module 200 and is used to adjust the electromagnetic parameters of the voltage measuring unit 120 to detect the broadband voltage signal of the power distribution network.

[0063] Exemplarily, the current measuring unit 110 can realize the measurement of industrial frequency current and 1MHz high-frequency current signal by adjusting and optimizing the internal structure and electrical parameters of the current measuring unit 110, and the broadband current signal output (i.e., the output end of the current measuring unit 110) is connected to the input terminals S1 and S2 of the signal isolation module 200.

[0064] Exemplarily, by adjusting and optimizing the internal electromagnetic parameters of the voltage measurement unit 120 , the power frequency voltage and 1 MHz high-frequency voltage signal measurement can be achieved, and the broadband voltage signal output (i.e., the output end of the voltage measurement unit 120 ) is connected to the S3 and S4 terminals of the signal isolation module 200 input end.

[0065] In an exemplary embodiment, Figure 2 As shown, the current measuring unit 110 includes an induction coil L and a first resistor R1.

[0066] The induction coil L is used to convert the current on the primary side of the induction coil L into an output voltage on the secondary side of the induction coil L.

[0067] The first resistor R1 is connected in parallel with the induction coil L, and is used for converting the output voltage of the secondary side of the induction coil L into a broadband current signal.

[0068] Exemplarily, the induction coil L may be a weakly-fed induction coil, and the first resistor R1 may be a sampling resistor. The current measurement unit 110 is composed of a weakly-fed induction coil and a sampling resistor connected in parallel to the secondary side of the weakly-fed induction coil.

[0069] Among them, the weakly fed induction coil is the core component of the current measurement unit, and its function is to convert the current of the distribution network into a corresponding magnetic field. When the current passes through the weakly fed induction coil, a magnetic field is generated, and the strength of the magnetic field is proportional to the magnitude of the current. The weakly fed induction coil has a smaller number of turns and a larger cross-sectional area so that a larger magnetic field can be generated under a smaller current. The output voltage on the secondary side of the weakly fed induction coil is proportional to the strength of the magnetic field, so the current in the circuit can be indirectly measured by measuring the output voltage on the secondary side of the coil.

[0070] The sampling resistor is a resistor connected in parallel to the secondary side of the weak-feed induction coil. Its function is to convert the output voltage of the secondary side of the coil into a current signal. When the output voltage of the secondary side of the coil acts on the sampling resistor, a current signal proportional to the output voltage is generated for subsequent current measurement and processing.

[0071] In an exemplary embodiment, Figure 2 As shown, the voltage measurement unit 120 includes a first capacitor C1 and a resistor-capacitor voltage-dividing structure, and the resistor-capacitor voltage-dividing structure includes a second capacitor C2 and a second resistor R2.

[0072] The first capacitor C1 is a voltage transformer equivalent capacitor.

[0073] The RC voltage divider structure includes a second capacitor C2 and a second resistor R2. The second resistor R2 is connected in parallel with the second capacitor C2. The RC voltage divider structure is connected in series with the first capacitor C1 to reduce the voltage of the broadband voltage signal for measurement.

[0074] Among them, the first capacitor C1 is the equivalent capacitor of the voltage transformer, and the resistor-capacitor voltage divider structure is used to further reduce the voltage output by the voltage transformer to make it suitable for subsequent measurement or protection equipment. The voltage divider composed of the second resistor R2 and the second capacitor C2 can reduce the voltage according to a specific ratio, and the second capacitor C2 can also play a filtering role to reduce high-frequency signal interference.

[0075] The above-mentioned current measurement unit 110 and voltage measurement unit 120 collect and measure broadband current signals through the induction coil and the first resistor, and collect and measure broadband current signals through the resistor-capacitor voltage divider structure and the first capacitor, thereby realizing high-precision collection of power frequency current, power frequency voltage, high-frequency current, and high-frequency voltage signals of the distribution network.

[0076] In an exemplary embodiment, the current measurement unit 110 is also used to obtain a first transfer function of the primary and secondary side signals of the distribution network; based on the first transfer function, the first amplitude-frequency characteristic and the first phase-frequency characteristic of the primary and secondary side signals are calculated; based on the first amplitude-frequency characteristic and the first phase-frequency characteristic, a numerical solution model of the current measurement unit is established; based on the numerical solution model of the current measurement unit, electrical optimization parameters are obtained; based on the electrical optimization parameters, the internal structure and electrical parameters of the current measurement unit are adjusted to obtain a wideband current signal.

[0077] Exemplarily, based on the principle analysis of the current measurement unit circuit diagram, the transfer function of the primary and secondary signals is obtained.

[0078]

[0079] in, Indicates mutual induction; Indicates the internal resistance of the induction coil; represents the self-inductance of the induction coil; is the equivalent capacitance of the induction coil; is the resistance value of the first resistor R1; s is the variable of Laplace transformation.

[0080] make The function expressions of the amplitude-frequency characteristic and the phase-frequency characteristic of the current measurement unit are calculated according to the transfer function.

[0081] Where j is an imaginary number and ω is the angular frequency.

[0082] The amplitude-frequency characteristic is:

[0083]

[0084] The phase-frequency characteristic is:

[0085]

[0086]

[0087] A numerical solution model of the current measurement unit is established according to the amplitude-frequency characteristic and phase-frequency characteristic function to solve the electromagnetic optimization parameters that take into account both industrial frequency and 1MHz high-frequency acquisition.

[0088] The internal structure and electromagnetic parameters of the sensor are adjusted according to the electromagnetic optimization parameters to achieve accurate acquisition of industrial frequency and high-frequency signals.

[0089] In an exemplary embodiment, the voltage measurement unit 120 is also used to obtain a second transfer function of the primary and secondary side signals of the distribution network; based on the second transfer function, the second amplitude-frequency characteristic and the second phase-frequency characteristic of the primary and secondary side signals are calculated; based on the second amplitude-frequency characteristic and the second phase-frequency characteristic, a numerical solution model of the voltage measurement unit is established; based on the numerical solution model of the voltage measurement unit, electromagnetic optimization parameters are obtained; based on the electromagnetic optimization parameters, the electromagnetic parameters of the voltage measurement unit are adjusted to obtain a wide-band voltage signal.

[0090] Exemplarily, based on the principle analysis of the voltage measurement unit circuit diagram, the transfer function of the primary and secondary signals is obtained.

[0091]

[0092] in, is the voltage transformer equivalent capacitance, i.e. the first capacitor C1, is the second capacitor C2 in the RC voltage divider structure, is the resistance value of the second resistor R2.

[0093] make The amplitude-frequency characteristic and phase-frequency characteristic function expressions of the voltage sensing unit are calculated according to the transfer function.

[0094] The amplitude-frequency characteristic is:

[0095]

[0096] The phase-frequency characteristic is:

[0098]

[0099] A numerical solution model of the voltage measurement unit is established according to the amplitude-frequency characteristic and phase-frequency characteristic function to solve the electromagnetic optimization parameters that take into account both industrial frequency and 1Mhz high-frequency sampling.

[0100] The sensor structure and electromagnetic parameters are adjusted according to the electromagnetic optimization parameters to achieve accurate acquisition of industrial frequency and high-frequency signals.

[0101] The above embodiment provides the optimization process of the electrical parameters and electromagnetic parameters of the current / voltage measurement unit, establishes a numerical solution model of the current / voltage measurement unit according to the amplitude-frequency characteristic and phase-frequency characteristic function, solves the electrical / electromagnetic optimization parameters that take into account both power frequency and high-frequency sampling, and realizes high-precision acquisition and measurement of power frequency current, power frequency voltage, high-frequency current, and high-frequency voltage signals of the distribution network.

[0102] The following describes the solution for implementing signal isolation and anti-interference in this application.

[0103] In an exemplary embodiment, Figure 3As shown, the signal isolation module 200 includes a current isolation unit 210 and a voltage isolation unit 220 .

[0104] The current isolation unit 210 is used to isolate the primary side and the secondary side of the broadband current signal.

[0105] The voltage isolation unit 220 is used to isolate the primary side and the secondary side of the broadband voltage signal.

[0106] Exemplarily, the signal isolation unit 200, which is composed of a current signal isolation unit 210 and a voltage signal isolation unit 220, isolates the primary side and the secondary side of the broadband current signal and the broadband voltage signal, reduces the interference of the primary side induced electromagnetic field and the external stray magnetic field on the secondary side signal, improves the sensor's anti-interference ability, and ensures the measurement accuracy of industrial frequency and high-frequency small signals.

[0107] In an exemplary embodiment, Figure 4 As shown, the current isolation unit 210 includes a phase a current isolation transformer 211, a phase b current isolation transformer 212, a phase c current isolation transformer 213, a zero-sequence current isolation transformer 214, and sampling resistors Ra, Rb, Rc, and Rd corresponding to each current isolation transformer;

[0108] The primary side of each current isolation transformer is connected to the input end of the sensor module, and the secondary side of each current isolation transformer is connected to the input end of the signal collection module 300, so as to isolate the three-phase input current of the primary side from the current output signal of the secondary side.

[0109] Exemplarily, the primary side of each of the above-mentioned isolation transformers is respectively connected to the a-phase, b-phase, c-phase, and zero-sequence terminals of the current measurement unit 110, and the secondary side is connected to the signal collection module 300 through the aS, bS, cS, and dS output terminals (including aS1, aS2, bS1, bS2, cS1, cS2, dS1, and dS2) corresponding to each isolation transformer. The connection method is as follows: Figure 4 As shown, the primary three-phase line current input is isolated from the secondary small signal output to reduce the interference of the primary line induced electromagnetic field on the secondary signal. Among them, the grounding of the primary side of each isolation transformer can reduce the interference of the coil induced voltage on signal acquisition, and output differential signals on the secondary side to reduce the interference of stray electromagnetic fields on signal transmission, thereby improving the anti-interference ability and acquisition accuracy of the current sensor small signal acquisition.

[0110] In an exemplary embodiment, Figure 5 As shown, the voltage isolation unit 220 includes a phase a voltage isolation transformer 221, a phase b voltage isolation transformer 222, and a phase c voltage isolation transformer 223;

[0111] The primary side of each voltage isolation transformer is connected to the output end of the sensor module, and the secondary side of each voltage isolation transformer is connected to the input end of the signal collection module 300, which is used to isolate the three-phase input voltage on the primary side from the three-phase voltage signal and zero-sequence voltage signal on the secondary side.

[0112] Exemplarily, the primary side of each voltage isolation transformer is connected to the a-phase, b-phase, and c-phase outputs of the voltage measurement unit 120, respectively, and the secondary side of each voltage isolation transformer is connected to the signal collection module through the aS, bS, cS, and dS output terminals (including aS3, aS4, bS3, bS4, cS3, cS4, dS3, and dS4). The connection method is as follows: Figure 5 As shown. The secondary side of each isolation transformer consists of two groups of output windings, one group outputs three-phase voltage signals, and the other group is connected into an open triangle to generate a zero-sequence voltage signal. The isolation transformer isolates the primary side three-phase voltage input from the secondary side phase voltage and zero-sequence voltage signal output. At the same time, the primary side is grounded to reduce the interference caused by the coil induced voltage, and the voltage signal is differentially transmitted to reduce the interference of stray electromagnetic fields on small signal transmission, which can effectively improve the voltage sensor's small signal acquisition anti-interference ability and acquisition accuracy.

[0113] like Figure 6 As shown, the signal collection module 300 includes a current signal input terminal 310 , a voltage signal input terminal 320 and a fully shielded aviation plug interface 330 .

[0114] The current signal input terminal 310 is connected to the fully shielded aviation plug interface and is used to collect the broadband current signal to the fully shielded aviation plug interface through differential transmission.

[0115] The voltage signal input terminal 320 is connected to the fully shielded aviation plug interface and is used to collect the broadband voltage signal to the fully shielded aviation plug interface through differential transmission.

[0116] The fully shielded aviation plug interface 330 is connected to the power distribution terminal to shield interference signals and transmit broadband current signals and broadband voltage signals to the power distribution terminal.

[0117] Among them, the fully shielded aviation plug interface 330 has a fully shielded design, which can effectively prevent electromagnetic interference and radio frequency interference, and ensure the stability and reliability of signal transmission.

[0118] Differential transmission is a signal transmission method that uses two signal lines to transmit signals, one of which transmits the positive value of the signal and the other transmits the negative value of the signal, which can improve the signal's anti-interference ability and transmission distance. In differential transmission, the two signal lines are placed closely in parallel so that they are subject to the same electromagnetic interference during transmission. Since the signals on the two signal lines are opposite, any external interference will affect the two signal lines at the same time, but because their signals are opposite, the interference can be offset at the receiving end.

[0119] Exemplarily, the current signal input terminal 310 and the voltage signal input terminal 320 collect the broadband current signal and the broadband voltage signal to the fully shielded aviation socket 330. The broadband current signal and the broadband voltage signal are transmitted using 4 pairs of two-twisted shielded wires for differential transmission, and the voltage and current signals are transmitted to the power distribution terminal for subsequent processing. The shielded wire adopts a double shielding layer design of aluminum foil + copper braided layer and is single-ended grounded, which can reduce external electromagnetic interference during signal transmission and improve the accuracy of small signal acquisition.

[0120] It can be understood that the above-mentioned broadband current and voltage sensor can also adopt other forms, and is not limited to the forms mentioned in the above embodiments, as long as it can achieve the function of completing the high-precision acquisition and measurement of broadband signals.

[0121] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0122] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A broadband current and voltage sensor, characterized in that: include: A sensor module connected to the three phases of the distribution network and used to detect a broadband current signal and a broadband voltage signal of the distribution network; A signal isolation module, the input end of which is connected to the output end of the sensor module, and is used to isolate the primary side and the secondary side of the broadband current signal and the broadband voltage signal; A signal collection module, the input end of which is connected to the output end of the signal isolation module, is used to transmit the broadband current signal and the broadband voltage signal to the power distribution terminal.

2. The broadband current and voltage sensor according to claim 1, characterized in that: The sensor module comprises: A current measuring unit, the output end of which is connected to the input end of the signal isolation module, and is used to adjust the internal structure and electrical parameters of the current measuring unit to detect the broadband current signal of the power distribution network; A voltage measuring unit, the output end of which is connected to the input end of the signal isolation module, is used to adjust the electromagnetic parameters of the voltage measuring unit to detect the broadband voltage signal of the power distribution network.

3. The broadband current and voltage sensor according to claim 2, characterized in that: The current measurement unit is also used to obtain a first transfer function of the primary and secondary side signals of the distribution network; based on the first transfer function, calculate the first amplitude-frequency characteristic and the first phase-frequency characteristic of the primary and secondary side signals; establish a numerical solution model of the current measurement unit based on the first amplitude-frequency characteristic and the first phase-frequency characteristic; obtain electrical optimization parameters based on the numerical solution model of the current measurement unit; and adjust the internal structure and electrical parameters of the current measurement unit based on the electrical optimization parameters to obtain the broadband current signal.

4. The broadband current and voltage sensor according to claim 2, characterized in that: The voltage measurement unit is also used to obtain the second transfer function of the primary and secondary side signals of the distribution network; according to the second transfer function, the second amplitude-frequency characteristic and the second phase-frequency characteristic of the primary and secondary side signals are calculated; according to the second amplitude-frequency characteristic and the second phase-frequency characteristic, a numerical solution model of the voltage measurement unit is established; according to the numerical solution model of the voltage measurement unit, electromagnetic optimization parameters are obtained; according to the electromagnetic optimization parameters, the electromagnetic parameters of the voltage measurement unit are adjusted to obtain the wide-band voltage signal.

5. The broadband current and voltage sensor according to claim 2, characterized in that: The current measuring unit comprises: An induction coil, used to convert the current on the primary side of the induction coil into an output voltage on the secondary side of the induction coil; The first resistor is connected in parallel with the induction coil and is used to convert the output voltage of the secondary side of the induction coil into the broadband current signal.

6. The broadband current and voltage sensor according to claim 2, characterized in that: The voltage measuring unit comprises: A first capacitor, wherein the first capacitor is a voltage transformer equivalent capacitor; The RC voltage divider structure includes a second capacitor and a second resistor, wherein the second resistor is connected in parallel with the second capacitor and the RC voltage divider structure is connected in series with the first capacitor, and is used to reduce the voltage of the broadband voltage signal for measurement.

7. The broadband current and voltage sensor according to claim 1, characterized in that: The signal isolation module comprises: A current isolation unit, used to isolate the primary side from the secondary side of the broadband current signal; The voltage isolation unit is used to isolate the primary side and the secondary side of the broadband voltage signal.

8. The broadband current and voltage sensor according to claim 7, characterized in that: The current isolation unit includes a phase a current isolation transformer, a phase b current isolation transformer, a phase c current isolation transformer, a zero-sequence current isolation transformer, and sampling resistors corresponding to each current isolation transformer; The primary side of each current isolation transformer is connected to the input end of the sensor module, and the secondary side of each current isolation transformer is connected to the input end of the signal collection module, so as to isolate the three-phase input current of the primary side from the current output signal of the secondary side.

9. The broadband current and voltage sensor according to claim 7, characterized in that: The voltage isolation unit includes a phase a voltage isolation transformer, a phase b voltage isolation transformer, and a phase c voltage isolation transformer; The primary side of each voltage isolation transformer is connected to the output end of the sensor module, and the secondary side of each voltage isolation transformer is connected to the input end of the signal collection module, so as to isolate the three-phase input voltage on the primary side from the three-phase voltage signal and zero-sequence voltage signal on the secondary side.

10. The broadband current and voltage sensor according to claim 1, characterized in that: The signal collection module comprises: The current signal input terminal is connected to the fully shielded aviation plug interface and is used to collect the broadband current signal to the fully shielded aviation plug interface by differential transmission; A voltage signal input terminal connected to the fully shielded aviation plug interface, and used to collect the broadband voltage signal to the fully shielded aviation plug interface by differential transmission; A fully shielded aviation plug interface is connected to the power distribution terminal to shield interference signals and transmit the broadband current signal and the broadband voltage signal to the power distribution terminal.

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