A non-contact current and voltage combined sensor and temperature compensation system

Abstract

The present application relates to the technical field of power transformers, and in particular to a contactless current and voltage combination sensor and a temperature compensation system, wherein the combination sensor comprises a current sensor, a voltage sensor, a signal processing circuit, a control circuit, a temperature measurement circuit and a self-test circuit; the control circuit is connected to the self-test circuit, the signal processing circuit and the temperature measurement circuit, obtains a temperature signal output by the temperature measurement circuit when the self-test circuit is started, and generates a compensation value based on the temperature signal, a standard signal and a self-test signal fed back by the signal processing circuit, and the control circuit compensates the output value of the combination sensor based on the compensation value; the standard signal is a standard current and a standard voltage obtained when the self-test wire is energized, and the self-test signal comprises a current self-test signal monitored by a corresponding current sensor and a voltage self-test signal monitored by a corresponding voltage sensor when the self-test circuit is started.

Description

Technical Field

[0001] The present application relates to the technical field of power transformers, and in particular to a contactless current and voltage combination sensor and a temperature compensation system. Background Art

[0002] Power sensor is a common electrical component that plays the role of electric energy metering in power systems. The measurement accuracy and reliability of power sensors are closely related to the safety and economy of power systems.

[0003] In the related art, power sensors mainly include current sensors and voltage sensors, which detect the current and voltage in the circuit respectively, and are independent sensors. At the same time, due to the different wiring methods of current sensors and voltage sensors, current sensors and voltage sensors also need to be detected separately during use.

[0004] The utility model patent with publication number CN221378143U discloses a non-contact self-calibration current and voltage integrated sensor, including a current sensor, a voltage sensor and a signal processing device. The current sensor includes a ring-shaped iron core coil, which is nested in a shielding shell and connected to the signal processing circuit. The voltage sensor includes a ring-shaped capacitive screen, which is connected to the signal processing circuit, and the signal processing circuit is connected to the self-calibration combined metering unit.

[0005] Although the above utility model patent discloses a technical solution of combining a current sensor and a voltage sensor into an integrated sensor, the combination of the current sensor and the voltage sensor causes temperature interference between the current sensor and the voltage sensor. For example, the temperature generated by the conductive coil of the current sensor affects the capacitive screen of the voltage sensor, thereby causing the temperature compensation of the combined sensor to have errors compared to the actual temperature influence. Summary of the invention

[0006] The purpose of the present application is to provide a non-contact current-voltage combined sensor and a temperature compensation system to improve the measurement accuracy of the combined sensor.

[0007] The above application objectives of this application are achieved through the following technical solutions:

[0008] In a first aspect, the present application provides a non-contact current-voltage combination sensor that adopts the following technical solution.

[0009] A non-contact current and voltage combination sensor, the combination sensor comprising a current sensor, a voltage sensor, a signal processing circuit, a control circuit, a temperature measurement circuit and a self-test circuit;

[0010] The current sensor comprises a ring-shaped iron core coil, which is nested in a shielding shell and connected to a signal processing circuit;

[0011] The voltage sensor comprises a capacitor ring, which is fixed to the inner hole wall of the shielding shell and connected to the signal processing circuit;

[0012] A temperature measuring circuit, used for detecting the temperature of the combined sensor;

[0013] The signal processing circuit is connected to the voltage sensor and the current sensor, and transmits the monitoring signals of the voltage sensor and the current sensor to the control circuit;

[0014] A self-test circuit includes a self-test wire and a standard power supply connected to the self-test wire, wherein the self-test wire passes through an inner hole of the shielding shell;

[0015] a control circuit connected to the self-checking circuit, the signal processing circuit and the temperature measuring circuit, obtaining a temperature signal output by the temperature measuring circuit when the self-checking circuit is started, and generating a compensation value according to the temperature signal, the standard signal and the self-checking signal fed back by the signal processing circuit, and the control circuit compensates the output value of the combined sensor according to the compensation value;

[0016] The standard signal is the standard current and standard voltage obtained when the self-test wire is energized. The self-test signal includes a current self-test signal monitored by a corresponding current sensor and a voltage self-test signal monitored by a corresponding voltage sensor when the self-test circuit is started.

[0017] In a preferred embodiment, the standard power supply includes a self-test power supply and a self-test coil, and the self-test coil is nested in a shielding shell and is used to charge the self-test power supply.

[0018] In a preferred embodiment, the temperature measurement circuit includes a temperature detection circuit and a temperature calibration circuit. The temperature detection circuit is connected to the control circuit via the temperature calibration circuit. The temperature calibration circuit calibrates the temperature detection signal output by the temperature detection circuit according to the temperature calibration value fed back by the control circuit and then outputs the temperature signal.

[0019] In a preferred embodiment, the control circuit determines the weight ratio of the compensation value and the temperature calibration value based on the temperature range of the temperature signal measured when the self-test circuit is started, and generates the compensation value and the temperature calibration value based on the weight ratio, the temperature signal, the standard signal and the self-test signal.

[0020] In a second aspect, the temperature compensation system provided in the present application adopts the following technical solution.

[0021] A temperature compensation system for the combined sensor, the temperature compensation system comprising:

[0022] An information storage module, used for storing standard signals;

[0023] A signal receiving module, used for receiving the temperature signal output by the temperature measuring circuit and the self-test signal fed back by the signal processing circuit when the self-test circuit is started;

[0024] A data processing module generates a compensation value and a temperature calibration value according to the temperature signal, the standard signal and the self-test signal;

[0025] The signal compensation module adjusts the temperature compensation value of the combined sensor according to the compensation value, and outputs a temperature calibration value so that the temperature measurement circuit calibrates the output temperature signal.

[0026] In a preferred embodiment, the method in which the data processing module generates the compensation value and the temperature calibration value according to the temperature signal, the standard signal and the self-test signal comprises:

[0027] Determining a weight ratio of the compensation value and the temperature calibration value according to a temperature interval in which a temperature signal measured when the self-test circuit is started is located;

[0028] The compensation value and the temperature calibration value are generated according to the weight ratio, the temperature signal, the standard signal and the self-test signal.

[0029] In a preferred embodiment, the temperature measurement circuit includes a temperature detection circuit and a temperature calibration circuit. The temperature calibration circuit calibrates the temperature detection signal output by the temperature detection circuit according to the temperature calibration value and then outputs a temperature signal.

[0030] In a preferred embodiment, the temperature calibration circuit comprises a temperature adder circuit, one input end of the temperature adder circuit is connected to the temperature detection circuit, and the other input end of the temperature adder circuit is connected to the signal compensation module.

[0031] In a preferred embodiment, the information storage module stores the specific gravity base number matched to each temperature interval, and the data processing module calculates the weight ratio Q according to the specific gravity base number and specific gravity interference. bj ;

[0032] Q bj =KP g ;

[0033] P g =Tk1+t p k2+I p k3+ k4;

[0034] K is the specific gravity base, P g is the specific gravity interference, T is the continuous power-on time of the combined sensor, t pis the average temperature of the combined sensor within the preset time, I p is the average current of the cable within the preset time, Z0 is the vibration measurement value of the combined sensor when the cable is energized, and k1, k2, k3, k4, and N are all constants.

[0035] In a preferred embodiment, the temperature compensation system further comprises a temperature compensation module. After the temperature compensation module performs a primary compensation on the output value of the combined sensor, the signal compensation module performs a secondary compensation on the output value of the combined sensor according to the temperature compensation value.

[0036] In summary, the present application includes the following beneficial technical effects: when the self-test circuit is started, the control circuit can obtain the self-test signal and the temperature signal, and the standard signal is pre-stored in the combined sensor. At this time, the control circuit can calculate the compensation value and the temperature calibration value based on the standard signal, the self-test signal and the temperature signal, thereby respectively compensating the output value of the combined sensor and controlling the temperature calibration circuit to calibrate the temperature detection signal output by the temperature detection circuit. By adding a compensation method for the compensation value on the basis of the original temperature compensation module, and also adding the adjustment of the output value of the temperature detection circuit, the combined sensor provided by the present application can be applied to current and voltage detection in a large current environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is an exploded diagram of the combined sensor in the embodiment of the present application.

[0038] Figure 2 It is a diagram of a combined sensor system in an embodiment of the present application.

[0039] Figure 3 It is a schematic diagram of a self-test circuit in an embodiment of the present application.

[0040] Figure 4 It is a schematic diagram of the positions of the self-test coil and the annular iron core coil in the embodiment of the present application.

[0041] Figure 5 It is a temperature compensation system diagram in the application embodiment.

[0042] Explanation of the reference numerals: 11, current sensor; 12, voltage sensor; 13, signal processing circuit; 14, control circuit; 15, temperature measurement circuit; 16, self-test circuit; 161, self-test coil; 162, self-test wire; 21, housing; 22, cover plate; 23, inner hole; 24, annular wall. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] In addition, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally means that the associated objects before and after are in an "or" relationship.

[0045] Reference Figure 1 and Figure 2 The present application provides a non-contact current and voltage combination sensor, which is applied to the field of large current power distribution. The combination sensor includes a current sensor 11, a voltage sensor 12, a signal processing circuit 13, a control circuit 14, a temperature measurement circuit 15 and a self-test circuit 16. The current sensor 11 and the voltage sensor 12 are arranged in a shielding shell, and the shielding shell is provided with an inner hole 23, through which the cable passes. When the cable is powered on, the current sensor 11 and the voltage sensor 12 respectively sense and output a current detection signal and a voltage detection signal.

[0046] The current sensor 11 is configured as a ring-shaped iron core coil, that is, the coil is wound around a ring-shaped iron core to form the current sensor 11, and the ring-shaped iron core coil is nested in a shielding shell, which includes a shell 21 and a cover plate 22. The inner hole 23 is formed by an annular wall 24 in the shell 21, and the ring-shaped iron core coil is nested outside the annular wall 24. After the annular iron core coil is cast in the shell 21 with insulating glue, the cover plate 22 is fixedly connected to the shell 21 by fixing screws. The voltage sensor 12 includes a capacitor ring, which is wrapped with a shielding copper mesh and fixed to the wall of the inner hole 23 of the shielding shell. The cable passes through the inner hole 23. When the cable is powered on, the current sensor 11 and the voltage sensor 12 detect the current and voltage of the cable through the principle of electromagnetic induction.

[0047] The signal processing circuit 13 is arranged in the shielding shell, and the signal processing circuit 13 is connected to the current sensor 11 and the voltage sensor 12, and is used to receive the current signal and the voltage signal detected by the current sensor 11 and the voltage sensor 12, and filter and amplify the current signal and the voltage signal. The working principle and structure of the signal processing circuit 13 are the same as those of the signal processing circuit 13 in the existing mutual inductor, and the present application scheme will not be described in detail.

[0048] The temperature measuring circuit 15 includes a temperature detection circuit and a temperature calibration circuit. The temperature detection circuit includes a temperature measuring probe arranged in a shielding shell. The temperature detection circuit detects the temperature of the combined sensor to output a temperature detection signal. The output end of the temperature detection circuit is connected to the control circuit 14 through the temperature calibration circuit. The temperature calibration circuit calibrates the temperature detection signal and then outputs the temperature signal. In a preferred example, the temperature measuring probe is located on one side of the annular wall 24 where the annular core coil is nested.

[0049] Reference Figure 3 The self-test circuit 16 includes a self-test wire 162, a standard power supply connected to the self-test wire 162, and a self-test coil 161. The self-test wire 162 passes through the inner hole 23 of the shielding shell, and the self-test coil 161 is nested in the inner hole 23 of the shielding shell. When the cable is powered on, the self-test wire 162 senses the current in the cable to charge the standard power supply; when the self-test circuit 16 is started, the standard power supply supplies power to the self-test wire 162. Since the standard power supply and the self-test wire 162 are both pre-set, when the self-test wire 162 is powered on, the actual voltage and current of the self-test wire 162 are both controllable fixed values. Among them, the standard power supply is connected to the control circuit 14 through a self-test controller. When the cable is powered off and the control circuit 14 receives a self-test start signal, the self-test controller controls the standard power supply to supply power to the self-test wire 162. Refer to Figure 4 The annular iron core coil and the self-test coil 161 are separated and fixed in the shielding shell by insulating glue.

[0050] The control circuit 14 is connected to the self-test circuit 16, the signal processing circuit 13 and the temperature measuring circuit 15, and obtains the temperature signal output by the temperature measuring circuit 15 when the self-test circuit 16 is started, and generates a compensation value and a temperature calibration value according to the temperature signal, the standard signal and the self-test signal fed back by the signal processing circuit 13, and compensates the output value of the combined sensor according to the compensation value and the temperature calibration value, and controls the temperature calibration circuit to calibrate the temperature detection signal output by the temperature detection circuit.

[0051] The standard signal is the standard current and standard voltage when the self-test wire 162 is powered on. The self-test signal includes a current self-test signal monitored by the corresponding current sensor 11 and a voltage self-test signal monitored by the corresponding voltage sensor 12 when the self-test circuit 16 is started.

[0052] The control circuit 14 determines the weight ratio of the compensation value and the temperature calibration value according to the temperature range of the temperature signal measured when the self-test circuit 16 is started, and generates the compensation value and the temperature calibration value according to the weight ratio, the temperature signal, the standard signal and the self-test signal.

[0053] Reference Figure 5In order to further illustrate the process in which the control circuit 14 in the embodiment of the present application adjusts the temperature compensation value of the combined sensor according to the temperature signal, the standard signal and the self-test signal, and calibrates the temperature signal output by the temperature measurement circuit 15, the present application also provides a temperature compensation system for the combined sensor, and the temperature compensation system includes: an information storage module, a signal receiving module, a data processing module and a signal compensation module.

[0054] The information storage module is used to store standard signals.

[0055] The signal receiving module is used to receive the temperature signal output by the temperature measuring circuit 15 and the self-test signal fed back by the signal processing circuit 13 when the self-test circuit 16 is started.

[0056] The data processing module generates a compensation value and a temperature calibration value according to the temperature signal, the standard signal and the self-test signal. Specifically, the data processing module determines a weight ratio of the compensation value and the temperature calibration value according to the temperature interval of the temperature signal measured when the self-test circuit 16 is started; and then generates the compensation value and the temperature calibration value according to the weight ratio, the temperature signal, the standard signal and the self-test signal.

[0057] The temperature interval is a temperature value range. Multiple temperature intervals are continuous. When the data processing module receives a temperature signal, the temperature corresponding to the temperature signal falls within a certain temperature interval. Each temperature interval is matched with a corresponding specific gravity base. The temperature interval and the specific gravity base are stored in the information storage module. The matching relationship between the temperature interval and the specific gravity base is manually formulated based on local environmental parameters.

[0058] The data processing module calculates the weight ratio through the specific gravity base and the specific gravity interference. The specific gravity interference represents the interference that affects the detection accuracy of the temperature measuring circuit 15. Specifically, during the operation of the combined sensor provided in the embodiment of the present application, since the voltage sensor 12 is located inside the annular iron core coil, the voltage sensor 12 under a large current environment will affect the detection accuracy of the temperature measuring probe. In the scheme of the present application, the signal compensation module is connected to the temperature compensation module and the temperature calibration circuit. The temperature compensation module is used to compensate the output value of the combined sensor according to the temperature signal. The signal compensation module adjusts the temperature compensation value of the temperature compensation module according to the compensation value, and outputs the temperature calibration value so that the temperature measuring circuit 15 calibrates the output temperature signal. That is, the signal compensation module calibrates the temperature measuring circuit 15 while adjusting the temperature compensation of the combined sensor. After the temperature compensation module compensates the output value of the combined sensor once, the signal compensation module compensates the output value of the combined sensor twice according to the temperature compensation value.

[0059] The temperature calibration circuit includes a temperature adder circuit, one input end of the temperature adder circuit is connected to the temperature detection circuit, and the other input end of the temperature adder is connected to the signal compensation module. The temperature compensation module uses a differential bridge to perform temperature compensation on the output of the combined sensor, and multiple compensation resistors are connected in parallel on both sides of the differential bridge. The compensation resistors are connected in series with a compensation switch, and the signal compensation module adjusts the temperature compensation value of the temperature compensation module by controlling the on and off of the compensation switch.

[0060] The method in which the data processing module calculates the weight ratio according to the specific gravity base and specific gravity interference includes:

[0061] Q bj =KP g ;

[0062] P g =Tk1+t p k2+I p k3+ k4;

[0063] Q bj is the weight ratio, K is the weight base, P g is the specific gravity interference, T is the continuous power-on time of the combined sensor, t p is the average temperature of the combined sensor within the preset time, I p is the average current of the cable within the preset time, Z0 is the vibration measurement value of the combined sensor when the cable is energized, and k1, k2, k3, k4, and N are all constants.

[0064] The weight ratio represents the ratio of the compensation value to the temperature calibration value. When the control circuit 14 obtains the self-test signal and the standard signal, the power difference is calculated based on the power difference between the standard signal and the self-test signal, and then the adjustment value is obtained based on the product of the power difference and the fixed constant. The power difference is the difference between the current and voltage product in the standard signal and the current and voltage product in the self-test signal. The fixed constant is a manually set constant. The adjustment value is decomposed into the compensation value and the temperature calibration value according to the weight ratio. For example, if the adjustment value is 3 and the weight ratio is 2, the decomposed compensation value is 2 and the temperature calibration value is 1.

[0065] The working principle of the combined sensor described in the present application is: when the self-test circuit 16 is started, the control circuit 14 can obtain the self-test signal and the temperature signal, and the standard signal is pre-stored in the combined sensor. At this time, the control circuit 14 can calculate the compensation value and the temperature calibration value based on the standard signal, the self-test signal and the temperature signal, thereby respectively compensating the output value of the combined sensor and controlling the temperature calibration circuit to calibrate the temperature detection signal output by the temperature detection circuit. By adding a compensation method of the compensation value on the basis of the original temperature compensation module, and also adding the adjustment of the output value of the temperature detection circuit, the combined sensor provided by the present application can be applied to current and voltage detection in a large current environment.

[0066] In the several examples provided in the present application, the disclosed structures may be one or more. For example, in one example, the self-test wire 162 is not connected to the capacitor ring, and in another example, at least one of the self-test wires 162 is connected to the capacitor ring; for another example, the combined sensor is not configured with a compensation resistor and a compensation switch, and the control circuit calibrates the output value of the temperature measurement circuit through a built-in program, etc.

Claims

1. A non-contact current-voltage combination sensor, characterized in that: The combined sensor comprises a current sensor (11), a voltage sensor (12), a signal processing circuit (13), a control circuit (14), a temperature measurement circuit (15) and a self-test circuit (16); The current sensor (11) comprises a ring-shaped iron core coil, which is nested in a shielding shell and connected to a signal processing circuit (13); The voltage sensor (12) comprises a capacitor ring, which is fixed to the wall of the inner hole (23) of the shielding shell and connected to the signal processing circuit (13); A temperature measuring circuit (15) for detecting the temperature of the combined sensor; The signal processing circuit (13) is connected to the voltage sensor (12) and the current sensor (11), and transmits monitoring signals of the voltage sensor (12) and the current sensor (11) to the control circuit (14); A self-test circuit (16), comprising a self-test wire (162) and a standard power supply connected to the self-test wire (162), wherein the self-test wire (162) passes through an inner hole (23) of the shielding shell; The control circuit (14) is connected to the self-test circuit (16), the signal processing circuit (13) and the temperature measurement circuit (15), and when the self-test circuit (16) is started, the temperature signal output by the temperature measurement circuit (15) is obtained, and a compensation value is generated according to the temperature signal, the standard signal and the self-test signal fed back by the signal processing circuit (13), and the control circuit (14) compensates the output value of the combined sensor according to the compensation value; the temperature measurement circuit (15) comprises a temperature detection circuit and a temperature calibration circuit, the temperature detection circuit is connected to the control circuit (14) via the temperature calibration circuit, and the temperature calibration circuit calibrates the temperature detection signal output by the temperature detection circuit according to the temperature calibration value fed back by the control circuit (14) and then outputs the temperature signal; The control circuit (14) determines a weight ratio of the compensation value and the temperature calibration value according to a temperature interval of a temperature signal measured when the self-test circuit (16) is started, and generates the compensation value and the temperature calibration value according to the weight ratio, the temperature signal, the standard signal and the self-test signal; Each temperature interval is matched with a corresponding specific gravity base, and the weight ratio is calculated based on the specific gravity base and specific gravity interference: Q bj ； Q bj =KP g ; P g =Tk1+t p k2+I p k3+ k4; K is the specific gravity base, P g is the specific gravity interference, T is the continuous power-on time of the combined sensor, t p is the average temperature of the combined sensor within the preset time, I p is the average current of the cable within the preset time, Z0 is the vibration measurement value of the combined sensor when the cable is powered on, k1, k2, k3, k4, and N are all constants; The standard signal is a standard current and a standard voltage obtained when the self-test wire (162) is powered on, and the self-test signal includes a current self-test signal monitored by a corresponding current sensor (11) and a voltage self-test signal monitored by a corresponding voltage sensor (12) when the self-test circuit (16) is started.

2. A non-contact current-voltage combined sensor according to claim 1, characterized in that: The standard power supply comprises a self-test power supply and a self-test coil (161); the self-test coil (161) is nested in a shielding shell and is used to charge the self-test power supply.

3. A temperature compensation system for the combined sensor according to claim 1 or 2, characterized in that: The temperature compensation system comprises: An information storage module, used for storing standard signals; A signal receiving module, used for receiving a temperature signal output by a temperature measuring circuit (15) and a self-test signal fed back by a signal processing circuit (13) when a self-test circuit (16) is started; A data processing module generates a compensation value and a temperature calibration value according to the temperature signal, the standard signal and the self-test signal; the method in which the data processing module generates a compensation value and a temperature calibration value according to the temperature signal, the standard signal and the self-test signal includes: Determining a weight ratio between the compensation value and the temperature calibration value according to the temperature interval of the temperature signal measured when the self-checking circuit (16) is started; The information storage module stores the specific gravity base number matched by each temperature interval, and the data processing module calculates the weight ratio according to the specific gravity base number and specific gravity interference: Q bj ； Q bj =KP g ; P g =Tk1+t p k2+I p k3+ k4; K is the specific gravity base, P g is the specific gravity interference, T is the continuous power-on time of the combined sensor, t p is the average temperature of the combined sensor within the preset time, I p is the average current of the cable within the preset time, Z0 is the vibration measurement value of the combined sensor when the cable is powered on, k1, k2, k3, k4, and N are all constants; generating the compensation value and the temperature calibration value according to the weight ratio, the temperature signal, the standard signal and the self-test signal; The signal compensation module adjusts the temperature compensation value of the combined sensor according to the compensation value, and outputs a temperature calibration value so that the temperature measurement circuit (15) calibrates the output temperature signal.

4. The temperature compensation system according to claim 3, characterized in that: The temperature measurement circuit (15) comprises a temperature detection circuit and a temperature calibration circuit. The temperature calibration circuit calibrates the temperature detection signal output by the temperature detection circuit according to the temperature calibration value and then outputs a temperature signal.

5. The temperature compensation system according to claim 4, characterized in that: The temperature calibration circuit comprises a temperature adder circuit, one input end of the temperature adder circuit is connected to the temperature detection circuit, and the other input end of the temperature adder circuit is connected to the signal compensation module.

6. The temperature compensation system according to claim 3, characterized in that: The temperature compensation system further comprises a temperature compensation module. After the temperature compensation module performs primary compensation on the output value of the combined sensor, the signal compensation module performs secondary compensation on the output value of the combined sensor according to the temperature compensation value.

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