CN207798899U - A kind of current sensor and monitoring system - Google Patents

Abstract

The present application discloses a current sensor, which includes an insulating plate, a first Rogowski coil and a second Rogowski coil. The first Rogowski coil is fixed on one side of the insulating plate, and the second Rogowski coil is fixed on the other side of the insulating plate. The number of turns of the first Rogowski coil is smaller than the number of turns of the second Rogowski coil. The current sensor can measure the signal of the line in the small current range at power frequency and in the large current range at high frequency. Therefore, it avoids the situation that when the traditional ferromagnetic current transformer is used for measurement, due to the existence of the iron core, it is easy to be saturated when the primary current contains a DC component, the range of the measured current becomes smaller, the frequency band is narrow, and the picked-up signal is easy to be distorted. In the process of measuring the fault current with a large amplitude, there will be no magnetic saturation phenomenon, and it has excellent linear characteristics, and is suitable for applications that require high current measurement accuracy. The present application also provides a monitoring system comprising the above-mentioned current sensor to complete the monitoring process.

Description

A current sensor and monitoring system

technical field

The present application relates to the technical field of electromagnetic measurement, in particular to a current sensor and a monitoring system.

Background technique

Current sensors are used more and more widely in power systems. In DC transmission systems, frequency conversion speed control devices, inverter devices, UPS power supplies, inverter welding machines, substations, electrolytic plating, CNC machine tools, microcomputer monitoring systems, power grid monitoring systems and various actual scenarios that require isolation and detection of current, the use of current The sensor detects non-sinusoidal current to judge whether the power circuit and equipment are in normal operation. The current sensor converts the detected information into electrical signals that meet certain standards or other required forms of signal output according to certain rules, so as to meet the requirements of information transmission, processing, storage, display, recording and control.

Current sensors can be roughly divided into two categories according to their working principles: one is a measuring device that determines the magnitude of the measured current based on the voltage drop of the measured current on a known resistance, such as a shunt; the other is based on the measured current. The measuring device that establishes the magnetic field to determine the magnitude of the measured current is a magnetic sensor, such as a ferromagnetic current transformer. The biggest problem with using a shunt for detection is that there is no isolation between the input and output, and when using a shunt to measure high frequency or high current, it is inevitably inductive. Therefore, when a shunt is connected to the power line, the waveform of the measured current will be affected, and the current signal cannot be truly transmitted.

Ferromagnetic current transformers have high insulation strength, stable performance, low power consumption, can withstand large loads, and can be installed without disconnecting the circuit under test. However, since the ferromagnetic current transformer uses iron core material, it does not have ideal magnetization characteristics, and it is easy to saturate when the primary current contains a DC component, so that the measured current range becomes smaller, the frequency band is narrow, and the picked-up signal is easily distorted. It is suitable for occasions requiring high accuracy of current measurement. For example, when detecting a transient current with an increased amplitude or a high di/dt current, the ferromagnetic current transformer cannot reflect the measured current without distortion, and the measurement error is relatively large.

Utility model content

The present application provides a current sensor and a monitoring system to solve the problems that the current sensor has a small detection current range, a narrow frequency band, and distortion of picked-up signals, resulting in large measurement errors.

A current sensor comprising an insulating plate, a first Rogowski coil and a second Rogowski coil;

A through hole is provided in the center of the insulating plate;

A wire is arranged on the axis of the through hole;

The first Rogowski coil is fixed on one side of the insulating plate;

The second Rogowski coil is fixed on the other side of the insulating plate;

The number of turns of the first Rogowski coil is less than the number of turns of the second Rogowski coil;

The axes of the first Rogowski coil and the second Rogowski coil are provided with skeletons with the same structure and size;

One end of the first Rogowski coil and the second Rogowski coil is provided with a first coil end;

The other ends of the first Rogowski coil and the second Rogowski coil are provided with a second coil end;

A first signal lead wire is provided on the end of the first coil;

The first signal lead is connected to the first coil terminal;

A second signal lead wire is provided on the end of the second coil;

The second signal lead is connected to the second coil end.

Further, the skeleton is composed of 4 round rods;

The four round rods are connected end to end by the first Rogowski coil and the second Rogowski coil to form a square structure.

Further, the insulating plate includes a first half-ring, a second half-ring, a first joint and a second joint;

One end of the first half-ring is connected to one end of the second half-ring through the first joint;

The other end of the first half ring is connected to the other end of the second half ring through the second joint.

Further, the first joint and the second joint are plug-in joints;

Both ends of the first coupling head and the second coupling head are in the shape of elastic bayonets.

Further, both the first Rogoswki coil and the second Rogowski coil are uniformly wound in a helical shape with enameled wire;

The outside of the first Rogowski coil and the second Rogowski coil is uniformly wound with a shielding layer by a thin conductive metal strip;

An insulating protective layer is provided outside the shielding layer.

Further, the insulating board is an epoxy resin board.

A monitoring system, the monitoring system includes the current sensor, an in-situ module, a remote module and an optical fiber;

The current sensor is electrically connected to the local module;

The local module is connected to the remote module through the optical fiber;

The on-site module includes a data acquisition unit and an electro-optical signal conversion unit;

The current sensor is electrically connected to the electro-optical signal conversion unit through the data acquisition unit;

The data acquisition unit is connected to the optical fiber through the electro-optical signal conversion unit;

The remote module includes a photoelectric signal conversion unit and a data processing and analysis unit;

The optical fiber is electrically connected to the data processing and analysis unit through the photoelectric signal conversion unit.

Further, the monitoring system also includes a non-metallic housing;

The current sensor, the local module, the remote module and the optical fiber are packaged inside the non-metallic housing.

The beneficial effect of this application is:

It can be seen from the above technical solutions that the present application provides a current sensor, which includes an insulating plate, a first Rogowski coil and a second Rogowski coil. The first Rogowski coil is fixed on one side of the insulating plate, and the second Rogowski coil is fixed on the other side of the insulating plate. The number of turns of the first Rogowski coil is smaller than the number of turns of the second Rogowski coil. The current sensor can measure the signal of the line in the small current range at power frequency and in the large current range at high frequency. Thereby, adopting the current sensor of the present application avoids that when the traditional ferromagnetic current transformer is used for measurement, due to the existence of an iron core, it is easy to be saturated when the primary current contains a DC component, the range of the measured current becomes smaller, the frequency band is narrow, and the pick-up signal Easily distorted. In the process of measuring the fault current with a large amplitude, there will be no magnetic saturation phenomenon, and it has excellent linear characteristics, and is suitable for applications that require high current measurement accuracy. The present application also provides a monitoring system comprising the above-mentioned current sensor to complete the monitoring process.

Description of drawings

In order to illustrate the technical solution of the present application more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, on the premise of not paying creative labor, Additional drawings can also be derived from these drawings.

FIG. 1 is a schematic structural diagram of a current sensor according to an embodiment of the present application;

FIG. 2 is a schematic diagram of an end face structure of a current sensor according to an embodiment of the present application;

Fig. 3 is a schematic diagram of a partial sectional structure of Fig. 2;

Fig. 4 is a kind of current sensor output analysis construction model of the embodiment of the present application;

5 is an enlarged view of a current sensor output analysis and construction model in an embodiment of the present application;

6 is a simulation analysis diagram of the number of coil segments in a current sensor according to an embodiment of the present application;

FIG. 7 is a schematic structural diagram of a monitoring system according to an embodiment of the present application.

Among them, 1-current sensor, 2-insulation plate, 3-first Rogowski coil, 4-second Rogowski coil, 5-through hole, 6-wire, 7-skeleton, 8-first coil end, 9-the first Second coil terminal, 10-first signal lead wire, 11-second signal lead wire, 12-round rod, 13-first half ring, 14-second half ring, 15-first joint head, 16-second joint Connector, 17-shielding layer, 18-insulation protection layer, 19-local module, 20-remote module, 21-optical fiber, 22-data acquisition unit, 23-electro-optical signal conversion unit, 24-photoelectric signal conversion unit, 25 - data processing and analysis unit, 26 - non-metal shell.

Detailed ways

Embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following examples do not represent all implementations consistent with this application.

Current sensors can be roughly divided into two categories according to their working principles: one is a measuring device that determines the magnitude of the measured current based on the voltage drop of the measured current on a known resistance, such as a shunt; the other is based on the measured current. The measuring device that establishes the magnetic field to determine the magnitude of the measured current is a magnetic sensor, such as a ferromagnetic current transformer. The biggest problem with using a shunt for detection is that there is no isolation between the input and output, and when using a shunt to measure high frequency or high current, it is inevitably inductive. Therefore, when a shunt is connected to the power line, the waveform of the measured current will be affected, and the current signal cannot be truly transmitted. Ferromagnetic current transformers have high insulation strength, stable performance, low power consumption, can withstand large loads, and can be installed without disconnecting the circuit under test. However, since the ferromagnetic current transformer uses iron core material, it does not have ideal magnetization characteristics, and it is easy to saturate when the primary current contains a DC component, so that the measured current range becomes smaller, the frequency band is narrow, and the picked-up signal is easily distorted. It is suitable for occasions requiring high accuracy of current measurement. For example, when detecting a transient current with an increased amplitude or a high di/dt current, the ferromagnetic current transformer cannot reflect the measured current without distortion, and the measurement error is relatively large.

The present application provides a current sensor, the current sensor 1 includes an insulating plate 2, a first Rogowski coil 3 and a second Rogowski coil 4;

The center of the insulating plate 2 is provided with a through hole 5;

A wire 6 is arranged on the axis of the through hole 5;

The first Rogowski coil 3 is fixed on one side of the insulating plate 2;

The second Rogowski coil 4 is fixed on the other side of the insulating plate 2;

The number of turns of the first Rogowski coil 3 is smaller than the number of turns of the second Rogowski coil 4;

A skeleton 7 with the same structure and size is arranged on the axis of the first Rogowski coil 3 and the second Rogowski coil 4;

One end of the first Rogowski coil 3 and the second Rogowski coil 4 is provided with a first coil end 8;

The other ends of the first Rogowski coil 3 and the second Rogowski coil 4 are provided with a second coil end 9;

A first signal lead wire 10 is provided on the first coil end 8;

The first signal lead wire 10 is connected to the first coil terminal 8;

The second coil end 9 is provided with a second signal lead wire 11;

The second signal lead 11 is connected to the second coil terminal 9 .

Specifically, refer to FIG. 1 which is a schematic structural diagram of a current sensor according to an embodiment of the present application, and FIG. 2 is a schematic diagram of an end face structure of a current sensor according to an embodiment of the present application;

The first Rogowski coil 3 is uniformly wound on the skeleton 7 of the axis of the first Rogowski coil 3 by using enameled wire. The second Rogowski coil 4 is uniformly wound on the skeleton 7 of the axis of the second Rogowski coil 4 using enameled wire. The skeleton 7 can be made of non-magnetic materials such as plastics and pottery, and its relative magnetic permeability is the same as that of air. Since the magnetic circuits of the first Rogowski coil 3 and the second Rogowski coil 4 do not contain iron cores, there is no saturation problem. The first Rogowski coil 3 is fixed on one side of the insulating board 2 , and the second Rogowski coil 4 is fixed on the other side of the insulating board 2 .

Referring to FIG. 4 , an output analysis construction model of a current sensor 1 according to an embodiment of the present application, and FIG. 5 is an enlarged view of an output analysis construction model of a current sensor 1 according to an embodiment of the present application. The specific analysis process of the output signal of the current sensor 1 is as follows.

Since the first Rogowski coil 3 and the second Rogowski coil 4 have the same structure, only the number of turns is different, only one model is required.

In Fig. 5, the magnetic induction intensity inside the k-th coil is:

The magnetic induction intensity outside is:

Among them, B _kn is the inner magnetic induction intensity of the kth coil, B _km is the outer magnetic induction intensity of the kth coil, μ _r μ ₀ is the environmental magnetic permeability, and i(t) is the alternating current at point O of the coil center, H _kn is the inner magnetic field strength of the coil with the kth turns, H _km is the outer magnetic field strength of the kth turns coil, l is the distance from the coil center O point to the inner side of the coil, d is the coil diameter, and d _k is the kth turns The vertical distance between the section where the coil is located and the section where the point O of the coil center is located.

If l>8d, then B _kn /B _km <1.008, it is approximately considered that the magnetic field of the coil section is equal everywhere.

The magnetic induction intensity perpendicular to the section direction of the k-th coil is:

Among them, B _k 'is the magnetic induction intensity perpendicular to the direction of the cross-section of the coil with the kth number of turns, l _k is the distance from the coil center O to the center of the coil cross-section.

The magnetic flux perpendicular to the cross-sectional direction of the k-th coil is:

Among them, φ _k is the magnetic flux perpendicular to the section direction of the coil with the kth turn, and S is the cross-sectional area of the kth turn.

in,

Magnetic link:

Voltage output:

Among them, N' represents the number of coil turns.

For example, if the primary rated current, that is, the coil center wire current is 100A, d=5mm, l=21mm, the number of turns N' of the first Rogowski coil 3=400 turns, and the number of turns N' of the second Rogowski coil 4 =2000 turns, at this time the output u _out of the two coils are 5.04mv and 25.24mv respectively.

Since the number of turns of the first Rogowski coil 3 is smaller than the number of turns of the second Rogowski coil 4 , the first Rogowski coil 3 is used for measuring larger currents, and the second Rogowski coil 4 is used for measuring weak currents. When the line is at power frequency, the first Rogowski coil 3 is used to detect the current; when the line is in a high-frequency fault state, the second Rogowski coil 4 is used to detect the current. The detected data is transmitted through the first signal lead 10 and the second signal lead 11 . Thus, the signals of the line in the small current range at power frequency and in the high current range at high frequency are detected. It can measure milliampere level in small current range and hundred ampere level current in large current range. Thereby, adopting the current sensor 1 of the present application avoids that when the traditional ferromagnetic current transformer is used for measurement, due to the existence of an iron core, it is easy to be saturated when the primary current contains a DC component, the range of the measured current becomes smaller, the frequency band is narrow, and the pick-up The signal is easily distorted. By designing the first Rogowski coil 3 and the second Rogowski coil 4 with the same structure but different numbers of turns, the signals in the small current range at power frequency and the large current range at high frequency can be measured. In the process of measuring the fault current with a large amplitude, there will be no magnetic saturation phenomenon, and it has excellent linear characteristics, and is suitable for applications that require high current measurement accuracy.

It can be known from the above technical solutions that the present application provides a current sensor, the current sensor 1 includes an insulating plate 2 , a first Rogowski coil 3 and a second Rogowski coil 4 . The first Rogowski coil 3 is fixed on one side of the insulating board 2 , and the second Rogowski coil 4 is fixed on the other side of the insulating board 2 . The number of turns of the first Rogowski coil 3 is smaller than the number of turns of the second Rogowski coil 4 . The current sensor can measure the signal of the line in the small current range at power frequency and in the large current range at high frequency. Thereby, adopting the current sensor 1 of the present application avoids that when the traditional ferromagnetic current transformer is used for measurement, due to the existence of an iron core, it is easy to be saturated when the primary current contains a DC component, the range of the measured current becomes smaller, the frequency band is narrow, and the pick-up The signal is easily distorted. In the process of measuring the fault current with a large amplitude, there will be no magnetic saturation phenomenon, and it has excellent linear characteristics, and is suitable for applications that require high current measurement accuracy. The present application also provides a monitoring system comprising the above-mentioned current sensor to complete the monitoring process.

Further, the skeleton 7 is composed of four round rods 12;

The four round rods 12 are connected end to end by the first Rogowski coil 3 and the second Rogowski coil 4 to form a square structure.

Specifically, referring to FIG. 6 , it is a simulation analysis diagram of the number of coils in a current sensor according to an embodiment of the present application. Where N represents the number of segments the coil is divided into, and d represents the diameter of the coil. Using MATLAB software to simulate the number of coils in the current sensor is 1, 2, 3, 4, 8, respectively, to obtain the relationship between the percentage error and the distance, that is, the coil diameter d. Thus, the influence of the number of segments N on the accuracy of circuit measurement results is obtained. It can be seen from Figure 6 that the percentage error of the circuit measurement results is different when the number of segments N is different. When using the current sensor 1 composed of 4 sections of coils evenly placed around the wire 6 to be tested, that is, when the angle between the adjacent sections of the coils in the current sensor is 90 degrees, within the range of the coil diameter d shown in Figure 6, the current sensor 1 The measured percentage errors are all less than 0.2%, meeting the requirements of measurement accuracy. When the number of segments N is less than 4, the angle between adjacent coils is less than 90 degrees, and it can be clearly seen that the percentage error of the measurement result is greater than that when the number of segments N is equal to 4. When the segment number N is greater than 4, it can be clearly seen that the percentage errors of the measurement results are less than 0.1% within the range of the coil diameter d shown in FIG. 6 . Based on the results obtained in Figure 6, when the coil diameter d is small, the percentage error of the measurement result is smaller when the number of segments N is larger. When the coil diameter d is larger, the percentage error of the measurement result under different coil segment numbers N is close. Therefore, taking into account the measurement accuracy and cost, four coils are selected to form the Rogowski coil to make the current sensor.

Four round rods 12 are used to form a square structure through the first Rogowski coil 3 and the second Rogowski coil 4 to form a square structure, which is easy to process and wind, and can be wound more in a smaller space. Large number of coil turns, easy to install in a small space.

Further, the insulating plate 2 includes a first half ring 13, a second half ring 14, a first joint 15 and a second joint 16;

One end of the first half ring 13 is connected to one end of the second half ring 14 through the first joint 15;

The other end of the first half ring 13 is connected to the other end of the second half ring 14 through the second joint 16 .

Specifically, both the first Rogowski coil 3 and the second Rogowski coil 4 are composed of 4 sections of coils, and the 4 sections of coils are divided into two groups, and each group has 2 sections of adjacent coils, forming an L-shaped section of 2 sections of adjacent coils, wherein any group of coils is located at the first One half ring 13, another set of coils is located in the second half ring 14. When the circuit needs to be tested, one end of the first half ring 13 is removed from one end of the first coupling head 15, and the insulating plate 2 is opened to form a split structure. The first half ring 13 goes around the circuit, so that the measured wire 6 is stuck in the middle of the first half ring 13 and the second half ring 14, and then the first half ring 13 is inserted into an end of the first coupling head 15, so that the entire current sensor 1 is in a closed loop. The signal output through the first signal lead 10 and the second signal lead 11 , that is, the output voltage U _out , can realize online monitoring of the current loop during operation. Furthermore, the current in the wire 6 to be tested can be detected conveniently, and the current loop in operation can be measured without disconnecting the wire 6 . The second coupling head 16 facilitates the rotational connection and installation of the other end of the first half ring 13 and the other end of the second half ring 14 .

Further, the first joint 15 and the second joint 16 are plug-in joints;

Both ends of the first coupling head 15 and the second coupling head 16 are elastic bayonet shapes.

Specifically, the first joint 15 and the second joint 16 are plug-in joints, so that the first half-ring 13 and the second half-ring 14 are connected by a plug-in butt joint, which is convenient for installation and saves installation space . The two ends of the first connecting head 15 and the second connecting head 16 are made into an elastic bayonet shape, which is labor-saving and convenient for connection.

Further, both the first Rogoswki coil 3 and the second Rogowski coil 4 are uniformly wound in a helical shape with enameled wire;

The outside of the first Rogowski coil 3 and the second Rogowski coil 4 is uniformly wound with a shielding layer 17 by a conductive metal strip;

An insulating protective layer 18 is provided outside the shielding layer.

Specifically, since the current sensor 1 of the present application is a magnetic sensor, the current sensor 1 is in an electromagnetic environment when performing detection. In order to ensure that the various devices of the current sensor 1 can work normally in the same electromagnetic environment without interfering with each other, that is, to improve the anti-electromagnetic interference ability of the current sensor 1, the outside of the first Rogowski coil 3 and the second Rogowski coil 4 are made of conductive A thin metal strip is evenly wound around the shielding layer 17 . The first coil end 8 and the shielding layer 17 at the same end are connected in series. The first coil end 8 and the shielding layer 17 at the same end are connected in series.

Further, the insulating board 2 is an epoxy resin board.

Specifically, the epoxy resin board is an excellent insulating material with high dielectric properties, surface leakage resistance, and arc resistance, thereby ensuring the insulating performance of the insulating board 2 . The epoxy resin board has excellent mechanical properties, thereby ensuring that the first Rogowski coil 3 and the second Rogowski coil 4 are stably installed on the insulating board 2 . The epoxy resin board has excellent alkali resistance, acid resistance and solvent resistance, thereby ensuring that the insulating board 2 has a longer service life.

A monitoring system comprising the current sensor 1, an on-site module 19, a remote module 20 and an optical fiber 21;

The current sensor 1 is electrically connected to the local module 19;

The local module 19 is connected to the remote module 20 through the optical fiber 21;

The on-site module 19 includes a data acquisition unit 22 and an electro-optical signal conversion unit 23;

The current sensor 1 is electrically connected to the electro-optical signal conversion unit 23 through the data acquisition unit 22;

The data acquisition unit 22 is connected to the optical fiber 21 through the electro-optical signal conversion unit 23;

The remote module 20 includes a photoelectric signal conversion unit 24 and a data processing and analysis unit 25;

The optical fiber 21 is electrically connected to the data processing and analysis unit 25 through the photoelectric signal conversion unit 24 .

Specifically, refer to FIG. 7 , which is a schematic structural diagram of a monitoring system according to an embodiment of the present application. The first signal lead 10 and the second signal lead 11 are directly connected to the local module 19 , so as to realize the electrical connection of the current sensor 1 and the local module 19 . Furthermore, the signals measured in the small current range at power frequency and the large current range at high frequency are input into the local module 19 .

The signal transmission medium of the optical fiber 21 has excellent electrical insulation performance. The electrical signal output by the current sensor 1 is collected by the data acquisition unit 22, and is digitally modulated by the electro-optical signal conversion unit 23 and converted into a digital optical pulse signal on the spot, and transmitted to the remote module 20 through the optical fiber 21 , using the photoelectric signal conversion unit to convert the optical pulse signal into an analog signal, and the data processing and analysis unit 25 performs data processing and analysis. The analysis results are used for parameter calculation, trend prediction, data storage, waveform display, etc. of the current in the measured wire 6 . The entire monitoring system with the current sensor 1 has high detection accuracy and can effectively monitor the operating state of the current loop; the system sensor is easy to install and small in size; and the optical fiber 21 is used for signal transmission, so that the monitoring system has excellent anti-electromagnetic interference capability, The system does not introduce additional errors, which improves the stability and reliability of the system.

Further, the monitoring system also includes a non-metallic housing 26;

The current sensor 1 , the local module 19 , the remote module 20 and the optical fiber 21 are packaged inside the non-metallic housing 26 .

Specifically, the non-metallic housing 26 provides a closed and dry environment for the current sensor 1 , the local module 19 , the remote module 20 , the optical fiber 21 , and the wire 6 under test, thereby ensuring the reliable operation of the monitoring system.

It can be known from the above technical solutions that the present application provides a current sensor, the current sensor 1 includes an insulating plate 2 , a first Rogowski coil 3 and a second Rogowski coil 4 . The first Rogowski coil 3 is fixed on one side of the insulating board 2 , and the second Rogowski coil 4 is fixed on the other side of the insulating board 2 . The number of turns of the first Rogowski coil 3 is smaller than the number of turns of the second Rogowski coil 4 . The current sensor can measure the signal of the line in the small current range at power frequency and in the large current range at high frequency. Thereby, adopting the current sensor 1 of the present application avoids that when the traditional ferromagnetic current transformer is used for measurement, due to the existence of an iron core, it is easy to be saturated when the primary current contains a DC component, the range of the measured current becomes smaller, the frequency band is narrow, and the pick-up The signal is easily distorted. In the process of measuring the fault current with a large amplitude, there will be no magnetic saturation phenomenon, and it has excellent linear characteristics, and is suitable for applications that require high current measurement accuracy. The present application also provides a monitoring system comprising the above-mentioned current sensor to complete the monitoring process.

It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity from another, and do not necessarily require or imply that there is a relationship between these entities. Any such actual relationship or sequence. Furthermore, other variations of the term "comprises" are intended to cover non-exclusive inclusions such that a device comprising a series of elements includes not only those elements but also other elements not expressly listed or is included as such a device inherent elements.

The similar parts between the embodiments provided in the present application can be referred to each other, and the specific implementations provided above are only a few examples under the general concept of the present application, and do not constitute a limitation of the protection scope of the present application. For those skilled in the art, any other implementations expanded based on the proposal of the present application without creative work shall fall within the scope of protection of the present application.

Claims (8)

1. A current sensor, characterized in that the current sensor (1) comprises an insulating plate (2), a first Rogowski coil (3) and a second Rogowski coil (4);

a through hole (5) is formed in the center of the insulating plate (2);

a lead (6) is arranged on the axis of the through hole (5);

the first Rogowski coil (3) is fixed on one surface of the insulating plate (2);

the second Rogowski coil (4) is fixed on the other surface of the insulating plate (2);

the number of turns of the first Rogowski coil (3) is smaller than the number of turns of the second Rogowski coil (4);

frameworks (7) with the same structure and size are arranged on the axes of the first Rogowski coil (3) and the second Rogowski coil (4);

one end of each of the first Rogowski coil (3) and the second Rogowski coil (4) is provided with a first coil end (8);

the other ends of the first Rogowski coil (3) and the second Rogowski coil (4) are provided with second coil end heads (9);

a first signal lead (10) is arranged on the first coil end (8);

the first signal lead (10) is connected with the first coil end (8);

a second signal lead (11) is arranged on the second coil end (9);

the second signal lead (11) is connected with the second coil end (9).

2. The current sensor according to claim 1, characterized in that the skeleton (7) consists of 4 rods (12);

the 4 round rods (12) are connected in a surrounding mode through the first Rogowski coil (3) and the second Rogowski coil (4) end to form a square structure.

3. The current sensor according to claim 2, characterized in that the insulating plate (2) comprises a first half-ring (13), a second half-ring (14), a first coupling head (15) and a second coupling head (16);

one end of the first half ring (13) is connected with one end of the second half ring (14) through the first coupling head (15);

the other end of the first half ring (13) is connected with the other end of the second half ring (14) through the second joint (16).

4. A current sensor according to claim 3, wherein said first coupling head (15) and said second coupling head (16) are plug-in coupling heads;

the two ends of the first coupling head (15) and the second coupling head (16) are in the shape of elastic bayonets.

5. The current sensor according to claim 1, characterized in that the first Rogowski coil (3) and the second Rogowski coil (4) are uniformly wound in a spiral shape using enameled wires;

the outer parts of the first Rogowski coil (3) and the second Rogowski coil (4) are uniformly wound with a shielding layer (17) by a conductive metal thin strip;

and an insulating protective layer (18) is arranged outside the shielding layer.

6. The current sensor according to claim 1, wherein the insulating plate (2) is an epoxy plate.

7. A monitoring system, characterized in that it comprises a current sensor (1) according to any one of claims 1 to 6, an in-situ module (19), a remote module (20) and an optical fiber (21);

the current sensor (1) is electrically connected with the in-situ module (19);

the local module (19) is connected with the remote module (20) through the optical fiber (21);

the local module (19) comprises a data acquisition unit (22) and an electro-optical signal conversion unit (23);

the current sensor (1) is electrically connected with the electro-optical signal conversion unit (23) through the data acquisition unit (22);

the data acquisition unit (22) is connected with the optical fiber (21) through the electro-optical signal conversion unit (23);

the remote module (20) comprises a photoelectric signal conversion unit (24) and a data processing and analyzing unit (25);

the optical fiber (21) is electrically connected with the data processing and analyzing unit (25) through the photoelectric signal conversion unit (24).

8. The monitoring system of claim 7, further comprising a non-metallic housing (26);

the current sensor (1), the in-situ module (19), the remote module (20) and the optical fiber (21) are enclosed inside the non-metallic housing (26).