Compact electronic current transformer

Abstract

The utility model discloses a compact electronic current transformer. The compact electronic current transformer comprises a shell, an induction coil, a sampling resistor and an output interface, the induction coil is fixedly arranged on the shell, and the shell is provided with an induction channel matched with the induction coil; the sampling resistor is fixedly arranged in the shell, and the sampling resistor is connected to the output end of the induction coil in parallel; the output interface is installed outside the shell, and the output interface is connected with the sampling resistor in parallel. According to the utility model, the to-be-monitored cable passes through the induction channel, the current of the to-be-monitored cable can be sampled and detected by using the electromagnetic induction principle, the current of the to-be-monitored cable can be quickly and conveniently obtained, and the cable current detection device has the characteristics of simple structure and convenience in use.

Description

Technical Field

[0001] The utility model relates to the field of current transformers, in particular to a compact electronic current transformer. Background Art

[0002] With the construction of smart grid, ring main unit, as an important equipment for segmentation, branching, demarcation and communication of distribution network, needs to have adaptive comprehensive local feeder automation function, short circuit / grounding fault detection, and realize local line selection, section positioning and isolation of single-phase grounding fault, and cooperate with the primary closing and secondary closing of the outgoing line switch of the substation. In order to ensure the stable and reliable electrical performance of the above equipment, the voltage sensor that provides current measurement and protection signal should fully reflect the characteristics and requirements of "low loss, energy saving and environmental protection, high efficiency, economy, stable and reliable performance and miniaturization".

[0003] At present, the ring network cabinet mainly adopts the traditional electromagnetic current transformer. Although the traditional electromagnetic current transformer can meet the current operation needs after long-term operation practice verification, with the increasing complexity of the power grid structure, the continuous increase of system capacity, and the increasing level of informatization and automation, the disadvantages of the traditional electromagnetic current transformer are becoming more and more obvious. The disadvantages of the traditional electromagnetic current transformer in the primary and secondary integration application of the ring network cabinet are mainly reflected in the following aspects: there is a magnetic saturation phenomenon. When the traditional electromagnetic current transformer is open-circuited during operation, the transformer will be burned, causing equipment or personal injury; the frequency response range is narrow, the linearity is poor, and the anti-interference ability is weak; the dynamic measurement range is narrow, and it is difficult to achieve a large range of measurement; the volume is large, the weight is heavy, and the self-loss is high; it needs to be connected to the relay protection and automation instrument through secondary conversion, and there are matching problems between devices; the amount of resource-based materials is large and the economy is poor. In order to meet the requirements of refined management of power grid line loss and realize the measurement of distribution network branch line loss, new requirements need to be put forward for the primary equipment voltage transformer to meet the requirements of measurement accuracy. With the rapid development of electronic technology, microcomputer-based relay protection devices have gradually occupied a dominant position. In relay protection and measurement, the energy flow and information flow of the control part are separated, so the monitoring equipment no longer needs high-power output transformer sampling.

[0004] Therefore, there is an urgent need to provide a compact electronic current transformer to solve the above problems. Utility Model Content

[0005] The utility model aims to provide a compact electronic current transformer to achieve fast and accurate current sampling and convenient installation.

[0006] In order to solve the above technical problems, the utility model provides a compact electronic current transformer, including a housing, an induction coil, a sampling resistor and an output interface;

[0007] The induction coil is fixedly arranged on the shell, and the shell is provided with an induction channel matching the induction coil;

[0008] The sampling resistor is fixedly arranged inside the housing, and the sampling resistor is connected in parallel to the output end of the induction coil;

[0009] The output interface is installed outside the housing, and the output interface is connected in parallel with the sampling resistor.

[0010] Further, the induction coil includes an iron core and a coil winding;

[0011] The iron core is a ring structure;

[0012] The coil winding is wound on the iron core, and the coil winding output end is connected in parallel with the sampling resistor.

[0013] Furthermore, the sampling resistor is a non-inductive resistor.

[0014] Furthermore, the output interface adopts an aviation socket.

[0015] Furthermore, the output end of the aviation socket is connected to a twisted shielded pair cable.

[0016] Furthermore, the housing includes two insulating shells, and the two insulating shells are connected by a mounting insert.

[0017] Furthermore, epoxy resin is filled between the two insulating shells.

[0018] Furthermore, the output interface is connected to the sampling resistor via a signal line, and the signal line is arranged inside the epoxy resin.

[0019] Compared with the prior art, the utility model has at least the following beneficial effects:

[0020] The utility model can sample and detect the current of the cable to be monitored by using the electromagnetic induction principle by passing the cable to be monitored through the induction channel, and can quickly and conveniently obtain the current of the cable to be monitored. It has the characteristics of simple structure and convenient use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the internal structure of the compact electronic current transformer of the utility model;

[0022] Figure 2 It is a schematic diagram of the cross-sectional structure of the compact electronic current transformer of the utility model;

[0023] Figure 3This is a schematic diagram of the external structure of the compact electronic current transformer of the utility model;

[0024] Figure 4 The utility model is a schematic diagram of the circuit connection structure of the compact electronic current transformer. DETAILED DESCRIPTION

[0025] The compact electronic current transformer of the utility model will be described in more detail below in conjunction with the schematic diagram, wherein the preferred embodiment of the utility model is shown, and it should be understood that the technicians in this field can modify the utility model described here, and still achieve the beneficial effects of the utility model. Therefore, the following description should be understood as being widely known to the technicians in this field, and not as a limitation to the utility model.

[0026] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the accompanying drawings are in very simplified form and in non-precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0027] like Figures 1 to 4 As shown, the embodiment of the utility model provides a compact electronic current transformer, including a housing 1 , an induction coil 2 , a sampling resistor 3 and an output interface 4 .

[0028] Specifically, the induction coil 2 is fixedly disposed inside the housing 1 , and an induction channel 5 matching the induction coil 2 is disposed on the housing 1 .

[0029] The sampling resistor 3 is fixedly disposed inside the housing 1 , and the sampling resistor 3 is connected in parallel to the output end of the induction coil 2 .

[0030] The output interface 4 is installed outside the housing 1 , and the output interface 4 is connected in parallel with the sampling resistor 3 .

[0031] In this embodiment, when the cable to be monitored passes through the sensing channel 5 and is powered on, an induced electromotive force is generated on the induction coil 2 due to electromagnetic induction, and the induction coil 2 and the sampling resistor 3 form a closed loop. At the same time, the output interface 4 outputs the voltage on the sampling resistor 3. Since the voltage on the sampling resistor 3 is proportional to the current and in phase, the I= U R , the induced current on one side of the induction coil 2 can be obtained, and then the current value of the cable to be monitored can be obtained by multiplying it with the mutual inductance coefficient.

[0032] In a specific embodiment, the housing 1 includes two insulating shells, and the two insulating shells are connected by mounting inserts 6, and epoxy resin 7 is filled between the two insulating shells. The housing 1 and the internal electronic components are potted with epoxy resin 7, so that the housing 1 becomes an integrated whole closed structure with good insulation effect. In addition, the full sealing technology is adopted, and epoxy resin 7 is used as the insulating material for potting, and the outer surface is molded at one time, which is convenient for production.

[0033] It should be noted that the current transformer can be directly mounted on the cable to be monitored for use, or it can be fixedly installed on the inner wall of the equipment for use. Since the current transformer is compact in design and has a small overall size, it can be installed in a smaller space and has a wider range of applications.

[0034] In addition, the output interface 4 is connected to the sampling resistor 3 via a signal line, and the signal line is arranged inside the epoxy resin 7. The epoxy resin 7 completely seals the electronic components and wires in the housing 1, thereby achieving a good insulation effect.

[0035] Furthermore, the induction coil 2 includes an iron core 8 and a coil winding 9 .

[0036] Specifically, the iron core 8 is a ring structure.

[0037] The coil winding 9 is wound on the iron core 8 , and an output end of the coil winding 9 is connected in parallel with the sampling resistor 3 .

[0038] In this embodiment, the coil winding 9 generates an induced electromotive force after sensing the current of the cable to be monitored by electromagnetic induction. In this process, the iron core 8 provides a magnetic circuit so that the magnetic flux lines can effectively pass through the coil, thereby realizing the transmission and conversion of electrical energy.

[0039] Furthermore, the sampling resistor 3 is a non-inductive resistor.

[0040] Specifically, non-inductive resistors refer to a type of resistor that can work in high-frequency circuits without generating inductance, thereby avoiding the impact of inductance on circuit performance. In high-frequency circuits, inductance can cause problems such as signal distortion, poor frequency response, and energy loss, so non-inductive resistors are needed to replace traditional resistors.

[0041] Furthermore, the output interface 4 adopts an aviation socket, and the output end of the aviation socket is connected to a twisted shielded pair cable 10 .

[0042] Specifically, the output interface 4 adopts an aviation socket, which can realize a detachable electrical connection between the twisted shielded pair wires 10 and the current transformer, and is convenient for use.

[0043] Compared with the prior art, the utility model has at least the following beneficial effects:

[0044] The utility model can sample and detect the current of the cable to be monitored by using the electromagnetic induction principle by passing the cable to be monitored through the induction channel, and can quickly and conveniently obtain the current of the cable to be monitored. It has the characteristics of simple structure and convenient use.

[0045] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A compact electronic current transformer, characterized in that: It includes a shell, an induction coil, a sampling resistor and an output interface; The induction coil is fixedly arranged inside the shell, and the shell is provided with an induction channel matching the induction coil; The sampling resistor is fixedly arranged inside the housing, and the sampling resistor is connected in parallel to the output end of the induction coil; The output interface is installed outside the housing, and the output interface is connected in parallel with the sampling resistor.

2. The compact electronic current transformer according to claim 1, characterized in that: The induction coil comprises an iron core and a coil winding; The iron core is a ring structure; The coil winding is wound on the iron core, and the coil winding output end is connected in parallel with the sampling resistor.

3. The compact electronic current transformer according to claim 1, characterized in that: The sampling resistor is a non-inductive resistor.

4. The compact electronic current transformer according to claim 1, characterized in that: The output interface adopts an aviation socket.

5. The compact electronic current transformer according to claim 4, characterized in that: The output end of the aviation socket is connected with a twisted shielded pair wire.

6. The compact electronic current transformer according to claim 1, characterized in that: The housing comprises two insulating shells, and the two insulating shells are connected by a mounting insert.

7. The compact electronic current transformer according to claim 6, characterized in that: Epoxy resin is filled between the two insulating shells.

8. The compact electronic current transformer according to claim 7, characterized in that: The output interface is connected to the sampling resistor via a signal line, and the signal line is arranged inside the epoxy resin.

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