Integrated device for realizing on-line monitoring of insulation to ground of medium-voltage system

Abstract

The utility model provides an integrated device for realizing medium voltage system ground insulation on-line monitoring, comprising a controller, a blocking capacitor, a first switch, a second switch and an isolation unit, the controller is electrically connected with the isolation unit, the blocking capacitor is connected in series with the first switch, the second switch is connected in series with the second switch, and the isolation unit is electrically connected with the controller. The first switch and the blocking capacitor are connected in parallel, the second switch is connected in parallel to the two ends of the first switch and the blocking capacitor, the isolation unit is electrically connected with the controller, and the controller is used for collecting neutral point current and controlling the first switch and the second switch to switch an opening state or a closing state according to the neutral point current. According to the utility model, on-line monitoring of the insulation performance of the medium-voltage system can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of power equipment monitoring, and particularly relates to an integrated device for realizing on-line monitoring of the insulation between a medium-voltage system and the ground. Background Art

[0002] The medium-voltage system plays an important role in the power system, and its operating stability directly affects the overall performance of the power system. However, the insulation performance of the medium-voltage system will be reduced due to various factors, such as equipment aging, environmental erosion, etc. Therefore, it is crucial to conduct real-time on-line monitoring of its insulation performance.

[0003] At present, the on-line insulation monitoring technologies for medium-voltage systems mainly include the dielectric loss angle tangent method, partial discharge method, etc. However, these methods have certain limitations in terms of measurement accuracy, real-time performance, reliability, etc. Therefore, it is of great significance to develop a new type of on-line insulation monitoring device for medium-voltage systems with high accuracy, real-time performance, and reliability. Summary of the Utility Model

[0004] In view of this, the problem to be solved by the utility model is to provide an integrated device for realizing on-line monitoring of the insulation between a medium-voltage system and the ground.

[0005] To solve the above technical problems, the technical solution adopted by the utility model is: an integrated device for realizing on-line monitoring of the insulation between a medium-voltage system and the ground, including a controller, a DC-blocking capacitor, a first switch, a second switch, and an isolation unit. The controller is electrically connected to the isolation unit. The DC-blocking capacitor is connected in series with the first switch. The second switch is connected in parallel across both ends of the first switch and the DC-blocking capacitor. The isolation unit is electrically connected to the controller. The controller is used to collect the neutral point current and control the switching of the first switch and the second switch between the open state and the closed state according to the neutral point current.

[0006] In the utility model, preferably, the isolation unit includes a first resistor, a fuse, and a high-voltage vacuum relay, which are connected in series in sequence.

[0007] In the utility model, preferably, a signal acquisition unit is externally connected to the isolation unit. The signal acquisition unit is used to collect the voltage signal and current signal of the medium-voltage system. The signal acquisition unit includes a voltage transformer and a current transformer connected in series.

[0008] In the utility model, preferably, the DC-blocking capacitor is fixedly arranged in the cabinet through a partition. An epoxy board is provided in the cabinet. The epoxy board is fixedly provided with a bypass contactor terminal and a discharge resistor. The DC-blocking capacitor is connected to the bypass contactor terminal. Both the discharge resistor and the DC-blocking capacitor are externally connected to a grounding terminal row.

[0009] In the present utility model, preferably, a heater is fixedly provided at the bottom of the cabinet body, and heat dissipation fans are fixedly provided on the inner walls of both sides of the cabinet body.

[0010] The present utility model has the following advantages and positive effects: The insulation on-line monitoring device of the present utility model has the advantages of strong adaptability, high precision, real-time performance, reliability, etc., and can realize the real-time on-line monitoring of the insulation performance of the medium-voltage system. When an insulation fault occurs, an alarm message can be sent to the operator in time, thereby effectively reducing the probability of power system faults and improving the overall performance of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings are used to provide a further understanding of the present utility model, and constitute a part of the specification. Together with the embodiments of the present utility model, they are used to explain the present utility model, and do not constitute a limitation to the present utility model. In the drawings:

[0012] Figure 1 is a schematic diagram of the principle of an integrated device for realizing on-line monitoring of the insulation between the medium-voltage system and the ground of the present utility model;

[0013] Figure 2 is a structural diagram of the cabinet body of an integrated device for realizing on-line monitoring of the insulation between the medium-voltage system and the ground of the present utility model;

[0014] In the figure: 1. Controller; 2. DC-blocking capacitor; 3. First switch; 4. Second switch; 5. Isolation unit; 6. First resistor; 7. Fuse; 8. High-voltage vacuum relay; 9. Voltage transformer; 10. Current transformer; 11. Partition board; 12. Cabinet body; 13. Epoxy board; 14. Bypass contactor terminal; 15. Discharge resistor; 16. Heater; 17. Heat dissipation fan. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0016] It should be noted that when a component is referred to as "fixed to" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intermediate component at the same time. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this article are for illustrative purposes only.

[0017] Unless otherwise defined, all technical and scientific terms used in this article have the same meaning as those commonly understood by those skilled in the technical field to which this utility model belongs. The terms used in the description of this utility model in this article are only for the purpose of describing specific embodiments and are not intended to limit this utility model. The term "and / or" used in this article includes any and all combinations of one or more of the related listed items.

[0018] Such as Figure 1As shown in the figure, the utility model provides an integrated device for realizing on-line monitoring of the insulation between the medium-voltage system and the ground, which includes a controller 1, a DC-blocking capacitor 2, a first switch 3, a second switch 4 and an isolation unit 5. The controller 1 is electrically connected to the isolation unit 5. The DC-blocking capacitor 2 is connected in series with the first switch 3. The second switch 4 is connected in parallel across both ends of the first switch 3 and the DC-blocking capacitor 2. The isolation unit 5 is electrically connected to the controller 1. The controller 1 is used to collect the neutral point current and control the switching of the first switch 3 and the second switch 4 between the open state and the closed state according to the neutral point current. The controller 1 is used to output a DC signal to the operating medium-voltage system, and at the same time process the DC current signal. After current-voltage conversion and passing through a divider, the measured insulation resistance value is displayed after analog-to-digital conversion. In addition, the controller 1 can collect the neutral point current and control the closing state of the first switch 3 and the second switch 4 through the change of the neutral point current. The DC-blocking capacitor 2 uses the characteristic of blocking DC and passing AC of the capacitor to isolate the DC signal injected by the controller 1 into the medium-voltage system so that it is not released to the ground. The first switch 3 is used to control whether the DC-blocking capacitor 2 is put into operation. Specifically, the controller 1 sends a closing or opening command to the first switch 3. The second switch 4 and the first switch 3 are in an interlocking relationship. When the second switch 4 is in the closed state, the first switch 3 is in the open state. On the contrary, when the second switch 4 is in the open state, the first switch 3 is in the closed state. The opening or closing state of the second switch 4 is controlled and switched by the controller 1. The controller 1 is electrically connected to an alarm unit. When a fault occurs in the insulation performance, an alarm message is sent to the operator through the alarm unit. The alarm message can specifically use prompts such as sound, light or mobile phone text messages. The alarm message includes information about the fault type, location and severity, so that the operator can take appropriate measures in time, thereby effectively reducing the probability of power system faults and improving the overall performance of the power system. The signal acquisition unit, the controller 1 and the alarm unit realize data transmission and communication through a data bus or a network.

[0019] In this embodiment, further, the isolation unit 5 includes a first resistor 6, a fuse 7 and a high-voltage vacuum relay 8. The first resistor 6, the fuse 7 and the high-voltage vacuum relay 8 are connected in series in sequence. The isolation unit 5 is used to isolate the controller 1 from the medium-voltage system.

[0020] In this embodiment, further, a signal acquisition unit is externally connected to the isolation unit 5. The signal acquisition unit is used to collect the voltage signal and current signal of the medium-voltage system. The signal acquisition unit includes a voltage transformer 9 and a current transformer 10 connected in series.

[0021] In this embodiment, further, the DC-blocking capacitor 2 is fixedly arranged in the cabinet body 12 through a partition board 11. An epoxy board 13 is arranged in the cabinet body 12. The epoxy board 13 is fixedly provided with a bypass contactor terminal 14 and a discharge resistor 15. The DC-blocking capacitor 2 is connected to the bypass contactor terminal 14. The discharge resistor 15 and the DC-blocking capacitor 2 are both externally connected with a grounding terminal row.

[0022] In this embodiment, further, a heater 16 is fixedly arranged at the bottom of the cabinet body 12, and heat dissipation fans 17 are fixedly arranged on the inner walls of both sides of the cabinet body 12. By arranging the heater 16, it can resist low-temperature environments, and the heat dissipation fans 17 are used to dissipate heat inside the cabinet body 12 in high-temperature environments, so as to enable the device to be applicable to a wider temperature range and still work normally.

[0023] The device further includes a power supply module for providing the power required by the device.

[0024] The device is an embedded device and can be integrated into a medium-voltage system or operate as an independent device.

[0025] The working principle and process of the present utility model are as follows: The controller 1 is used to output a DC signal to the operating medium-voltage system, and at the same time process the DC current signal. After current-voltage conversion and passing through a divider, the measured insulation resistance value is displayed after analog-to-digital conversion. In addition, the controller 1 can collect the neutral point current and control the closing states of the first switch 3 and the second switch 4 through the change of the neutral point current. The DC-blocking capacitor 2 utilizes the characteristic of blocking DC and passing AC of the capacitor to isolate the DC signal injected into the medium-voltage system by the controller 1 so that it is not released to the ground. The first switch 3 is used to control whether the DC-blocking capacitor 2 is put into operation. Specifically, the controller 1 sends a closing or opening command to the first switch 3. The second switch 4 and the first switch 3 are in an interlocking relationship. When the second switch 4 is in the closing state, the first switch 3 is in the opening state, and vice versa. When the second switch 4 is in the opening state, the first switch 3 is in the closing state. The opening or closing state of the second switch 4 is controlled and switched by the controller 1. The controller 1 is electrically connected to an alarm unit. When a fault occurs in the insulation performance, an alarm message is sent to the operator through the alarm unit. The alarm message can specifically be in the form of sound, light, or mobile phone text message, etc. The alarm message includes information such as the fault type, location, and severity, so that the operator can take appropriate measures in time, thereby effectively reducing the probability of power system faults and improving the overall performance of the power system. The insulation on-line monitoring device of the present invention can be widely applied to various medium-voltage systems, including but not limited to the fields of electric power, petrochemical, and metallurgy.

[0026] The above has described the embodiments of the present utility model in detail, but the above content is only the preferred embodiments of the present utility model and cannot be considered as defining the scope of implementation of the present utility model. Any equivalent changes and improvements made within the scope of the present utility model shall still fall within the scope covered by this patent.

Claims

1. An integrated device for realizing online monitoring of insulation of a medium voltage system to ground, characterized in that: The invention comprises a controller, a DC blocking capacitor, a first switch, a second switch and an isolation unit, wherein the controller is electrically connected to the isolation unit, the DC blocking capacitor is connected in series with the first switch, the second switch is connected in parallel to the first switch and the DC blocking capacitor, the isolation unit is electrically connected to the controller, and the controller is used to collect the neutral point current and control the first switch and the second switch to switch to an open state or a closed state according to the neutral point current.

2. The integrated device for realizing online monitoring of insulation between medium voltage system and ground according to claim 1, characterized in that: The isolation unit includes a first resistor, a fuse and a high-voltage vacuum relay, and the first resistor, the fuse and the high-voltage vacuum relay are connected in series in sequence.

3. The integrated device for realizing online monitoring of insulation between medium voltage system and ground according to claim 1, characterized in that: The isolation unit is externally connected to a signal acquisition unit, and the signal acquisition unit is used to acquire voltage signals and current signals of a medium voltage system. The signal acquisition unit includes a voltage transformer and a current transformer connected in series.

4. The integrated device for realizing online monitoring of insulation between medium voltage system and ground according to claim 1, characterized in that: The DC blocking capacitor is fixed in the cabinet through a partition. The cabinet is provided with an epoxy board. The epoxy board is fixed with a bypass contactor terminal and a discharge resistor. The DC blocking capacitor is connected to the bypass contactor terminal. The discharge resistor and the DC blocking capacitor are both externally connected to a grounding terminal block.

5. The integrated device for realizing online monitoring of insulation between medium voltage system and ground according to claim 4, characterized in that: A heater is fixedly arranged at the bottom of the cabinet, and cooling fans are fixedly arranged on the inner walls on both sides of the cabinet.

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