Residual voltage detector of distribution network terminal

Abstract

A residual voltage detector of a distribution network terminal comprises a power supply module and a residual voltage detection module, the output end of the power supply module is connected with the input end of the residual voltage detection module, and the residual voltage detection module comprises a wire inlet side and a load side; a wire inlet side comprises a first voltage comparator U2 and a first latch U3A, a VCC pin of the first voltage comparator U2 is electrically connected with the power supply module, and the first latch U3A and the first voltage comparator U2 are connected in series through a first Nmos transistor Q1; the load side comprises a third voltage comparator U4 and a second latch U3B, the second voltage comparator U4 is electrically connected with the power supply module, and the second latch U3B and the third voltage comparator U4 are connected in series through a second Nmos tube Q3. The residual voltage is detected by arranging the wire inlet side circuit and the load side circuit, multiple feeder lines can be detected at the same time, and the detection efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of residual voltage detection technology, specifically a residual voltage detector for a distribution network terminal. Background Technology

[0002] The State Grid Corporation's professional testing guidelines for integrated primary and secondary pole-mounted switches and ring main units have the following requirements: When the terminal loses power and there is no backup power supply, if there is a voltage ≥50%Un on the line for a duration ≥80ms, the pole-mounted load switch should be able to complete reverse blocking.

[0003] In existing technologies, one approach to residual voltage detectors typically uses transformers for detection. However, this method is bulky, making it inconvenient and costly to use in space-constrained devices such as distribution network feeder terminals. Another approach uses a low-power MCU to acquire a threshold value from the input signal to trigger residual voltage detection. This method involves complex circuitry, programming, and manufacturing processes. Utility Model Content

[0004] The purpose of this invention is to provide a residual voltage detector for a distribution network terminal to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A residual voltage detector for a distribution network terminal includes a power supply module and a residual voltage detection module. The output terminal of the power supply module is connected to the input terminal of the residual voltage detection module. The residual voltage detection module includes an incoming line side and a load side.

[0007] The input side includes a first voltage comparator U2 and a first latch U3A. The VCC pin of the first voltage comparator U2 is electrically connected to the power supply module. The first latch U3A and the first voltage comparator U2 are connected in series through a first NMOS transistor Q1. The LBI pin of the first voltage comparator U2 is connected to a first voltage divider resistor R17 and a second voltage divider resistor R12. The first voltage divider resistor R17 and the second voltage divider resistor R12 are connected in parallel. Both the first voltage divider resistor R17 and the second voltage divider resistor R12 are connected to the feed line.

[0008] The load side includes a second voltage comparator U4 and a second latch U3B. The second voltage comparator U4 is electrically connected to the power supply module, and the second latch U3B and the second voltage comparator U4 are connected in series through a second NMOS transistor Q3.

[0009] In one possible implementation, the power supply module includes a battery interface P18, a first capacitor C8, a second capacitor C9, and a third capacitor C10. The first capacitor C8, the second capacitor C9, and the third capacitor C10 are connected in parallel. The first capacitor C8 is connected to a first diode D13. The positive pin of the first diode D13 is connected to the VCC pin of the first voltage comparator U2. The positive pin of the third capacitor C10 is connected to the VCC pin of the second voltage comparator U4.

[0010] In one possible implementation, a third diode D8 is provided between the second voltage divider resistor R12 or the first voltage divider resistor R17 and the feed line.

[0011] In one possible implementation, the LBI pin of the second voltage comparator U4 is connected to the third voltage divider resistor R20 and the fourth voltage divider resistor R24, which are connected in parallel. The third voltage divider resistor R20 or the fourth voltage divider resistor R24 ​​is connected to the feed line through the fourth diode D11.

[0012] In one possible implementation, one pin of the first latch U3A is connected to one end of the second diode D9, the other end of the second diode D9 is connected to the fifth voltage divider resistor R16, the fifth voltage divider resistor R16 is connected in series with the sixth voltage divider resistor R28, and the sixth voltage divider resistor R28 is connected to one pin of the second latch through the fourth diode D12.

[0013] In one possible implementation, the first latch U3A is connected to the connector via a seventh voltage divider resistor R15, and the second latch U3B is connected to the connector via an eighth voltage divider resistor R26. The connector is used to transmit the detected residual voltage signal.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] 1. By setting up two circuits on the incoming side and the load side to detect residual voltage, multiple feeder lines can be detected simultaneously, resulting in high detection efficiency;

[0016] 2. The circuit structure is simple and the cost is low, which effectively saves internal space and production costs of the distribution network feeder terminal. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0018] Figure 2 This is a circuit diagram of the residual pressure detection module of this utility model.

[0019] Figure 3 This is a circuit diagram of the power supply module of this utility model;

[0020] Figure 4 This is a flowchart illustrating the process of this utility model. Detailed Implementation

[0021] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0022] like Figures 1-4 As shown, a residual voltage detector for a distribution network terminal includes a power supply module 10 and a residual voltage detection module 20. The output terminal of the power supply module 10 is connected to the input terminal of the residual voltage detection module 20. The residual voltage detection module 20 includes an incoming line side (phase A) and a load side (phase C).

[0023] The input side includes a first voltage comparator U2 and a first latch U3A. The VCC pin of the first voltage comparator U2 is electrically connected to the power supply module. The first latch U3A and the first voltage comparator U2 are connected in series through a first NMOS transistor Q1. The LBI pin of the first voltage comparator U2 is connected to a first voltage divider resistor R17 and a second voltage divider resistor R12. The first voltage divider resistor R17 and the second voltage divider resistor R12 are connected in parallel. Both the first voltage divider resistor R17 and the second voltage divider resistor R12 are connected to the feed line.

[0024] The load side includes a second voltage comparator U4 and a second latch U3B. The second voltage comparator U4 is electrically connected to the power supply module, and the second latch U3B and the second voltage comparator U4 are connected in series through a second NMOS transistor Q3.

[0025] The power supply module 10 includes a battery interface P18, a first capacitor C8, a second capacitor C9, and a third capacitor C10. The first capacitor C8, second capacitor C9, and third capacitor C10 are connected in parallel. The first capacitor C8 is connected to a first diode D13, and the positive terminal of the first diode D13 is connected to the VCC pin of the first voltage comparator U2. The positive terminal of the third capacitor C10 is connected to the VCC pin of the second voltage comparator U4. The negative terminal of the first capacitor C8 is grounded to ensure the operational stability of the power supply module. Similarly, grounding wires are provided for grounding protection in the first voltage comparator U2, the second voltage comparator U4, the first latch U3A, and the second latch U3B.

[0026] A third diode D8 is provided between the second voltage divider resistor R12 or the first voltage divider resistor R17 and the feed line. The LBI pin of the second voltage comparator U4 is connected to the third voltage divider resistor R20 and the fourth voltage divider resistor R24. The third voltage divider resistor R20 and the fourth voltage divider resistor R24 ​​are connected in parallel. The third voltage divider resistor R20 or the fourth voltage divider resistor R24 ​​is connected to the feed line through a fourth diode D11. Connecting the residual voltage detector of this invention to the feed line can realize the residual voltage detection of a single feed line.

[0027] In this invention, the input side and the load side are interconnected, specifically by connecting one pin of the first latch U3A ( Figure 2 The pin labeled "6" on U3A is connected to one end of the second diode D9. The other end of the second diode D9 is connected to the fifth voltage divider resistor R16. The fifth voltage divider resistor R16 is connected in series with the sixth voltage divider resistor R28. The sixth voltage divider resistor R28 is connected to one of the pins of the second latch U3B through the fourth diode D12. Figure 2 The pin connection of the U3B (pin numbered "8").

[0028] To transmit the residual voltage signal detected by the residual voltage detector to the protection device processor for residual voltage analysis, a connector for transmitting the detected residual voltage signal is also provided on the residual voltage detector. The first latch U3A is connected to the connector through the seventh voltage divider resistor R15, and the second latch U3B is connected to the connector through the eighth voltage divider resistor R26.

[0029] The working principle of this invention is as follows: When a power supply to the protection device fails and a momentary voltage or residual voltage occurs in the switching line, a residual voltage detection module is provided to detect the residual voltage on the feeder line. When the residual voltage detection module detects an external residual voltage on the feeder line, it outputs a residual voltage detection signal DE1 or DE2 to the protection device processor. The protection device processor then generates a closing interlock signal to prevent the switch from closing to the faulty line. After the protection device completes normal operation, the protection device processor outputs a reset signal RE to the residual voltage detection module, putting the residual voltage detection module into a reset state. Simultaneously, the power supply to the protection device can also generate a control signal to control the residual voltage detection module to be in a stopped detection state during normal operation of the protection device.

[0030] During operation, when the external residual voltage input exceeds the reference voltage, the first latch U3A or U3B is triggered to latch the residual voltage signal. After the protection device is powered normally, a fault is detected on the line via signal DE1 or DE2, preventing the switch from closing to the faulty line. After the protection device completes normal operation, the controller can issue a reset signal RE. The reset signal RE input turns the circuit on, and the reset pin of the first latch U3A or the second latch U3B remains high. Thus, the first latch U3A or the second latch U3B remains in the reset state. Even if a residual voltage signal triggers on the line later, the first latch U3A or the second latch U3B will not participate in the detection; the controller handles it through software residual voltage mode. Once the controller is powered off, the backup battery provides the voltage required by the logic chip. The first latch U3A or the second latch U3B re-enters the latching trigger state. The logic chip in this circuit has very low power consumption, around 0.3uA. Therefore, the battery can last a long time.

[0031] This invention features two residual voltage detectors, one on the incoming line side and one on the load side. Their combination allows for simultaneous detection of multiple feeder lines, resulting in high detection efficiency. This significantly reduces internal space and production costs in distribution network feeder terminals.

[0032] In the description of this utility model, it should be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "other end", "upper", "side", "top", "inner", "front", "center", "both ends", "left and right", "front and back", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0033] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "setting," "connection," "fixing," "screw connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A residual voltage detector for a distribution network terminal, comprising a power supply module (10) and a residual voltage detection module (20), wherein the output terminal of the power supply module (10) is connected to the input terminal of the residual voltage detection module (20), characterized in that, The residual voltage detection module (20) includes an input side and a load side; The incoming line side includes a first voltage comparator (U2) and a first latch (U3A). The VCC pin of the first voltage comparator (U2) is electrically connected to the power supply module (10). The first latch (U3A) and the first voltage comparator (U2) are connected in series through a first NMOS transistor (Q1). The LBI pin of the first voltage comparator (U2) is connected to a first voltage divider resistor (R17) and a second voltage divider resistor (R12). The first voltage divider resistor (R17) and the second voltage divider resistor (R12) are connected in parallel. Both the first voltage divider resistor (R17) and the second voltage divider resistor (R12) are connected to the feeder line. The load side includes a second voltage comparator (U4) and a second latch (U3B). The second voltage comparator (U4) is electrically connected to the power supply module (10), and the second latch (U3B) and the second voltage comparator (U4) are connected in series through a second NMOS transistor (Q3).

2. The residual voltage detector of the distribution network terminal according to claim 1, characterized in that, The power supply module (10) includes a battery interface (P18), a first capacitor (C8), a second capacitor (C9), and a third capacitor (C10). The first capacitor (C8), the second capacitor (C9), and the third capacitor (C10) are connected in parallel. The first capacitor (C8) is connected to a first diode (D13). The positive terminal of the first diode (D13) is connected to the VCC pin of the first voltage comparator (U2). The positive terminal of the third capacitor (C10) is connected to the VCC pin of the second voltage comparator (U4).

3. The residual voltage detector of the distribution network terminal according to claim 1, characterized in that, A third diode (D8) is provided between the first voltage divider resistor (R17) or the second voltage divider resistor (R12) and the feed line.

4. The residual voltage detector of the distribution network terminal according to claim 1, characterized in that, The LBI pin of the second voltage comparator (U4) is connected to the third voltage divider resistor (R20) and the fourth voltage divider resistor (R24), which are connected in parallel. The third voltage divider resistor (R20) or the fourth voltage divider resistor (R24) is connected to the feed line through the fourth diode (D11).

5. The residual voltage detector of the distribution network terminal according to claim 1, characterized in that, One of the pins on the first latch (U3A) is connected to one end of the second diode (D9), and the other end of the second diode (D9) is connected to the fifth voltage divider resistor (R16). The fifth voltage divider resistor (R16) is connected in series with the sixth voltage divider resistor (R28), and the sixth voltage divider resistor (R28) is connected to one of the pins on the second latch (U3B) through the fourth diode (D12).

6. The residual voltage detector of the distribution network terminal according to claim 1, characterized in that, The first latch (U3A) is connected to the connector via the seventh voltage divider resistor (R15), and the second latch (U3B) is connected to the connector via the eighth voltage divider resistor (R26). The connector is used to transmit the detected residual voltage signal.

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