A kind of anti-reverse connection three-phase relay on-off detection device for electric energy meter

Abstract

The utility model discloses a kind of anti-reverse connection three-phase relay on-off detection devices for electric energy meter, including power module, MCU control module, detection module, alarm module and photoelectric communication module;MCU control module is connected with power module, detection module, photoelectric communication module, detection module is connected with alarm module, photoelectric communication module is connected with host computer;The utility model provides a kind of anti-reverse connection three-phase relay on-off detection device for electric energy meter of low-power consumption, high accuracy rate detection relay pulls gate.

Description

Technical Field

[0001] This utility model relates to the field of electricity meter technology, and more specifically, it relates to a three-phase relay continuity detection device for electricity meters to prevent reverse connection. Background Technology

[0002] Relays, as crucial circuit components in smart grids, significantly impact the foundational support of the entire smart grid and provide essential underlying support for the digitalization of smart grid operation and maintenance. Traditional electricity meters, after issuing tripping commands, cannot definitively determine whether the relays have reliably executed the tripping action. Furthermore, traditional electricity meters lack adequate protection against reverse connection faults in their relays. During field installation, if phase wires are reversed or neutral / live wires are incorrectly connected, traditional solutions rely heavily on mechanical marking or manual inspection, lacking real-time electronic detection mechanisms. Reverse currents generated by incorrect field installations can also burn out relay coils; existing fuses, with response delays exceeding 100 ms, are still insufficient to block instantaneous inrush currents.

[0003] Traditional electricity meter relay testing, especially in detecting on / off states, has very low accuracy. The mainstream solution uses current transformers (CTs) for overall sampling, but this cannot identify single-phase relay faults (such as phase sticking or failure to operate). Load fluctuations easily lead to misjudgments, with a false alarm rate as high as 12% (Source: *Electrical Measurement & Instrumentation*, 2023). The data integrity and real-time performance of relay operation counts are also extremely poor. Therefore, there is an urgent need for corresponding testing devices to provide better and more efficient detection. Utility Model Content

[0004] This invention overcomes the shortcomings of the prior art and provides a three-phase relay continuity detection device for energy meters that detects relay tripping with low power consumption and high accuracy.

[0005] The technical solution of this utility model is as follows:

[0006] A reverse connection protection three-phase relay continuity detection device for an energy meter includes a power supply module, an MCU control module, a detection module, an alarm module, and a photoelectric communication module; the MCU control module is connected to the power supply module, the detection module, and the photoelectric communication module; the detection module is connected to the alarm module; and the photoelectric communication module is connected to a host computer.

[0007] The power module provides low-power power to the entire device; the MCU control module is used for signal processing and data accumulation.

[0008] The detection module includes a three-phase detection circuit, and each phase circuit contains a reverse connection protection detection unit; it detects the voltage difference between the input terminals through optocouplers and rectifier diodes, and outputs a waveform signal when the wiring is incorrect;

[0009] The alarm module illuminates its alarm light and controls the relay to disconnect when a wiring error is detected, thus protecting the back-end circuitry.

[0010] The optoelectronic communication module is used to transmit the number of relay actions accumulated by the MCU control module to the host computer.

[0011] Furthermore, the reverse connection protection detection unit includes a rectifier diode, a current-limiting resistor, and an optocoupler isolator, with the specific connections as follows:

[0012] The front-end of a certain phase of the three-phase detection circuit is connected to pin 1 of rectifier diode M7. Pin 2 of rectifier diode M7 is connected to one end of resistor R1. The other end of resistor R1 is connected to pin 1 of optocoupler E6. Pin 2 of optocoupler E6 is connected to the rear-end of the same phase of the three-phase detection circuit. Pin 3 of optocoupler E6 is grounded. Pin 4 of optocoupler E6 is connected to one end of resistor R29 and the MCU control module. The other end of resistor R29 is connected to 3.3V.

[0013] Among them, rectifier diode M7 is used to rectify AC power into DC power; resistor R1 limits current to prevent overcurrent from damaging optocoupler E6; when an error occurs in the wiring of optocoupler E6, a waveform signal is generated at the output terminal.

[0014] Furthermore, each phase detection circuit of the detection module also includes a continuity signal acquisition unit, which outputs a low-level signal to the MCU control module when relay EP3 is correctly closed;

[0015] Specifically, it includes resistor R20, resistor R19, relay EP3, optocoupler E9, optocoupler E4, resistor R24, light-emitting diode D9, resistor R9, and DP4 rectifier diode M7;

[0016] One end of resistor R20 is connected to 3.3V, and the other end of resistor R20 is connected to pin 1 of optocoupler E9. Pin 2 of optocoupler E9 is connected to the MCU control module. Pin 3 of optocoupler E9 is connected to one end of resistor R19, and pin 4 of optocoupler E9 is connected to 3.3V. The other end of resistor R19 is connected to pin 1 of relay EP3. Pin 2 of relay EP3 is grounded. Pin 3 of relay EP3 is connected to pin 1 of optocoupler E4, and pin 4 of relay EP3 is connected to the downstream terminal of a certain phase. Pin 2 of optocoupler E4 is grounded, pin 3 of optocoupler E4 is grounded, and pin 4 of optocoupler E4 is connected to one end of resistor R24 ​​and one end of the MCU control module. The other end of resistor R24 ​​is connected to 3.3V.

[0017] Pin 4 of optocoupler E9 is connected to the positive terminal of LED D9. The negative terminal of LED D9 is connected to one end of resistor R9. The other end of resistor R9 is connected to pin 1 of rectifier diode M7 (DP4). Pin 2 of rectifier diode M7 (DP4) is connected to the same phase preceding stage.

[0018] Furthermore, the alarm module includes a resistor R68 and a light-emitting diode D8. One end of the resistor R68 is connected to one end of the MCU control module, and the other end of the resistor R68 is connected to the positive terminal of the light-emitting diode D8. The negative terminal of the light-emitting diode D8 is grounded.

[0019] Furthermore, the optoelectronic communication module is replaced with an RS-485 communication module.

[0020] Furthermore, each phase circuit of the detection module operates independently. When any phase detects that the relay is closed, it sends a low-level signal to the MCU control module, and the MCU control module independently accumulates the number of single-phase actions.

[0021] The advantages of this utility model are:

[0022] This solution can clearly determine whether the relay has reliably executed the opening and closing command after the host computer issues it. It can provide a warning when the wiring is incorrect, and the circuit also has protective measures to prevent high-voltage damage to the device if the testing personnel fail to read the warning and connect the wiring incorrectly.

[0023] Because relay failures may not be limited to the overall relay circuit breaker failure, but more often involve a specific circuit failing, corresponding detection designs are needed for all three relay circuits. Existing technology involves communication between a host computer and a meter, using the meter's returned information to determine whether the circuit breaker tripped successfully. However, in reality, some meters frequently return incorrect information under high temperature and humidity conditions, returning a success message even when the relay failed to trip, leading to completely inaccurate experiments. This proposed solution effectively avoids this situation, improving reliability.

[0024] This solution prioritizes convenience, employing a removable battery power supply and featuring an overall low-power design. It also incorporates photoelectric communication to report the actual number of circuit breaker openings and closings to the system. The circuit includes incorrect connection indicators and protection devices, further enhancing its portability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall module of this utility model;

[0026] Figure 2 This is a circuit diagram of the reverse polarity detection unit for the C-phase of this utility model;

[0027] Figure 3This is a circuit diagram of the MCU control module of this utility model;

[0028] Figure 4 This is a circuit diagram of the on / off signal acquisition unit of this utility model;

[0029] Figure 5 This is a circuit diagram of the alarm module of this utility model. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments are merely specific descriptions of the present invention, and their purpose is to enable those skilled in the art to better understand the technical solution of the present invention, and should not be regarded as limitations on the present invention. Example

[0031] like Figures 1 to 5 As shown, a three-phase relay on / off detection device for electricity meters with reverse connection protection includes a power supply module, an MCU control module, a detection module, an alarm module, and a photoelectric communication module. The MCU control module is connected to the power supply module, the detection module, and the photoelectric communication module; the detection module is connected to the alarm module; and the photoelectric communication module is connected to a host computer. This solution, through integrated design and the coordinated operation of the power supply, MCU, detection, alarm, and communication modules, achieves comprehensive monitoring of the relay on / off status of the electricity meter, improving system reliability.

[0032] The power module provides low-power power to the entire device; the MCU control module is used for signal processing and data accumulation.

[0033] The detection module includes a three-phase detection circuit, and each phase circuit contains a reverse connection protection detection unit; it detects the voltage difference between the input terminals through optocouplers and rectifier diodes, and outputs a waveform signal when the wiring is incorrect.

[0034] The alarm module illuminates its alarm light and controls the relay to disconnect when a wiring error is detected, thus protecting the back-end circuitry.

[0035] The optoelectronic communication module is used to transmit the number of relay actions accumulated by the MCU control module to the host computer.

[0036] Specifically, the power module uses a 3.6V pluggable battery to power the MCU control module and other modules.

[0037] When reverse wiring is detected, the alarm light on the alarm module illuminates, alerting the user to incorrect wiring. When the relay successfully completes one opening and closing cycle, the detection module outputs a signal, which is transmitted to the MCU control module. The MCU control module then processes this signal and accumulates the values. Upon completion of the detection, the data is transmitted to the host computer via the photoelectric communication module for comparison.

[0038] Preferably, the reverse connection protection detection unit includes a rectifier diode, a current-limiting resistor, and an optocoupler isolator. Taking phase C of a three-phase system as an example, its specific connection is as follows: Figure 2 As shown:

[0039] The C-phase preamp of the three-phase detection circuit is connected to pin 1 of DP5 rectifier diode M7. Pin 2 of DP5 rectifier diode M7 is connected to one end of resistor R1. The other end of resistor R1 is connected to pin 1 of optocoupler E6. Pin 2 of optocoupler E6 is connected to the postamp of the same phase of the three-phase detection circuit. Pin 3 of optocoupler E6 is grounded. Pin 4 of optocoupler E6 is connected to one end of resistor R29 and the MCU control module. The other end of resistor R29 is connected to 3.3V.

[0040] Among them, DP5 rectifier diode M7 is used to rectify AC power into DC power; resistor R1 limits current to prevent overcurrent from damaging optocoupler E6; when an error occurs in the wiring of optocoupler E6, a waveform signal is generated at the output terminal.

[0041] When the C-phase preamplifier and C-phase output terminals are correctly connected to the circuit, no current signal is transmitted to the RELAY_TEST_C2 pin of the MCU control module due to the lack of voltage difference; therefore, RELAY_TEST_C2 remains high. However, when the C-phase preamplifier and C-phase output terminals are incorrectly connected (e.g., connected to the A-phase preamplifier and neutral wire), current flows from the C-phase preamplifier through DP5 rectifier diode M7, resistor R1, and optocoupler E6 back to the C-phase output terminal due to the voltage difference. Optocoupler E6 transmits this signal to pins 3 and 4. In this case, the waveform at RELAY_TEST_C2 will resemble a sine wave. (DP5 rectifier diode M7's function is rectification, preventing AC power from damaging components such as optocouplers. Resistor R1's function is current limiting, preventing excessive current from damaging optocoupler E6. Optocoupler E6's function is to isolate and transmit signals, separating the high-voltage 220V AC power from the low-voltage power at the chip end. Resistor R29 acts as a pull-up resistor, ensuring that the level at RELAY_TEST_C2 is high when there is no signal. RELAY_TEST_C2 is connected to pin 8 of the microcontroller in the MCU control module; it is normally high when there is no signal, and displays a sawtooth-like waveform when there is a signal.)

[0042] Preferably, each phase detection circuit of the detection module also includes a continuity signal acquisition unit, which outputs a low-level signal to the MCU control module when the relay EP3 is correctly closed.

[0043] Specifically, such as Figure 4As shown, it includes resistor R20, resistor R19, relay EP3, optocoupler E9, optocoupler E4, resistor R24, light-emitting diode D9, resistor R9, and DP4 rectifier diode M7;

[0044] One end of resistor R20 is connected to 3.3V, and the other end of resistor R20 is connected to pin 1 of optocoupler E9. Pin 2 of optocoupler E9 is connected to the MCU control module. Pin 3 of optocoupler E9 is connected to one end of resistor R19, and pin 4 of optocoupler E9 is connected to 3.3V. The other end of resistor R19 is connected to pin 1 of relay EP3. Pin 2 of relay EP3 is grounded. Pin 3 of relay EP3 is connected to pin 1 of optocoupler E4, and pin 4 of relay EP3 is connected to the downstream terminal of a certain phase. Pin 2 of optocoupler E4 is grounded, pin 3 of optocoupler E4 is grounded, and pin 4 of optocoupler E4 is connected to one end of resistor R24 ​​and one end of the MCU control module. The other end of resistor R24 ​​is connected to 3.3V.

[0045] Pin 4 of optocoupler E9 is connected to the positive terminal of LED D9. The negative terminal of LED D9 is connected to one end of resistor R9. The other end of resistor R9 is connected to pin 1 of rectifier diode M7 (DP4). Pin 2 of rectifier diode M7 (DP4) is connected to the same phase preceding stage.

[0046] Resistors R20, R19, and R9 limit current to prevent excessive current from damaging optocoupler E9, solid-state relay EP3, and LED D9. Resistor R24 ​​acts as a pull-up resistor. DP4 and rectifier diode M7 prevent AC current from damaging LED D9 in case of incorrect wiring.

[0047] The alarm module is as follows Figure 5 The diagram illustrates phase C as an example, including resistor R68 and LED D8. One end of resistor R68 is connected to one end of the MCU control module, and the other end of resistor R68 is connected to the positive terminal of LED D8. The negative terminal of LED D8 is grounded. Resistor R68 serves to limit current, preventing excessive current from damaging LED D8.

[0048] When the wiring is incorrect, RELAY_TEST_C3 becomes a high-level signal, which is transmitted to the solid-state relay EP3 through optocoupler E9 and resistor R19. After receiving the signal, EP3 disables pins 3 and 4, keeping them in the open state to protect downstream circuits such as optocoupler E4.

[0049] When the connection is correct, RELAY_TEST_C3 is a low-level signal, transmitted to the solid-state relay EP3 via optocoupler E9 and resistor R19. Upon receiving the signal, EP3 closes its pins 3 and 4. When the solid-state relay EP3 is closed (equivalent to a short circuit between the C-phase front and rear stages), a complete circuit is formed, LED D9 lights up, optocoupler E4 conducts, and the RELAY_TEST_C signal goes low. The counter in the MCU control module is incremented by one.

[0050] The C phase is used as an example here. The other two phases, A and B, are designed based on the same principle.

[0051] like Figure 3 As shown, C2 and C6 in the MCU control module are decoupling capacitors, which reduce high-frequency noise and improve the stability of the microcontroller operation in the MCU control module. The microcontroller's IR_RXD and IR_TXD are optoelectronic serial ports for communication with the host computer.

[0052] When an incorrect connection is made, RELAY_TEST_C2 receives a sawtooth wave signal, RELAY_TEST_C3 outputs a high level, ALarm1 outputs a high level, and the alarm light illuminates, alerting the user to the incorrect connection. (At this time, solid-state relay EP3 disconnects, thus protecting the downstream circuitry.)

[0053] When the connection is correct, RELAY_TEST_C2 receives a high-level signal lasting longer than 500ms, RELAY_TEST_C3 outputs a low level, solid-state relay EP3 closes, and the red light flashes (indicating successful relay closure). When RELAY_TEST_C receives a low-level signal, the MCU control module increments the counter by one.

[0054] Preferably, the optoelectronic communication module can be replaced with an RS-485 communication module. Each phase circuit of the detection module operates independently. When any phase detects a relay closure, it sends a low-level signal to the MCU control module, which independently accumulates the number of single-phase actions.

[0055] In summary, this solution can clearly determine whether the relay has reliably executed the opening and closing command after the host computer issues it. It can provide a warning when the wiring is incorrect, and the circuit also has protective measures in place to prevent high-voltage damage to the device if testing personnel fail to read the warning and connect the wiring incorrectly.

[0056] It is worth noting that the other technical features of this utility model are all existing technologies, and therefore will not be described in detail.

[0057] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the concept of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A three-phase relay continuity detection device for reverse connection protection in an electricity meter, characterized in that, It includes a power supply module, an MCU control module, a detection module, an alarm module, and an optoelectronic communication module; the MCU control module is connected to the power supply module, the detection module, and the optoelectronic communication module; the detection module is connected to the alarm module; and the optoelectronic communication module is connected to the host computer. The power module provides low-power power to the entire device; the MCU control module is used for signal processing and data accumulation. The detection module includes a three-phase detection circuit, and each phase circuit contains a reverse connection protection detection unit; it detects the voltage difference between the input terminals through optocouplers and rectifier diodes, and outputs a waveform signal when the wiring is incorrect; The alarm module illuminates its alarm light and controls the relay to disconnect when a wiring error is detected, thus protecting the back-end circuitry. The optoelectronic communication module is used to transmit the number of relay actions accumulated by the MCU control module to the host computer.

2. The reverse connection protection three-phase relay continuity detection device for an energy meter according to claim 1, characterized in that: The reverse connection protection detection unit includes a rectifier diode, a current-limiting resistor, and an optocoupler isolator, with the following specific connections: The front-end of a certain phase of the three-phase detection circuit is connected to pin 1 of rectifier diode M7. Pin 2 of rectifier diode M7 is connected to one end of resistor R1. The other end of resistor R1 is connected to pin 1 of optocoupler E6. Pin 2 of optocoupler E6 is connected to the rear-end of the same phase of the three-phase detection circuit. Pin 3 of optocoupler E6 is grounded. Pin 4 of optocoupler E6 is connected to one end of resistor R29 and the MCU control module. The other end of resistor R29 is connected to 3.3V. Among them, rectifier diode M7 is used to rectify AC power into DC power; resistor R1 limits current to prevent overcurrent from damaging optocoupler E6; when an error occurs in the wiring of optocoupler E6, a waveform signal is generated at the output terminal.

3. The reverse connection protection three-phase relay continuity detection device for an energy meter according to claim 1, characterized in that: Each phase detection circuit of the detection module also includes a continuity signal acquisition unit. When relay EP3 is correctly closed, it outputs a low-level signal to the MCU control module. Specifically, it includes resistor R20, resistor R19, relay EP3, optocoupler E9, optocoupler E4, resistor R24, light-emitting diode D9, resistor R9, and DP4 rectifier diode M7; One end of resistor R20 is connected to 3.3V, and the other end of resistor R20 is connected to pin 1 of optocoupler E9. Pin 2 of optocoupler E9 is connected to the MCU control module. Pin 3 of optocoupler E9 is connected to one end of resistor R19, and pin 4 of optocoupler E9 is connected to 3.3V. The other end of resistor R19 is connected to pin 1 of relay EP3. Pin 2 of relay EP3 is grounded. Pin 3 of relay EP3 is connected to pin 1 of optocoupler E4, and pin 4 of relay EP3 is connected to the downstream terminal of a certain phase. Pin 2 of optocoupler E4 is grounded, pin 3 of optocoupler E4 is grounded, and pin 4 of optocoupler E4 is connected to one end of resistor R24 ​​and one end of the MCU control module. The other end of resistor R24 ​​is connected to 3.3V. Pin 4 of optocoupler E9 is connected to the positive terminal of LED D9. The negative terminal of LED D9 is connected to one end of resistor R9. The other end of resistor R9 is connected to pin 1 of rectifier diode M7 (DP4). Pin 2 of rectifier diode M7 (DP4) is connected to the same phase preceding stage.

4. The reverse connection protection three-phase relay continuity detection device for an energy meter according to claim 1, characterized in that: The alarm module includes a resistor R68 and a light-emitting diode D8. One end of the resistor R68 is connected to one end of the MCU control module, and the other end of the resistor R68 is connected to the positive terminal of the light-emitting diode D8. The negative terminal of the light-emitting diode D8 is grounded.

5. The reverse connection protection three-phase relay continuity detection device for an energy meter according to claim 1, characterized in that: The optoelectronic communication module was replaced with an RS-485 communication module.

6. The three-phase relay continuity detection device for reverse connection protection in an energy meter according to claim 1, characterized in that: Each phase circuit of the detection module operates independently. When any phase detects that the relay is closed, it sends a low-level signal to the MCU control module. The MCU control module independently accumulates the number of single-phase actions.

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