Intelligent electric power metering terminal box with data traceability function

Abstract

The application discloses a kind of intelligent electric power metering terminal box with data traceability function, including shell and the MCU being located in shell, and MCU is connected with clock circuit and data storage;MCU is connected with multiple relay drivers, and relay driver is connected voltage control relay and current short-circuit relay respectively;Voltage control relay is turned on in operating state, and current short-circuit relay is in first combination state to make current loop access electric energy metering;In the state of meter change, voltage control relay is disconnected, and current short-circuit relay is in second combination state to make current loop short-circuit bypass.When state switches, MCU reads time information from clock circuit, generates event record data containing switching time, state before switching and state after switching and stores into data storage.It realizes the combination of electronic intelligent control and data traceability function, solves the problems of traditional mechanical terminal box, such as complicated operation, poor safety, lack of data traceability, etc., and is suitable for electric power system electric energy measurement field.

Description

Technical Field

[0001] This invention relates to the field of power metering equipment technology, and in particular to an intelligent power metering junction box with data traceability function, especially a power metering junction box that realizes intelligent switching between operating status and meter replacement status based on microcontroller and relay electronic control, and records data traceability of operation events. Background Technology

[0002] The junction box for electricity metering is an indispensable and important piece of equipment in a power metering system. It is mainly used to connect metering devices such as current transformers and voltage transformers to electricity meters and data acquisition terminals, enabling on / off control of the voltage circuit and short-circuiting and serial connection of the current circuit. The reliability and ease of operation of the junction box directly affect the accuracy of electricity metering and the efficiency of power operation and maintenance.

[0003] Currently, the widely used electricity metering junction boxes in power systems primarily employ mechanical linkage structures to achieve circuit switching operations. In traditional mechanical junction boxes, voltage and current connecting plates are manually moved, relying on the physical contact of the metal connecting plates to achieve the switching on and off of voltage circuits and the shorting of current circuits. This traditional operating method has several problems. First, the operation process is cumbersome and prone to errors. In scenarios such as electricity meter replacement, calibration, or fault handling, maintenance personnel need to follow a prescribed operating sequence, using a screwdriver to move the voltage and current connecting plates one by one. Voltage connecting plates need to be disconnected, and current connecting plates need to be shorted. The operation involves many steps and strict requirements for the sequence, and even slight carelessness can lead to misoperation, causing personal injury or equipment damage. Second, it places extremely high safety requirements on operators. The operation of traditional junction boxes involves live work, requiring operators to directly contact the metal connecting plates inside the junction box, posing a risk of electric shock. The confined working space further increases the difficulty and danger of the operation. Secondly, traditional mechanical junction boxes have a slow switching speed, with a complete meter replacement operation typically taking 15 to 20 minutes. During this time, electricity metering is interrupted, resulting in the inability to effectively compensate for lost electricity and causing economic losses for power supply companies. Furthermore, mechanical junction boxes are prone to poor contact and oxidation corrosion over long-term use, affecting the reliability of circuit continuity and consequently the accuracy of electricity metering. Finally, traditional junction boxes lack the ability to record and trace the operation process. Information such as when the meter replacement operation was performed, how the circuit status changed before and after the operation, and who the operator was cannot be traced, creating difficulties in handling metering disputes, determining responsibility, and managing operations.

[0004] With the continuous development of smart grid construction, power metering equipment is transforming from "single metering devices" to "data acquisition and edge control terminals." In recent years, some improvement solutions have emerged in the industry. For example, Chinese patent CN221224977U discloses a combined junction box for automatic open-circuit and short-circuit power metering, which automates operation by controlling the opening and shorting of voltage and current contacts via relays on a circuit board. Another example is Chinese patent application CN121613159A, which discloses an intelligent analytical junction box and its control system, possessing voltage and current data sampling, comparison, and transmission functions. However, while these existing solutions address the issues of operational convenience and safety to some extent, they still have the following shortcomings: Firstly, they do not solve the problem of tracing and recording operational events, lacking the ability to record complete data for key events such as meter replacement and status switching; secondly, their data recording functions mainly focus on the acquisition of voltage and current data, rather than tracing the operational events themselves. In the event of metering disputes or the need to trace historical operations, existing junction boxes cannot provide reliable evidence of the events.

[0005] Therefore, there is an urgent need for an intelligent power metering junction box that can realize electronic intelligent control of voltage and current circuits, and at the same time has the function of recording and tracing operation event data, in order to solve the many problems existing in the above-mentioned existing technologies. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide an intelligent power metering junction box with data traceability. This box replaces the traditional mechanical junction box structure with a microcontroller (MCU) and relay electronic control system, enabling automatic and rapid switching between operating and meter-changing states. It integrates a clock circuit and data storage to accurately timestamp and store each state-switching event, providing complete event traceability for power metering operations. This invention effectively solves the problems of cumbersome operation, poor security, slow switching speed, and lack of data traceability in traditional mechanical junction boxes, while significantly improving the accuracy of power metering and the level of informatization in operation and maintenance management.

[0007] The above-mentioned objective of this invention is achieved through the following technical solutions:

[0008] A smart power metering junction box with data traceability includes a housing containing an MCU (Microcontroller Unit). The MCU is connected to a clock circuit and a data storage device. The MCU is connected to multiple relay drivers, which are respectively connected to a voltage control relay for controlling the on / off state of the voltage circuit and a current short-circuit relay for controlling the short-circuit state of the current circuit. The MCU is configured to control the voltage control relay and the current short-circuit relay to switch between a running state and a meter-changing state. In the running state, the voltage control relay is turned on, connecting the voltage circuit, and the current short-circuit relay is in a first combined state, allowing the current circuit to connect to the energy meter for metering. In the meter-changing state, the voltage control relay is turned off, disconnecting the voltage circuit, and the current short-circuit relay is in a second combined state, allowing the current circuit to bypass and not flow through the energy meter. When the junction box switches between the running state and the meter-changing state, the MCU reads time information from the clock circuit, generates event record data including the switching time, the state before the switching, and the state after the switching, and writes the event record data into the data storage device for storage.

[0009] In a specific embodiment of the present invention, the MCU is connected to the clock circuit and the data memory via a data interface Type-C, and the power supply is provided to the MCU via the data interface Type-C; the MCU is connected to 10 relay drivers K1 to K10, and each of the 10 relay drivers K1 to K10 is connected to a relay control coil, for a total of 10 relay control coils L1 to L10.

[0010] The housing is provided with 7 sets of circuit structures, specifically including:

[0011] The first circuit structure includes a 3P terminal, a relay 1, an indicator light 1, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 1, and the indicator light 1 is connected to the relay 1. The 1-2P yellow terminals are the voltage phase A, which is controlled by the relay to turn on and off. When the power is on, the red indicator light is on, and when the power is off, the green indicator light is on.

[0012] The second circuit structure includes electrically connected ia terminals and 1i terminals, electrically connected 3P terminals and ia terminals, and electrically connected 3i terminals and 3i terminals. Relay 2 and indicator light 2 are connected between electrically connected ia terminals, 1i terminals and electrically connected 3P terminals, and ia terminals. Relay 3 and indicator light 3 are connected between electrically connected 3P terminals, ia terminals and electrically connected 3i terminals and 3i terminals. The yellow 3P terminal is the voltage phase A, which is controlled by the relay to turn on and off. When energized, the red indicator light is on, and when de-energized, the green indicator light is on.

[0013] The third circuit structure includes a 3P terminal, a relay 4, an indicator light 4, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 4, and the indicator light 4 is connected to the relay 4. The 1-2P green terminal is the voltage phase A, which is controlled by the relay to turn on and off. When the power is on, the red indicator light is on, and when the power is off, the green indicator light is on.

[0014] The fourth circuit structure includes electrically connected ib terminals and 3P terminals, electrically connected 3P terminals and ia terminals, and electrically connected 3i terminals and 3i terminals. Relay 5 and indicator light 5 are connected between electrically connected ib terminals, 3P terminals and electrically connected 3P terminals and ia terminals. Relay 6 and indicator light 6 are connected between electrically connected 3P terminals, ia terminals and electrically connected 3i terminals and 3i terminals. Among them, the green 3-3P terminal is the voltage A phase, which is controlled by the relay to turn on and off. When energized, the red indicator light is on, and when de-energized, the green indicator light is on.

[0015] The fifth circuit structure includes a 3P terminal, a relay 7, an indicator light 7, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 7, and the indicator light 7 is connected to the relay 7. The 1-2P red terminal is the voltage phase A, which is controlled by the relay to turn on and off. When the power is on, the red indicator light is on, and when the power is off, the green indicator light is on.

[0016] The sixth circuit structure includes electrically connected IC terminals and 3P terminals, electrically connected 3P terminals and ia terminals, and electrically connected ia terminals and 3P terminals. Relay 8 and indicator light 8 are connected between electrically connected IC terminals, 3P terminals and electrically connected 3P terminals and ia terminals. Relay 9 and indicator light 9 are connected between electrically connected 3P terminals, ia terminals and electrically connected ia terminals and 3P terminals. Among them, the red terminal of 3-3P is the voltage A phase, which is controlled by the relay to turn on and off. When energized, the red indicator light is on, and when de-energized, the green indicator light is on.

[0017] The seventh circuit structure includes a 3P terminal, a relay 10, an indicator light 10, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 10, and the indicator light 10 is connected to the relay 10. The 1-2P blue terminals are the voltage phase A, which is controlled by the relay to turn on and off. When the power is on, the red indicator light is on, and when the power is off, the green indicator light is on.

[0018] In the above 7 circuit structures, the voltage control relays include relays 1, 4, 7, and 10, which are used to control the on / off state of the three outputs of phase A and phase N, respectively; the current short-circuit relays include relays 2, 3, 5, 6, 8, and 9, which are divided into three pairs and correspond to the control of the current loops of phase A, phase B, and phase C, respectively; among them, relays 2, 5, and 8 are running short-circuit relays, and relays 3, 6, and 9 are meter replacement short-circuit relays.

[0019] The junction box has two operating states:

[0020] Operating status: Relays 1, 4, 7, and 10 are in the ON state; relays 2, 5, and 8 are in the ON state; relays 3, 6, and 9 are in the OFF state. Under operating conditions, the voltage circuit is normally connected, and the energy meter is normally connected to the voltage circuit for energy measurement; in the current circuit, current flows normally through the short-circuit formed by relays 2, 5, and 8, and the energy meter normally measures the current.

[0021] Meter replacement status: Relays 1, 4, 7, and 10 are in the open state; relays 2, 5, and 8 are in the open state; relays 3, 6, and 9 are in the closed state. In this state, the voltage circuit is disconnected, and the energy meter is disconnected from the voltage circuit, ensuring operator safety. In the current circuit, the current continues to conduct through the short-circuit formed by relays 3, 6, and 9, ensuring that the secondary circuit of the current transformer will not be open-circuited. Simultaneously, the energy meter is disconnected from the current circuit, allowing for safe meter replacement.

[0022] By intelligently switching between the two states, this invention enables the safe and rapid replacement of electricity meters or the performance of calibration operations without power outages, ensuring the personal safety of operators and avoiding power loss caused by power outages.

[0023] Furthermore, the MCU has a built-in state switching control program, which is configured such that when a meter replacement command is received, the MCU controls each relay to switch states according to a preset timing sequence via a relay driver. The preset timing sequence includes: first, controlling relays 1, 4, 7, and 10 to disconnect, cutting off the voltage circuit; then, controlling relays 2, 5, and 8 to disconnect, and relays 3, 6, and 9 to conduct, completing the switch of the current circuit from the operating short-circuit state to the meter replacement short-circuit state. Through reasonable timing control, it is ensured that dangerous situations such as a live voltage circuit disconnection or a momentary open circuit in the current circuit will not occur during the switching process, thus protecting the safety of equipment and personnel.

[0024] Furthermore, the clock circuit provides a precise time reference for the MCU, and the data memory stores state switching event records. When the junction box switches between a running state and a meter-changing state, the MCU reads the current time information from the clock circuit, generates event record data including the switching time, the state before the switch, the state after the switch, and the operation type, and writes the event record data into the data memory for storage. In this way, every meter-changing operation or state switch can be completely recorded, forming a traceable data archive.

[0025] Furthermore, the data storage is a non-volatile memory, capable of retaining the stored data without loss after power failure. Preferably, the data storage is an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a Flash memory.

[0026] Furthermore, the Type-C data interface is not only used to connect the clock circuit and data storage, and to provide power, but also to communicate with external data reading devices. Maintenance personnel can connect a handheld terminal or computer via the Type-C interface to read historical event records stored in the data storage, enabling data export, analysis, and tracing.

[0027] Furthermore, the MCU is also connected to a wireless communication module, which is used to upload state switching event records to a remote monitoring platform in real time. This allows administrators to remotely monitor the status changes and operational status of the junction box in real time, further enhancing the level of intelligent management.

[0028] Furthermore, the outer surface of the housing is provided with a status indicator panel, which has two status indicator lights corresponding to the running state and the meter replacement state, respectively, as well as a status switching button. Maintenance personnel can trigger the junction box to switch from the running state to the meter replacement state, or vice versa, with a single press of the status switching button. The operation is simple and quick, eliminating the need to manually adjust each connection piece, significantly improving operational efficiency and safety.

[0029] Furthermore, the outer surface of the housing is also provided with an LCD screen to display information such as the current working status, the last switching time, and the cumulative number of switching times, so that maintenance personnel can easily check it on-site.

[0030] Furthermore, the relay is a magnetic latching relay, which can maintain the contact state before the power failure after the power is cut off, so that the current circuit will not be accidentally disconnected in the event of an unexpected power failure of the junction box, thus ensuring the safety of the secondary circuit of the current transformer.

[0031] In summary, compared with the prior art, the present invention has at least one of the following beneficial technical effects:

[0032] Electronic intelligent control ensures safe and efficient operation: This invention replaces the traditional mechanical connection structure with an MCU and relay electronic control system, realizing electronic, one-button switching of voltage and current circuit states. It eliminates the need for maintenance personnel to manually move the connecting pieces, avoiding direct contact with live parts and significantly reducing the risk of electric shock and operational difficulty. The one-button switching operation can be completed in seconds. Compared to traditional methods, meter replacement time is reduced from 15-20 minutes to just seconds, significantly improving work efficiency.

[0033] Comprehensive Data Traceability Function: This invention integrates a clock circuit and a data storage device to accurately record and store each state switching event. The recorded content includes key information such as switching time, pre-switching state, post-switching state, and operation type, forming a complete event log. In the event of metering disputes or the need to trace historical operations, data can be exported via a Type-C interface or wireless communication module, providing reliable traceability evidence. This function effectively solves the problem of "black box" operation in traditional junction boxes, providing technical support for standardized management and accountability of power metering.

[0034] Safe and reliable operation: This invention uses preset timing control logic to ensure that the voltage circuit is disconnected first and the current circuit switches later during state switching, eliminating the safety hazards of voltage circuit disconnection while energized and current circuit instantaneous open circuit. Simultaneously, the use of a magnetic latching relay ensures that even in the event of an unexpected power outage at the junction box, the current circuit remains short-circuited, ensuring that the secondary circuit of the current transformer will not open and guaranteeing equipment safety.

[0035] Uninterrupted meter replacement, avoiding power loss: During meter replacement, the current loop remains short-circuited and conductive via the meter replacement short-circuit relay, ensuring the secondary circuit of the current transformer remains closed. This ensures uninterrupted power supply to the user, enabling uninterrupted meter replacement. There are no metering gaps during replacement, avoiding power loss and subsequent recovery difficulties caused by power outages in traditional methods.

[0036] Visualized and Information-Based Management: This invention features a status indicator panel and an LCD screen, which can intuitively display the current operating status and historical operation information. Through a wireless communication module, status switching events can be uploaded to a remote monitoring platform in real time, enabling remote monitoring, early warning, and management, aligning with the development trend of information-based management in smart grids.

[0037] Compact structure and easy to promote: This invention integrates core components such as MCU, relay, clock circuit, and data storage into a junction box housing. The structure is compact and the size is compatible with traditional junction boxes, making it easy to directly replace and install in existing metering devices. It has good prospects for promotion and application. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of the intelligent power metering junction box in an embodiment of the present invention.

[0039] Figure 2 This is a top view of the intelligent power metering junction box in an embodiment of the present invention.

[0040] Figure 3 This is a circuit block diagram of the intelligent power metering junction box in an embodiment of the present invention.

[0041] Figure 4 This is a schematic diagram of the external status indicator panel of the housing in an embodiment of the present invention.

[0042] Reference numerals: 100, housing; 101, MCU; 102, data interface Type-C; 103, clock circuit; 104, data memory. Detailed Implementation

[0043] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0044] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0046] Example 1:

[0047] like Figures 1 to 4 As shown in the figure, this embodiment provides an intelligent power metering junction box with data traceability function.

[0048] like Figure 1 and Figure 2 As shown, the intelligent power metering junction box of the present invention includes a housing 100, which is made of flame-retardant engineering plastic and has good insulation performance and mechanical strength. The housing 100 has a circuit board inside, on which core electronic components such as an MCU 101 (microcontroller unit), a relay driver array, a relay array, a clock circuit 103, and a data storage device 104 are integrated.

[0049] like Figure 3 As shown, MCU101 employs a 32-bit ARM Cortex-M series microcontroller, characterized by strong processing power, low power consumption, and rich peripheral interfaces. MCU101 is connected to the clock circuit 103 and the data memory 104 via a Type-C data interface 102. The Type-C data interface 102 adopts the USB Type-C physical interface standard, offering advantages such as good reversible plug compatibility, high data transfer rate, and strong power supply capability. In this invention, the Type-C data interface 102 simultaneously performs three functions: first, providing operating power to MCU101; second, serving as a data communication channel between MCU101 and the clock circuit 103 and data memory 104; and third, serving as an external communication interface for connecting to external data reading devices or a host computer.

[0050] The clock circuit 103 uses a high-precision real-time clock chip with a built-in crystal oscillator and backup battery, enabling it to continue timing even when the main power supply to the junction box is interrupted, ensuring the continuity and accuracy of time information. The clock circuit 103 provides the MCU 101 with precise date and time information (year, month, day, hour, minute, second), with an accuracy of ±1 second / day.

[0051] The data storage 104 uses an EEPROM (Electrically Erasable Programmable Read-Only Memory) with a capacity of 64KB, supports 1 million erase / write cycles, and has a data retention time of over 100 years. The data storage 104 is used to store state transition event logs; the stored data will not be lost even if the junction box is powered off.

[0052] The MCU101 is connected to 10 relay drivers K1 to K10, each corresponding to a relay control coil L1 to L10. The relay drivers K1 to K10 use Darlington transistor array chips, providing sufficient drive current to reliably drive the relay coil. When the MCU101's I / O port outputs a control signal, the corresponding relay driver conducts, energizing the relay coil, and the relay contacts actuate accordingly, realizing the circuit's on / off control. The relays are magnetically latched relays, characterized by low power consumption, large contact capacity, and power-off retention.

[0053] The housing 100 is equipped with 7 sets of circuit structures, which correspond to the connection and control of the three-phase voltage circuit (phase A, phase B, phase C and phase N) and the three-phase current circuit (phase A, phase B and phase C).

[0054] The first circuit structure corresponds to the first output control of phase A voltage. Specifically, it includes a 3P terminal, relay 1, indicator light 1, and two 1P terminals. The 3P terminal is used to connect the phase A voltage signal from the voltage transformer. The two 1P terminals are output terminals, used to connect to the phase A voltage input terminal of the energy meter. The contacts of relay 1 are connected in series between the 3P terminal and the two 1P terminals. When the coil L1 of relay 1 is energized, the contacts close, the 3P terminal and the two 1P terminals conduct, and the phase A voltage signal is output to the energy meter; when the coil of relay 1 is de-energized, the contacts open, cutting off the output of the phase A voltage signal. Indicator light 1 is connected in parallel across the contacts of relay 1, including a red LED and a green LED, each connected in series by two current-limiting resistors. When relay 1 is on, the red LED lights up; when relay 1 is off, the green LED lights up. The color of the indicator light allows maintenance personnel to visually determine the on / off status of the voltage circuit. In this circuit structure, the 1-2P yellow terminals are the phase A voltage output terminals.

[0055] The second circuit structure corresponds to the control loop of phase A of the current. Controlling the current loop is relatively complex, requiring simultaneous normal serial current flow during operation and short-circuiting of the current during meter switching. This circuit structure includes electrically connected terminals ia and 1i, electrically connected terminals 3P and ia, and electrically connected terminals 3i and 3i.

[0056] Relay 2 and indicator light 2 are connected between the electrical connection terminals ia and 1i and the electrical connection terminals 3P and ia. When relay 2 is on, the circuit between terminals ia and 1i is completed, and the circuit between terminals 3P and ia is completed. Current flows from terminals ia to 1i, passes through the A-phase current coil of the energy meter, and forms a current measurement circuit in the operating state. When relay 2 is off, this current path is interrupted.

[0057] Relay 3 and indicator light 3 are connected between the 3P and ia terminals of the electrical connection and between the 3i and 3i terminals of the electrical connection. When relay 3 is on, a short circuit is formed between the 3P and ia terminals and between the 3i and 3i terminals. The current flows directly through the short circuit without passing through the A-phase current coil of the energy meter, realizing the current bypass function in the meter replacement state. Indicator lights 2 and 3 also use red and green dual-color LEDs to indicate the on / off status of the corresponding relays. In this circuit structure, the 3P yellow terminal is the voltage A-phase terminal.

[0058] Interlocking logic is provided between relay 2 and relay 3, which is controlled by the software program of MCU101 to ensure that relay 2 and relay 3 will not be turned on at the same time under any circumstances, thus avoiding abnormal state of current circuit.

[0059] The third circuit group corresponds to the second output control of phase A voltage (green terminal group). It includes a 3P terminal, relay 4, indicator light 4, and two 1P terminals. The two 1P terminals are connected to the 3P terminal via relay 4, and indicator light 4 is connected to relay 4. When relay 4 is on, the 3P terminal is connected to the two 1P terminals; when relay 4 is off, the path is broken. In this circuit group, the 1-2P green terminals are the phase A voltage output terminals. This group functions similarly to the first circuit group, providing the phase A voltage signal to another energy meter or data acquisition terminal, thus achieving multi-channel output control of the same voltage signal.

[0060] The fourth circuit structure corresponds to the control loop for the B-phase current. This includes electrical connections between terminals ib and 3P, 3P and ia, and 3i and 3i. Relay 5 and indicator light 5 are connected between terminals ib, 3P, ia, and ib, respectively, to control the B-phase current measurement loop during operation. Relay 6 and indicator light 6 are connected between terminals 3P, ia, and 3i and 3i, respectively, to control the B-phase current short-circuit loop during meter switching. Relays 5 and 6 are also interlocked by the MCU101 software to ensure they do not conduct simultaneously. In this circuit structure, the green 3-3P terminal represents the A-phase voltage terminal.

[0061] The fifth circuit group corresponds to the third output control of phase A voltage (red terminal group). It includes a 3P terminal, relay 7, indicator light 7, and two 1P terminals. The two 1P terminals are connected to the 3P terminal via relay 7, and indicator light 7 is connected to relay 7. In this circuit group, the 1-2P red terminals are the phase A voltage output terminals. Thus, phase A voltage has a total of three sets of output control terminals (yellow, green, and red), which can correspond to three different metering devices.

[0062] The sixth circuit group corresponds to the control circuit for the C-phase current. It includes electrical connections between the IC and 3P terminals, between the 3P and ia terminals, and between the ia and 3P terminals. Relay 8 and indicator light 8 are connected between the IC and 3P terminals, and between the 3P and ia terminals, respectively, to control the C-phase current measurement circuit during operation. Relay 9 and indicator light 9 are connected between the 3P and ia terminals, and between the ia and 3P terminals, respectively, to control the C-phase current short-circuit circuit during meter switching. In this circuit group, the red 3-3P terminal is the voltage A-phase terminal.

[0063] The seventh circuit structure corresponds to the control loop for the N-phase (neutral) voltage. It includes a 3P terminal, relay 10, indicator light 10, and two 1P terminals. The two 1P terminals are connected to the 3P terminal via relay 10, and indicator light 10 is connected to relay 10. In this circuit structure, the blue 1-2P terminals are the A-phase voltage terminals (actually the neutral / neutral line). Although the neutral line does not need frequent switching under normal circumstances, setting up relay control facilitates unified management and achieves complete isolation during meter replacement.

[0064] In the above 7 circuit structures, the functions of the 10 relays are classified as follows:

[0065] Voltage control relays: Relays 1, 4, 7, and 10. These four relays control the on / off state of the three outputs (yellow, green, and red) of phase A and phase N, respectively. In operation, these four relays are in the conducting state, and the energy meter is connected to the voltage circuit for normal metering. In meter replacement mode, these four relays are in the open state, isolating the energy meter from the voltage circuit to ensure operational safety.

[0066] Current short-circuit relays: Relays 2, 3, 5, 6, 8, and 9. These six relays are divided into three pairs (2 and 3 correspond to phase A, 5 and 6 to phase B, and 8 and 9 to phase C). In each pair, one relay is the operating short-circuit relay (2, 5, and 8), and the other is the meter-changing short-circuit relay (3, 6, and 9). In operating mode, relays 2, 5, and 8 are conducting, while relays 3, 6, and 9 are disengaged. Current flows through relays 2, 5, and 8 into the energy meter for metering. In meter-changing mode, relays 2, 5, and 8 are disengaged, while relays 3, 6, and 9 are conducting. Current flows directly through relays 3, 6, and 9, bypassing the energy meter, thus achieving uninterrupted meter changing.

[0067] The junction box of the present invention has two distinct working states: running state and meter replacement state.

[0068] During operation, the status of each relay is as follows:

[0069] Voltage-controlled relays: Relays 1, 4, 7, and 10 are on, and the voltage circuit is powered normally;

[0070] Current short-circuit relay: Relays 2, 5, and 8 are turned on, while relays 3, 6, and 9 are turned off, allowing the current to flow normally through the energy meter for measurement.

[0071] When in operation, the electricity meter measures voltage and current normally, the user's electricity consumption data is accurately recorded, and the indicator lights in the junction box show the corresponding operating status.

[0072] like Figure 4 As shown, under the condition of meter replacement, the status of each relay is as follows:

[0073] Voltage-controlled relays: Relays 1, 4, 7, and 10 are disconnected, and the voltage circuit is cut off;

[0074] Current short-circuit relay: Relays 2, 5, and 8 are disconnected, while relays 3, 6, and 9 are connected. The current is bypassed and short-circuited, no longer flowing through the energy meter.

[0075] During meter replacement, the electricity meter is isolated from both the voltage and current circuits, allowing maintenance personnel to safely remove the old meter and install the new one. Simultaneously, the current circuit remains conductive via relays 3, 6, and 9, ensuring the secondary circuit of the current transformer remains uninterrupted. This guarantees uninterrupted power supply to the user, achieving true "uninterrupted meter replacement." This design effectively avoids the metering gaps caused by power outages and the difficulties in subsequent data recovery that often occur with traditional meter replacement methods.

[0076] The MCU101's built-in state switching control program follows strict timing logic to ensure a safe and reliable switching process.

[0077] When the junction box switches from the running state to the meter changing state, the MCU101 executes control according to the following timing sequence:

[0078] Step 1: The MCU101 controls the relay drivers K1, K4, K7, and K10 to de-energize the coils of relays 1, 4, 7, and 10, causing the contacts to open and the voltage circuit to be cut off. At this time, the voltage input terminal of the energy meter is isolated from the voltage source, ensuring the safety of subsequent operations.

[0079] Step 2: Delay for 20 milliseconds to ensure the relay contacts are completely disconnected.

[0080] Step 3: The MCU101 controls the relay drivers K2, K5, and K8 to de-energize the coils of relays 2, 5, and 8, open the contacts, and cut off the current measurement circuit in the running state.

[0081] Step 4: Delay for 10 milliseconds.

[0082] Step 5: The MCU101 controls the relay drivers K3, K6, and K9 to activate the coils of relays 3, 6, and 9, close the contacts, and establish a current short-circuit circuit in the meter changing state.

[0083] Step 6: MCU101 reads the current time from clock circuit 103, generates event log data and writes it to data memory 104, and updates the status indicator light at the same time.

[0084] When the junction box returns from the meter-changing state to the running state, the MCU101 executes control according to the reverse timing sequence:

[0085] Step 1: The MCU101 controls the relay drivers K3, K6, and K9 to operate, causing relays 3, 6, and 9 to disconnect and cut off the current short-circuit circuit in the meter changing state;

[0086] Step 2: Delay for 10 milliseconds;

[0087] Step 3: MCU101 controls relay drivers K2, K5, and K8 to activate relays 2, 5, and 8, restoring the current measurement circuit in the operating state;

[0088] Step 4: Delay for 20 milliseconds;

[0089] Step 5: The MCU101 controls the relay drivers K1, K4, K7, and K10 to activate relays 1, 4, 7, and 10, restoring power supply to the voltage circuit.

[0090] Step 6: MCU101 records the recovery event and writes it to the data memory.

[0091] The timing control described above ensures that the current loop will never be completely disconnected (i.e., the secondary circuit of the current transformer is open) at any moment, and also avoids the safety hazards that may be caused by operating the current loop while the voltage loop is energized.

[0092] The data traceability function is one of the core innovations of this invention. Its implementation relies on the coordinated operation of the clock circuit 103, the data memory 104, and the MCU 101.

[0093] Each state transition event corresponds to one event record. The data structure of the event record includes the following fields:

[0094] Record sequence number: starting from 1 and incrementing by 1 with each event record, up to a maximum of 65535 events;

[0095] Event types include "Running status → Table change status", "Table change status → Running status", "Manual switching", "Remote control switching", and "Abnormal reset".

[0096] Event timestamp: Date and time information accurate to the second, in the format "YYYY-MM-DD HH:MM:SS";

[0097] State before switching: Record the relay state combination before switching;

[0098] Post-switch status: Record the relay status combination after the switch;

[0099] Checksum: Generated using the CRC16 checksum algorithm, used to verify the integrity of event log data and prevent data tampering.

[0100] Each event record occupies 64 bytes of storage space, and the 64KB data memory can store approximately 1000 event records. When the storage space is nearly full, the MCU101 employs a cyclic overwrite strategy, automatically overwriting the oldest event record to ensure that the latest operation record is always stored.

[0101] Each time a state transition operation is performed, MCU101 automatically calls the event recording function, reads the current time from clock circuit 103, assembles the event recording data according to the data structure described above, calculates the CRC16 checksum, and then writes the complete event recording data into data memory 104. The entire recording process is completed within 10 milliseconds, without affecting the real-time performance of the state transition operation.

[0102] Maintenance personnel can connect to external devices via the data interface Type-C102 to read historical event records stored in the data storage device 104.

[0103] Connection Method 1: Connect the junction box to your laptop using a Type-C data cable, run the dedicated data reading software, and export all event log data. Data export formats supported include CSV (comma-separated values) and Excel, facilitating data analysis and report generation on your computer.

[0104] Connection Method 2: Connect to a smartphone or tablet using a Type-C to USB-OTG cable and read event log data via a mobile application. The mobile application supports graphical display of the data, allowing users to intuitively view the historical status change curves and operation time distribution of the junction box.

[0105] Connection Method 3: The junction box can be equipped with a wireless communication module, which can upload event records to the cloud monitoring platform in real time via Wi-Fi or 4G / 5G networks. Administrators can view the junction box's operating status and historical operation records in real time from any location using a web browser or mobile application, enabling remote operation and maintenance management.

[0106] To ensure the authenticity and non-repudiation of event record data, this invention employs multiple anti-tampering measures:

[0107] (1) The event log data contains a CRC16 checksum. Any modification to the data will result in a checksum mismatch, which can be detected.

[0108] (2) The data storage 104 adopts a hardware write protection mechanism. It is in read-only state during normal operation. The write protection is temporarily removed by the MCU 101 through software instructions only when recording events. The write protection is restored immediately after the recording is completed.

[0109] (3) The clock information of the clock circuit 103 cannot be directly modified through the external interface. It can only be calibrated through a special encryption command to prevent human tampering with the timestamp;

[0110] (4) The housing 100 adopts an anti-tamper design. Once the housing is illegally opened, the MCU 101 will detect the opening signal and record an "illegal opening" event record, and at the same time, it will alarm through the indicator light.

[0111] A status indicator panel is provided on the outer surface of the housing 100. The status indicator panel includes the following components:

[0112] Operating status indicator light: Green, illuminates when the junction box is in operation;

[0113] Meter replacement status indicator: yellow, illuminates when the junction box is in meter replacement mode;

[0114] Status switching button: Press once to trigger the switching between running status and table changing status;

[0115] LCD screen: Displays information such as current working status, last switching time, cumulative switching count, and remaining data storage capacity;

[0116] Fault alarm indicator: Red. It flashes as an alarm when an abnormality is detected (such as relay failure, clock malfunction, storage error, etc.).

[0117] When operating on-site, maintenance personnel can switch between the running state and the meter replacement state simply by pressing the status switch button, eliminating the need to manually adjust each connection piece with a screwdriver. This reduces operation time from the traditional 15-20 minutes to just seconds, significantly improving work efficiency and operational safety. The LCD screen provides clear status feedback, helping maintenance personnel understand the current status and historical operation information of the junction box.

[0118] The junction box of this invention employs two power supply methods working in tandem:

[0119] The main power supply provides 5V DC voltage through the Type-C102 data interface, which is converted to 3.3V by the internal voltage regulator circuit to power the core circuits such as MCU101, relay drivers K1 to K10, clock circuit 103, and data memory 104. The main power supply comes from an external adapter or an auxiliary power supply from the electricity meter.

[0120] The clock circuit 103 has an internal backup battery that continues to supply power to the clock chip when the main power supply is interrupted, ensuring that time information is not lost.

[0121] The relay uses a magnetic latching relay, which is characterized by the fact that it only consumes electrical energy momentarily when the coil is energized to switch the contact state, and no continuous power supply is required after the contacts stabilize. This characteristic makes the overall power consumption of the junction box extremely low, with an average power consumption of less than 0.5W in operation and less than 0.3W in meter changing mode, meeting the requirements of energy conservation and environmental protection.

[0122] Example 2

[0123] This embodiment adds remote control functionality based on Embodiment 1.

[0124] The MCU101 is extended with a wireless communication module via a Type-C102 data interface. The wireless communication module can be one or more of the following: Wi-Fi module, 4G module, NB-IoT module, or LoRa module, selected according to the actual application scenario.

[0125] Through the wireless communication module, the junction box can establish a two-way communication connection with the remote monitoring platform. On the one hand, the junction box can upload status information and event log data to the remote monitoring platform in real time; on the other hand, the remote monitoring platform can send control commands to the junction box to remotely trigger status switching operations.

[0126] Remote control commands also follow preset timing control logic to ensure operational safety. Simultaneously, each remote control operation generates event log data, including operation time, operation source (remote control), and status before and after the switch, ensuring the traceability of remote operations.

[0127] Example 3

[0128] This embodiment adds a metering data acquisition function based on the above embodiment.

[0129] The MCU101 uses its built-in ADC (analog-to-digital converter) or an external dedicated metering chip to collect electrical parameters such as voltage, current, and power from each voltage and current loop. It then writes this metering data, along with a timestamp, into the data storage 104 at fixed time intervals (e.g., every 15 minutes). In this way, the junction box not only records operational events but also metering data, forming a more complete data archive.

[0130] When a metering dispute occurs, managers can simultaneously retrieve operation event records and metering data records to conduct correlation analysis and source tracing, such as determining whether there are abnormal changes in electricity metering data before and after a meter replacement operation, thereby accurately locating the cause of the problem.

[0131] The present invention relates to an intelligent power metering junction box with data traceability function, which can be directly applied to the field of power system power metering and used as a core interface device for connecting current transformers, power meters, and data acquisition terminals.

[0132] The product of this invention can be widely applied to the following scenarios:

[0133] (1) The power metering system at the substations and distribution stations of the power supply company;

[0134] (2) Dedicated transformer metering points for industrial and commercial users;

[0135] (3) Centralized metering boxes in residential communities;

[0136] (4) Grid connection metering points for new energy power generation (photovoltaic, wind power);

[0137] (5) Various metering sites that require regular replacement of electricity meters or on-site calibration.

[0138] The product of this invention can be seamlessly integrated with existing metering equipment. Its size and terminal layout are compatible with traditional junction boxes, making it easy to directly replace and install in existing metering devices without requiring large-scale modifications to existing wiring, thus lowering the barrier to promotion and application.

[0139] The core electronic components of this invention are all mature industrial-grade components, with stable supply and controllable costs. The MCU is a general-purpose 32-bit microcontroller, the clock circuit uses a standard real-time clock chip, the data storage uses a general-purpose EEPROM chip, and the relays are mature and reliable magnetic latching relays. The product manufacturing process is mature and can be mass-produced on conventional electronic manufacturing production lines, providing a solid foundation for industrial production.

[0140] This invention complies with the usage conditions and technical requirements of power metering junction boxes in group standards such as "Power Metering Junction Box" (T / ZIUR 0003-2025) and industry standards such as "Technical Specification for Plug-in Power Meter Terminal Box" (T / CEC 1132-2025), and can meet the latest development needs of smart grids for the informatization and intelligence of metering equipment.

[0141] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A smart power metering junction box with data traceability function, comprising a housing (100), characterized in that: The housing (100) contains an MCU (101), which is connected to a clock circuit (103) and a data storage device (104). The MCU (101) is connected to multiple relay drivers, which are respectively connected to voltage control relays for controlling the on / off state of voltage loops and current short-circuit relays for controlling the short-circuit state of current loops. The MCU (101) is configured to control the voltage control relay and the current short-circuit relay to switch between the running state and the meter changing state; In the operating state, the voltage control relay is turned on to connect the voltage circuit, and the current short-circuit relay is in the first combination state to connect the current circuit to the energy meter for metering. In the meter replacement state, the voltage control relay is disconnected to disconnect the voltage circuit, and the current short-circuit relay is in the second combination state to short-circuit the current circuit and prevent it from flowing through the energy meter. When the junction box switches between the running state and the meter changing state, the MCU (101) reads the time information from the clock circuit (103), generates event record data including the switching time, the state before switching and the state after switching, and writes the event record data into the data memory (104) for storage.

2. The intelligent power metering junction box with data traceability function according to claim 1, characterized in that, The MCU (101) is connected to the clock circuit (103) and the data memory (104) through the data interface Type-C (102). The power supply is provided to the MCU (101) through the data interface Type-C (102). The MCU (101) is connected to 10 relay drivers K1 to K10. Each of the 10 relay drivers K1 to K10 is connected to a relay control coil. The total of 10 relay control coils are L1 to L10.

3. The intelligent power metering junction box with data traceability function according to claim 2, characterized in that, The housing (100) is provided with 7 sets of circuit structures, among which: The first circuit structure includes a 3P terminal, a relay 1, an indicator light 1, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 1, and the indicator light 1 is connected to the relay 1. The second circuit structure includes electrically connected ia terminal and 1i terminal, electrically connected 3P terminal and ia terminal, electrically connected 3i terminal and 3i terminal, relay 2 and indicator light 2 are connected between electrically connected ia terminal, 1i terminal and electrically connected 3P terminal, ia terminal, and relay 3 and indicator light 3 are connected between electrically connected 3P terminal, ia terminal and electrically connected 3i terminal and 3i terminal. The third circuit structure includes a 3P terminal, a relay 4, an indicator light 4, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 4, and the indicator light 4 is connected to the relay 4. The fourth circuit structure includes electrically connected ib terminals and 3P terminals, electrically connected 3P terminals and ia terminals, and electrically connected 3i terminals and 3i terminals. Relay 5 and indicator light 5 are connected between electrically connected ib terminals, 3P terminals and electrically connected 3P terminals and ia terminals. Relay 6 and indicator light 6 are connected between electrically connected 3P terminals, ia terminals and electrically connected 3i terminals and 3i terminals. The fifth circuit structure includes a 3P terminal, a relay 7, an indicator light 7, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 7, and the indicator light 7 is connected to the relay 7. The sixth circuit structure includes electrically connected IC terminals and 3P terminals, electrically connected 3P terminals and ia terminals, and electrically connected ia terminals and 3P terminals. Relay 8 and indicator light 8 are connected between electrically connected IC terminals, 3P terminals and electrically connected 3P terminals and ia terminals. Relay 9 and indicator light 9 are connected between electrically connected 3P terminals, ia terminals and electrically connected ia terminals and 3P terminals. The seventh circuit structure includes a 3P terminal, a relay 10, an indicator light 10, and two 1P terminals. The two 1P terminals are connected to the 3P terminal through the relay 10, and the indicator light 10 is connected to the relay 10. The voltage control relays include relays 1, 4, 7, and 10, and the current short-circuit relays include relays 2, 3, 5, 6, 8, and 9. Relays 2, 5, and 8 are operating short-circuit relays, and relays 3, 6, and 9 are meter replacement short-circuit relays.

4. The intelligent power metering junction box with data traceability function according to claim 3, characterized in that, The MCU (101) has a built-in state switching control program, which is configured to: when a table replacement instruction is received, the MCU (101) controls each relay to switch states according to a preset timing sequence through a relay driver; the preset timing sequence includes: first controlling relays 1, 4, 7, and 10 to disconnect, then controlling relays 2, 5, and 8 to disconnect, and finally controlling relays 3, 6, and 9 to turn on.

5. A smart power metering junction box with data traceability function according to claim 4, characterized in that, The state switching control program is also configured such that when a recovery command is received, the MCU (101) controls each relay to return to the running state in the opposite sequence through the relay driver, that is, first controls relays 3, 6 and 9 to disconnect, then controls relays 2, 5 and 8 to turn on, and finally controls relays 1, 4, 7 and 10 to turn on.

6. The intelligent power metering junction box with data traceability function according to claim 1, characterized in that, The event log data includes a record number, event type, event timestamp, state before switching, state after switching, and a verification code; the verification code is generated using the CRC16 check algorithm and is used to verify the integrity of the event log data.

7. The intelligent power metering junction box with data traceability function according to claim 1, characterized in that, The data interface Type-C (102) is used to connect to an external data reading device to export the event record data stored in the data memory (104); the data interface Type-C (102) also serves as a data communication channel between the clock circuit (103), the data memory (104) and the MCU (101).

8. A smart power metering junction box with data traceability function according to claim 1, characterized in that, The MCU (101) is also connected to a wireless communication module, which is used to upload the event recording data to the remote monitoring platform in real time; the wireless communication module is at least one of Wi-Fi module, 4G module, NB-IoT module or LoRa module.

9. A smart power metering junction box with data traceability function according to claim 1, characterized in that, The outer surface of the housing (100) is provided with a status indicator panel, which is provided with a running status indicator and a meter replacement status indicator corresponding to the running status and the meter replacement status, respectively, as well as a status switching button; when the status switching button is pressed, it triggers the junction box to switch between the running status and the meter replacement status.

10. A smart power metering junction box with data traceability function according to claim 9, characterized in that, The status indicator panel is also equipped with an LCD screen for displaying at least one of the following information: current working status, last switching time, and cumulative switching count.

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