A user-unaware power-off meter replacement device and method based on thyristor bypass

Abstract

The present invention discloses a user-unaware non-powered meter replacement device and method based on thyristor bypass. A main bypass and an auxiliary bypass are added. Thyristor switches are provided in both the main bypass and the auxiliary bypass. The closing operation of the thyristor switch is controlled by a control circuit, and the opening and closing of each phase contact have better consistency, avoiding the leakage current generated when the bypass is switched in and out, which may cause the leakage protector to trip and be damaged. The device and the meter replacement method can also ensure non-powered meter replacement when the staff is replacing the meter, ensuring seamless power supply to users.

Description

Technical Field

[0001] The present invention relates to the field of electric meters, and particularly to a user-unaware non-powered meter replacement device and method based on thyristor bypass. Background Art

[0002] In recent years, with the rapid development of the smart grid and the improvement of residents' living standards, the coordination and exchange between the power network, the power market, and users have become increasingly close. Users' demand for precise and lean power consumption services has been growing continuously, and their acceptance of planned power outages has been decreasing. Among them, the smart electricity meter, as a metering terminal at the customer side, is an indispensable and important part of the power data collection in the smart grid (especially the smart distribution network), and is the basis for carrying out fair and open power transactions. Due to different suppliers, categories, and arrival batches of smart electricity meters, their service life varies. To ensure the accuracy, reliability, and unity of power measurement values and safeguard the interests of both power supply and consumption parties, smart electricity meters need to be rotated regularly. However, in the current smart electricity meter replacement work, the replacement of directly-connected smart electricity meters must be carried out during a power outage, which has drawbacks such as affecting users' normal power consumption, complaints caused by users' refusal to cooperate, low work efficiency of meter replacement, and potential risk of incorrect wiring. For the power grid company, the inefficient meter replacement work will waste a large amount of labor costs and reduce the company's economic benefits. Frequent power outage meter replacement operations will also pose a risk of user complaints. For power users, the long power outage time for meter replacement will affect normal production and life and cause a large amount of economic losses to users. To comprehensively ensure reliable power supply and further meet the electricity demand for social and economic development, the research on non-power outage meter replacement technology is imperative. To improve the service level of "obtaining electricity", continuously optimize the electricity business environment, and greatly reduce the power outage time and frequency, so as to meet users' growing demand for high-quality power. The optimization of the meter replacement process and the improvement of technology are one of the key tasks, and also the last "one kilometer" of the current non-power outage operation. In a low-voltage distribution network circuit with a leakage protection switch, when replacing the meter, if directly bypassed and supplied through clips between the upper port of the meter and the lower port of the air circuit breaker, during the bypass supply process, due to the inconsistency of the mechanical disconnection and closing of the air circuit breaker contacts, a leakage current will occur in the circuit, which will cause the leakage protection device to operate. Because of the existence of the bypass supply, when the leakage protection device operates due to leakage and the lower port is energized, it will cause the coil in the leakage protection device to short-circuit, or the operating switch in the leakage protection device to burn out or overcurrent and explode due to overcurrent, resulting in the failure of the bypass supply.

[0003] For example, a "switching device for replacing an electricity meter without power interruption" disclosed in a Chinese patent document, with the publication number CN113484567A, includes a metering box, a first electricity meter fixed inside the metering box, an incoming line connected to the incoming end of the first electricity meter, and an outgoing line connected to the outgoing end of the first electricity meter; a first switch installed on the incoming line and a second switch installed on the outgoing line, where the first switch is used to control the on-off of the incoming line, and the second switch is used to control the passage of the outgoing line; a connecting line connecting the incoming line and the outgoing line and a third switch installed on the connecting line, where the third switch is used to control the on-off of the connecting line. The first switch is located between the connection point of the connecting line and the incoming line and the incoming end of the metering box, and the second switch is located between the connection point of the connecting line and the outgoing line and the outgoing end of the metering box; through this invention, during the process of replacing the electricity meter, it will not affect the normal power consumption of users. However, electric leakage is likely to occur during the electricity meter replacement process. At the same time, since it includes three switches, the electricity meter replacement process is troublesome, the safety of the electricity meter replacement process cannot be guaranteed, and there is a time difference during the process of turning on and off the switches, so it is impossible to ensure that users are unaware of the electricity meter replacement process. Summary of the Invention

[0004] The present invention mainly aims at the problems of the existing non-powered electricity meter replacement process being cumbersome, complex to operate, and having a risk of electric leakage leading to circuit failure; it provides a user-unaware non-powered electricity meter replacement device and method based on thyristor bypass, adding a main bypass and an auxiliary bypass. Both the main bypass and the auxiliary bypass are provided with thyristor switches, and the closing operation of the thyristor switches is controlled by a control circuit. The opening and closing of each phase contact have better consistency, avoiding the generation of leakage current when the bypass is switched in and out, which may cause the leakage protection to trip and be damaged. This device and the electricity meter replacement method can also ensure that the electricity meter is replaced without power when the staff is replacing the electricity meter, ensuring seamless power supply to users.

[0005] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0006] A user-unaware non-powered electricity meter replacement device based on thyristor bypass, the main circuit includes a three-phase AC power supply, an air circuit breaker, an electricity meter, a first leakage protector, and a load connected in sequence; the main bypass includes a second leakage protector, a thyristor SCR1, a power diode, and an electricity meter connected in sequence; the auxiliary bypass includes a thyristor SCR2; the control circuit includes a controller and a conditioning circuit connected in sequence, and the controller is connected to the thyristor SCR1 and the thyristor SCR2 to control the switching in and out of the main bypass and the auxiliary bypass.

[0007] The main bypass and the auxiliary bypass are added. Both the main bypass and the auxiliary bypass are provided with thyristor switches, and the closing operation of the thyristor switches is controlled by a control circuit. The opening and closing of each phase contact have better consistency, avoiding the generation of leakage current when the bypass is switched in and out, which may cause the leakage protection to trip and be damaged. At the same time, through the main bypass and the auxiliary bypass, it is ensured that users during the electricity meter replacement process of the main circuit are not affected by the power cut of the electricity meter.

[0008] Preferably, the main bypass is connected to the main circuit through the No. 1 connection point and the No. 3 connection point; the auxiliary bypass is connected to the main circuit through the No. 1 connection point and the No. 2 connection point. The functions of the auxiliary bypass and the main bypass are different. The main bypass mainly ensures that the power consumption of the load is not affected during the power-off process of the electricity meter. Therefore, the main bypass is connected behind the power supply and in front of the load. The auxiliary bypass mainly ensures that there are no problems such as electric leakage due to unstable voltage during the power-on process of the electricity meter. Therefore, the auxiliary bypass is connected to the input and output terminals of the electricity meter.

[0009] Preferably, the No. 1 connection point is arranged at the input end of the three-phase AC power supply and the input end of the air circuit breaker; the No. 2 connection point is arranged at the output end of the air circuit breaker and the input end of the electricity meter; the No. 3 connection point is arranged at the output end of the first leakage protector and the input end of the load.

[0010] Preferably, there is another phase sequence detection module for judging the phase sequence between the connections; the Va terminal of the phase sequence detection module is connected to the No. 1 connection point, the Vb terminal of the phase sequence detection module is connected to the thyristor SCR2, and the Vc terminal of the phase sequence detection module is connected to the No. 3 connection point; the V+ terminal of the phase sequence detection module is connected to the conditioning circuit.

[0011] Preferably, the control circuit includes a power supply module, a main chip, a configuration screen, measuring point 1, measuring point 2, and measuring point 3; the power supply module is connected to the main chip, and the main chip is connected to the configuration screen through serial port isolation; the thyristors SCR1 and SCR2 are connected to the main chip; the measuring points 1, 2, and 3 are all connected to the main chip; the data collected by the measuring points 1, 2, and 3 are all preprocessed and then transmitted to the main chip. In the control circuit, the YX-DSPTMS320F28335 core board module produced by Nanjing Yanxu is used, which has stable performance and high control reliability. The thyristor SCR1\SCR2 modules of the main bypass and the auxiliary bypass are controlled by the DSP. The turn-on and cut-out logic of SCR1 and SCR2 needs to be automatically judged by the DSP according to the states in the detection circuit, reducing the human intervention factor. The voltages of measuring points 1, 2, and 3 are sampled through AD acquisition to perform intelligent judgment in each stage of the circuit operation. The voltage signal part is preprocessed by the operational amplifier chip TL074IDT, and the various states of the judged circuit are displayed on the 7-inch configuration display screen. Serial communication is used between the configuration screen and the DSP. In order to ensure reliable communication, the serial port isolation chip ISO3082 is used.

[0012] A method for replacing the electricity meter without power perception and without power for users based on thyristor bypass uses the above device. The steps of the method for replacing the electricity meter without power perception and without power for users are as follows:

[0013] Step S1: Use power clamps to connect the main bypass to the main circuit through the No. 1 connection point and the No. 3 connection point; use power clamps to connect the auxiliary bypass to the main circuit through the No. 1 connection point and the No. 2 connection point, where the No. 1 connection point is the common connection point of the main bypass and the auxiliary bypass;

[0014] Step S2: Detect the voltages at the No. 1 connection point, the No. 2 connection point, and the No. 3 connection point respectively to judge the phase sequence; if the phase sequence is correct, control the buzzer to emit a prompt sound; if the phase sequence is incorrect, the buzzer will sound continuously, and a phase sequence error prompt will be displayed on the controller configuration board; at this time, adjust the power clamping sequence and detect again until the phase sequence is correct;

[0015] Step S3: Manually open the air circuit breaker to cut off the main circuit. After the controller detects that the three-phase voltages Ua, Ub, and Uc of the three-phase AC power supply at the No. 2 connection point are all powered off, the thyristor SCR1 trigger circuit is powered on, and the controller controls the thyristor SCR1 to conduct; at this time, the load is powered by the bypass circuit;

[0016] Step S4: Manually open the first leakage protector;

[0017] Step S5: Determine that both the output terminals of the main circuit ammeter are powered off, and start changing the meter.

[0018] Detect the phase sequence during the power change process through the controller to ensure that the wiring is correct; use the air circuit breaker to switch the power supply for the load in the circuit, convert it to the main bypass to supply power to the load, and detect in advance whether the leakage protector is closed to ensure the safety of the overall circuit. At the same time, use the controller to control the thyristor SCR1 to ensure seamless conversion to the main bypass power supply during the circuit conversion. The second leakage protector plays a role in protecting against leakage during the main bypass power supply process; use the switching between the main bypass and the main circuit to ensure a seamless meter change for the user.

[0019] Preferably, the circuit is restored according to the following steps after changing the meter:

[0020] Step S6: After changing the meter, manually close the first leakage protector; when the controller detects that the three-phase phase voltages Ua, Ub, and Uc of the three-phase AC power supply change from the powered-off state to the powered-on state, delay for 1 second to ensure that the first leakage protector has been closed; control the thyristor SCR1 trigger circuit to be powered off, and at the same time power on the thyristor SCR2 trigger circuit. At this time, the thyristor SCR2 conducts, and the thyristor SCR1 disconnects;

[0021] Step S7: Manually close the air circuit breaker on the main circuit. After the thyristor SCR2 is short-circuited by the air circuit breaker, it automatically disconnects; the controller detects that the voltage difference at the No. 1 connection point and the No. 2 connection point is 0;

[0022] Step S8: Remove the power clamps at the No. 1 connection point, the No. 2 connection point, and the No. 3 connection point.

[0023] At this time, the air circuit breaker of the main circuit is not closed yet. The load is powered through the auxiliary bypass circuit to the ammeter and the leakage protector in the main circuit. During the switching from the main bypass to the auxiliary bypass, in order to achieve seamless and consistent switching, power diodes are added in the main bypass. Due to the existence of the conduction voltage drop when the diode conducts, the conduction voltages of the auxiliary bypass and the main bypass are quite different and will not conduct simultaneously. When a turn-off signal is given to the thyristor SCR1, the thyristor SCR1 cannot be turned off when there is current. The turn-off signal given to the thyristor SCR1 actually stops the conduction trigger. However, when SCR2 is turned on, the impedance of the auxiliary bypass of SCR2 is much smaller than that of the main bypass. Therefore, the current naturally transfers to the auxiliary bypass, and the main bypass is naturally cut off after the conduction signal is removed. After the air circuit breaker is closed and a 40ms delay occurs, the trigger circuit of the thyristor SCR2 is powered off. The conduction impedance of the air circuit breaker is much lower than the conduction impedance of the thyristor SCR2. After the air circuit breaker is reliably closed, after the conduction signal of the thyristor SCR2 is removed, the current naturally transfers to the air circuit breaker, and the thyristor SCR2 will naturally turn off.

[0024] The beneficial effects of the present invention are as follows:

[0025] The main bypass and the auxiliary bypass are added. Both the main bypass and the auxiliary bypass are provided with thyristor switches. The closing operation of the thyristor switches is controlled by a control circuit, and the opening and closing of each phase contact have better consistency, avoiding the leakage current generated when the bypass is put in and cut out, which may cause the leakage protector to trip and be damaged. This device and the meter replacement method can also ensure that the meter can be replaced without power when the staff is replacing the meter, ensuring seamless power supply to users. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the structural schematic diagram of the circuit;

[0027] Figure 2 is the flow chart of the non-sensing power conversion method;

[0028] Figure 3 is the structural diagram of the main bypass and the auxiliary bypass. DETAILED DESCRIPTION OF THE INVENTION

[0029] The exemplary embodiments of the embodiments of the present invention will be introduced in detail below. More specific detailed information is provided in the following description to provide a comprehensive understanding of the embodiments of the present invention.

[0030] Figure 1The main circuit includes a three-phase AC power supply, an air circuit breaker, an electricity meter, a first leakage protector, and a load, which are connected in sequence; the auxiliary bypass includes a thyristor SCR2; the main bypass includes a second leakage protector, a thyristor SCR1, a power diode, and an electricity meter, which are connected in sequence; the control circuit includes a controller and a conditioning circuit, which are connected in sequence. The controller is connected to the thyristor SCR1 and the thyristor SCR2 to control the switching in and out of the main bypass and the auxiliary bypass. In order to automatically switch the main bypass and the auxiliary bypass in and out according to the state of meter replacement, it is necessary to monitor the voltage at the connection points of the main bypass and the auxiliary bypass in the main circuit to judge the state of the main circuit. To prevent phase sequence errors during wiring, a phase sequence detection module is specially set in the device.

[0031] The process of user-unaware non-powered meter replacement based on thyristor bypass is as follows:

[0032] Step S1: Use power clips to connect the main bypass to the main circuit through the No. 1 connection point and the No. 3 connection point; use power clips to connect the auxiliary bypass to the main circuit through the No. 1 connection point and the No. 2 connection point, where the No. 1 connection point is the common connection point of the main bypass and the auxiliary bypass;

[0033] Step S2: Automatic phase sequence detection;

[0034] By detecting the voltages at the No. 1 connection point, the No. 2 connection point, and the No. 3 connection point respectively, after judging that the phase sequence is correct, the control buzzer gives a prompt sound for the next step. If the phase sequence is incorrect, the buzzer sounds continuously, and a phase sequence error prompt is given on the LCD screen on the panel. At this time, it is necessary to adjust the clip order and detect again until the phase sequence detection is passed;

[0035] Step S3: Manually separate the air circuit breaker. When the controller detects that the three-phase phase voltages of Ua / Ub / Uc 2 at the output end No. 2 connection point of the air circuit breaker are all powered off, immediately power on the trigger circuit of the thyristor SCR1 to control the thyristor SCR1 to conduct. The bypass conducts, and the main circuit is powered off. The bypass is automatically connected, and the load power supply starts to be transferred by the bypass circuit.

[0036] Step S4: With the power supply already transferred by the bypass circuit, manually turn on the leakage protector in the main circuit;

[0037] Step S5: Both the upper and lower ports of the electricity meter part of the main circuit are powered off, and the meter replacement starts;

[0038] Step S6: After the meter replacement is completed, manually close the leakage protector. When the controller detects that the three-phase phase voltages of Ua / Ub / Uc 1 change from the power-off state to the powered state, a 1-second delay is ensured to make sure the leakage protector is completely closed. Then, the trigger circuit of thyristor SCR1 is powered off, and at the same time, the trigger circuit of thyristor SCR2 is powered on. Thyristor SCR2 conducts, and thyristor SCR1 disconnects. At this time, the air circuit breaker of the main circuit is not closed yet, and the load is powered by the auxiliary bypass circuit through the electricity meter and the leakage protector in the main circuit. During the switching from the main bypass to the auxiliary bypass, in order to achieve seamless and consistent switching, a power diode is added to the main bypass. Due to the existence of the conduction voltage drop when the diode conducts, there is a large difference in the conduction voltages between the auxiliary bypass and the main bypass, and they will not conduct simultaneously. When a turn-off signal is given to thyristor SCR1, thyristor SCR1 cannot be turned off when there is current. The turn-off signal for thyristor SCR1 actually stops the conduction trigger. However, when thyristor SCR2 is turned on, the impedance of the auxiliary bypass of thyristor SCR2 is much smaller than that of the main bypass, so the current naturally transfers to the auxiliary bypass, and the main bypass is naturally cut off after the conduction signal is removed.

[0039] Step S7: Manually close the air circuit breaker on the main circuit. After thyristor SCR2 is short-circuited by the air circuit breaker, it naturally disconnects. When the controller detects that the voltage difference between 1 and 2 is 0, that is, after the air circuit breaker is closed, a 40-ms delay is set, and then the trigger circuit of thyristor SCR2 is powered off. The conduction impedance of the air circuit breaker KK is much lower than that of thyristor SCR2. After the air circuit breaker is reliably closed, after the conduction signal of thyristor SCR2 is removed, the current naturally transfers to the air circuit breaker, and thyristor SCR2 will naturally turn off.

[0040] Step S8: Remove the power clamps at connection points 1, 2, and 3.

Claims

1. A user-unaware power-off meter replacement device based on thyristor bypass, characterized in that the main circuit includes a three-phase AC power supply, an air circuit breaker, a meter, a first leakage protector, and a load connected in sequence; the main bypass includes a second leakage protector, a thyristor SCR1, a power diode, and a meter connected in sequence; the auxiliary bypass includes a thyristor SCR2; the control circuit includes a controller and a conditioning circuit connected in sequence. The controller is connected to the thyristor SCR1 and the thyristor SCR2 to control the switching in and out of the main bypass and the auxiliary bypass; the main bypass is connected to the main circuit through the No. 1 connection point and the No. 3 connection point; the auxiliary bypass is connected to the main circuit through the No. 1 connection point and the No. 2 connection point. The No. 1 connection point is set at the output end of the three-phase AC power supply and the input end of the air circuit breaker; the No. 2 connection point is set at the output end of the air circuit breaker and the input end of the meter; the No. 3 connection point is set at the output end of the first leakage protector and the input end of the load; a phase sequence detection module is also included to judge the phase sequence between the connections.

2. The user-unaware and non-powered meter replacement device based on thyristor bypass according to claim 1, characterized in that: The main bypass and the auxiliary bypass are added. Both the main bypass and the auxiliary bypass are provided with thyristor switches. The closing operation of the thyristor switches is controlled by the control circuit, and the opening and closing of each phase contact have better consistency.

3. The user-unaware non-powered meter replacement device based on thyristor bypass according to claim 1, characterized in that: The functions of the auxiliary bypass and the main bypass are different. The main bypass ensures that the power consumption of the load is not affected during the power-off process of the meter.

4. The user-unaware and non-powered meter replacement device based on thyristor bypass according to claim 3, characterized in that: The Va terminal of the phase sequence detection module is connected to the No. 1 connection point, the Vb terminal of the phase sequence detection module is connected to the thyristor SCR2, and the Vc terminal of the phase sequence detection module is connected to the No. 3 connection point; the V+ terminal of the phase sequence detection module is connected to the conditioning circuit.

5. The user-unaware non-powered meter replacement device based on thyristor bypass according to claim 1, characterized in that: The control circuit includes a power supply module, a main chip, a configuration screen, measuring point 1, measuring point 2, and measuring point 3; the power supply module is connected to the main chip, and the main chip is connected to the configuration screen through serial port isolation; the thyristor SCR1 and the thyristor SCR2 are connected to the main chip; the measuring point 1, the measuring point 2, and the measuring point 3 are all connected to the main chip; the data collected by the measuring point 1, the measuring point 2, and the measuring point 3 are all preprocessed and then transmitted to the main chip.

6. A method for replacing a meter without power while the user is unaware, based on thyristor bypass, using the device described in claims 1 to 5 above, characterized in that: The steps of the user-unaware power-off meter replacement method are as follows: Step S1: Use power clamps to connect the main bypass to the main circuit through the No. 1 connection point and the No. 3 connection point; use power clamps to connect the auxiliary bypass to the main circuit through the No. 1 connection point and the No. 2 connection point, where the No. 1 connection point is the common connection point of the main bypass and the auxiliary bypass; Step S2: Detect the voltages at the No. 1 connection point, the No. 2 connection point, and the No. 3 connection point respectively to judge the phase sequence; if the phase sequence is correct, control the buzzer to emit a prompt sound; if the phase sequence is incorrect, the buzzer will sound continuously, and a phase sequence error prompt will be displayed on the controller configuration board; at this time, adjust the power clamping sequence and detect again until the phase sequence is correct; Step S3: Manually open the air circuit breaker to cut off the main circuit. After the controller detects that the Ua, Ub, and Uc three-phase voltages of the three-phase AC power supply at the No. 2 connection point are all powered off, the trigger circuit of the thyristor SCR1 is powered on, and the controller controls the thyristor SCR1 to conduct; at this time, the load is powered by the bypass circuit; Step S4: Manually open the first leakage protector; Step S5: Determine that both the output ends of the main circuit meter are powered off, and start replacing the meter.

7. A method for replacing a power meter without power supply and without user awareness based on thyristor bypass, characterized in that: After replacing the meter, restore the circuit according to the following steps: Step S6: After the meter replacement is completed, manually close the first leakage protector; when the controller detects that the three-phase phase voltages Ua, Ub, and Uc of the three-phase AC power supply change from the power-off state to the powered-on state, delay for 1 second to ensure that the first leakage protector has been closed; control the thyristor SCR1 trigger circuit to cut off the power, and at the same time power on the thyristor SCR2 trigger circuit. At this time, the thyristor SCR2 conducts and the thyristor SCR1 disconnects; Step S7: Manually close the air circuit breaker on the main circuit. After the thyristor SCR2 is short-circuited by the air circuit breaker, it automatically disconnects; the controller detects that the voltage difference at the No. 1 connection point and the No. 2 connection point is 0; Step S8: Remove the power clamps at the No. 1 connection point, the No. 2 connection point, and the No. 3 connection point.

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