Relay-based tripping control method and three-phase energy meter

Abstract

This application relates to the field of relay technology and discloses a relay tripping control method and a three-phase energy meter. The method includes: acquiring the three-phase current values ​​of the relay, wherein the three-phase current values ​​include the first-phase current value of the first current phase, the second-phase current value of the second current phase, and the third-phase current value of the third current phase in the three-phase circuit connected to the relay; determining the current zero-crossing detection phase based on the first-phase current value, the second-phase current value, the third-phase current value, and a preset current threshold; and controlling the relay to trip based on the current zero-crossing detection phase, so as to realize that the relay trips at the current zero-crossing point. This application improves the service life of the relay.

Description

Technical Field

[0001] This application relates to the field of relay technology, and in particular to a relay-based circuit breaker control method and a three-phase energy meter. Background Technology

[0002] With the rapid development of relays, users have placed higher demands on the relay-based tripping control methods.

[0003] Traditional relay-based tripping control directly disconnects the relay in real time upon receiving a tripping request, essentially performing random tripping based on the relay's tripping demand. This method has certain drawbacks. Random tripping might occur at maximum current (where the inductive load environment creates a large back electromotive force at the relay contacts), potentially damaging the relay contacts due to this significant back electromotive force. Therefore, this type of relay-based tripping control can lead to damage to the relay contacts due to the large back electromotive force, resulting in a shorter relay lifespan. Summary of the Invention

[0004] The main purpose of this application is to propose a relay-based tripping control method and a three-phase energy meter, aiming to solve the technical problem of the short service life of relays.

[0005] To achieve the above objectives, this application provides a relay-based circuit breaker control method, which includes the following steps:

[0006] Obtain the three-phase current value of the relay, wherein the three-phase current value includes the first phase current value of the first current phase, the second phase current value of the second current phase, and the third phase current value of the third current phase in the three-phase circuit connected to the relay;

[0007] The zero-crossing detection phase is determined based on the first phase current value, the second phase current value, the third phase current value, and a preset current threshold. The relay is then controlled to trip based on the zero-crossing detection phase, so that the relay trips at the current zero-crossing point.

[0008] In one embodiment, the step of determining the current zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value, and a preset current threshold includes:

[0009] If at least one of the first phase current value, the second phase current value, and the third phase current value is greater than a preset current threshold, the detection phase is determined by selecting the detection phase based on the first phase current value, the second phase current value, the third phase current value, and the preset current.

[0010] In one embodiment, the relay-based tripping control method further includes:

[0011] When the first phase current value, the second phase current value, and the third phase current value are all less than or equal to a preset current threshold, the relay is controlled to trip.

[0012] In one embodiment, the step of selecting the detection phase and determining the zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value, and a preset current includes:

[0013] Determine the maximum current value among the first phase current value, the second phase current value, and the third phase current value;

[0014] If the current phase corresponding to the maximum current value is a preset current selection detection phase, then the selected detection phase is determined as the current zero-crossing detection phase.

[0015] If the current phase corresponding to the maximum current value is not the preset current selection detection phase, determine the target current value corresponding to the preset current selection detection phase among the first phase current value, the second phase current value, and the third phase current value, and determine the current zero-crossing detection phase based on the maximum current value and the target current value.

[0016] In one embodiment, the step of determining the current zero-crossing detection phase based on the maximum current value and the target current value includes:

[0017] Determine the current difference between the maximum current value and the target current value;

[0018] If the current difference is greater than a preset difference threshold, the current phase corresponding to the maximum current value is taken as the current zero-crossing detection phase.

[0019] If the current difference is less than or equal to the difference threshold, the preset current selection detection phase is used as the current zero-crossing detection phase.

[0020] In one embodiment, the step of controlling the relay to trip based on the current zero-crossing detection phase includes:

[0021] Obtain the real-time current value of the current zero-crossing detection phase;

[0022] When the real-time current value is a preset zero-crossing current value, the relay is controlled to trip.

[0023] In one embodiment, after the step of controlling the relay to trip based on the current zero-crossing detection phase, the method includes:

[0024] Determine the tripping action duration corresponding to the zero-crossing current detection;

[0025] The tripping interval of the current zero-crossing detection phase is determined based on the tripping action duration and the preset current cycle duration.

[0026] In one embodiment, the relay-based tripping control method further includes:

[0027] After receiving a power-off control command each time, a current phase is selected from the first current phase, the second current phase, and the third current phase in a polling manner as the preset current selection and detection phase.

[0028] In one embodiment, after the step of controlling the relay to trip based on the current zero-crossing detection phase, the method includes:

[0029] When the current zero-crossing detection phase is the preset current selection detection phase, the next preset current selection detection phase is determined by polling, and the step of obtaining the three-phase current value of the relay is performed based on the next preset current selection detection phase.

[0030] If the current zero-crossing detection phase is not the preset current selection detection phase, the step of obtaining the three-phase current value of the relay is performed, or the next preset current selection detection phase is determined by polling, and the step of obtaining the three-phase current value of the relay is performed based on the next preset current selection detection phase.

[0031] This application also provides a three-phase energy meter, the three-phase energy meter comprising:

[0032] The relay is connected to a three-phase circuit;

[0033] A circuit breaker controller, wherein the circuit breaker controller is connected to the control terminal of the relay;

[0034] The circuit breaker controller is also used to perform the steps of the circuit breaker control method for relays as described above.

[0035] This application provides a method for controlling the tripping of a relay. The method involves acquiring the three-phase current values ​​of the relay, wherein the three-phase current values ​​include the first-phase current value of the first current phase, the second-phase current value of the second current phase, and the third-phase current value of the third current phase in the three-phase circuit connected to the relay; determining the current zero-crossing detection phase based on the first-phase current value, the second-phase current value, the third-phase current value, and a preset current threshold; and controlling the relay to trip based on the current zero-crossing detection phase, so as to realize that the relay trips at the current zero-crossing point.

[0036] By analyzing the current values ​​of the first, second, and third phases in the three-phase circuit connected to the relay, along with a preset current threshold, the zero-crossing detection phase is determined. The relay is then controlled to trip when the current in the zero-crossing detection phase crosses zero, meaning the current flowing through this phase is minimized, resulting in the lowest possible back electromotive force (EMF). This avoids the damage to the relay contacts caused by the large back EMF that can result from random tripping during maximum current conditions (where the inductive load environment creates a large back EMF at the relay contacts). By controlling the relay to trip at the zero-crossing detection phase, the maximum current is avoided, thus extending the relay's lifespan. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the relay-based circuit breaker controller structure in the hardware operating environment involved in the embodiments of this application;

[0039] Figure 2 This is a schematic flowchart of a relay-based circuit breaker control method according to an embodiment of this application;

[0040] Figure 3 This is a schematic diagram of a control flow for a relay-based circuit breaker control method according to an embodiment of this application;

[0041] Figure 4 This is a schematic diagram of a module of a three-phase energy meter according to an embodiment of this application;

[0042] Figure 5 This is a schematic diagram of a gate control module according to an embodiment of this application.

[0043] Explanation of icon numbers:

[0044] 0001, Communication bus; 0002, Acquisition interface; 0003, Processor; 0004, Processing interface; 0005, Memory; 100, Three-phase energy meter; 10, Relay; 20, Circuit breaker; 200, Three-phase circuit.

[0045] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0047] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0048] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0049] Reference Figure 1 , Figure 1 This is a schematic diagram of the relay-based circuit breaker controller structure in the hardware operating environment involved in the embodiments of this application.

[0050] like Figure 1As shown, the circuit breaker controller for this relay may include: a processor 0003, such as a central processing unit (CPU), a communication bus 0001, an acquisition interface 0002, a processing interface 0004, and a memory 0005. The communication bus 0001 is used to establish communication between these components. The acquisition interface 0002 may include an information acquisition device or an acquisition unit such as a computer; optionally, the acquisition interface 0002 may also include a standard wired interface or a wireless interface. The processing interface 0004 may optionally include a standard wired interface or a wireless interface. The memory 0005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 0005 may also be a storage device independent of the aforementioned processor 0003.

[0051] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the relay-based circuit breaker controller and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0052] like Figure 1 As shown, the memory 0005, which is a computer storage medium, may include an acquisition interface module, a processing interface module, and a relay-based circuit breaker control program.

[0053] exist Figure 1 In the relay-operated control controller shown, the communication bus 0001 is mainly used to realize the connection and communication between components; the acquisition interface 0002 is mainly used to connect to the backend server and communicate with the backend server; the processing interface 0004 is mainly used to connect to the deployment end (user end) and communicate with the deployment end. The processor 0003 and the memory 0005 in the relay-operated control controller of this application can be set in the relay-operated control controller. The relay-operated control controller calls the relay-operated control program stored in the memory 0005 through the processor 0003 and executes the relay-operated control method provided in the embodiment of this application.

[0054] Based on the above hardware structure, an embodiment of the relay-based circuit breaker control method of this application is proposed.

[0055] In one embodiment of this application, as Figure 2 As shown, Figure 2 This is a flowchart illustrating a relay-based tripping control method according to an embodiment of this application. The relay-based tripping control method includes:

[0056] Step S10: Obtain the three-phase current value of the relay, wherein the three-phase current value includes the first phase current value of the first current phase, the second phase current value of the second current phase, and the third phase current value of the third current phase in the three-phase circuit connected to the relay.

[0057] For example, when a relay is tripped, it is equivalent to being under an inductive load (i.e., the relay can be roughly equivalent to an inductor). In this inductive load environment, the inductive load current changes rapidly at the moment the relay disconnects. According to Faraday's law of electromagnetic induction, e = -L*di / dt, a very high back electromotive force (EMF) is generated, where e is the back EMF, L is the inductance, and di / dt is the rate of change of current. This causes a momentary high voltage (up to 10 times the power supply current) between the switch contacts. This high voltage may cause an electric arc between the contacts, which can damage or melt them. When the inductive load is disconnected, the larger the current, the greater the impact on the contacts and the higher the degree of damage. According to the IEC 62052-31 standard (international standard issued by the International Electrotechnical Commission for product safety requirements and testing of electrical energy metering equipment), if the load switch built into the energy meter is to meet the UC3 certification standard requirements, which involves the performance requirements of the load switch (such as a magnetic latching relay) under short-circuit current, the load switch needs to complete 5000 resistive load opening and closing tests (one opening and closing of the load switch is considered as one opening and closing test) under 1.15 times the rated current. Then, the same load switch should continue to complete 5000 0.5L inductive load opening and closing tests. However, tests show that under a voltage of 253V (1.15*220V), using a random trip control method to control the relay, a 100A three-phase relay can generally meet the 30,000-cycle test requirement with a 100A resistive load. However, after 5,000 trips with a 100A resistive load, subsequent trip-closing tests with a 100A, 0.5L inductive load rarely exceed 5,000 cycles for most 100A magnetic latching relays on the market, with a lifespan generally around 4,500 cycles. If a 100A three-phase relay needs to simultaneously meet the 5,000-cycle lifespan requirements for both a 100A resistive load and a 100A, 0.5L inductive load, the relay cost needs to be significantly increased (i.e., by increasing the relay's resistance to back electromotive force through hardware design).

[0058] In this embodiment, the three-phase circuit can be a power grid or other circuits. That is, the relay can be a three-phase relay connected to the power grid, or a three-phase relay connected to a device that transmits or generates electrical energy. The three-phase relay can be a three-phase magnetic latching relay, a three-phase circuit breaker, etc. When relay-based tripping control is required (i.e., there is a demand for tripping), the tripping control is performed by acquiring the three-phase current value of the relay. The tripping demand can be generated by the user or internally by the relay, and the tripping control process of the relay in this application will be executed based on this demand. Alternatively, after the tripping control process of the relay in this application is determined, the time point when the relay can perform tripping control can be recorded, and the tripping control can be directly performed based on the recorded time point according to the tripping demand. The zero-crossing detection phase is determined based on the three-phase current values ​​of the relay and a preset current threshold. This means that the phase selected for zero-crossing detection is chosen based on the three-phase current values ​​and the preset current threshold. After zero-crossing detection of this phase, the relay is tripped at the zero-crossing point to prevent damage caused by excessive current during tripping, thus extending the relay's lifespan. Alternatively, a phase can be selected directly through polling. In this case, the actual current value doesn't need to be considered; the zero-crossing detection process is simply executed based on the tripping requirement. The three-phase current values ​​include the current values ​​from the three-phase AC power source connected to the relay, i.e., the three current values ​​from the three phases. The first current phase refers to the first current phase in a three-phase circuit, such as phase A. The first phase current value refers to the current value in the first current phase. The second current phase refers to the second current phase in a three-phase circuit, such as phase B. The second phase current value refers to the current value in the second current phase. The third current phase refers to the third current phase in a three-phase circuit, such as phase C. The preset current threshold is a user-defined current threshold. This threshold can be positively correlated with the current that the relay contacts can withstand, and it determines whether current is flowing through, thus ensuring the reliability of the tripping control. The current zero-crossing detection phase refers to the current phase that needs to be detected based on the three-phase current and the preset current threshold; it is one of the three current phases. Polling refers to selecting one current phase sequentially from multiple current phases, and each current phase will be selected once in one poll, such as a→b→c→a→b→c→… polling method.

[0059] Step S20: Determine the current zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value and the preset current threshold, and control the relay to trip based on the current zero-crossing detection phase, so as to realize the relay tripping at the current zero-crossing point.

[0060] In this embodiment, after determining the current zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value, and a preset current threshold, the current of that phase is detected to have crossed zero in real time. When the current zero-crossing detection phase is detected to have crossed zero, the relay is controlled to trip, thus achieving relay tripping at the current zero-crossing point. Because when one phase current crosses zero, the currents of the other two phases are approximately 0.8 times the current value, the currents of the other two phases will not be at their maximum value, thereby reducing the damage to the relay contacts caused by the high current of the other two phases. Furthermore, by controlling the tripping of a single phase through zero-crossing detection, this application ensures that, under inductive load conditions, the three contacts of the three-phase relay bear the instantaneous back electromotive force evenly when the relay trips (because each of the three phases has a current value of approximately 0.8, this greatly balances the wear and tear on the three relay contacts), and any contact of the three-phase relay can avoid tripping at the highest current point, effectively improving the service life of the relay.

[0061] This embodiment provides a relay tripping control method. It acquires the three-phase current values ​​of the relay, including the first-phase current value of the first current phase, the second-phase current value of the second current phase, and the third-phase current value of the third current phase in the three-phase circuit connected to the relay. Based on the first-phase current value, the second-phase current value, the third-phase current value, and a preset current threshold, a current zero-crossing detection phase is determined. The relay is then controlled to trip at the current zero-crossing point. By using the first-phase current value, the second-phase current value, the third-phase current value, and the preset current threshold in the three-phase circuit connected to the relay, the relay trips at the current zero-crossing point of the current zero-crossing detection phase. At this point, the current flowing through the current zero-crossing detection phase is minimized, thus minimizing the back electromotive force generated by this current. This avoids the problem in existing technologies where random tripping might occur at the maximum current (where the inductive load environment causes a large back electromotive force to be generated at the relay contacts), which could damage the relay contacts. By controlling the relay to trip when the current of the current-zero detection phase crosses zero, the phenomenon of tripping at the maximum current is avoided, thereby improving the service life of the relay.

[0062] In one embodiment, a first embodiment of the relay-based tripping control method proposes a second embodiment of this application, which includes the step of determining the current zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value, and a preset current threshold, comprising:

[0063] Step S11: If at least one of the first phase current value, the second phase current value, and the third phase current value is greater than the preset current threshold, the detection phase is selected based on the first phase current value, the second phase current value, the third phase current value, and the preset current to determine the current zero-crossing detection phase.

[0064] In this embodiment, before determining the zero-crossing detection phase, the need for zero-crossing detection is first determined based on the three-phase current values. This is primarily based on whether the current three-phase current values ​​pose a risk of damaging the relay contacts and whether there is current in the three-phase circuit itself. If there is no current, subsequent zero-crossing detection is unnecessary to ensure the reliability of the zero-crossing detection. By determining whether any of the first-phase current values ​​of the first current phase, the second-phase current value of the second current phase, and the third-phase current value of the third current phase in the three-phase circuit exceeds a preset current threshold, it is determined that there is a risk of damaging the relay contacts when at least one of the three current values ​​exceeds the preset current threshold. Therefore, the zero-crossing detection phase is determined based on the first-phase current value, the second-phase current value, the third-phase current value, and the preset current selection detection phase. The preset current selection detection phase refers to the current phase selected for zero-crossing current detection during each execution of the trip control process. Further, refer to... Figure 3 , Figure 3 This is a schematic diagram of the control flow of a relay tripping control method according to an embodiment of this application. When the relay trips for the first time, phase A current is designated as the zero-crossing detection phase (i.e., a preset current selection detection phase; other current phases can also be used, such as prioritizing phase C as the preset current selection detection phase during the first trip). When the relay is not tripping for the first time, the zero-crossing detection phase can be determined based on a polling method. Then, it is determined whether zero-crossing detection control tripping is needed by detecting whether at least one phase current is greater than the minimum specified operating current (i.e., a preset current threshold, such as 30% Imax, which can be adjusted according to actual conditions; Imax is the maximum current of the relay). If one phase current is greater than the preset current threshold, it is determined that tripping at this time would damage the contacts on that phase of the relay (the current phase greater than the preset current threshold). Therefore, this phase is designated as the current zero-crossing detection phase, and the zero-crossing current moment of that phase is determined. Tripping control is then performed at the zero-crossing current moment, thus avoiding damage to the relay contacts and improving the relay's service life.

[0065] Furthermore, the step of selecting the detection phase and determining the zero-crossing detection phase based on the three-phase current values ​​and the preset current also includes:

[0066] Step S111: Determine the maximum current value among the first phase current value, the second phase current value, and the third phase current value.

[0067] Step S112: If the current phase corresponding to the maximum current value is the preset current selection detection phase, determine the selected detection phase as the current zero-crossing detection phase.

[0068] Step S113: If the current phase corresponding to the maximum current value is not the preset current selection detection phase, determine the target current value corresponding to the preset current selection detection phase among the first phase current value, the second phase current value, and the third phase current value, and determine the current zero-crossing detection phase based on the maximum current value and the target current value.

[0069] In this embodiment, when it is determined that current zero-crossing detection is required, the maximum current value among the first-phase current value, the second-phase current value, and the third-phase current value is determined. That is, the largest current value among the three current values ​​is selected as the maximum current value, and then it is determined whether the current phase corresponding to the maximum current value should be selected as the current zero-crossing detection phase. In other words, if the current phase corresponding to the maximum current value is a preset current selection detection phase, then the selected detection phase is determined as the current zero-crossing detection phase. Conversely, if the current phase corresponding to the maximum current value is not a preset current selection detection phase, then the target current value corresponding to the selected detection phase among the first-phase current value, the second-phase current value, and the third-phase current value is determined. The current zero-crossing detection phase is determined based on the maximum current value and the target current value. Here, the target current value refers to the current value corresponding to the selected detection phase, which is one of the first-phase current value, the second-phase current value, and the third-phase current value. This allows us to determine the zero-crossing detection phase based on the maximum and target current values. After zero-crossing detection is performed on the phase, the relay can be tripped, preventing damage to the relay contacts of a phase caused by a high current and ensuring the service life of the relay contacts in that phase.

[0070] Furthermore, the step of determining the zero-crossing detection phase based on the maximum current value and the target current value includes:

[0071] Step S1131: Determine the current difference between the maximum current value and the target current value;

[0072] Step S1132: If the current difference is greater than the preset difference threshold, the current phase corresponding to the maximum current value is taken as the current zero-crossing detection phase.

[0073] Step S1133: When the current difference is less than or equal to the difference threshold, the preset current selection detection phase is used as the current zero-crossing detection phase.

[0074] In this embodiment, when determining the current zero-crossing detection phase based on the maximum current value and the target current value, the current difference between the maximum current value and the target current value is determined. If the current difference is greater than a preset difference threshold, the current phase corresponding to the maximum current value is selected as the current zero-crossing detection phase. That is, the current phase corresponding to the maximum current value is prioritized for zero-crossing detection to avoid damage to the relay contacts due to excessive current in that phase. Conversely, if the current difference is less than or equal to the preset difference threshold, the selected detection phase is used as the current zero-crossing detection phase. In this case, a preset current selection phase is still used. The advantage of designing a preset difference threshold here is to avoid identification errors caused by fluctuations in the acquired current, thereby ensuring the accuracy of determining the maximum current value and ensuring the accuracy of determining the current zero-crossing detection phase and subsequent tripping control.

[0075] In another embodiment, refer to Figure 3 The system can detect whether the ratio of the current value of other phases to the current value of a specified zero-crossing detection phase (preset current selection detection phase) is greater than a certain percentage (e.g., 120%, which is greater than 20% of the denominator, or it can be greater than 20% of the numerator; this percentage can be adjusted appropriately according to application requirements). If the ratio is greater than the specified percentage, the current phase corresponding to the maximum current value is used as the current zero-crossing detection phase, and a phase change record is made for the current zero-crossing detection phase, i.e., it is recorded that this phase has been used as the current zero-crossing detection phase. If the ratio is less than or equal to the specified percentage, the already specified current zero-crossing detection phase is used, i.e., the preset current selection detection phase is used as the current zero-crossing detection phase, so as to accurately determine the current zero-crossing detection phase for the current of that phase. In this way, the current phase with the maximum current value can be accurately overcurrent detected, so as to ensure that the relay contacts on the current phase with the maximum current value will not be damaged, thereby increasing the service life of the relay.

[0076] In one embodiment, following the first and / or second embodiments of the relay-based circuit breaker control method, a third embodiment of this application is proposed, wherein the relay-based circuit breaker control method further includes:

[0077] Step S12: If the first phase current value, the second phase current value, and the third phase current value are all less than or equal to the preset current threshold, control the relay to trip.

[0078] In this embodiment, in addition to current zero-crossing detection, the relay can be controlled to trip when the first-phase current value, the second-phase current value, and the third-phase current value are all less than or equal to a preset current threshold. That is, if it is determined that the three-phase current values ​​do not pose a risk of damage to the three contacts of the relay, then tripping control can be directly performed. Furthermore, the previously selected detection phase can be used for the next relay tripping control, or the next detection phase can be selected using a polling method for the next relay tripping control.

[0079] In one embodiment, the first, second, and / or third embodiments of the relay-based tripping control method are followed by a fourth embodiment of this application, which includes the step of controlling the relay to trip based on the current zero-crossing detection phase, comprising:

[0080] Step S21: Obtain the real-time current value of the current zero-crossing detection phase;

[0081] Step S22: When the real-time current value is the preset zero-crossing current value, control the relay to trip.

[0082] In this embodiment, after determining the current zero-crossing detection phase, the relay's tripping is controlled. This is achieved by acquiring the real-time current value of the current zero-crossing detection phase and controlling the relay to trip when the real-time current value is a preset zero-crossing current value. Specifically, the relay trips when the current on the current zero-crossing detection phase crosses zero. At this point, the average instantaneous back electromotive force borne by the three contacts of the relay is minimized, thus protecting the relay contacts and extending the relay's lifespan. It is worth noting that because the entire detection process is very short, it does not affect the real-time performance of the overall control. Further details can be found in... Figure 3 After determining the phase for current zero-crossing detection, current zero-crossing detection is performed on the corresponding phase current. When the current of the phase for current zero-crossing detection crosses zero, the relay is tripped, thereby reducing the instantaneous back electromotive force on the relay contacts and improving the service life of the relay.

[0083] In one embodiment, regarding the relay tripping control method of this application, the following performance test was conducted using energy meters from the same batch with a built-in 100A current-rated magnetic latching relay. The test content was as follows: Experiment 1: Under a 253V, 100A resistive load, the test was conducted to determine how many tripping cycles the relay would need to complete before it would be damaged; Experiment 2: After 5000 tripping cycles under a 253V, 100A resistive load, a further tripping cycle under a 100A, 0.5L inductive load was conducted to determine how many more tripping cycles the relay would need to complete before it would be damaged. Five energy meters were randomly selected from both control methods for the experiment, and the relays were subjected to life tests according to the IEC62052-31 UC3 test standard, with a test current of 100A for each meter. Using a random trip control method to control the tripping and closing of the three-phase relays, the average number of tripping and closing cycles when 5 energy meters failed was 31,664 (29,056, 30,439, 34,253, 31,726, and 32,849 respectively). Using the zero-crossing current detection method of this application to control the tripping and closing of the three-phase relays, the average number of tripping and closing cycles when 5 energy meters failed was 35,593 (35,326, 35,623, 34,873, 35,963, and 36,182 respectively). Comparing the two control methods, the zero-crossing current detection method of this application can effectively improve the service life of the relays by about 12%, and the service life consistency of the relays is better (i.e., the zero-crossing current detection method of this application uses a polling method to detect the zero-crossing point). In Experiment 2, 5 energy meters were randomly selected for both control methods, and the relays were subjected to a life test according to the IEC62052-31 UC3 test standard, with a test current of 100A for both methods. Using a random trip control method to control the tripping and closing of three-phase relays, 5000 resistive load tests were first conducted, followed by 0.5L inductive load tests. The average number of tripping and closing cycles when five energy meters failed was 4530 (4465, 4339, 4533, 4726, and 4589 respectively). Using the zero-crossing current detection method of this application to control the tripping and closing of three-phase relays, 5000 resistive load tests were first conducted, followed by 0.5L inductive load tests. The average number of tripping and closing cycles when five energy meters failed was 5321 (5176, 5262, 5303, 5199, and 5218 respectively). Comparing the two control methods, the zero-crossing current detection method of this application can effectively improve the service life of the relays, increasing the service life by approximately 15% under 0.5L inductive load conditions, and also exhibiting better consistency in relay lifespan.

[0084] In one embodiment, after the step of controlling the relay to trip based on the current zero-crossing detection phase, the following steps are included:

[0085] Step S23: Determine the tripping action duration corresponding to the current zero-crossing detection;

[0086] Step S24: Determine the tripping interval of the current zero-crossing detection phase based on the tripping action duration and the preset current cycle duration.

[0087] In this embodiment, after the relay controlling the current zero-crossing detection phase trips, the tripping time is recorded for use in the next cycle. Before performing the entire relay tripping control, the tripping action duration of the relay on each current phase (A, B, and C) at the current zero-crossing point is obtained and saved. After determining that the relay controlling the current zero-crossing detection phase trips, the tripping action duration corresponding to the current zero-crossing detection is determined. Then, based on the tripping action duration and the preset current cycle duration, the tripping interval duration of the current zero-crossing detection phase is determined. The tripping action duration refers to the time from receiving the command to the completion of the tripping action. The tripping interval duration refers to the interval between two zero-crossing points, ensuring that the tripping action is performed only at the next zero-crossing point. The preset current cycle duration refers to the cycle duration of the three-phase current, which is the time point when the relay can perform tripping control (tripping interval duration) directly trained and recorded to facilitate rapid tripping control. In other words, after determining the tripping interval, the next time the current zero-crossing detection phase is determined, tripping control can be directly performed based on the corresponding tripping interval, without needing to perform current zero-crossing detection on that current phase, thus greatly improving the efficiency of tripping control. Assuming the preset current cycle duration is Ds, the tripping action duration is Fs, and Ns is the action proximity value, then the tripping interval duration Ts = Ds - Fs - Ns will be determined. For example, if Ds is 20ms, Fs is 12ms, and Ns is 0.2ms, then the tripping interval duration Ts = 20 - 12 - 0.2 = 7.8ms. Further details can be found by referring to... Figure 3 After detecting the zero-crossing of the corresponding current phase, and combining this with the already acquired relay tripping duration at the zero-crossing point of the corresponding phase current, a suitable time Ts is delayed before the relay trips. This ensures that the relay contacts close when the specified current zero-crossing detection phase approaches the zero-crossing point of the next cycle, serving as the basis for subsequent relay control on that phase. It's worth noting that once the tripping interval duration for each current phase is determined, the arrival time of the closest tripping interval can be directly determined in subsequent tripping control, allowing for tripping control based on that time point. This improves the efficiency of tripping control. Furthermore, since the arrival times of all tripping interval durations satisfy the current zero-crossing condition, tripping at the highest current point can be avoided, effectively extending the relay's lifespan.

[0088] In one embodiment, based on the first, second, third, and / or fourth embodiments of the relay-based circuit breaker control method, a fifth embodiment of the relay-based circuit breaker control method of this application is proposed. The relay-based circuit breaker control method further includes:

[0089] Step S00: After receiving a trip control command each time, select one current phase from the first current phase, the second current phase, and the third current phase in the three-phase circuit as the preset current selection detection phase in a polling manner.

[0090] In this embodiment, to ensure the uniformity of the lifespan of the three relay contacts and the uniformity of control over the three-phase power in the three-phase circuit, after each receiving of a trip control command, a current phase is selected as the preset current selection detection phase from the first, second, and third current phases of the three-phase circuit using a polling method. This ensures the uniformity of the relay's trip control at zero crossing in different current phases, thereby guaranteeing the uniformity of the lifespan of each contact on the relay. In other words, there is no problem of frequently needing to replace the relay due to the damage of a single relay contact, which would increase the relay's operating cost. The trip control command refers to the command that requires tripping the relay.

[0091] Furthermore, following the steps of controlling the relay to trip based on the current zero-crossing detection phase, the process includes:

[0092] Step S30: When the current zero-crossing detection phase is the preset current selection detection phase, determine the next preset current selection detection phase by polling, and perform the step of obtaining the three-phase current value of the relay based on the next preset current selection detection phase.

[0093] Step S40: If the current zero-crossing detection phase is not the preset current selection detection phase, perform the step of obtaining the three-phase current value of the relay, or determine the next preset current selection detection phase by polling, and perform the step of obtaining the three-phase current value of the relay based on the next preset current selection detection phase.

[0094] In this embodiment, after the trip control is performed based on the current zero-crossing detection phase, a new current zero-crossing detection phase can be selected as the preset current selection detection phase, or no new preset current selection detection phase can be selected. That is, it determines whether the current zero-crossing detection phase has been changed, and switches between the two scenarios for control. After selecting a detection phase, regardless of whether it is used, the next detection phase can be selected in a polling manner to perform the step of obtaining the three-phase current value of the relay. Alternatively, after selecting a detection phase, the next detection phase can be selected in a polling manner only after that detection phase is used, thus ensuring the number of times each detection phase is used. This makes the trip control of the three current phases more uniform throughout the entire trip control process, ensuring even use of the relay contacts on the corresponding current phases and guaranteeing consistent relay contact lifespan.

[0095] Corresponding to the above embodiments, this application also proposes a three-phase energy meter.

[0096] like Figure 4 As shown, the three-phase energy meter in this application embodiment may include:

[0097] Relay 10 is connected to a three-phase circuit, such as power grid 200 (generally a three-phase relay, but it can also be a single-phase relay; this application describes it as a three-phase relay).

[0098] The circuit breaker controller 20 is connected to the control terminal of the relay 10.

[0099] The circuit breaker controller 20 is also used to perform the steps of the circuit breaker control method embodiment of the relay as described in any of the above.

[0100] In this embodiment, the three-phase energy meter can be applied to any three-phase energy meter. This embodiment takes a three-phase energy meter on a three-phase circuit as an example for illustration. The three-phase energy meter on a three-phase circuit includes a relay 10 and a circuit breaker controller 20.

[0101] According to the three-phase energy meter of this application embodiment, the trip controller 20 obtains the three-phase current values ​​of the relay, wherein the three-phase current values ​​include the first-phase current value of the first current phase, the second-phase current value of the second current phase, and the third-phase current value of the third current phase on the three-phase circuit connected to the relay; determines the current zero-crossing detection phase based on the first-phase current value, the second-phase current value, the third-phase current value, and a preset current threshold, and controls the relay to trip based on the current zero-crossing detection phase, so as to realize that the relay trips at the current zero-crossing point. By determining the current zero-crossing detection phase based on the first-phase current value, the second-phase current value, the third-phase current value, and the preset current threshold on the three-phase circuit connected to the relay, the relay is controlled to trip when the current of the current zero-crossing detection phase crosses zero, that is, the current on the current zero-crossing detection phase is the minimum when tripping at this time, so the back electromotive force brought by this current is the minimum. This avoids the problem in existing technologies where random tripping might occur at the maximum current (where the inductive load environment causes a large back electromotive force at the relay contacts), which could damage the relay contacts. By controlling the relay to trip when the current in the zero-crossing detection phase crosses zero, the phenomenon of tripping at the maximum current is avoided, thus improving the relay's lifespan. It's worth noting that a current-collecting instrument can be designed into the three-phase energy meter to collect the three-phase current values ​​and transmit them back to the tripping controller 20 for processing. Of course, the three-phase energy meter can also include more instruments, which will not be discussed here.

[0102] This application also provides a circuit breaker controller, as shown in the reference. Figure 5 , Figure 5This is a schematic diagram of a circuit breaker controller module according to an embodiment of this application. The circuit breaker controller includes:

[0103] The data acquisition module A01 is used to acquire the three-phase current values ​​of the relay. The three-phase current values ​​include the first phase current value of the first current phase, the second phase current value of the second current phase, and the third phase current value of the third current phase in the three-phase circuit connected to the relay.

[0104] The circuit breaker control module A02 is used to determine the current zero-crossing detection phase based on the first phase current value, the second phase current value, the third phase current value and the preset current threshold, and to control the relay to cut off the circuit breaker based on the current zero-crossing detection phase, so as to realize that the relay cuts off the circuit breaker at the current zero-crossing point.

[0105] This application also provides a storage medium, which is a computer storage medium.

[0106] The storage medium of this application stores a relay-based circuit breaker control program, which, when executed by a processor, implements the steps of the relay-based circuit breaker control method described above.

[0107] The method implemented when the relay tripping control program running on the processor is executed can be referred to in various embodiments of the relay tripping control method of this application, and will not be repeated here.

[0108] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0109] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0110] The above description is merely an optional embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the inventive concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for controlling the tripping of a relay, characterized in that, The relay-based tripping control method includes the following steps: Obtain the three-phase current value of the relay, wherein the three-phase current value includes the first phase current value of the first current phase, the second phase current value of the second current phase, and the third phase current value of the third current phase in the three-phase circuit connected to the relay; If at least one of the first-phase current values, the second-phase current value, and the third-phase current value is greater than a preset current threshold, the maximum current value among the three phases is determined. If the current phase corresponding to the maximum current value is a preset current selection detection phase, the preset current selection detection phase is determined as the current zero-crossing detection phase. The preset current selection detection phase refers to the current phase selected in a poll before each execution of the tripping control procedure to detect the zero-crossing current. If the current phase corresponding to the maximum current value is not a preset current selection detection phase, the preset current selection detection phase is determined to be the current zero-crossing detection phase. The target current value is determined from the first phase current value, the second phase current value, and the third phase current value, wherein the target current value is one of the first phase current value, the second phase current value, and the third phase current value. The current difference between the maximum current value and the target current value is determined. If the current difference is greater than a preset difference threshold, the current phase corresponding to the maximum current value is selected as the current zero-crossing detection phase. If the current difference is less than or equal to the difference threshold, the preset current selection detection phase is selected as the current zero-crossing detection phase. The relay is controlled to trip according to the current zero-crossing detection phase, so that the relay trips at the current zero-crossing point. Specifically, when the first phase current value, the second phase current value, and the third phase current value are all less than or equal to a preset current threshold, the relay is controlled to trip.

2. The relay-based tripping control method as described in claim 1, characterized in that, The step of controlling the relay to trip based on the current zero-crossing detection phase includes: Obtain the real-time current value of the current zero-crossing detection phase; When the real-time current value is a preset zero-crossing current value, the relay is controlled to trip.

3. The relay-based tripping control method as described in claim 1, characterized in that, After the step of controlling the relay to trip based on the current zero-crossing detection phase, the following steps are included: Determine the tripping action duration corresponding to the zero-crossing current detection; The tripping interval of the current zero-crossing detection phase is determined based on the tripping action duration and the preset current cycle duration.

4. The relay-based tripping control method as described in claim 1, characterized in that, The relay-based tripping control method further includes: After receiving a power-off control command each time, a current phase is selected from the first current phase, the second current phase, and the third current phase in a polling manner as the preset current selection and detection phase.

5. The relay-based tripping control method as described in claim 4, characterized in that, After the step of controlling the relay to trip based on the current zero-crossing detection phase, the following steps are included: When the current zero-crossing detection phase is the preset current selection detection phase, the next preset current selection detection phase is determined by polling, and the step of obtaining the three-phase current value of the relay is performed based on the next preset current selection detection phase. If the current zero-crossing detection phase is not the preset current selection detection phase, the step of obtaining the three-phase current value of the relay is performed, or the next preset current selection detection phase is determined by polling, and the step of obtaining the three-phase current value of the relay is performed based on the next preset current selection detection phase.

6. A three-phase electricity meter, characterized in that, The three-phase energy meter includes: The relay is connected to a three-phase circuit; A circuit breaker controller, wherein the circuit breaker controller is connected to the control terminal of the relay; The circuit breaker controller is also used to perform the steps of the circuit breaker control method for the relay as described in any one of claims 1 to 5.

Images