Relay closing control method and three-phase electric energy meter

Abstract

The invention relates to the field of relays, and discloses a closing control method of a relay and a three-phase electric energy meter, and the method comprises the steps: obtaining a three-phase voltage value of the relay, a first phase voltage value of the first voltage phase, a second phase voltage value of the second voltage phase and a third phase voltage value of the third voltage phase; and selecting a detection phase according to the first phase voltage value, the second phase voltage value, the third phase voltage value and a preset voltage to determine a voltage zero-crossing detection phase, and controlling the relay to be switched on according to the voltage zero-crossing detection phase so as to realize switching on of the relay at a voltage zero-crossing point. The service life of the relay is prolonged.

Description

Technical Field

[0001] The present application relates to the field of relays, and in particular to a relay closing control method and a three-phase electric energy meter. Background Art

[0002] With the rapid development of relays, users have higher requirements for the closing control method of relays.

[0003] The traditional relay closing control method directly executes the control to close the relay in real time upon receiving the relay closing request, that is, random closing is performed based on the relay closing request. This relay closing control method has certain drawbacks. Random closing may occur at maximum voltage (at this time, the capacitive load environment of the closing causes the maximum voltage to generate a large inrush current on the relay contacts). This large inrush current may damage the relay contacts. In other words, this relay closing control method will damage the relay contacts due to the large inrush current, resulting in a short relay life. Summary of the Invention

[0004] The main purpose of this application is to propose a relay closing control method and a three-phase electric energy meter, aiming to solve the technical problem of how the service life of the relay is not long.

[0005] To achieve the above-mentioned object, the present application provides a relay closing control method, the relay closing control method comprising the following steps:

[0006] Obtaining three-phase voltage values ​​of the relay, wherein the three-phase voltage values ​​include a first phase voltage value of a first voltage phase, a second phase voltage value of a second voltage phase, and a third phase voltage value of a third voltage phase on a three-phase circuit connected to the relay;

[0007] A detection phase is selected according to the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage to determine the voltage zero crossing detection phase, and the relay is controlled to close according to the voltage zero crossing detection phase to achieve the relay closing at the voltage zero crossing point.

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

[0009] determining a maximum voltage value, which is the largest voltage value among the first phase voltage value, the second phase voltage value, and the third phase voltage value;

[0010] In a case where the voltage phase corresponding to the maximum voltage value is the preset voltage selection detection phase, determining the selected detection phase as the voltage zero-crossing detection phase;

[0011] When the voltage phase corresponding to the maximum voltage value is not the preset voltage selection detection phase, the target voltage value corresponding to the selected detection phase among the first phase voltage value, the second phase voltage value and the third phase voltage value is determined, and the voltage zero-crossing detection phase is determined according to the maximum voltage value and the target voltage value.

[0012] In one embodiment, the step of determining the voltage zero-crossing detection phase according to the maximum voltage value and the target voltage value includes:

[0013] determining a voltage difference between the maximum voltage value and the target voltage value;

[0014] When the voltage difference is greater than a preset difference threshold, the voltage phase corresponding to the maximum voltage value is used as the voltage zero-crossing detection phase;

[0015] When the voltage difference is less than or equal to a preset difference threshold, the selected detection phase is used as the voltage zero-crossing detection phase.

[0016] In one embodiment, the step of controlling the relay to close according to the voltage zero-crossing detection phase includes:

[0017] Obtaining a real-time voltage value of the voltage zero-crossing detection phase;

[0018] When the real-time voltage value is a preset zero-crossing voltage value, the relay is controlled to close.

[0019] In one embodiment, after the step of controlling the relay to close according to the voltage zero-crossing detection phase, the method further comprises:

[0020] Determine the closing action duration corresponding to the voltage zero-crossing detection;

[0021] The closing interval duration of the voltage zero-crossing detection phase is determined based on the closing action duration and a preset voltage cycle duration.

[0022] In one embodiment, after the step of obtaining the three-phase voltage value of the relay, the following steps are included:

[0023] When at least one phase voltage value among the first phase voltage value, the second phase voltage value and the third phase voltage value is greater than a preset voltage threshold, the step of selecting a detection phase and determining a voltage zero-crossing detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage is performed.

[0024] In one embodiment, after the step of obtaining the three-phase voltage value of the relay, the method further includes:

[0025] When the first phase voltage value, the second phase voltage value, and the third phase voltage value are all less than or equal to a preset voltage threshold, the relay is controlled to close.

[0026] In one embodiment, the relay closing control method further includes:

[0027] After receiving a closing control instruction each time, the first voltage phase, the second voltage phase, and the third voltage phase are selected as detection phases of the preset voltage in a polling manner.

[0028] In one embodiment, after the step of controlling the relay to close according to the voltage zero-crossing detection phase, the method further comprises:

[0029] In a case where the voltage zero-crossing detection phase is a preset voltage selection detection phase, determining a next preset voltage selection detection phase, and performing the step of obtaining the three-phase voltage values ​​of the relay based on the next preset voltage selection detection phase;

[0030] In the case that the voltage zero-crossing detection phase is not the preset voltage selection detection phase, the next preset voltage selection detection phase is determined, and based on the next preset voltage selection detection phase, the step of obtaining the three-phase voltage value of the relay is executed, or the step of obtaining the three-phase voltage value of the relay is executed.

[0031] The present application also provides a three-phase electric energy meter, comprising:

[0032] a relay, the relay being connected to a power grid;

[0033] A closing controller connected to a control terminal of the relay;

[0034] The closing controller is also used to execute the steps of the above-mentioned relay closing control method.

[0035] The present application provides a closing control method for a relay, by obtaining the three-phase voltage value of the relay, wherein the three-phase voltage value includes the first phase voltage value of the first voltage phase, the second phase voltage value of the second voltage phase, and the third phase voltage value of the third voltage phase on the three-phase circuit connected to the relay; selecting a detection phase according to the first phase voltage value, the second phase voltage value, the third phase voltage value, and a preset voltage to determine the voltage zero-crossing detection phase, and controlling the closing of the relay according to the voltage zero-crossing detection phase to achieve the closing of the relay at the voltage zero-crossing point.

[0036] By selecting a detection phase based on the first-phase voltage value, the second-phase voltage value, the third-phase voltage value, and a preset voltage in a three-phase circuit connected to the relay, a voltage zero-crossing detection phase is determined, so that the relay is controlled to close when the voltage of the voltage zero-crossing detection phase crosses zero. This avoids the phenomenon in the prior art where random closing may occur at maximum voltage (at this time, the capacitive load environment of closing causes the maximum voltage to generate a large inrush current at the relay contacts), which may cause damage to the relay contacts due to the large inrush current. By controlling the relay to close when the voltage of the voltage zero-crossing detection phase crosses zero, the phenomenon of closing at maximum voltage is avoided, thereby improving the service life of the relay. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0038] Figure 1 It is a structural diagram of a closing controller of a relay in a hardware operating environment involved in an embodiment of the present application;

[0039] Figure 2 Schematic diagram of a flow chart of a relay closing control method according to an embodiment of the present application;

[0040] Figure 3 A control flow diagram of a closing control method of a relay according to an embodiment of the present application;

[0041] Figure 4 A schematic diagram of a module of a three-phase electric energy meter according to an embodiment of the present application;

[0042] Figure 5 Schematic diagram of a closing controller module according to an embodiment of the present application.

[0043] Description of Figure Numbers:

[0044] 0001, communication bus; 0002, acquisition interface; 0003, processor; 0004, processing interface; 0005, memory; 100, three-phase energy meter; 10, relay; 20, closing controller; 200, power grid.

[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 DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0048] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0049] Reference Figure 1 , Figure 1 This is a structural diagram of a relay closing controller in the hardware operating environment involved in the embodiment of the present application.

[0050] like Figure 1 As shown, the closing controller of the 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. Among them, the communication bus 0001 is used to realize the connection and communication between these components. The acquisition interface 0002 may include an information acquisition device and an acquisition unit such as a computer. Optionally, the acquisition interface 0002 may also include a standard wired interface and a wireless interface. The processing interface 0004 may optionally include a standard wired interface and a wireless interface. The memory 0005 may be a high-speed random access memory (RAM) or a stable non-volatile memory (NVM), such as a disk storage. 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 in the figure does not constitute a limitation on the closing controller of the relay, and may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0052] like Figure 1 As shown, the memory 0005 as a computer storage medium may include an acquisition interface module, a processing interface module and a relay closing control program.

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

[0054] Based on the above hardware structure, an embodiment of the closing control method of the relay of the present application is proposed.

[0055] In one embodiment of the present application, Figure 2 As shown, Figure 2 1 is a flow chart of a relay closing control method according to an embodiment of the present application. The relay closing control method includes:

[0056] Step S10, obtaining three-phase voltage values ​​of the relay, wherein the three-phase voltage values ​​include a first phase voltage value of a first voltage phase, a second phase voltage value of a second voltage phase, and a third phase voltage value of a third voltage phase on a three-phase circuit connected to the relay;

[0057] For example, when the relay is closed, it is equivalent to being under a capacitive load (that is, the relay can be roughly equivalent to a capacitor at this time). That is, when the relay is in a capacitive load environment, at the moment the relay is closed, since the voltage across the capacitor cannot change suddenly, a huge instantaneous surge current will be generated. This instantaneous surge current can reach several times the current in the closed state. The instantaneous surge current satisfies I=C*dV / dt, where C is the equivalent capacitance value and dV / dt refers to the rate of change of voltage. At this time, if the energy generated by the instantaneous surge current and the relay contact resistance is large enough, it may damage or burn the relay contacts. Therefore, at the moment the relay is closed, the greater the instantaneous surge current generated, the greater the energy generated by the instantaneous surge current and the relay contact resistance, the greater the impact on the contacts, and the higher the degree of damage to the contacts. If the control is closed at the highest point where the relay is connected to the power grid, there will be a point where dV / dt is the maximum, that is, the energy generated by the instantaneous surge current and the relay contact resistance is the maximum, which will cause damage to the relay contacts.

[0058] In this embodiment, 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 electric energy. The three-phase relay can be a three-phase magnetic latching relay, a three-phase circuit breaker, or any other switch associated with three-phase alternating current. When the relay needs to be closed, the closing control is performed by obtaining the three-phase voltage value of the relay (which can be executed according to the closing control requirement or in other situations, such as directly training and recording the time point when the relay can be closed and storing it for subsequent use). The voltage zero-crossing detection phase is determined based on the three-phase voltage value of the relay and the preset voltage. That is, based on the three-phase voltage value, it is determined whether to use the user-defined preset voltage selection detection phase as the voltage zero-crossing detection phase or to use other voltage phases as the voltage zero-crossing detection phase. After the voltage zero-crossing detection phase is zero-crossed, the relay can be closed to avoid damage to the relay caused by excessive voltage when the relay is closed, thereby increasing the service life of the relay. The three-phase voltage value includes the voltage value at the three-phase AC source such as the power grid connected to the relay, that is, the three voltage values ​​on the three voltage phases. It can also be other locations that generate and transmit three-phase AC power, which is not limited here. For example, the first voltage phase refers to the first voltage phase on the power grid, such as phase A on the power grid, and the first phase voltage value refers to the voltage value on the first voltage phase. The second voltage phase refers to the second voltage phase on the power grid, such as phase B on the power grid, and the second phase voltage value refers to the voltage value on the second voltage phase. The third voltage phase refers to the third voltage phase on the power grid, such as phase C on the power grid, and the third phase voltage value refers to the voltage value on the third voltage phase. The preset voltage selection detection phase refers to the voltage phase selected by the user as the voltage phase for detecting zero-crossing voltage. The voltage zero-crossing detection phase refers to the voltage phase that needs to be detected based on the three-phase voltage. This voltage phase is one of the three voltage phases, and can also be directly the preset voltage selection detection phase.

[0059] Step S20, selecting a detection phase to determine a voltage zero crossing detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage, and controlling the relay to close according to the voltage zero crossing detection phase to achieve relay closing at the voltage zero crossing point.

[0060] In this embodiment, after the voltage zero crossing detection phase is determined based on the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage, the voltage of the phase will be subjected to real-time zero crossing detection, so that when the voltage zero crossing detection phase is detected to be voltage zero, the relay will be controlled to close, so as to achieve the relay closing at the voltage zero crossing point. Because when the voltage of one phase in the three-phase voltage crosses zero, the voltage of the other two phases is about 0.8 or so voltage value, then at this time the voltage of the other two phases will not be the case of the maximum voltage value, thereby reducing the damage to the relay contacts due to the high voltage of the other two phases. Further, the present application controls the closing of the relay by performing zero crossing detection on a phase, so that the three contacts of the three-phase relay can withstand the instantaneous inrush current when the relay is closed evenly in a capacitive load environment (because the three phases will have a voltage value of about 0.8 themselves, which greatly balances the consumption of the three contacts of the relay), and any contact of the three-phase relay can avoid closing at the highest voltage point, which can effectively improve the service life of the relay.

[0061] For example, the following experiments were conducted to test the random closing and zero-crossing detection closing control of this application. Using an energy meter from the same batch with a built-in 100A magnetic latching relay, the effects were tested under the following conditions: 253V, 100A, 0.8C capacitive load closing and opening (ensuring that no power was applied during closing, and closing the circuit breaker was tested for the number of times the magnetic latching relay would be damaged). Five three-phase electricity meters with the same performance were randomly inspected using the random closing control method and the zero-crossing detection control closing method of the present application, and a 100A, 0.8C relay life test was performed. The random closing control method was used to control the opening and closing of the three-phase relay. The average number of opening and closing times of the five electricity meters when they failed was 12542 times (respectively: 12553, 13049, 14263, 11862, and 10984); the zero-crossing detection control closing method of the present application was used to control the opening and closing of the three-phase relay. The average number of opening and closing times of the five electricity meters when they failed was 15118 times (respectively: 15389, 15516, 14897, 14762, and 15028). Comparing the two closing control methods, the zero-crossing detection control closing method of the present application can effectively increase the service life of the relay by about 20%, and the relay has better life consistency performance (that is, the consumption of the three contacts is consistent, and there will be no situation where a certain contact is damaged a long number of times in advance. Generally, the number of times the three contacts fail is not much different).

[0062] This embodiment provides a method for controlling the closing of a relay, by obtaining the three-phase voltage values ​​of the relay, wherein the three-phase voltage values ​​include the first-phase voltage value of the first voltage phase, the second-phase voltage value of the second voltage phase, and the third-phase voltage value of the third voltage phase on the three-phase circuit connected to the relay; selecting a detection phase based on the first-phase voltage value, the second-phase voltage value, the third-phase voltage value, and a preset voltage to determine a voltage zero-crossing detection phase, and controlling the closing of the relay based on the voltage zero-crossing detection phase to achieve closing of the relay at the voltage zero-crossing point. By selecting a detection phase based on the first-phase voltage value, the second-phase voltage value, the third-phase voltage value, and the preset voltage on the three-phase circuit connected to the relay, a voltage zero-crossing detection phase is determined, so as to control the closing of the relay when the voltage of the voltage zero-crossing detection phase crosses the zero point. This avoids the problem in the prior art that random closing may be performed at the maximum voltage (at this time, the capacitive load environment of the closing causes the maximum voltage to form a large impact current at the relay contacts), which may cause damage to the relay contacts due to the large impact current. By controlling the relay to close when the voltage of the voltage zero-crossing detection phase passes through zero, the phenomenon of closing at the maximum voltage is avoided, thereby improving the service life of the relay.

[0063] In one embodiment, based on the first embodiment of the relay closing control method, a second embodiment of the present application is proposed, wherein the step of selecting a detection phase and determining a voltage zero-crossing detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value, and the preset voltage further includes:

[0064] Step S21, determining a maximum voltage value which is the largest among the first phase voltage value, the second phase voltage value, and the third phase voltage value;

[0065] Step S22, when the voltage phase corresponding to the maximum voltage value is the preset voltage selection detection phase, determining to select the detection phase as the voltage zero-crossing detection phase;

[0066] Step S23, when the voltage phase corresponding to the maximum voltage value is not the preset voltage selection detection phase, determine the target voltage value corresponding to the selected detection phase among the first phase voltage value, the second phase voltage value and the third phase voltage value, and determine the voltage zero crossing detection phase according to the maximum voltage value and the target voltage value.

[0067] In this embodiment, when it is determined that the voltage zero crossing needs to be detected, the maximum voltage value of the first phase voltage value, the second phase voltage value, and the third phase voltage value will be determined, that is, the maximum voltage value among the three voltage values ​​will be selected as the maximum voltage value, and the voltage phase corresponding to the maximum voltage value will be determined as the voltage zero crossing detection phase. In other words, when the voltage phase corresponding to the large voltage value is the preset voltage selection detection phase, the detection phase is determined to be the voltage zero crossing detection phase. Conversely, when the voltage phase corresponding to the maximum voltage value is not the preset voltage selection detection phase, the target voltage value corresponding to the detection phase among the first phase voltage value, the second phase voltage value, and the third phase voltage value is determined, and the voltage zero crossing detection phase is determined based on the maximum voltage value and the target voltage value. Wherein, the target voltage value refers to the voltage value corresponding to the selected detection, and the voltage value is one of the first phase voltage value, the second phase voltage value, and the third phase voltage value. Then, the voltage zero-crossing detection phase can be determined based on the maximum voltage value and the target voltage value, so that after the voltage zero-crossing detection phase is subsequently zero-crossed, the relay can be controlled to close, thereby avoiding the problem of higher voltage in a certain voltage phase causing damage to the relay contacts of that phase, thereby ensuring the service life of the relay contacts of that phase.

[0068] Furthermore, the step of determining the voltage zero-crossing detection phase according to the maximum voltage value and the target voltage value includes:

[0069] Step S231, determining the voltage difference between the maximum voltage value and the target voltage value;

[0070] Step S232: When the voltage difference is greater than a preset difference threshold, the voltage phase corresponding to the maximum voltage value is used as the voltage zero-crossing detection phase;

[0071] Step S233: When the voltage difference is less than or equal to the preset difference threshold, the detection phase is selected as the voltage zero-crossing detection phase.

[0072] In this embodiment, when determining the voltage zero-crossing detection phase based on the maximum voltage value and the target voltage value, the voltage difference between the maximum voltage value and the target voltage value is determined. Then, when the voltage difference is greater than a preset difference threshold, the voltage phase corresponding to the maximum voltage value is used as the voltage zero-crossing detection phase. That is, at this time, the voltage phase corresponding to the maximum voltage value is preferentially subjected to zero-crossing detection to avoid damage to the contacts on the relay due to excessive voltage of that phase. Conversely, when the voltage difference is less than or equal to the preset difference threshold, the detection phase is selected as the voltage zero-crossing detection phase. That is, at this time, any detection phase is selected as the voltage zero-crossing detection phase. The advantage of designing a preset difference threshold here is that it avoids recognition errors caused by fluctuations in the collected voltage, thereby ensuring the accuracy of determining the maximum voltage value, thereby ensuring the accuracy of determining the voltage zero-crossing detection phase and subsequent closing control.

[0073] In another embodiment, reference may be made to Figure 3 , Figure 3 This is a control flow diagram of a relay closing control method involved in an embodiment of the present application. When detecting whether the ratio of the phase voltage values ​​of other phases and the phase voltage value of the specified zero-crossing detection phase (selected detection phase) is greater than a specified percentage (for example, the specified percentage can be 120%, that is, 20% greater than the larger value, which can be adjusted appropriately according to application requirements), if the ratio is greater than a specified percentage, the voltage phase corresponding to the maximum voltage value is used as the voltage zero-crossing detection phase, and a phase replacement record of the voltage zero-crossing detection phase is made, that is, a record is made that the phase has been used as the voltage zero-crossing detection phase; if the ratio is less than or equal to a specified percentage, the specified voltage zero-crossing detection phase is used, that is, the detection phase is selected as the voltage zero-crossing detection phase, so as to accurately determine the voltage zero-crossing detection phase to perform zero-crossing detection on the phase voltage, and then the voltage phase with the maximum voltage value can be accurately detected for overcurrent, so as to ensure that the relay contacts on the voltage phase with the maximum voltage value will not be damaged, thereby increasing the service life of the relay.

[0074] In one embodiment, based on the first embodiment and / or the second embodiment of the relay closing control method, a third embodiment of the present application is proposed, which includes, after the step of obtaining the three-phase voltage value of the relay:

[0075] Step S101, when at least one phase voltage value among the first phase voltage value, the second phase voltage value and the third phase voltage value is greater than the preset voltage threshold, execute the step of selecting the detection phase and determining the voltage zero-crossing detection phase according to the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage.

[0076] In this embodiment, before determining the voltage zero-crossing detection phase, it can be determined whether zero-crossing detection is required based on the three-phase voltage value, mainly based on determining whether the three-phase voltage value at this time has the risk of causing damage to the relay contacts. By determining whether there is a voltage value greater than the preset voltage threshold value among the first-phase voltage value of the first voltage phase, the second-phase voltage value of the second voltage phase and the third-phase voltage value of the third voltage phase on the power grid, and then when there is at least one voltage value greater than the preset voltage threshold value among the three voltage values, it will be determined that there is a risk of causing damage to the relay contacts at this time, and the step of selecting the detection phase to determine the voltage zero-crossing detection phase based on the first-phase voltage value, the second-phase voltage value, the third-phase voltage value and the preset voltage will be executed. Of course, the voltage zero-crossing detection phase can also be determined directly without considering the voltage size, because the voltage exists at all times, so there is no need to detect the voltage size before performing zero-crossing detection. Among them, the preset voltage threshold refers to the voltage threshold defined by the user, and the threshold can be positively correlated with the voltage that the relay contacts can withstand. Further, reference can be made to Figure 3When the relay is closed for the first time, the A-phase voltage is designated as the zero-crossing detection phase (i.e., the preset voltage selection detection phase. Of course, it can also be a phase selected by other users, such as using phase C as the preset voltage selection detection phase for the first closing). Then, it is determined whether zero-crossing detection control is needed to control closing. The three-phase voltage is detected to see whether at least one phase voltage is greater than the minimum specified operating voltage (i.e., the preset voltage threshold, such as 60% Un, which can be adjusted according to actual conditions. Un is the rated voltage of the relay). If one phase voltage is greater than the preset voltage threshold, it is determined that closing the relay at this time will cause damage to the contacts of that phase (the phase with a voltage greater than the preset voltage threshold). The voltage zero-crossing detection phase will be determined to determine the zero-crossing voltage moment. Then, closing control is performed at the moment of zero-crossing voltage, which can avoid damage to the relay contacts and thus increase the service life of the relay.

[0077] Furthermore, after the step of obtaining the three-phase voltage value of the relay, the method further includes:

[0078] Step S102 : When the first phase voltage value, the second phase voltage value, and the third phase voltage value are all less than or equal to a preset voltage threshold, controlling the relay to close.

[0079] In this embodiment, in addition to the need to perform voltage zero-crossing detection, the relay can also be controlled to close when the first-phase voltage value, the second-phase voltage value and the third-phase voltage value are all less than or equal to the preset voltage threshold. That is, at this time, it is determined that the three-phase voltage value does not pose a risk of damage to the three contacts of the relay, and the closing control can be performed directly. At the same time, the originally selected detection phase can continue to be used for the next relay closing control.

[0080] In one embodiment, based on the first embodiment, the second embodiment, and / or the third embodiment of the relay closing control method, a fourth embodiment of the present application is proposed, wherein the step of controlling the relay closing according to the voltage zero-crossing detection phase includes:

[0081] Step S21, obtaining the real-time voltage value of the voltage zero-crossing detection phase;

[0082] Step S22: When the real-time voltage value is the preset zero-crossing voltage value, control the relay to close.

[0083] In this embodiment, after the voltage zero-crossing detection phase is determined, the closing of the relay will be controlled by obtaining the real-time voltage value of the voltage zero-crossing detection phase in real time, and then controlling the relay to close when the real-time voltage value is the preset zero-crossing voltage value, that is, controlling the relay to close when the voltage on the voltage zero-crossing detection phase crosses the zero point. At this time, the average value of the instantaneous impact current borne by the three contacts on the relay is the smallest, so as to protect the relay contacts and thus improve the service life of the relay. Further, please refer to Figure 3After determining the voltage zero-crossing detection phase, perform voltage zero-crossing detection on the corresponding phase voltage to control the relay to close when the voltage zero-crossing detection phase voltage crosses zero, thereby reducing the instantaneous impact current on the relay contacts and improving the service life of the relay.

[0084] In one embodiment, after the step of detecting the phase-control relay closing according to the voltage zero crossing, the method includes:

[0085] Step S23, determining the closing action duration corresponding to the voltage zero-crossing detection;

[0086] Step S24: determining the closing interval duration of the voltage zero-crossing detection phase based on the closing action duration and the preset voltage cycle duration.

[0087] In this embodiment, after the phase control relay is closed according to the voltage zero-crossing detection, the closing time is also recorded so as to perform closing control in the next cycle. Before the entire relay closing control is performed, the relay closing action time of each phase A\B\C voltage crossing the zero point must be obtained and saved separately. After the voltage zero-crossing detection phase is determined to control the relay closing, the closing action duration corresponding to the voltage zero-crossing detection will be determined, and then the closing interval duration of the voltage zero-crossing detection phase will be determined based on the closing action duration and the preset voltage cycle duration. The closing action duration refers to the time from the relay receiving the instruction to the completion of closing. The closing interval duration refers to the closing interval duration between two zero-crossing points, that is, to ensure that the closing action is performed at the next zero point. The preset voltage cycle duration refers to the cycle duration of the three-phase voltage. Assuming that the preset voltage cycle duration is As, the closing action duration is Bs, and n is the action proximity value, the closing interval duration can be determined as As-Bs-n. If As is 20ms, Bs is 11ms, and n is 0.2ms, the closing interval duration is 20-11-0.2=8.8ms. Further, you can refer to Figure 3 After the corresponding voltage phase voltage is measured to have passed zero, the relay action time when the corresponding phase voltage has passed zero is combined with the obtained relay action time, and a suitable time is delayed to control the relay closing, ensuring that the relay contacts are closed when the specified voltage zero-crossing detection phase is close to the zero-crossing point of the next cycle, so as to serve as the basis for the subsequent relay control on this phase. It is worth noting that as long as the closing interval duration of each stored voltage phase is determined, the time point at which the closest closing interval duration arrives can be directly determined in the subsequent closing control, so as to perform closing control based on this time point, thereby improving the efficiency of closing control. At the same time, if all the closing interval durations arrive at the time points that meet the voltage zero-crossing point, the phenomenon of closing at the highest voltage point can be avoided, which can effectively improve the service life of the relay.

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

[0089] Step S00: After receiving a power-off control instruction each time, the first voltage phase, the second voltage phase and the third voltage phase on the three-phase circuit are selected as detection phases as preset voltages in a polling manner.

[0090] In this embodiment, in order to ensure the uniformity of the service life of the three contacts of the relay and the uniformity of the control of the three-phase electricity of the power grid, each time after receiving the closing control instruction, the first voltage phase, the second voltage phase and the third voltage phase on the three-phase circuit can be selected as the preset voltage detection phase in a polling manner, and then the closing control time corresponding to the first voltage phase, the second voltage phase and the third voltage phase is determined to ensure the uniformity of the zero-crossing closing control of the relay in different voltage phases, and then ensure the uniformity of the service life of each contact on the relay, that is, there will be no problem of increasing the cost of using the relay due to frequent damage to a relay contact. The closing control instruction refers to the instruction that requires closing control of the relay.

[0091] Furthermore, after the step of controlling the relay to close according to the voltage zero-crossing detection, the method further includes:

[0092] Step S30, when the voltage zero-crossing detection phase is the preset voltage selection detection phase, determining the next preset voltage selection detection phase, and performing the step of obtaining the three-phase voltage values ​​of the relay based on the next preset voltage selection detection phase;

[0093] Step S40, when the voltage zero-crossing detection phase is not the preset voltage selection detection phase, determine the next preset voltage selection detection phase, and execute the step of obtaining the three-phase voltage value of the relay based on the next preset voltage selection detection phase, or execute the step of obtaining the three-phase voltage value of the relay.

[0094] In this embodiment, after the closing control is performed based on the voltage zero-crossing detection phase, it can be determined whether the voltage zero-crossing detection phase is the preset voltage selection detection phase or not, that is, the situation in which the voltage zero-crossing detection phase is replaced can be determined, and control can be performed based on the two situations. After selecting a selected detection phase, the next selected detection phase can be selected to perform the step of obtaining the three-phase voltage value of the relay regardless of whether it is used. Alternatively, after selecting a selected detection phase, the next selected detection phase can be selected to perform the step of obtaining the three-phase voltage value of the relay only after the selected detection phase is used. This can ensure the number of times each selected detection phase is used, so that the closing control of the three voltage phases is more uniform in the entire closing control, so as to ensure that the relay contacts on the corresponding voltage phases are evenly used, and to ensure the consistency of the service life of the relay contacts.

[0095] Corresponding to the above embodiment, the present application also proposes a three-phase electric energy meter.

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

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

[0098] A closing controller 20 connected to a control terminal of the relay 10;

[0099] The closing controller 20 is further configured to execute the steps of any of the above embodiments of the closing control method for a relay.

[0100] In this embodiment, the three-phase electric energy meter can be applicable to any three-phase electric energy meter. This embodiment is described by taking a three-phase electric energy meter on a power grid as an example. The three-phase electric energy meter on the power grid includes a relay 10 and a closing controller 20.

[0101] According to the three-phase electric energy meter of the embodiment of the present application, the closing controller 20 obtains the three-phase voltage value of the relay, wherein the three-phase voltage value includes the first phase voltage value of the first voltage phase, the second phase voltage value of the second voltage phase, and the third phase voltage value of the third voltage phase on the three-phase circuit connected to the relay; selects a detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value, and the preset voltage to determine the voltage zero-crossing detection phase, and controls the relay to close based on the voltage zero-crossing detection phase to achieve the relay closing at the voltage zero-crossing point. By selecting a detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value, and the preset voltage on the three-phase circuit connected to the relay, the voltage zero-crossing detection phase is determined, so as to control the relay to close when the voltage of the voltage zero-crossing detection phase crosses the zero point. This avoids the problem in the prior art whereby random closing may occur at maximum voltage (at this time, the capacitive load environment of the closing causes the maximum voltage to generate a large inrush current at the relay contacts), which may damage the relay contacts due to the large inrush current. By controlling the relay to close when the voltage of the voltage zero-crossing detection phase crosses the zero point, the phenomenon of closing at maximum voltage is avoided, thereby increasing the service life of the relay. It is worth noting that a voltage acquisition instrument can be designed in the three-phase electric energy meter to collect the three-phase voltage values ​​and transmit them to the return circuit breaker controller 20 for processing. Of course, the three-phase electric energy meter can also include more instruments, which are not described one by one here.

[0102] This application also provides a closing controller, referring to Figure 5 , Figure 5 This is a schematic diagram of a closing controller module according to an embodiment of the present application. The closing controller includes:

[0103] A data acquisition module A01 is used to acquire the three-phase voltage value of the relay, wherein the three-phase voltage value includes a first phase voltage value of a first voltage phase, a second phase voltage value of a second voltage phase, and a third phase voltage value of a third voltage phase on a three-phase circuit connected to the relay;

[0104] The closing control module A02 is used to select the detection phase according to the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage to determine the voltage zero crossing detection phase, and control the relay closing according to the voltage zero crossing detection phase to realize the relay closing at the voltage zero crossing point.

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

[0106] The storage medium of the present application stores a relay closing control program, and when the relay closing control program is executed by the processor, the steps of the relay closing control method as described above are implemented.

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

[0108] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0109] The serial numbers of the above embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

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

Claims

1. A relay closing control method, characterized in that: The relay closing control method comprises the following steps: Obtaining three-phase voltage values ​​of the relay, wherein the three-phase voltage values ​​include a first phase voltage value of a first voltage phase, a second phase voltage value of a second voltage phase, and a third phase voltage value of a third voltage phase on a three-phase circuit connected to the relay; A detection phase is selected according to the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage to determine the voltage zero crossing detection phase, and the relay is controlled to close according to the voltage zero crossing detection phase to achieve the relay closing at the voltage zero crossing point.

2. The relay closing control method according to claim 1, wherein: The step of selecting a detection phase and determining a voltage zero-crossing detection phase according to the first phase voltage value, the second phase voltage value, the third phase voltage value, and a preset voltage includes: determining a maximum voltage value, which is the largest voltage value among the first phase voltage value, the second phase voltage value, and the third phase voltage value; In a case where the voltage phase corresponding to the maximum voltage value is the preset voltage selection detection phase, determining the selected detection phase as the voltage zero-crossing detection phase; When the voltage phase corresponding to the maximum voltage value is not the preset voltage selection detection phase, the target voltage value corresponding to the selected detection phase among the first phase voltage value, the second phase voltage value and the third phase voltage value is determined, and the voltage zero-crossing detection phase is determined according to the maximum voltage value and the target voltage value.

3. The relay closing control method according to claim 2, wherein: The step of determining the voltage zero-crossing detection phase according to the maximum voltage value and the target voltage value includes: determining a voltage difference between the maximum voltage value and the target voltage value; When the voltage difference is greater than a preset difference threshold, the voltage phase corresponding to the maximum voltage value is used as the voltage zero-crossing detection phase; When the voltage difference is less than or equal to a preset difference threshold, the selected detection phase is used as the voltage zero-crossing detection phase.

4. The relay closing control method according to claim 1, wherein: The step of controlling the relay to close according to the voltage zero-crossing detection phase comprises: Obtaining a real-time voltage value of the voltage zero-crossing detection phase; When the real-time voltage value is a preset zero-crossing voltage value, the relay is controlled to close.

5. The relay closing control method according to claim 1, wherein: After the step of controlling the relay to close according to the voltage zero-crossing detection phase, the method further comprises: Determine the closing action duration corresponding to the voltage zero-crossing detection; The closing interval duration of the voltage zero-crossing detection phase is determined based on the closing action duration and a preset voltage cycle duration.

6. The relay closing control method according to claim 1, wherein: After the step of obtaining the three-phase voltage value of the relay, the method further comprises: When at least one phase voltage value among the first phase voltage value, the second phase voltage value and the third phase voltage value is greater than a preset voltage threshold, the step of selecting a detection phase and determining a voltage zero-crossing detection phase based on the first phase voltage value, the second phase voltage value, the third phase voltage value and the preset voltage is performed.

7. The relay closing control method according to claim 1, wherein: After the step of obtaining the three-phase voltage value of the relay, the method further includes: When the first phase voltage value, the second phase voltage value, and the third phase voltage value are all less than or equal to a preset voltage threshold, the relay is controlled to close.

8. The relay closing control method according to any one of claims 1 to 7, characterized in that: The relay closing control method further includes: After receiving a closing control instruction each time, the first voltage phase, the second voltage phase, and the third voltage phase are selected as detection phases of the preset voltage in a polling manner.

9. The relay closing control method according to claim 8, wherein: After the step of controlling the relay to close according to the voltage zero-crossing detection phase, the method further comprises: In a case where the voltage zero-crossing detection phase is a preset voltage selection detection phase, determining a next preset voltage selection detection phase, and performing the step of obtaining the three-phase voltage values ​​of the relay based on the next preset voltage selection detection phase; In the case that the voltage zero-crossing detection phase is not the preset voltage selection detection phase, the next preset voltage selection detection phase is determined, and based on the next preset voltage selection detection phase, the step of obtaining the three-phase voltage value of the relay is executed, or the step of obtaining the three-phase voltage value of the relay is executed.

10. A three-phase electric energy meter, characterized in that: The three-phase electric energy meter comprises: a relay, wherein the relay is connected to a three-phase circuit; A closing controller connected to a control terminal of the relay; The closing controller is further configured to execute the steps of the relay closing control method according to any one of claims 1 to 9.

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