The starting control module and its control method of the motor protection controller

Abstract

This invention belongs to the field of motor starting protection technology, and specifically relates to a starting control module and its control method for a motor protection controller. This invention provides a novel starting control module and its control method for a motor protection controller. Upon receiving a current signal, the module first determines the priority of the current signal, processing higher-priority current signals first, and lower-priority current signals sequentially. After determining the priority, the current signal is logically processed in a logic tree, and the motor is started based on the judgment result. This setup simplifies the detection steps, and by processing the fault logically in the logic tree, it improves the detection speed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of starting protection of electric machines, and particularly relates to a starting control module of an electric motor protection controller and a control method thereof. BACKGROUND

[0002] Electric motors can be used in aerospace, automobiles, electric power, and chemical industry, and many devices in various fields are controlled by electric motors. If direct starting is used, the starting current is too large to be withstood by the electric motor. In order to solve this problem, the electric motor uses a step-down starting mode. In this mode, a self-coupled transformer is used to reduce the starting voltage applied to the stator winding of the electric motor during starting of the electric motor. After the electric motor is started, the electric motor is disconnected from the self-coupled transformer, so that the electric motor can operate normally under full voltage.

[0003] In addition, with the acceleration of production rhythm and the large-scale of production equipment, the power of the electric motor used is also increasing, and the monitoring and protection of the operation of the electric motor are also becoming more and more important. The electric motor protection controller provides many technologies and functions that cannot be completed by conventional protection for the comprehensive protection of the electric motor, and has technologies and functions that conventional relay protection does not have. However, the electric motor protection controller currently uses a plurality of fault parallel detection modes, and the detection speed is slow. SUMMARY

[0004] In view of the above problems, the present application provides a new starting control module of an electric motor protection controller and a control method thereof.

[0005] The specific technical scheme of the present application is as follows:

[0006] The present application provides a starting control module of an electric motor protection controller for self-coupled transformer starting, comprising the following parts:

[0007] A signal acquisition unit configured to receive three-phase current signals acquired by an internal mutual inductor and / or leakage current signals acquired by an external mutual inductor;

[0008] A signal processing unit configured to judge the priority of the three-phase current signals and / or the leakage current signals, and send the current signals to corresponding positions in a logic tree according to the priority level, each position of the logic tree performing protection logic judgment on the current signals and generating corresponding protection events and judgment results;

[0009] A signal output unit configured to send a switching-off or switching-on instruction to a relay according to the level of the protection events and the judgment results, and the relay controls a contactor to switch off or switch on a circuit.

[0010] A control method of a starting control module of an electric motor protection controller, comprising the following steps:

[0011] Receive three-phase current signals collected by built-in mutual inductors and / or leakage current signals collected by external mutual inductors;

[0012] Determine the priority of the three-phase current signals and / or the leakage current signals, and send the current signals to corresponding positions in a logic tree according to the priority level, respectively perform protection logic determination on the current signals by using each position of the logic tree, and generate corresponding protection events and determination results;

[0013] Send the cut-off or on command to the motor according to the level of the protection event and the determination result.

[0014] The beneficial effects of the present application are as follows:

[0015] The present application provides a new starting control module of a motor protection controller and a control method thereof. After receiving the current signals, the priority of the current signals is determined first. The current signals with high priority are processed preferentially, and the current signals with low priority are processed sequentially. After determining the priority, the current signals are processed by logic determination in a logic tree. The starting of the motor is controlled according to the determination result. The setting simplifies the detection step, and improves the detection speed by performing logic determination on the fault in the logic tree. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The structure block diagram of the starting control module of the motor protection controller in the present application is shown in the figure.

[0017] Figure 2 The structure block diagram of the signal processing unit in the present application is shown in the figure.

[0018] Figure 3 The flow chart of the logic tree in the present application is shown in the figure.

[0019] Figures 4-5 The structure block diagram of the logic tree in the present application is shown in the figure.

[0020] Figure 6 The flow chart of the starting of the autotransformer of the motor protection controller in the present application is shown in the figure.

[0021] Figure 7 The time table of the thermal overload action characteristic in the present application is shown in the figure.

[0022] Figure 8 The overload characteristic curve diagram in the present application is shown in the figure.

[0023] Figure 9 The flow chart of the starting control module of the motor protection controller in the present application is shown in the figure. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with the drawings and the following embodiments.

[0025] As Figure 6 shown, the motor protection controller's autotransformer starting circuit, including the main circuit and the control circuit for controlling the main circuit; the main circuit is connected to the circuit breaker QF and the contactor KMB after connecting to the motor, and the motor has a relay K3 and a transformer in parallel at both ends, and the transformer is connected with the contactor KMA; the control circuit includes a sampling circuit, a switch output control circuit and a switch input control circuit; a processing module is arranged on the main circuit, which processes the signals collected by the sampling circuit and sends signals to the switch input control circuit for processing and then entering the switch output control circuit, and the signals are output to the relay K3 along the corresponding output of the switch output control circuit, and the relay K3 controls the contactor to act to control the motor to reduce the stator voltage to start or send a fault abnormal signal to the display module.

[0026] The main circuit includes three-phase live wires A, B and C, and the three-phase live wires A, B and C are connected to the main circuit breaker QF and the contactor KMB after connecting to the motor.

[0027] The sampling circuit controls the built-in mutual inductor CT and / or the external mutual inductor to collect current signals and / or leakage current signals, and the sampling resistor collects voltage signals, the sampling resistor is provided with three, which are connected to the three-phase live wires A, B and C, respectively, to form a-phase voltage Ua, b-phase voltage Ub and c-phase voltage Uc, respectively, the upper end of the built-in mutual inductor CT forms a-phase current Ia, b-phase current Ib and c-phase current Ic, respectively, and the lower connection end forms rated current In.

[0028] The terminal DI2 in the switch input control circuit is connected to the contactor KMA, the terminal DI4 is connected to the contactor KMB, and the terminal DI1 is connected to the circuit breaker QF; the normally open contact of the contactor KMA and the relay K3 are connected to the terminal D011 in the switch output control circuit, the normally closed contact of the contactor KMB and the KMA coil are connected to the terminal D022 and are connected in parallel with the terminal D011, the relay K3 is closed to control the contactor KMA and KMB to be connected with the transformer to control the step-down start; the normally closed contact of the contactor KMA and the KMB coil are connected to the terminal D032, the normally open contact of the contactor KMB is connected in parallel between the terminal D032 and D031, and the relay K3 controls the contactor KMA to be disconnected and the KMB to be connected with the transformer to be disconnected, to control the full-voltage start.

[0029] As Figure 1 shown, the present application provides a starting control module of a motor protection controller, which is used for autotransformer starting, and has the following parts:

[0030] The signal acquisition unit 1 is configured to receive three-phase current signals collected by a built-in mutual inductor and / or leakage current signals collected by an external mutual inductor;

[0031] Signal processing unit 2 is configured to determine the priority of three-phase current signals and / or leakage current signals, and send the current signals to the corresponding positions in the logic tree according to the priority level. Each position in the logic tree performs protection logic judgment on the current signals and generates corresponding protection events and judgment results.

[0032] Signal output unit 3 is configured to send a cut-off or connection command to the relay according to the level of the protection event and the judgment result, and the relay controls the contactor to cut off the circuit or connect the circuit.

[0033] This invention provides a novel autotransformer starting control module for a motor protection controller. Upon receiving a current signal, the module first determines the priority of the current signal, processing higher priority signals first and lower priority signals sequentially. After determining the priority, the current signal is logically processed in a logic tree, and the motor is controlled to start based on the judgment result. This setting simplifies the detection steps, and the logical judgment of the fault in the logic tree improves the detection speed.

[0034] In this embodiment, the start-up control module is the processing module in the autotransformer start-up circuit, which is used to process the collected current signals. In this embodiment, the processed current signals are all converted into digital signals.

[0035] In the signal processing unit 2, the positions on the logic tree are thermal overload position, start-up timeout position, phase loss and imbalance position, short circuit position, leakage current position, and current overload position, respectively. The protection events generated at each position are thermal overload protection, start-up timeout protection, phase loss and imbalance protection, short circuit protection, leakage current protection, and current overload protection, respectively. The current signals are divided into two priorities according to their magnitude. Those that meet the first preset range belong to the first priority, and those that do not meet the first preset range belong to the second priority. The first priority current signals are processed first. The current signals include three-phase current signals and / or leakage current signals.

[0036] like Figure 2 As shown, the signal processing unit 2 in this embodiment includes the following parts:

[0037] The priority judgment submodule 201 is configured to compare the current signal with the first preset range to determine the priority of the current signal. If it belongs to the first priority, it sends an instruction to the protection judgment submodule 202. If it belongs to the second priority, it sends the current signal to the logic tree from the beginning position for judgment.

[0038] The protection judgment sub-module 202 is configured to compare the current signal with the second and third preset ranges, if the current signal belongs to the second preset range, the current signal is sent to the short circuit position after adding a first level mark for judgment, if the current signal belongs to the third preset range, the current signal is sent to the thermal overload position after adding a first level mark for judgment.

[0039] As shown in the logic tree in the embodiment, the judgment of the current overload position includes the following parts: Figures 3-4

[0040] The current overload protection sub-module 203 is configured to compare the maximum value of the three-phase current with the current overload setting value, to judge whether the maximum value of the current signal is within the range of the current overload setting value, if yes, a judgment instruction is sent to the overload range judgment sub-module 204, if no, an instruction is sent to the start-up timeout protection sub-module 205;

[0041] The overload range judgment sub-module 204 is configured to judge the level to which the maximum value of the three-phase current belongs within the range of the current overload setting value, if the maximum value of the three-phase current belongs to the first or second level range, the current signal is sent to the open-phase imbalance position for judgment, if the maximum value of the three-phase current belongs to the third level range, a current overload protection event is generated and a cut-off instruction is sent to the signal output unit 3, the range of the current position includes three levels, wherein the first level is a range that does not affect the performance of the motor protection controller, the second level is a range within the maximum limit of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller;

[0042] The start-up timeout protection sub-module 205 is configured to start timing after receiving the three-phase current of the current signal, compare each phase current with the rated current after the timing ends, if all the three-phase currents are less than the rated current, start-up timeout is started, the current signal is sent to the short circuit position for judgment, if one phase current is greater than the rated current, the current signal is sent to the thermal overload position for judgment, if two or three phases are greater than the rated current, start-up timeout is started, a start-up timeout protection event is generated and a cut-off instruction is sent to the signal output unit 3.

[0043] As shown in the logic tree in the embodiment, the judgment of the open-phase imbalance position includes the following parts: Figures 3-4

[0044] The open-phase protection judgment sub-module 206 is configured to judge whether one or two phase currents are less than 0.05 times of the rated current of the motor, if yes, an instruction is sent to the imbalance protection judgment sub-module 209, if no, an instruction is sent to the current judgment sub-module 207;

[0045] ​​The current judgment submodule 207 is configured to judge whether the maximum current value in the three-phase current is greater than 0.2 times the rated current of the motor, and if not, send an instruction to the imbalance protection judgment submodule 209, and if yes, send an instruction to the range level judgment submodule 208.

[0046] The range level judgment submodule 208 is configured to judge whether the maximum value of the three-phase current in the overload range judgment submodule 204 belongs to the first level or the second level of the current positioning range, and if it is the first level, send an instruction to the imbalance protection judgment submodule 209, and if it is the second level, generate a phase loss protection event and send a cut-off instruction to the signal output unit 3.

[0047] The imbalance protection judgment submodule 209 is configured to calculate the imbalance degree of the three-phase current, and judge whether the imbalance degree is greater than the imbalance degree threshold, and if not, the motor does not have imbalance, and the current signal is sent to the leakage position for judgment, and if yes, an instruction is sent to the imbalance rate judgment submodule 210.

[0048] The imbalance rate judgment submodule 210 is configured to calculate the imbalance rate and compare the imbalance rate with the action setting value, and if less than the action setting value, the current signal is sent to the leakage position for judgment, and if greater than or equal to the action setting value, a three-phase imbalance protection event is generated and an instruction is sent to the threshold level judgment submodule 211, wherein the imbalance degree P = MAX(I phase - Xn) / Xn x 100%, I phase represents the phase current, and Xn represents the three-phase average value of the three-phase current, and the imbalance rate The calculation formula of the imbalance rate is as follows:

[0049] I represents the motor operating current, Iav represents the three-phase current average effective value, and Irl represents the motor full load current.

[0050] The threshold level judgment submodule 211 is configured to judge whether the imbalance rate belongs to the first level or the second level of the range of the action setting value, and if it is the first level, the current signal is sent to the leakage position for judgment, and if it is the second level, a three-phase imbalance protection event is generated and a cut-off instruction is sent to the signal output unit 3; wherein the range of the action setting value is divided into two levels, the first level is the range of the performance limit value of the motor protection controller which does not affect, and the second level is the range which affects the performance of the motor protection controller.

[0051] As shown in Figures 3-4 , the judgment of the leakage position in the logic tree in the embodiment includes the following parts:

[0052] Leakage protection submodule 212 is configured to calculate the vector sum of three-phase current in the current signal, and determine whether the vector sum is 0, if yes, there is no leakage current, send an instruction to the first level flag determination submodule 214, if not, generate a leakage protection event and send an instruction to the fixed value determination submodule 213;

[0053] Fixed value determination submodule 213 is configured to compare the leakage current in the current signal with the leakage current fixed value, if less than the leakage current fixed value, send an instruction to the first level flag determination submodule 214, otherwise, send a cut-off instruction to the leakage protection event generation and signal output unit 3;

[0054] First level flag determination submodule 214 is configured to determine whether the current signal has a first level flag, a short circuit flag and / or a thermal overload flag, if yes, add a second level flag to the current signal and send it to the current overload position for determination, if not, send an on instruction to the signal output unit 3.

[0055] As shown in Figure 3 , Figure 5 The determination of the short circuit position in the logic tree in the embodiment includes the following parts:

[0056] Level flag determination submodule 215 is configured to determine whether the current signal has a flag, if not, send an instruction to the short circuit protection submodule 216, if only has a first level flag, send a determination instruction to the short circuit protection submodule 216 and a flag instruction to the short circuit flag submodule 219, if has first level, second level, thermal overload and short circuit flags, send an on instruction to the signal output unit 3, if has first level, second level and short circuit flags at the same time, send an output instruction to the short circuit protection submodule 216 and the short circuit output submodule 218;

[0057] Short circuit protection submodule 216 is configured to compare the maximum value of three-phase current in the current signal with the short circuit current fixed value, determine whether the current signal is within the range of the short circuit current fixed value, if yes, send a determination instruction to the short circuit range determination submodule 217, if not, generate a short circuit protection event and send an on instruction to the signal output unit 3;

[0058] The short-circuit range judgment submodule 217 is configured to judge the level to which the maximum value of the three-phase current belongs in the short-circuit current fixed value range, and send an instruction to the short-circuit output submodule 218 if it is in the first or second level range, and generate a short-circuit protection event and send a switching-on instruction to the signal output unit 3 if it is in the third level range, wherein the current fixed value range includes three levels, the first level is a range that does not affect the performance of the motor protection controller, the second level is a range that does not affect the maximum limit value of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller;

[0059] The short-circuit output submodule 218 is configured to judge whether an output instruction sent by the level mark judgment submodule 215 is received, and generate a short-circuit protection event and send a switching-on instruction to the signal output unit 3 if yes, and send a mark instruction to the short-circuit mark submodule 219 if no.

[0060] The short-circuit mark submodule 219 is configured to judge whether a mark instruction sent by the level mark judgment submodule 215 is received, and send the current signal with a short-circuit mark to the thermal overload position for judgment if yes, and directly send the current signal to the thermal overload position for judgment if no.

[0061] As shown in Figure 3 , Figure 5 The judgment of the thermal overload position in the logic tree in the embodiment includes the following parts:

[0062] The mark judgment submodule 220 is configured to judge whether the current signal has a mark, and send a judgment instruction to the thermal overload protection submodule 221 and a mark instruction to the thermal overload mark submodule 225 if it has a first level mark and / or a short-circuit mark, send a switching-on instruction to the signal output unit 3 if it has a first level, a second level, a thermal overload and a short-circuit mark, and send a switching-off instruction to the signal output unit 3 if it has a first level, a second level and a thermal overload mark.

[0063] The thermal overload protection submodule 221 is configured to judge whether one or two phases of the three-phase current are less than 0.05 times the rated current of the motor, and send an instruction to the thermal capacity judgment submodule 222 if yes, and send an instruction to the thermal overload mark submodule 225 if no.

[0064] The thermal capacity judgment submodule 222 is configured to calculate the steady-state thermal capacity and the current thermal capacity of the motor, and expand the steady-state thermal capacity into a capacity range, and judge whether the current thermal capacity is in the capacity range, and send an instruction to the thermal overload mark submodule 225 if no, and send an instruction to the capacity range submodule 223 if yes; wherein the calculation formulas of the steady-state thermal capacity Cc and the current thermal capacity C are as follows:

[0065] Irl represents the motor rated current, KT represents the motor cold and hot state curve ratio, which is selected in the range of 20% to 100%, and the selection principle is: motor hot state allowed locked-rotor time / motor cold state allowed locked-rotor time*100%;

[0066] C=C CH ×e -t冷 / T , CCH represents the thermal capacity before parking or the thermal capacity at the moment when the motor operating current decreases, the value is 100%, T represents the set cooling time / 5, tcool represents the cooling time that has passed;

[0067] The capacity range submodule 223 is configured to determine whether the current thermal capacity is in the level to which the capacity range belongs, and if it is in the first level, sends an instruction to the thermal overload marking submodule 225, if it is in the second level, sends an instruction to the level superposition judgment submodule 224, and if it is in the third level range, generates a thermal overload protection event and sends a cut-off instruction to the signal output unit 3. The capacity range includes three levels, wherein the first level is a range that does not affect the performance of the motor protection controller, the second level is a range within the maximum limit of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller.

[0068] The level superposition judgment submodule 224 is configured to determine whether the maximum value of the three-phase current in the short-circuit protection event is in the first level or the second level of the short-circuit current fixed value range, and if it is in the first level, sends an instruction to the thermal overload marking submodule 225, and if it is in the second level, generates a thermal overload protection event and sends a cut-off instruction to the signal output unit 3.

[0069] The thermal overload marking submodule 225 is configured to determine whether a marking instruction sent by the marking judgment submodule 220 is received, and if so, adds a thermal overload mark to the current signal and sends the current signal to the leakage position for judgment, and if not, sends the current signal to the leakage position for judgment.

[0070] In this embodiment, the thermal overload protection is further described. The overload protection reflects the average heating condition of the stator and rotor windings, and prevents the motor from overheating. The overload and asymmetric overload of the motor are mainly protected, the motor is protected by calculating the thermal capacity, and the starting time of the contactor is determined by calculating the delay characteristic t, so as to control the protection action of the motor, protect the safety of the motor equipment, increase the accuracy of the judgment, and further improve the detection sensitivity.

[0071] In this embodiment, when the motor is in an overload fault operation, the controller calculates the thermal capacity of the motor according to the heating characteristics of the motor, and protects the motor. Among them, K is the curve coefficient corresponding to the curve number, and t is the actual action time. The overload characteristic is as follows: Figure 7The overload action characteristic time table and Figure 8 The overload characteristic curve shown; the controller's thermal capacity to the motor in percentage, maximum 100%.

[0072] In this embodiment, after receiving the current signal, the priority level of the signal is judged according to the first pre-set range, and the signal of the first priority level is processed preferentially. As known from the above description, the first priority level corresponds to short-circuit protection and thermal overload protection, so it is necessary to judge these two events first. Thus, after judging the short-circuit protection or the thermal overload protection, the time is still within the extension time of the timing limit, effectively improving the detection speed.

[0073] The logic judgment of current overload and open-phase protection will be described in detail below:

[0074] The rated current of the motor is 4A, and if the current of the motor at start-up is 27A, then the current belongs to the first pre-set range (10, 100). Starting from the current overload position in the logic tree, if the current at start-up is 1500, which is in the second pre-set range (1000, 20000), it is sent to the short-circuit position for judgment, and if the current at start-up is 0.2, which is in the third pre-set range (0.01, 0.4), it is sent to the thermal overload position for judgment.

[0075] When judging the current overload, if the received three-phase currents are IA-20A, IB-25A, and IB-22A, then the maximum current is 25A. Then, the level to which 25A belongs in the current overload setting range is judged. The first level range is (20, 30), the second level range is (30, 40), and the third level range is (40, 50). Then, 25A belongs to the first level range, so the open-phase imbalance is directly judged. If the maximum current is 33A, then the open-phase imbalance is also judged. If the maximum current is 47A, then the current overload generates a current overload protection event and sends a cut-off command.

[0076] When judging the open-phase in the open-phase imbalance, if the rated current is 30A, then 0.05 times the rated current of the motor is 1.5A. If all three-phase currents are greater than 1.5A, the maximum current is judged. If IA is 1A, then the imbalance is judged. In the maximum value judgment, 25A or 33A is greater than 0.2 times the rated current of the motor, which is 6A. At this time, the range of the maximum current in the current overload needs to be judged. If it is 25A, then the imbalance protection is judged. If it is 33A, then it is a double fault, and a cut-off command needs to be sent.

[0077] The logic judgment of the remaining protection events in this embodiment is also performed according to the above method.

[0078] In this embodiment, after receiving the judgment result, the signal output unit 3 determines the level of the protection event that sends the cut-off command or the on command. If it is a priority processing level, the judgment result of the corresponding protection event is processed first, and the cut-off or on command is sent to the corresponding relay after the delay time is reached. If it is a sequential processing level, the judgment result of the corresponding protection event is processed sequentially, and the cut-off or on command is sent to the corresponding relay after the delay time is reached. The protection events with priority processing level include short circuit protection and thermal overload protection, and the protection events with sequential processing level include start-up timeout protection, phase loss imbalance protection, leakage protection, and current overload protection.

[0079] In practice, due to the very short time interval of current acquisition, two current signals may produce judgment results simultaneously. For example, the first current signal belongs to the second priority level, and is processed sequentially until the leakage location is determined to be non-leakage, sending an on command. The second current signal belongs to the first priority level, and is judged first at the short circuit location, resulting in a cut-off and sending a cut-off command. At this time, the two signals may arrive at the signal output unit at the same time. However, since the short circuit protection event generated at the short circuit location is a priority level, the cut-off command is processed first. Since each protection event uses time-limited protection, the timer starts after receiving the cut-off command, and the contactor is controlled to cut off the circuit when the delay time is reached. In this embodiment, the protection events are divided into priorities, and the signals sent by the priority level events are processed first, which can improve processing efficiency.

[0080] The starting protection in this invention includes not only the protection events mentioned above, but also contactor disconnection protection, definite timing protection, undervoltage protection, overvoltage protection, and phase sequence protection.

[0081] In another embodiment, such as Figure 9 As shown, a control method for a motor protection controller starting control module includes the following steps:

[0082] Receives three-phase current signals collected by the built-in current transformer and / or leakage current signals collected by the external current transformer;

[0083] The priority of the three-phase current signal and / or leakage current signal is determined, and the current signal is sent to the corresponding position in the logic tree according to the priority level. The protection logic judgment of the current signal is performed at each position of the logic tree, and the corresponding protection event and judgment result are generated.

[0084] Based on the level of the protection event and the judgment result, a cut-off or connection command is sent to the motor (i.e., a command is sent to the motor's relay, which controls the on / off state of the contactor).

[0085] The application provides a new motor protection controller self-coupled transformer starting control module control method, after receiving the current signal, first judging the priority of the current signal, the current signal with high priority is processed first, the current signal with low priority is processed in sequence, after judging the priority, the current signal is processed in the logic tree, and the motor is controlled according to the judgment result, the setting simplifies the detection step, and the fault is processed in the logic tree, and the detection speed is improved.

[0086] Although this specification contains many specific implementation details, these should not be construed as limiting the scope of any inventions or of what can be claimed, but as a description of particular implementations of specific inventions. Certain features that are described in this specification in the context of separate implementations can also be implemented in combination with one another. Conversely, various features that are described in the context of one implementation can also be implemented separately from one another. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination and the claimed combination can be directed to a sub-combination or variations of a sub-combination.

[0087] In certain cases, multitasking and parallel processing can be advantageous. Moreover, the separation of various system modules and components in the implementations described above should not be understood as requiring such separation in all implementations.

[0088] Particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. For example, the acts recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes described in the figures need not be performed in the order shown or sequentially. In some implementations, multitasking and parallel processing can be advantageous.

Claims

1. A start control module of a motor protection controller for autotransformer starting, characterized by, The application relates to a signal processing method for motor protection controller, which comprises the following parts: a signal collecting unit (1) configured to receive three-phase current signals collected by built-in mutual inductors and / or leakage current signals collected by external mutual inductors; a signal processing unit (2) configured to judge the priority of the three-phase current signals and / or the leakage current signals and send the current signals to corresponding positions in a logic tree according to the priority level, wherein each position in the logic tree respectively judges the protection logic of the current signals and generates corresponding protection events and judgment results; a signal output unit (3) configured to send cut-off or connection instructions to the motor according to the level of the protection events and the judgment results; in the signal processing unit (2), each position in the logic tree is respectively a thermal overload position, a starting timeout position, a phase loss imbalance position, a short circuit position, a leakage position and a current overload position, and the protection events generated by the positions are respectively thermal overload protection, starting timeout protection, phase loss imbalance protection, short circuit protection, leakage protection and current overload protection; the current signals are divided into two priority levels according to their sizes, the current signals meeting a first preset range belong to a second priority level, and the current signals not meeting the first preset range belong to a first priority level, the current signals of the first priority level are preferentially processed, and the current signals include the three-phase current signals and / or the leakage current signals; the signal processing unit (2) comprises the following parts: a priority judgment sub-module (201) configured to compare the current signals with the first preset range, judge the priority of the current signals, send an instruction to a protection judgment sub-module (202) if the current signals belong to the first priority level, and send the current signals to the logic tree from the starting position for judgment if the current signals belong to the second priority level; the protection judgment sub-module (202) is configured to compare the current signals with second and third preset ranges, send the current signals to the short circuit position for judgment after adding a first level mark if the current signals belong to the second preset range, and send the current signals to the thermal overload position for judgment after adding the first level mark if the current signals belong to the third preset range; the judgment of the current overload position in the logic tree specifically comprises the following parts: a current overload protection sub-module (203) configured to compare the maximum value in the three-phase current with a current overload setting value, judge whether the maximum value of the current signals is within the range of the current overload setting value, send a judgment instruction to an overload range judgment sub-module (204) if yes, and send an instruction to a starting timeout protection sub-module (205) if no; the overload range judgment sub-module (204) is configured to judge the level to which the maximum value of the three-phase current belongs in the range of the current overload setting value, send the current signals to the phase loss imbalance position for judgment if the maximum value is within the first or second level range, generate a current overload protection event and send a cut-off instruction to the signal output unit (3) if the maximum value is within the third level range, and the range of the current setting value comprises three levels, wherein the first level is a range not affecting the performance of the motor protection controller, the second level is a range within the maximum limit of the motor protection controller, and the third level is a range affecting the performance of the motor protection controller. The start-up time-out protection submodule (205) is configured to start timing after receiving the three-phase current of the current signal, compare each phase current with the rated current after the timing ends, send the current signal to the short-circuit position for judgment if the three-phase current is less than the rated current, send the current signal to the thermal overload position for judgment if one phase current is greater than the rated current, and send the current signal to the short-circuit position for judgment if two or three phases are greater than the rated current, start the time-out, generate a start-up time-out protection event, and send a shutdown instruction to the signal output unit (3); The signal output unit (3) receives the judgment result, judges the level of the protection event sending the shutdown instruction or the on instruction, processes the judgment result of the corresponding protection event preferentially if it is a priority processing level, sends the shutdown or on instruction to the corresponding relay after the delay time is reached, processes the judgment result of the corresponding protection event sequentially if it is a sequential processing level, and sends the shutdown instruction or the on instruction to the corresponding relay after the delay time is reached, wherein the protection events of the priority processing level include the short-circuit protection and the thermal overload protection, and the protection events of the sequential processing level include the start-up time-out protection, the open-phase imbalance protection, the leakage protection, and the current overload protection.

2. The start control module of the motor protection controller of claim 1, wherein, The judgment of the open-phase imbalance position in the logic tree includes the following parts: The open-phase protection judgment submodule (206) is configured to judge whether one phase or two phases of the current are less than 0.05 times the rated current of the motor, send an instruction to the imbalance protection judgment submodule (209) if yes, and send an instruction to the current judgment submodule (207) if no; The current judgment submodule (207) is configured to judge whether the maximum current value in the three-phase current is greater than 0.2 times the rated current of the motor, send an instruction to the imbalance protection judgment submodule (209) if no, and send an instruction to the range level judgment submodule (208) if yes; The range level judgment submodule (208) is configured to judge whether the maximum value of the three-phase current in the overload range judgment submodule (204) belongs to the first level or the second level of the current positioning range, send an instruction to the imbalance protection judgment submodule (209) if it is the first level, and generate an open-phase protection event and send a shutdown instruction to the signal output unit (3) if it is the second level; The imbalance protection judgment submodule (209) is configured to calculate the imbalance degree of the three-phase current, judge whether the imbalance degree is greater than the imbalance degree threshold, and send the current signal to the leakage position for judgment if the motor does not have imbalance and the imbalance degree is not greater than the imbalance degree threshold, and send an instruction to the imbalance rate judgment submodule (210) if yes. The imbalance rate judging submodule (210) is configured to calculate the imbalance rate, compare the imbalance rate with the action setting value, if less than the action setting value, send the current signal to the leakage position for judgment, if greater than or equal to the action setting value, generate a three-phase imbalance protection event and send an instruction to the threshold level judging submodule (211), wherein the imbalance degree P = MAX(I phase-Xn) / Xn x 100%, I phase represents the phase current, Xn represents the three-phase average value of the three-phase current, and the imbalance rate The calculation formula of the imbalance rate is as follows: I represents the motor operating current, Iav represents the average effective value of three-phase current, and Irl represents the motor full load current. The threshold level judgment submodule (211) is configured to judge whether the unbalance rate belongs to a first level or a second level of a range of action setting values, if the first level, the current signal is sent to a leakage position for judgment, if the second level, a three-phase unbalance protection event is generated and a cut-off instruction is sent to the signal output unit (3); wherein the range of the action setting values is divided into two levels, the first level is a range of non-affecting performance limit values of the motor protection controller, and the second level is a range of affecting performance of the motor protection controller.

3. The start control module of the motor protection controller of claim 2, wherein, The leakage position judgment in the logic tree includes the following parts: The leakage protection submodule (212) is configured to calculate a vector sum of three-phase currents in the current signal, and judge whether the vector sum is 0, if yes, there is no leakage current, an instruction is sent to the first level mark judgment submodule (214), if not, a leakage protection event is generated and an instruction is sent to the setting value judgment submodule (213); The setting value judgment submodule (213) is configured to compare the leakage current in the current signal with a leakage current setting value, if less than the leakage current setting value, an instruction is sent to the first level mark judgment submodule (214), otherwise, a leakage protection event is generated and a cut-off instruction is sent to the signal output unit (3); The first level mark judgment submodule (214) is configured to judge whether the current signal has a first level mark, a short circuit mark and / or a thermal overload mark, if yes, a second level mark is added to the current signal and sent to a current overload position for judgment, if not, an on instruction is sent to the signal output unit (3).

4. The start control module of the motor protection controller of claim 3, wherein, The short circuit position judgment in the logic tree includes the following parts: The level mark judgment submodule (215) is configured to judge whether the current signal has a mark, if not, an instruction is sent to the short circuit protection submodule (216), if only has the first level mark, a judgment instruction is sent to the short circuit protection submodule (216) and a mark instruction is sent to the short circuit mark submodule (219), if has the first level, the second level, the thermal overload and the short circuit mark, an on instruction is sent to the signal output unit (3), if has the first level, the second level and the thermal overload mark at the same time, an output instruction is sent to the short circuit protection submodule (216) and the short circuit output submodule (218); The short circuit protection submodule (216) is configured to compare a maximum value of three-phase currents in the current signal with a short circuit current setting value, judge whether the current signal is in the range of the short circuit current setting value, if yes, a judgment instruction is sent to the short circuit range judgment submodule (217), if not, a short circuit protection event is generated and an on instruction is sent to the signal output unit (3); The short-circuit range judging submodule (217) is configured to judge the level to which the maximum value of the three-phase current belongs in the short-circuit current fixed value range, and send an instruction to the short-circuit output submodule (218) if it is in the first or second level range, and generate a short-circuit protection event and send a switching-on instruction to the signal output unit (3) if it is in the third level range, wherein the current fixed value range includes three levels, the first level is a range that does not affect the performance of the motor protection controller, the second level is a range that does not affect the maximum limit value of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller; The short-circuit output submodule (218) is configured to judge whether an output instruction sent by the level mark judging submodule (215) is received, and generate a short-circuit protection event and send a switching-on instruction to the signal output unit (3) if yes, and send a mark instruction to the short-circuit mark submodule (219) if no; The short-circuit mark submodule (219) is configured to judge whether a mark instruction sent by the level mark judging submodule (215) is received, and send the current signal with a short-circuit mark to the thermal overload position for judgment if yes, and directly send the current signal to the thermal overload position for judgment if no.

5. The start control module of the motor protection controller of claim 4, wherein, The judgment of the thermal overload position in the logic tree includes the following parts: The mark judging submodule (220) is configured to judge whether the current signal has a mark, and send a judgment instruction to the thermal overload protection submodule (221) and a mark instruction to the thermal overload mark submodule (225) if it has a first level mark and / or a short-circuit mark, send a switching-on instruction to the signal output unit (3) if it has a first level, a second level, a thermal overload and a short-circuit mark, and send a switching-off instruction to the signal output unit (3) if it has a first level, a second level and a thermal overload mark; The thermal overload protection submodule (221) is configured to judge whether one or two phases of the three-phase current are less than 0.05 times the rated current of the motor, and send an instruction to the thermal capacity judging submodule (222) if yes, and send an instruction to the thermal overload mark submodule (225) if no; The thermal capacity judging submodule (222) is configured to calculate the steady-state thermal capacity and the current thermal capacity of the motor, expand the steady-state thermal capacity into a capacity range, and judge whether the current thermal capacity is in the capacity range, and send an instruction to the thermal overload mark submodule (225) if no, and send an instruction to the capacity range submodule (223) if yes; wherein the calculation formulas of the steady-state thermal capacity Cc and the current thermal capacity C are as follows: Irl represents the rated current of the motor, KT represents the motor cold and hot state curve ratio, which is selected in the range of 20% to 100%, and the selection principle is: motor hot state allowed locked-rotor time / motor cold state allowed locked-rotor time*100%; C = C CH x e -t冷 / T CCH represents the thermal capacity of the motor before parking or the thermal capacity at the moment of the motor current drop, with a value of 100%, T represents the set cooling time / 5, tcool represents the cooling time already elapsed; The capacity range submodule (223) is configured to determine the level to which the current heat capacity belongs in the capacity range, and if it belongs to the first level, send an instruction to the thermal overload flag submodule (225), if it belongs to the second level, send an instruction to the level superposition judgment submodule (224), and if it belongs to the third level range, generate a thermal overload protection event and send a cut-off instruction to the signal output unit (3). The capacity range includes three levels, wherein the first level is a range that does not affect the performance of the motor protection controller, the second level is a range within the maximum limit of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller. The level superposition judgment submodule (224) is configured to determine whether the maximum value of the three-phase current in the short-circuit protection event belongs to the first level or the second level in the short-circuit current fixed value range, and if it belongs to the first level, send an instruction to the thermal overload flag submodule (225), and if it belongs to the second level, generate a thermal overload protection event and send a cut-off instruction to the signal output unit (3). The thermal overload flag submodule (225) is configured to determine whether a flag instruction sent by the flag judgment submodule (220) is received, and if so, add a thermal overload flag to the current signal and send the current signal to the leakage position for judgment, and if not, send the current signal to the leakage position for judgment.

6. A control method for starting control module of the motor protection controller according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: Receiving three-phase current signals collected by a built-in mutual inductor and / or leakage current signals collected by an external mutual inductor; Determining the priority of the three-phase current signals and / or the leakage current signals, and sending the current signals to corresponding positions in a logic tree according to the level of the priority, respectively performing protection logic judgment on the current signals at each position of the logic tree, and generating corresponding protection events and judgment results; According to the level of the protection event and the judgment result, sending a cut-off or on instruction to the motor.

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