CN115173745A - Starting control module of motor protection controller and control method thereof - Google Patents

Abstract

The invention belongs to the technical field of starting protection of motors, and particularly relates to a starting control module of a motor protection controller and a control method thereof. The invention provides a starting control module of a novel motor protection controller and a control method thereof, after receiving a current signal, the priority of the current signal is judged, the current signal with high priority is processed preferentially, the current signal with low priority is processed sequentially, after the priority is judged, the current signal is processed logically in a logic tree, and the motor is controlled to play according to the judgment result.

Description

Starting control module of motor protection controller and control method thereof

Technical Field

The invention belongs to the technical field of starting protection of motors, and particularly relates to a starting control module of a motor protection controller and a control method thereof.

Background

The motor can be used to many fields such as space flight, car, electric power and chemical industry, and many equipment in each field adopt motor control more, if adopt direct start, starting process impulse current is too big and leads to the motor to bear, in order to solve this problem, the motor adopts the starting mode of step-down start, and this mode utilizes autotransformer to reduce the starting voltage who adds on motor stator winding when the motor starts, treats after the motor starts, makes motor and autotransformer break away from again to normal motion under full pressure.

In addition, along with the acceleration of production rhythm and the large-scale production equipment, the power of the matched motor is increased, and the monitoring and protection on the operation of the motor are also more and more important. The motor protection controller provides a plurality of technologies and functions which cannot be completed by conventional protection for the comprehensive protection of the motor, and has the technologies and functions which cannot be completed by conventional relay protection, but the conventional motor protection controller usually adopts a mode of parallel detection of a plurality of faults and has a slow detection speed.

Disclosure of Invention

In view of the above problems, the present invention provides a novel start control module of a motor protection controller and a control method thereof.

The specific technical scheme of the invention is as follows:

the invention provides a starting control module of a motor protection controller, which is used for starting an autotransformer and comprises the following parts:

the signal acquisition unit is configured to receive a three-phase current signal acquired by the built-in mutual inductor and/or a leakage current signal acquired by the external mutual inductor;

the signal processing unit is configured to judge the priority of the three-phase current signal and/or the leakage current signal, send the current signal to a corresponding position in a logic tree according to the priority level, and each position of the logic tree carries out protection logic judgment on the current signal respectively and generates a corresponding protection event and a judgment result;

and a signal output unit configured to transmit a switch-off or switch-on command to the relay according to the level of the protection event and the determination result, the relay controlling the contactor to switch off or on the circuit.

A control method of a motor protection controller starting control module comprises the following steps:

receiving a three-phase current signal collected by an internal mutual inductor and/or a leakage current signal collected by an external mutual inductor;

judging the priority of the three-phase current signal and/or the leakage current signal, sending the current signal to corresponding positions in a logic tree according to the priority level, respectively carrying out protection logic judgment on the current signal by utilizing each position of the logic tree, and generating a corresponding protection event and a judgment result;

and sending a switch-off or switch-on command to the motor according to the level of the protection event and the judgment result.

The invention has the following beneficial effects:

the invention provides a novel starting control module of a motor protection controller and a control method thereof, after receiving a current signal, the priority of the current signal is judged, the current signal with high priority is processed preferentially, the current signal with low priority is processed sequentially, after the priority is judged, the current signal is processed logically in a logic tree, the motor is controlled to play according to the judgment result, the setting simplifies the detection step, the fault is processed logically in the logic tree, and the detection speed is improved.

Drawings

FIG. 1 is a block diagram of a start control module of the motor protection controller of the present invention;

FIG. 2 is a block diagram of a signal processing unit according to the present invention;

FIG. 3 is a flow chart of a logical tree of the present invention;

FIGS. 4-5 are block diagrams of the structure of the logic tree of the present invention;

FIG. 6 is a flow chart of the autotransformer start of the motor protection controller of the present invention;

FIG. 7 is a table of thermal overload behavior characteristics of the present invention;

FIG. 8 is a graph of overload characteristics according to the present invention;

FIG. 9 is a flow chart of a start control module of the motor protection controller of the present invention.

Detailed Description

The invention is explained in more detail below with reference to the figures and the following examples.

As shown in fig. 6, the autotransformer starting circuit of the motor protection controller includes a main circuit and a control circuit controlling the main circuit; the main circuit is correspondingly connected with a breaker QF and a contactor KMB and then is connected into a motor, a relay K3 and a transformer are connected in parallel at two ends of the motor, and the contactor KMA is connected onto the transformer; the control circuit comprises a sampling circuit, a switch output control circuit and a switch input control circuit; the main circuit is provided with a processing module which is used for processing the signals collected by the sampling circuit, sending the signals to the switch input control circuit for processing and then entering the switch output control circuit, the signals are output to the relay K3 along the corresponding output of the switch output control circuit, and the relay K3 controls the action of the contactor so as to control the motor to reduce the stator voltage for starting or send fault abnormal signals to the display module.

The main circuit comprises three-phase live wires A, B, C and N, wherein the three-phase live wires A, B and C are respectively led out from the main circuit breaker QF corresponding to the connection wire and connected with the motor after being connected with the contactor KMB.

The sampling circuit controls the built-In mutual inductor CT and/or the external mutual inductor to acquire current signals and/or leakage current signals and the sampling resistor to acquire voltage signals, the number of the sampling resistors is three, the three sampling resistors are respectively connected with the three-phase live wires A, B and C and respectively form a phase voltage Ua, a phase voltage Ub and a phase voltage Uc, the upper end of the built-In mutual inductor CT correspondingly forms a phase current Ia, a phase current Ib and a phase current Ic, and the lower terminal forms a rated current In.

A terminal DI2 and a contactor KMA in the switch input control circuit are in a connection state, a terminal DI4 and a contactor KMB are in a connection state, and a terminal DI1 is connected with a breaker QF; a normally open contact of a contactor KMA and a relay K3 are connected to a terminal D011 in the switch output control circuit, a normally closed contact and a KMA coil of a contactor KMB are connected to a terminal D022 and connected with the terminal D011 in parallel, and the relay K3 closes the control contactor KMA and the KMB to be connected with a transformer so as to control voltage reduction starting; connect contactor KMA's normally closed contact and KMB coil on the terminal D032, parallel connection contactor KMB's normally open contact between terminal D032 and the D031, relay K3's control contactor KMA disconnection and KMB switch-on break away from with the transformer to control the full pressure and start.

As shown in fig. 1, the present invention provides a starting control module of a motor protection controller, which is used for starting an autotransformer, and is characterized by comprising the following parts:

the signal acquisition unit 1 is configured to receive a three-phase current signal acquired by an internal mutual inductor and/or a leakage current signal acquired by an external mutual inductor;

the signal processing unit 2 is configured to judge the priority of the three-phase current signal and/or the leakage current signal, and send the current signal to a corresponding position in a logic tree according to the priority level, and each position of the logic tree carries out protection logic judgment on the current signal respectively and generates a corresponding protection event and a judgment result;

and a signal output unit 3 configured to transmit a switch-off or switch-on command to the relay, which controls the contactor to switch off or on the circuit, according to the level of the protection event and the determination result.

The invention provides a new auto-transformer starting control module of a motor protection controller, which judges the priority of a current signal firstly after receiving the current signal, the current signal with high priority is processed preferentially, the current signal with low priority is processed sequentially, after the priority is judged, the current signal is processed logically in a logic tree, and the motor is controlled to play according to the judgment result.

The starting control module in this embodiment is a processing module in the auto-transformer starting circuit, and is configured to process the acquired current signal, and the current signal processed in this embodiment is a signal converted into a digital quantity.

In the signal processing unit 2, each position on the logic tree is a thermal overload position, a start timeout position, a phase-failure unbalance position, a short circuit position, a leakage position and a current overload position, and protection events correspondingly generated at each position are thermal overload protection, start timeout protection, phase-failure unbalance protection, short circuit protection, leakage protection and current overload protection respectively; the current signals are divided into two priorities according to the sizes of the current signals, the current signals which meet a first preset range and belong to a first priority and do not meet the first preset range and belong to a second priority are processed preferentially, and the current signals comprise three-phase current signals and/or leakage current signals.

As shown in fig. 2, the signal processing unit 2 in this embodiment includes the following parts:

the priority judging submodule 201 is configured to compare the current signal with a first preset range, judge the priority of the current signal, send an instruction to the protection judging submodule 202 if the current signal belongs to the first priority, and send the current signal to the logic tree self-starting position for judgment if the current signal belongs to the second priority;

and the protection judgment sub-module 202 is configured to compare the current signal with the second and third preset ranges, and if the current signal belongs to the second preset range, the current signal is added with the first-stage mark and then sent to the short-circuit position for judgment, and if the current signal belongs to the third preset range, the current signal is added with the first-stage mark and then sent to the thermal overload position for judgment.

As shown in fig. 3 to 4, the judgment of the current overload position in the logic tree in this embodiment specifically includes the following steps:

the current overload protection submodule 203 is configured to compare the maximum value of the three-phase current with a current overload fixed value, judge whether the maximum value of the current signal is within the range of the current overload fixed value, if so, send a judgment instruction to the overload range judgment submodule 204, and if not, send an instruction to the start timeout protection submodule 205;

the overload range judging submodule 204 is configured to judge the level to which the maximum value of the three-phase current belongs within a current overload fixed value range, if the maximum value is within a first or second level range, a current signal is sent to a phase-lacking unbalanced position for judgment, if the maximum value is within a third level range, a current overload protection event is generated and a cutting-off instruction is sent to the signal output unit 3, and the current positioning range comprises three levels, wherein the first level is a range which does not influence the performance of the motor protection controller, the second level is a range which does not influence the maximum limit value of the motor protection controller, and the third level is a range which influences the performance of the motor protection controller;

the start timeout protection sub-module 205 is configured to start timing after receiving the three-phase currents of the current signals, compare each phase of current with the rated current after the timing is finished, if the three-phase currents are smaller than the rated current, start not to timeout, send the current signals to the short-circuit position for judgment, if one phase of current is larger than the rated current, send the current signals to the thermal overload position for judgment, if two or three phases of current are larger than the rated current, start timeout, generate start timeout protection events and send a cutting instruction to the signal output unit 3.

As shown in fig. 3 to fig. 4, the determining of the phase-lacking imbalance position in the logic tree in this embodiment includes the following parts:

a phase-lack protection judgment submodule 206 configured to judge whether there is a motor rated current of which one-phase or two-phase current is less than 0.05 times, if so, send an instruction to an unbalance protection judgment submodule 209, and if not, send an instruction to a current judgment submodule 207;

a current judgment submodule 207 configured to judge whether a maximum current value of the three-phase current is greater than 0.2 times of a rated current of the motor, if not, send an instruction to an unbalance protection judgment submodule 209, and if so, send an instruction to a range level judgment submodule 208;

a range level determination submodule 208 configured to determine whether the maximum value of the three-phase current in the overload range determination submodule 204 belongs to a first level or a second level of the current positioning range, if the maximum value belongs to the first level or the second level, send an instruction to the unbalance protection determination submodule 209, and if the maximum value belongs to the second level, generate an open-phase protection event and send a cut-off instruction to the signal output unit 3;

the imbalance protection judging submodule 209 is configured to calculate the imbalance of the three-phase current, judge whether the imbalance is greater than an imbalance threshold, if not, send a current signal to a leakage position for judgment if the imbalance does not occur in the motor, and if so, send an instruction to the imbalance rate judging submodule 210;

an unbalance rate determination submodule 210 configured to calculate an unbalance rate, compare the unbalance rate with an action set value, if the unbalance rate is smaller than the action set value, send a current signal to a leakage position for determination, and if the unbalance rate is greater than or equal to the action set value, generate a three-phase unbalance protection event and send an instruction to the threshold level determination submodule 211, where an unbalance degree P = MAX (I phase-Xn)/Xn × 100%, the I phase represents a phase current, the Xn represents a three-phase average value of three-phase currents, and the unbalance rate

The calculation formula of (c) is as follows:

i represents the running current of the motor, iav represents the average effective value of three-phase current, and Irl represents the full-load current of the motor;

a threshold level determination sub-module 211 configured to determine whether the imbalance rate belongs to a first level or a second level of a range in which the action setting value is located, if the imbalance rate belongs to the first level, send the current signal to the leakage position for determination, and if the imbalance rate belongs to the second level, generate a three-phase imbalance protection event and send a cut-off instruction to the signal output unit 3; the range of the action set value is divided into two levels, wherein the first level is a range which does not influence the performance limit value of the motor protection controller, and the second level is a range which influences the performance of the motor protection controller.

As shown in fig. 3 to fig. 4, the determination of the leakage position in the logic tree in this embodiment includes the following steps:

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

a constant value judgment submodule 213 configured to compare the leakage current in the current signal with a leakage current constant value, and send an instruction to the first-stage mark judgment submodule 214 when the leakage current is smaller than the leakage current constant value, otherwise, send a cut-off instruction to the leakage protection event generation and signal output unit 3;

and a first-stage mark judging submodule 214 configured to judge whether the current signal has a first-stage mark, a short-circuit mark and/or a thermal overload mark, add a second-stage mark to the current signal and send the current signal to a current overload position for judgment if the current signal has the first-stage mark, the short-circuit mark and/or the thermal overload mark, and send a switch-on instruction to the signal output unit 3 if the current signal has the second-stage mark.

As shown in fig. 3 and fig. 5, the determination of the short-circuit position in the logic tree in this embodiment includes the following parts:

a level mark judging submodule 215 configured to judge whether the current signal has a mark, if not, send an instruction to the short-circuit protection submodule 216, if only the first-level mark is carried, send a judgment instruction to the short-circuit protection submodule 216 and send a mark instruction to the short-circuit mark submodule 219, if the first-level, second-level, thermal overload and short-circuit marks are carried, send a turn-on instruction to the signal output unit 3, and if the first-level, second-level and short-circuit marks are carried at the same time, send an output instruction to the short-circuit protection submodule 216 and the short-circuit output submodule 218;

a short-circuit protection sub-module 216 configured to compare the maximum value of the three-phase current in the current signal with a short-circuit current fixed value, determine whether the current signal is within a range of the short-circuit current fixed value, if so, send a determination instruction to the short-circuit range determination sub-module 217, and if not, generate a short-circuit protection event and send a switch-on instruction to the signal output unit 3;

a short-circuit range determination submodule 217 configured to determine a level to which a maximum value of the three-phase current belongs within a short-circuit current constant value range, send a command to the short-circuit output submodule 218 if the maximum value is within a first or second level range, generate a short-circuit protection event and send a cut-off command to the signal output unit 3 if the maximum value is within a third level range, where the current constant value range includes three levels, a first level is a range that does not affect the performance of the motor protection controller, a second level is a range that does not affect the maximum limit value of the motor protection controller, and a third level is a range that affects the performance of the motor protection controller;

a short circuit output sub-module 218 configured to determine whether an output instruction sent by the level flag determination sub-module 215 is received, if yes, generate a short circuit protection event and send a switch-on instruction to the signal output unit 3, and if not, send a flag instruction to the short circuit flag sub-module 219;

and the short-circuit marking submodule 219 is configured to determine whether a marking instruction sent by the level marking determination submodule 215 is received, if so, send the current signal to the thermal overload position after adding the short-circuit mark to the current signal for determination, and if not, directly send the current signal to the thermal overload position for determination.

As shown in fig. 3 and fig. 5, the determination of the thermal overload location in the logic tree in this embodiment includes the following steps:

a flag judging submodule 220 configured to judge whether the current signal has a flag, send a judgment instruction to the thermal overload protection submodule 221 and a flag instruction to the thermal overload flag submodule 225 if the current signal has a first-stage flag and/or a short-circuit flag, send a turn-on instruction to the signal output unit 3 if the current signal has a first-stage, second-stage, thermal overload, and short-circuit flag, and send a turn-off instruction to the signal output unit 3 if the current signal has a first-stage, second-stage, and thermal overload flag;

the thermal overload protection sub-module 221 is configured to judge whether one-phase or two-phase current in the three-phase current is less than 0.05 times of rated current of the motor, if so, send an instruction to the thermal capacity judgment sub-module 222, and if not, send an instruction to the thermal overload marking sub-module 225;

a heat capacity determination submodule 222 configured to calculate a steady-state heat capacity and a current heat capacity of the motor, expand the steady-state heat capacity into a capacity range, and determine whether the current heat capacity is within the capacity range, if not, send an instruction to the thermal overload flag submodule 225, and if so, send an instruction to the capacity range submodule 223; the calculation formulas of the steady-state heat capacity Cc and the current heat capacity C are respectively as follows:

irl represents the rated current of the motor, KT represents the proportion of the cold-hot state curve of the motor, the selection range is 20-100%, and the selection principle is as follows: the motor hot state allowed locked-rotor time/motor cold state allowed locked-rotor time is 100%;

C＝C _CH ×e ^tCool/T CCH represents the heat capacity of the motor before parking or the heat capacity at the moment when the running current of the motor is reduced, the value is 100 percent, T represents the set cooling time/5, and tCool represents the elapsed cooling time;

a capacity range submodule 223 configured to judge that the current heat capacity is at a level to which the capacity range belongs, and to transmit an instruction to the thermal overload flag submodule 225 if at a first level, an instruction to the level superimposition judging submodule 224 if at a second level, and to generate a thermal overload protection event and transmit a cut-off instruction to the signal output unit 3 if at a third level, the capacity range including 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 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;

a level superposition judging submodule 224 configured to judge whether a maximum value of a three-phase current in the short-circuit protection event is at a first level or a second level of a short-circuit current constant value range, if the maximum value is at the first level, send an instruction to the thermal overload marking submodule 225, and if the maximum value is at the second level, generate a thermal overload protection event and send a cutting instruction to the signal output unit 3;

and the thermal overload marking submodule 225 is configured to judge whether a marking instruction sent by the marking judgment submodule 220 is received, if so, send the current signal to the electric leakage position for judgment after adding the thermal overload mark to the current signal, and if not, send the current signal to the electric leakage position for judgment.

In the present embodiment, the thermal overload protection is mainly described further, and the overload protection reflects the average heating condition of the stator and rotor windings to prevent the motor from overheating. The overload and asymmetric overload protection device mainly protects the overload and asymmetric overload of the motor, protects the motor by calculating the thermal capacity, and determines the starting time of the contactor by calculating the delay characteristic t, so that the protection action of the motor is controlled, the safety of motor equipment is protected, the judgment accuracy is increased, and the detection sensitivity is further improved.

In the embodiment, when the motor runs in overload fault, the controller calculates the heat capacity of the motor according to the heating characteristic of the motor, so as to protect the motor. And K is the curve coefficient corresponding to the curve number, and t is the actual action time. The overload characteristic is shown in the overload operation characteristic time chart shown in fig. 7 and the overload characteristic graph shown in fig. 8; the controller heat capacity to the motor is given as a percentage maximum of 100%.

In the embodiment, after the current signal is received, the priority level of the signal is judged according to the first preset range, the signal at the first priority level is processed preferentially, and according to the description, the first priority level corresponds to the short-circuit protection and the thermal overload protection, so that the two events need to be judged first, and the detection speed is effectively improved when the time after the short-circuit protection or the thermal overload protection is judged or the time is within the extension time of the timing limit.

The following is specifically described in terms of logic decisions for current overload and phase loss protection:

the rated current of the motor is 4A, if the current at the time of starting the motor is 27A, the current belongs to a first preset range (10, 100), the judgment is started from the current overload position in the logic tree, if the current at the time of starting the current is 1500, the current is transmitted to the short-circuit position for judgment in a second preset range (1000, 20000), if the current at the time of starting the current is 0.2, the current is transmitted to the thermal overload position for judgment in a third preset range (0.01, 0.4).

When current overload judgment is carried out, if the received three-phase currents are IA-20A, IB-25A and IB-22A, the maximum current is 25A, then the grade of the 25A in the current overload constant value range is judged, the first grade range is (20, 30), the second grade range is (30, 40) and the third grade range is (40, 50), the 25A belongs to the first grade range, phase-lack unbalance judgment is directly carried out, if the maximum current is 33A, phase-lack unbalance judgment is also carried out, and if the maximum current is 47A, the current is overloaded, a current overload protection event is generated, and a cutting-off command is sent.

When the phase loss judgment in the phase loss unbalance is carried out, if the rated current is 30A, 0.05 times of the rated current of the motor is 1.5A, the three-phase current is larger than 1.5A, the judgment of the maximum value of the current is carried out, if IA is 1A, the unbalance judgment is carried out, if 25 or 33A is larger than 0.2 times of the rated current 6A of the motor, the range where the maximum current in the current overload exists needs to be judged at the moment, if the maximum current is 25A, the judgment of the unbalance protection is carried out, and if the maximum current is 33A, a double fault needs to be sent out.

The logic judgment of the remaining protection events in this embodiment is also performed with reference to the above method idea.

In this embodiment, after receiving the determination result, the signal output unit 3 determines the level of the protection event that sends the cut-off instruction or the turn-on instruction, if the level is a priority processing level, the determination result sent by the corresponding protection event is processed preferentially, after the delay time is reached, the cut-off instruction or the turn-on instruction is sent to the corresponding relay, if the level is a sequential processing level, the determination result sent by the corresponding protection event is processed sequentially, and after the delay time is reached, the cut-off instruction or the turn-on instruction is sent to the corresponding relay, where the protection event at the priority processing level includes short-circuit protection and thermal overload protection, and the protection event at the sequential processing level includes start timeout protection, open-phase imbalance protection, leakage protection, and current overload protection.

In practice, because the time interval of current collection is very short, there may be two current signals that output the judgment result at the same time, if the first current signal belongs to the second priority, the electric leakage position is judged as no electric leakage by sequential processing, and a switch-on instruction is sent, while the second current signal belongs to the first level, the judgment is preferentially carried out at the short-circuit position, the result is switch-off, and a switch-off instruction is sent, at this moment, the two signals may arrive at the signal output unit at the same time, but because the short-circuit protection event generated at the short-circuit position belongs to the priority processing level, the switch-off instruction is processed first; because each protection event adopts fixed time limit protection, the time is started after a cutting-off instruction is received, and the cutting-off circuit of the contactor is controlled when the time delay is reached; in the embodiment, the protection events are prioritized, and the signals sent by the events with priority processing levels are processed preferentially, so that the processing efficiency can be improved.

The starting protection in the invention not only comprises the protection events, but also comprises contactor breaking protection, timing limit protection, undervoltage protection, overvoltage protection, phase sequence protection and the like.

In another embodiment, as shown in fig. 9, a control method of a motor protection controller start control module includes the steps of:

receiving a three-phase current signal acquired by an internal mutual inductor and/or a leakage current signal acquired by an external mutual inductor;

judging the priority of the three-phase current signal and/or the leakage current signal, sending the current signal to corresponding positions in a logic tree according to the priority level, respectively carrying out protection logic judgment on the current signal by utilizing each position of the logic tree, and generating a corresponding protection event and a judgment result;

and sending a cut-off or cut-in command to the motor (namely sending a command to a relay of the motor and controlling the on-off of the contactor through the relay) according to the level of the protection event and the judgment result.

The invention provides a new control method of an autotransformer starting control module of a motor protection controller, which comprises the steps of judging the priority of a current signal after receiving the current signal, carrying out priority processing on the current signal with high priority, carrying out sequence processing on the current signal with low priority, carrying out logic judgment processing on the current signal in a logic tree after judging the priority, and controlling the motor to function according to a judgment result.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features that may embody particular implementations of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in combination 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 may be directed to a subcombination or variation of a subcombination.

In certain situations, multitasking and parallel processing may be advantageous. Moreover, the separation of various system modules and components in the embodiments described above should not be understood as requiring such separation in all embodiments.

Particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. For example, the activities recited in the claims can be performed in a different order and still achieve desirable results. As one example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain implementations, multitasking and parallel processing may be advantageous.

Claims (10)

1. A starting control module of a motor protection controller is used for starting an autotransformer, and is characterized by comprising the following parts:

the signal acquisition unit (1) is configured to receive a three-phase current signal acquired by an internal mutual inductor and/or a leakage current signal acquired by an external mutual inductor;

the signal processing unit (2) is configured to judge the priority of the three-phase current signal and/or the leakage current signal, and send the current signal to the corresponding position in the logic tree according to the priority level, and each position of the logic tree carries out protection logic judgment on the current signal respectively and generates a corresponding protection event and a judgment result;

a signal output unit (3) configured to send a switch-off or switch-on command to the motor according to the level of the protection event and the determination result.

2. The start control module of the motor protection controller according to claim 1, wherein in the signal processing unit (2), each position in the logic tree is a thermal overload position, a start timeout position, a phase loss unbalance position, a short circuit position, a leakage position and a current overload position, and the protection events generated corresponding to each position are thermal overload protection, start timeout protection, phase loss unbalance protection, short circuit protection, leakage protection and current overload protection; the current signals are divided into two priorities according to the sizes of the current signals, the current signals which meet the first preset range and belong to the second priority and do not meet the first preset range and belong to the first priority are processed preferentially, and the current signals comprise three-phase current signals and/or leakage current signals.

3. The starting control module of the motor protection controller according to claim 2, characterized in that the signal processing unit (2) comprises the following parts:

the priority judging submodule (201) is configured to compare the current signal with a first preset range, judge the priority of the current signal, send an instruction to the protection judging submodule (202) if the current signal belongs to the first priority, and send the current signal to the logic tree self-starting position for judging if the current signal belongs to the second priority;

and 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 added with the first-stage mark and then sent to the short-circuit position for judgment, and if the current signal belongs to the third preset range, the current signal is added with the first-stage mark and then sent to the thermal overload position for judgment.

4. The start control module of the motor protection controller according to claim 3, wherein the determination of the current overload location in the logic tree specifically comprises:

the current overload protection sub-module (203) is configured to compare the maximum value of the three-phase current with a current overload fixed value, judge whether the maximum value of the current signal is within the range of the current overload fixed value, if so, send a judgment instruction to the overload range judgment sub-module (204), and if not, send an instruction to the starting overtime protection sub-module (205);

the overload range judging submodule (204) is configured to judge the level of the maximum value of the three-phase current in a current overload constant value range, if the maximum value of the three-phase current is in a first or second level range, a current signal is sent to a phase-lack unbalance position for judgment, if the maximum value of the three-phase current is in a third level range, a current overload protection event is generated, and a cutting-off instruction is sent to the signal output unit (3), wherein the current positioning range comprises three levels, the first level is a range which does not influence the performance of the motor protection controller, the second level is a range which does not influence the maximum limit value of the motor protection controller, and the third level is a range which influences the performance of the motor protection controller;

the starting overtime protection sub-module (205) is configured to start timing after receiving three-phase currents of the current signals, compare each phase of current with a rated current after timing is finished, if the three-phase currents are smaller than the rated current, starting is not overtime, send the current signals to a short-circuit position for judgment, if one phase of current is larger than the rated current, send the current signals to a thermal overload position for judgment, if two or three phases of current are larger than the rated current, starting overtime is conducted, start overtime protection events are generated, and cut-off instructions are sent to the signal output unit (3).

5. The startup control module of a motor protection controller according to claim 4, wherein the determination of the location of the phase loss imbalance in the logic tree includes:

the open-phase protection judging submodule (206) is configured to judge whether one-phase or two-phase current is less than 0.05 time of rated current of the motor, if so, an instruction is sent to the unbalance protection judging submodule (209), and if not, an instruction is sent to the current judging submodule (207);

the current judgment submodule (207) is configured to judge whether the maximum current value in the three-phase current is greater than 0.2 time of the rated current of the motor, if not, an instruction is sent to the unbalance protection judgment submodule (209), and if yes, an instruction is sent to the range level judgment submodule (208);

the range level judging submodule (208) is configured to judge whether the maximum value of the three-phase current in the overload range judging submodule (204) belongs to the first level or the second level of the current positioning range, if the maximum value belongs to the first level, an instruction is sent to the unbalance protection judging submodule (209), and if the maximum value belongs to the second level, an open-phase protection event is generated and a cutting instruction is sent to the signal output unit (3);

the unbalance protection judging submodule (209) is configured to calculate the unbalance degree of the three-phase current, judge whether the unbalance degree is larger than an unbalance degree threshold value or not, if not, the motor is not unbalanced, send a current signal to an electric leakage position for judgment, and if yes, send an instruction to the unbalance rate judging submodule (210);

an unbalance rate determination submodule (210) configured to calculate an unbalance rate, compare the unbalance rate with an action set value, if the unbalance rate is smaller than the action set value, send a current signal to a leakage position for determination, and if the unbalance rate is greater than or equal to the action set value, generate a three-phase unbalance protection event and send an instruction to a threshold level determination submodule (211), wherein an unbalance degree P = MAX (I phase-Xn)/Xn × 100%, the I phase represents a phase current, xn represents a three-phase average value of three-phase currents, and the unbalance rate is determined by the unbalance rate determination submodule (211)

The calculation formula of (a) is as follows:

i represents the motor running current, iav represents the average effective value of the three-phase current, and Irl represents the full-load current of the motor;

a threshold level judgment sub-module (211) configured to judge whether the unbalance rate belongs to a first level or a second level of a range in which the action set value is located, if the unbalance rate belongs to the first level, send a current signal to a leakage position for judgment, and if the unbalance rate belongs to the second level, generate a three-phase unbalance protection event and send a cut-off instruction to the signal output unit (3); the range of the action set value is divided into two levels, wherein the first level is a range which does not influence the performance limit value of the motor protection controller, and the second level is a range which influences the performance of the motor protection controller.

6. The startup control module of a motor protection controller according to claim 5, wherein the determination of the location of the electrical leakage in the logic tree includes:

the leakage protection submodule (212) is configured to calculate the vector sum of three-phase currents in the current signal, judge whether the vector sum is 0, if yes, no leakage current exists, send an instruction to the first-stage mark judgment submodule (214), and if not, generate a leakage protection event and send an instruction to the fixed value judgment submodule (213);

the constant value judgment sub-module (213) is configured to compare the leakage current in the current signal with a leakage current constant value, and when the leakage current is smaller than the leakage current constant value, the constant value judgment sub-module sends an instruction to the first-stage mark judgment sub-module (214), otherwise, the constant value judgment sub-module sends a cutting-off instruction to the leakage protection event generation and signal output unit (3);

and the first-stage mark judging submodule (214) is configured to judge whether the current signal is provided with a first-stage mark, a short-circuit mark and/or a thermal overload mark, if so, add a second-stage mark to the current signal and send the current signal to a current overload position for judgment, and if not, send a switch-on instruction to the signal output unit (3).

7. The startup control module of a motor protection controller according to claim 6, wherein the determination of the short circuit position in the logic tree includes:

a level mark judging submodule (215) configured to judge whether the current signal has a mark, if not, send an instruction to a short-circuit protection submodule (216), if only the current signal has a first-level mark, send a judging instruction to the short-circuit protection submodule (216) and send a mark instruction to a short-circuit mark submodule (219), if the current signal has the first-level, second-level, thermal overload and short-circuit marks, send a turn-on instruction to a signal output unit (3), and if the current signal has the first-level, second-level and thermal overload marks, send an output instruction to the short-circuit protection submodule (216) and the short-circuit output submodule (218);

the short-circuit protection sub-module (216) is configured to compare the maximum value of the three-phase current in the current signal with a short-circuit current constant value, judge whether the current signal is in the range of the short-circuit current constant value, if so, send a judgment instruction to the short-circuit range judgment sub-module (217), and if not, generate a short-circuit protection event and send a switch-on instruction to the signal output unit (3);

a short-circuit range judgment submodule (217) configured to judge a level to which the maximum value of the three-phase current belongs within a short-circuit current constant value range, and if the maximum value is within a first or second level range, to send a command to a short-circuit output submodule (218), and if the maximum value is within a third level range, to generate a short-circuit protection event and send a cut-off command to a signal output unit (3), the current constant value range including 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 that does not affect the performance of the motor protection controller, and the third level is a range that affects the performance of the motor protection controller;

a short circuit output sub-module (218) configured to determine whether an output instruction sent by the level flag determination sub-module (215) is received, if so, generate a short circuit protection event and send a switch-on instruction to the signal output unit (3), and if not, send a flag instruction to the short circuit flag sub-module (219);

and the short circuit marking submodule (219) is configured to judge whether a marking instruction sent by the level marking judging submodule (215) is received, if so, the current signal is added with a short circuit mark and then sent to a thermal overload position for judgment, and if not, the current signal is directly sent to the thermal overload position for judgment.

8. The start control module of a motor protection controller according to claim 7, wherein the determination of the location of the thermal overload in the logic tree comprises:

a mark judging submodule (220) configured to judge whether the current signal has a mark, if the current signal has a first-stage mark and/or a short-circuit mark, send a judgment instruction to the thermal overload protection submodule (221) and a mark instruction to the thermal overload mark submodule (225), if the current signal has a first-stage mark, a second-stage mark, a thermal overload mark and a short-circuit mark, send a switch-on instruction to the signal output unit (3), and if the current signal has a first-stage mark, a second-stage mark and a thermal overload mark, send a switch-off instruction to the signal output unit (3);

the thermal overload protection sub-module (221) is configured to judge whether one-phase or two-phase current in the three-phase current is less than 0.05 time of rated current of the motor, if so, an instruction is sent to the thermal capacity judging sub-module (222), and if not, an instruction is sent to the thermal overload marking sub-module (225);

the heat capacity judging sub-module (222) is configured to calculate the steady-state heat capacity and the current heat capacity of the motor, judge whether the current heat capacity is in the capacity range after the steady-state heat capacity is expanded into the capacity range, if not, send an instruction to the heat overload marking sub-module (225), and if so, send an instruction to the capacity range sub-module (223); the calculation formulas of the steady-state heat capacity Cc and the current heat capacity C are respectively as follows:

irl represents the rated current of the motor, KT represents the proportion of the cold-hot state curve of the motor, the selection range is 20% -100%, and the selection principle is as follows: the motor hot state allowed locked-rotor time/the motor cold state allowed locked-rotor time is 100%;

C＝C _CH ×e ^tCool/T CCH represents the heat capacity of the motor before parking or the heat capacity at the time when the running current of the motor is reduced, the value is 100 percent, T represents the set cooling time/5, and tCool represents the elapsed cooling time;

a capacity range submodule (223) configured to determine a level to which the current heat capacity belongs in a capacity range, and if the level is a first level, to send an instruction to the thermal overload flag submodule (225), if the level is a second level, to send an instruction to the level overlap determination submodule (224), and if the level is a third level, to generate a thermal overload protection event and send a cut-off instruction to the signal output unit (3), the capacity range including 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 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 level superposition judging submodule (224) is configured to judge whether the maximum value of the three-phase current in the short-circuit protection event is in a first level or a second level of a short-circuit current constant value range, if the maximum value is in the first level, an instruction is sent to the thermal overload marking submodule (225), and if the maximum value is in the second level, a thermal overload protection event is generated and a cutting instruction is sent to the signal output unit (3);

and the thermal overload marking submodule (225) is configured to judge whether a marking instruction sent by the marking judging submodule (220) is received, if so, the current signal is added with the thermal overload mark and then sent to the electric leakage position for judgment, and if not, the current signal is sent to the electric leakage position for judgment.

9. The start control module of the motor protection controller according to claim 1, wherein the signal output unit (3) determines a level of a protection event for transmitting a turn-off command or a turn-on command after receiving the determination result, preferentially processes the determination result transmitted by the corresponding protection event if the determination result is a priority processing level, transmits the turn-off command or the turn-on command to the corresponding relay after the delay time is reached, sequentially processes the determination result transmitted by the corresponding protection event if the determination result is a sequential processing level, and transmits the turn-off command or the turn-on command to the corresponding relay after the delay time is reached, wherein the protection event at the priority processing level includes short-circuit protection and thermal overload protection, and the protection event at the sequential processing level includes start timeout protection, open-phase unbalance protection, leakage protection, and current overload protection.

10. A control method of starting a control module using the motor protection controller according to any one of claims 1 to 9, comprising the steps of:

receiving a three-phase current signal acquired by an internal mutual inductor and/or a leakage current signal acquired by an external mutual inductor;

judging the priority of the three-phase current signal and/or the leakage current signal, sending the current signal to corresponding positions in a logic tree according to the priority level, respectively carrying out protection logic judgment on the current signal by utilizing each position of the logic tree, and generating a corresponding protection event and a judgment result;

and sending a switch-off or switch-on command to the motor according to the level of the protection event and the judgment result.

Images