CN115275938A - Motor protection setting method and device - Google Patents
Motor protection setting method and device Download PDFInfo
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- CN115275938A CN115275938A CN202210936870.4A CN202210936870A CN115275938A CN 115275938 A CN115275938 A CN 115275938A CN 202210936870 A CN202210936870 A CN 202210936870A CN 115275938 A CN115275938 A CN 115275938A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/006—Calibration or setting of parameters
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- Protection Of Generators And Motors (AREA)
- Motor And Converter Starters (AREA)
Abstract
The invention is suitable for the field of power systems and automation, and provides a motor protection setting method and a device, wherein the setting method comprises the following steps: firstly, setting the starting time of a motor; then, the protection constant value and the sensitivity coefficient of the protection method are adjusted according to the set motor starting time. The protection method mainly comprises the following steps: current quick-break protection, overload protection, single-phase grounding protection and load overcurrent protection. The method and the device reduce the misoperation times of the device by setting the starting time of the motor and four typical protection methods, avoid tripping of protection actions in the starting process of the motor, and greatly improve the accuracy and reliability of the judgment of the self-identification motor starting time of the device.
Description
Technical Field
The invention belongs to the field of electric power systems and automation thereof, and particularly relates to a motor protection setting method and device.
Background
The conventional method for measuring the starting time of the motor is that the shorter one of the actual starting time and the predicted starting time of the measured motor is used as the starting time of the motor. However, in actual operation, the starting current is not always an ideal rising and falling curve due to the mass of the motor and the cable. The judgment mode always has the problem that the starting time of the motor measured by the device is small, the current and the unbalanced current of the motor are still large after the starting time measured by the device, and the inverse time limit action is not timed again after the motor is started, so that the setting values of the inverse time limit overcurrent, the quick break and the negative sequence overcurrent are avoided, and the false operation switching is protected.
Disclosure of Invention
In view of the above problems, in one aspect, the present invention provides a motor protection setting method, which includes a protection device, and the method includes:
setting the starting time of the motor;
and adjusting the protection constant value and the sensitivity coefficient of the protection device according to the set motor starting time.
Further, the setting of the motor start time includes:
acquiring actual starting time and predicted starting time of a motor;
judging whether the actual starting time of the motor is larger than the predicted starting time or not;
when the actual starting time of the motor is greater than the predicted starting time, taking the actual starting time as the adjusted starting time;
when the actual starting time of the motor is less than the predicted starting time, the predicted starting time is taken as the adjusted starting time.
Further, the adjusting the protection setting value and the sensitivity coefficient of the protection device includes:
setting a current quick-break protection value through setting a first protection fixed value and a sensitivity coefficient of a motor;
setting overload protection through setting the inverse time limit overcurrent value of the motor;
setting single-phase earth protection through setting the minimum sensitivity coefficient when the single-phase earth protection fault occurs;
setting the negative sequence current protection through setting a second protection constant value of the motor;
further, the setting the current quick-break protection by setting the first protection fixed value and the sensitivity coefficient of the motor includes:
and setting a first protection fixed value, wherein the first protection fixed value comprises a current quick-break protection high fixed value and a current quick-break protection low fixed value.
And setting a sensitivity coefficient, wherein the sensitivity coefficient is the sensitivity of short-circuit current flowing through the protection device when two phases of the motor terminal are short-circuited in the minimum operation mode, the sensitivity of the short-circuit current is not lower than R, and R is greater than 1.
Further, the high constant value of the current quick-break protection is opened in the starting process of the motor, and the low constant value of the current quick-break protection is opened after the motor is started.
Further, the high fixed value of the current quick-break protection is set according to the starting current of the motor, the starting current of the motor is set to be R1 times of the rated current of the motor, and R1 is larger than 1;
the low constant value of the current quick-break protection is set according to R2 times of the high constant value of the current quick-break protection, and R2 is less than 1.
Further, the setting of the overload protection by setting the inverse time limit overcurrent value of the motor includes:
setting an inverse time limit overcurrent high definite value and an inverse time limit overcurrent low definite value; the inverse time limit overcurrent low fixed value is set according to the rated current of the motor and the adjusted starting time of the motor; the inverse time limit overcurrent high fixed value is set according to R3 times of the inverse time limit overcurrent low fixed value, and R3 is more than 1;
or
The inverse time limit overcurrent value is set according to the rated current and the starting time of the motor, and the inverse time limit overcurrent is reckoning after the motor is started.
Further, the single-phase earth protection is set according to R4 of the minimum sensitivity coefficient when the single-phase earth fault occurs through setting the minimum sensitivity coefficient when the single-phase earth protection fault occurs, and the R4 is larger than 1.
Further, the setting the negative sequence current protection by setting the second protection constant of the motor includes:
setting a second protection fixed value, wherein the second protection fixed value comprises a negative sequence current protection high fixed value and a negative sequence current protection low fixed value; the negative sequence current protection low fixed value is set according to a negative sequence current which avoids normal operation, the negative sequence current protection high fixed value is set according to R5 times of the negative sequence current protection low fixed value, and R5 is larger than 1.
In another aspect, the present invention further provides a motor protection setting device, where the motor protection setting device includes:
a protection device;
a motor start time setting unit;
and a protective device setting unit.
The motor start time setting unit is configured to set a motor start time, which is a longer time of an expected start time of the motor and an actual start time of the motor.
It should be noted that the protection device setting unit includes:
the current quick-break protection setting module is used for setting current quick-break protection through setting a first protection setting value and a sensitivity coefficient of the motor;
the overload protection setting module is used for setting the overload protection through setting the inverse time limit overcurrent value of the motor;
the single-phase grounding protection setting module is used for setting the single-phase grounding protection through setting the minimum sensitivity coefficient when the single-phase grounding protection fault occurs;
the negative sequence current protection setting module is used for setting the negative sequence current protection through setting a second protection constant value of the motor;
it should be noted that the first protection fixed value in the current quick-break protection setting module includes a current quick-break protection high fixed value and a current quick-break protection low fixed value.
It should be noted that the overload protection setting module sets an inverse time limit overcurrent high fixed value and an inverse time limit overcurrent low fixed value.
It should be noted that, the single-phase earth protection setting module sets the single-phase earth protection according to a multiple of the minimum sensitivity coefficient when the single-phase earth fault occurs.
It should be further noted that the second protection fixed value in the negative sequence current protection setting module includes a negative sequence current protection high fixed value and a negative sequence current protection low fixed value.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a motor protection method and a device, which set the starting time of a motor on one hand, and reduce the sensitivity of open-circuit inverse time limit overcurrent protection and low-value quick-break protection of the motor in a hot rolling area within an allowable range on the other hand, namely, set values of the inverse time limit overcurrent protection and the low-value quick-break protection are increased to ensure that the inverse time limit overcurrent protection and the low-value quick-break protection avoid the starting time of the motor, thereby reducing the misoperation times, avoiding the tripping of protection action during power transmission and ensuring the accuracy and the reliability of the judgment of the self-identification motor starting time of the device.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 illustrates a flow chart of a method of protecting a motor in accordance with an embodiment of the present invention;
fig. 2 shows a schematic structural diagram of a motor protection device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention relates to a motor protection setting method and a motor protection setting device, which take hot rolling area finish rolling 4#, 5# descaling pumps (1400 kW high-voltage asynchronous motors) as an example, wherein the transformation ratio of a phase current transformer is 200/5, the rated current of the motor is 100A, the protection device related to the invention is a south self PSM690 series protection device, and the protection device is provided with a function of self-identifying the starting time of the motor.
In an embodiment of the present invention, fig. 1 shows a flowchart of a motor protection setting method in an embodiment of the present invention, which includes a protection device, and the method includes:
step 1: setting the starting time of the motor;
step 2: and adjusting the protection constant value and the sensitivity coefficient of the protection device according to the set motor starting time.
Wherein the method comprises the following steps: the setting of the motor start time includes:
acquiring actual starting time and predicted starting time of a motor;
judging whether the actual starting time of the motor is larger than the predicted starting time or not;
when the actual start-up time of the motor is greater than the expected start-up time, taking the actual starting time as the adjusted starting time;
when the actual starting time of the motor is less than the predicted starting time, the predicted starting time is taken as the adjusted starting time.
In one embodiment of the invention, the device has the function of self-identifying the starting time of the motor. Wherein the means measures the motor start time is the time elapsed between when the maximum phase current of the motor abruptly changes from zero to 10% In until the start current after an overshoot drops to 120% In (In is the motor rated current).
Meanwhile, a fixed value of the starting time of the motor is input, which represents the time from starting to the time that the rotating speed reaches the rated rotating speed of the motor and can be set to be 1.2 times of the longest starting time of the motor.
In one embodiment of the invention, the device is provided with a function of self-recognizing the motor start time; setting the starting time of the motor to be 1.2 times of the longest starting time (25 s) of the motor, and setting the starting time to be 30s;
wherein the step 2: the adjusting of the protection constant value and the sensitivity coefficient of the protection device includes:
setting the current quick-break protection through setting a first protection fixed value and a sensitivity coefficient of the motor;
setting overload protection through setting the inverse time limit overcurrent value of the motor;
setting single-phase earth protection through setting the minimum sensitivity coefficient when the single-phase earth protection fault occurs;
and setting the negative sequence current protection through setting a second protection constant value of the motor.
The method for setting the current quick-break protection by setting the first protection fixed value and the sensitivity coefficient of the motor comprises the following steps:
setting a first protection fixed value, wherein the first protection fixed value comprises a current quick-break protection high fixed value and a current quick-break protection low fixed value.
And setting a sensitivity coefficient, wherein the sensitivity coefficient is the sensitivity of short-circuit current flowing through the protection device when two phases of the motor terminal are short-circuited in the minimum operation mode, the sensitivity of the short-circuit current is not lower than R, and R is greater than 1.
The minimum operation mode refers to the short-circuit current passing through the relay protection device when the number of units put into operation in the system is minimum and the capacity is minimum. In general, the short-circuit current value of the minimum operation mode is used to verify the sensitivity of the relay protection device.
Wherein, the short-circuit current sensitivity is not lower than 1.5 according to the requirement of the current national standard GB/T14285 technical Specification for Relay protection and safety automatic device.
Further, the high constant value of the current quick-break protection is opened in the starting process of the motor, and the low constant value of the current quick-break protection is opened after the motor is started;
setting the high fixed value of the current quick-break protection according to the starting current of the motor, wherein the setting of the starting current of the motor is 10-12 In of the rated current of the motor, and In is the rated current of the motor;
the low constant value of the current quick-break protection is set according to 50-60% of the high constant value of the current quick-break protection.
In one embodiment related by the invention, the high constant value of the current quick-break protection is set to 30A,0s, the low constant value is set to 50-60% of the high constant value, and the setting is 15A-18A, 0s.
In an embodiment of the present invention, the setting the overload protection by setting an inverse time limit overcurrent value of the motor includes:
setting an inverse time limit overcurrent high fixed value and an inverse time limit overcurrent low fixed value; the inverse time limit overcurrent low fixed value is set according to the rated current of the motor and the adjusted starting time of the motor; the inverse time limit overcurrent high fixed value is set according to 1.5 to 2 times of the inverse time limit overcurrent low fixed value;
or
The inverse time limit overcurrent value is set according to the rated current and the starting time of the motor, and the inverse time limit overcurrent is re-timed after the motor is started.
In one embodiment related by the invention, the inverse time limit overflowing is also set according to a high fixed value and a low fixed value, the action time is 30s when the fixed value is 2.5A and 2 times, and the action time is 30s when the fixed value is 3.75-5A and 2 times; or the action time is 30s when the inverse time limit value is 2.5A and the 2-time limit value is constant, but the inverse time limit value should be counted again after the motor is started.
In an embodiment of the invention, the setting of the single-phase earth protection is performed according to a minimum sensitivity coefficient 1.3 when the protected unit has the single-phase earth fault by setting the minimum sensitivity coefficient when the single-phase earth protection fault occurs.
In one embodiment related by the invention, the single-phase grounding protection is unchanged according to a conventional setting method, and the setting is 30A and 0.5s.
In an embodiment of the invention, the setting of the negative sequence current protection by setting the second protection constant of the electric machine comprises:
setting a second protection fixed value, wherein the second protection fixed value comprises a negative sequence current protection high fixed value and a negative sequence current protection low fixed value; the negative sequence current protection low fixed value is set according to the negative sequence current which avoids normal operation, and the negative sequence current protection high fixed value is set according to 1.5-2 times of the negative sequence current protection low fixed value.
In one embodiment of the present invention, the negative sequence current protection is set at a high/low constant value, the low constant value is set at a negative sequence current (30% In) avoiding normal operation, the setting is 0.75a and 0.5s, the high constant value is set at 1.5 to 2 times the low constant value, the setting is 1.125A to 1.5A and 0.5s, wherein In is a motor rated current.
Correspondingly, in order to execute the above method, a motor protection setting device is further designed, and fig. 2 shows a schematic structural diagram of the motor protection setting device in the embodiment of the present invention, which is characterized in that the motor protection setting device includes:
a protection device;
a motor start time setting unit;
and a protection device setting unit.
The motor starting time setting unit is used for setting motor starting time, and the motor starting time is the longer time of the predicted starting time of the motor and the actual starting time of the motor.
Further, the protection device setting unit includes:
the current quick-break protection setting module is used for setting the current quick-break protection through setting a first protection fixed value and a sensitivity coefficient of the motor;
the overload protection setting module is used for setting the overload protection through setting the inverse time limit overcurrent value of the motor;
the single-phase grounding protection setting module is used for setting the single-phase grounding protection through setting the minimum sensitivity coefficient when the single-phase grounding protection fault occurs;
the negative sequence current protection setting module is used for setting the negative sequence current protection through setting a second protection constant value of the motor;
the first protection fixed value in the current quick-break protection setting module comprises a current quick-break protection high fixed value and a current quick-break protection low fixed value.
Similarly, the overload protection setting module sets an inverse time limit overcurrent high fixed value and an inverse time limit overcurrent low fixed value.
The single-phase earth protection setting module sets the single-phase earth protection according to the multiple of the minimum sensitivity coefficient when the single-phase earth fault occurs, and in one embodiment of the invention, the setting is carried out according to the minimum sensitivity of 1.3 when the single-phase earth fault occurs to the protected element, wherein the specific setting is 30A and 0.5s.
And the second protection fixed value in the negative sequence current protection setting module comprises a negative sequence current protection high fixed value and a negative sequence current protection low fixed value.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (12)
1. A motor protection setting method is characterized by comprising a protection device, and the method comprises the following steps:
setting the starting time of the motor;
and adjusting the protection constant value and the sensitivity coefficient of the protection device according to the set motor starting time.
2. The motor protection tuning method of claim 1, wherein the setting a motor start time comprises:
acquiring actual starting time and predicted starting time of a motor;
judging whether the actual starting time of the motor is larger than the predicted starting time or not;
when the actual starting time of the motor is larger than the predicted starting time, taking the actual starting time as the adjusted starting time;
when the actual starting time of the motor is less than the predicted starting time, the predicted starting time is taken as the adjusted starting time.
3. The motor protection setting method according to claim 1, wherein the adjusting of the protection constant and the sensitivity coefficient of the protection device comprises:
setting the current quick-break protection through setting a first protection fixed value and a sensitivity coefficient of the motor;
setting overload protection through setting the inverse time limit overcurrent value of the motor;
setting single-phase earth protection through setting the minimum sensitivity coefficient when the single-phase earth protection fault occurs;
and setting the negative sequence current protection through setting a second protection constant value of the motor.
4. The motor protection setting method according to any one of claims 1 or 3, wherein the setting of the current snap protection by setting the first protection setting value and the sensitivity coefficient of the motor comprises:
setting a first protection fixed value, wherein the first protection fixed value comprises a current quick-break protection high fixed value and a current quick-break protection low fixed value;
and setting a sensitivity coefficient, wherein the sensitivity coefficient is the sensitivity of short-circuit current flowing through the protection device when two phases of the motor terminal are short-circuited in the minimum operation mode, the sensitivity of the short-circuit current is not lower than R, and R is greater than 1.
5. The motor protection setting method according to claim 4, wherein the high fixed value of the current quick-break protection is opened during the motor starting process, and the low fixed value of the current quick-break protection is opened after the motor starting is completed.
6. The motor protection setting method according to claim 3, wherein the high setting value of the current quick-break protection is set according to a motor starting current, the motor starting current setting is R1 times of a rated current of a motor, and the R1 is more than 1;
the low constant value of the current quick-break protection is set according to R2 times of the high constant value of the current quick-break protection, and R2 is less than 1.
7. The motor protection setting method of claim 3, wherein setting overload protection by setting an inverse time limit overcurrent value of a motor comprises:
setting an inverse time limit overcurrent high definite value and an inverse time limit overcurrent low definite value; the inverse time limit overcurrent low fixed value is set according to the rated current of the motor and the adjusted starting time of the motor; the inverse time limit overcurrent high fixed value is set according to R3 times of the inverse time limit overcurrent low fixed value, and R3 is more than 1;
or
The inverse time limit overcurrent value is set according to the rated current and the starting time of the motor, and the inverse time limit overcurrent is reckoning after the motor is started.
8. The motor protection setting method according to claim 3, wherein the setting of the single-phase earth protection is performed by setting a minimum sensitivity coefficient when a single-phase earth protection fault occurs, and the setting of the single-phase earth protection is performed according to a minimum sensitivity coefficient R4 when the single-phase earth fault occurs, wherein R4 is greater than 1.
9. The motor protection setting method of claim 3, wherein setting negative sequence current protection by setting a second protection constant of the motor comprises:
setting a second protection fixed value, wherein the second protection fixed value comprises a negative sequence current protection high fixed value and a negative sequence current protection low fixed value; the negative sequence current protection low fixed value is set according to a negative sequence current which avoids normal operation, the negative sequence current protection high fixed value is set according to R5 times of the negative sequence current protection low fixed value, and R5 is larger than 1.
10. A motor protection setting device is characterized by comprising:
a protection device;
a motor start time setting unit;
and a protective device setting unit.
11. The motor protection tuning device according to claim 10, wherein the motor start time setting unit is configured to set a motor start time, which is a longer time of a predicted start time of the motor and an actual start time of the motor.
12. The motor protection tuning device of claim 10, wherein the protection device tuning unit comprises:
the current quick-break protection setting module is used for setting current quick-break protection through setting a first protection setting value and a sensitivity coefficient of the motor;
the overload protection setting module is used for setting the overload protection through setting the inverse time limit overcurrent value of the motor;
the single-phase grounding protection setting module is used for setting the single-phase grounding protection through setting the minimum sensitivity coefficient when the single-phase grounding protection fault occurs;
and the negative sequence current protection setting module is used for setting the negative sequence current protection through setting a second protection constant value of the motor.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210936870.4A CN115275938A (en) | 2022-08-05 | 2022-08-05 | Motor protection setting method and device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210936870.4A CN115275938A (en) | 2022-08-05 | 2022-08-05 | Motor protection setting method and device |
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| CN115275938A true CN115275938A (en) | 2022-11-01 |
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| CN202210936870.4A Pending CN115275938A (en) | 2022-08-05 | 2022-08-05 | Motor protection setting method and device |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116191358A (en) * | 2022-11-25 | 2023-05-30 | 云南电网有限责任公司昆明供电局 | Method for improving quick-break protection performance of asynchronous motor |
| CN116231589A (en) * | 2022-11-28 | 2023-06-06 | 云南电网有限责任公司昆明供电局 | Current quick-break protection method without matching with motor starting current |
-
2022
- 2022-08-05 CN CN202210936870.4A patent/CN115275938A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116191358A (en) * | 2022-11-25 | 2023-05-30 | 云南电网有限责任公司昆明供电局 | Method for improving quick-break protection performance of asynchronous motor |
| CN116231589A (en) * | 2022-11-28 | 2023-06-06 | 云南电网有限责任公司昆明供电局 | Current quick-break protection method without matching with motor starting current |
| CN116231589B (en) * | 2022-11-28 | 2023-09-29 | 云南电网有限责任公司昆明供电局 | Current quick-break protection method without matching with motor starting current |
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