CN115498945A - Salient pole synchronous motor fault monitoring method and device based on double reaction theory - Google Patents
Salient pole synchronous motor fault monitoring method and device based on double reaction theory Download PDFInfo
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- CN115498945A CN115498945A CN202211192379.1A CN202211192379A CN115498945A CN 115498945 A CN115498945 A CN 115498945A CN 202211192379 A CN202211192379 A CN 202211192379A CN 115498945 A CN115498945 A CN 115498945A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/032—Preventing damage to the motor, e.g. setting individual current limits for different drive conditions
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/34—Testing dynamo-electric machines
- G01R31/346—Testing of armature or field windings
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/52—Testing for short-circuits, leakage current or ground faults
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
- H02P21/22—Current control, e.g. using a current control loop
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P25/00—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
- H02P25/02—Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the kind of motor
- H02P25/022—Synchronous motors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
- H02P29/02—Providing protection against overload without automatic interruption of supply
- H02P29/024—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
- H02P29/027—Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load the fault being an over-current
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2207/00—Indexing scheme relating to controlling arrangements characterised by the type of motor
- H02P2207/05—Synchronous machines, e.g. with permanent magnets or DC excitation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Tests Of Circuit Breakers, Generators, And Electric Motors (AREA)
Abstract
A method and a device for monitoring faults of a salient pole synchronous motor based on a double reaction theory are used for acquiring fault monitoring data of the salient pole synchronous motor, and comprise the following steps: the positive sequence component of the terminal phase voltage, the positive sequence component of the terminal phase current, the actual excitation direct current, the quadrature axis synchronous reactance and the direct axis synchronous reactance; calculating the excitation electromotive force corresponding to the actual excitation direct current based on the no-load characteristic function; calculating the actual induced excitation electromotive force in the stator winding by utilizing fault monitoring data based on the electromagnetic relation and the double reaction theory of the salient pole synchronous motor; calculating the difference ratio between the excitation electromotive force and the actual induced excitation electromotive force in the stator winding; if the difference ratio is less than or equal to the short-circuit degree fixed value, judging that the salient pole synchronous motor normally operates; and if the rotor turn-to-turn short circuit fault is larger than the short circuit degree fixed value, judging that the salient pole synchronous motor has the rotor turn-to-turn short circuit fault. The invention realizes the online real-time monitoring of the turn-to-turn short circuit fault of the rotor winding of the salient pole synchronous motor such as a hydraulic generator or a generating motor.
Description
Technical Field
The invention belongs to the technical field of relay protection and online monitoring of power systems, and relates to a method and a device for monitoring faults of a salient pole synchronous motor based on a double reaction theory.
Background
The turn-to-turn short circuit of the rotor winding is a common electrical fault of the synchronous motor, can cause a series of adverse effects such as increase of exciting current, reduction of output reactive power, aggravation of unit vibration and the like, if the adverse effects are not processed in time, the adverse effects can be deteriorated into more serious rotor grounding fault and large shaft magnetization fault, and the shaft neck and the bearing bush can be burned in serious conditions, so that a huge threat is brought to safe and stable operation of the unit and a power system.
In the prior art, although some conventional methods for monitoring turn-to-turn short circuit faults of a rotor, which are commonly used on site, are applied for many years, the conventional methods are only suitable for offline fault monitoring and positioning and cannot be used for actual operation conditions. Besides the stable rotor turn-to-turn short circuit caused by poor processing technology, insulation defects and the like, faults caused by mutual extrusion and displacement deformation among the windings due to the centrifugal force borne by the excitation winding in the high-speed rotation of the rotor, thermal deformation of the excitation winding, local overheating caused by poor ventilation and the like are usually displayed only when the rotor runs under actual working conditions. Therefore, it is necessary to realize online monitoring of turn-to-turn short circuit fault of the rotor winding.
In recent years, experts and scholars at home and abroad carry out a great deal of research on-line monitoring of turn-to-turn short circuit faults of synchronous motors and provide a plurality of methods. The methods either need to modify field devices and loops, or lack pertinence in monitoring fault characteristics, or need a large amount of sample data, and have limitations in practical application to engineering sites. A fault monitoring principle based on unbalanced current of a stator phase winding is suitable for a hydroelectric generating set (a salient pole synchronous motor) provided with a neutral point branch current transformer, and related achievements are well applied to some hydroelectric power plants. However, in some fields, a neutral point transformer (CT) configuration is selected for the main protection sensitivity, for example, a neutral point CT of a certain field unit takes a set of currents from a first branch and a second branch, and a set of currents from a third branch and a fourth branch, and in this neutral point CT configuration, the harmonic components of faults generated by the first branch and the second branch are equal in magnitude and opposite in direction, and the harmonic components of faults generated by the third branch and the fourth branch are equal in magnitude and opposite in direction when a rotor inter-turn fault occurs, so that the fault monitoring principle based on the unbalanced stator Current is not applicable. In addition, the fault monitoring principle based on rotor excitation magnetomotive force is applied to a turbonator (a non-salient pole synchronous motor) without the installation condition of a branch current transformer, and the fault monitoring principle also has a better effect. However, the electromagnetic analysis method based on the non-salient pole synchronous motor with uniform air gaps cannot be applied to the salient pole synchronous motor with non-uniform air gaps.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a salient pole synchronous motor fault monitoring method and device based on a double reaction theory, which considers the implementation and engineering implementation usability based on the excitation current fault characteristics and the double reaction theory for analyzing the electromagnetic relation of the salient pole synchronous motor, can be used for hydropower stations and pumped storage power stations, and realizes the online real-time monitoring of the inter-turn short circuit fault of the rotor winding of the salient pole synchronous motor such as a hydraulic generator or a generating motor.
The invention adopts the following technical scheme.
The invention provides a salient pole synchronous motor fault monitoring method based on a double reaction theory, which comprises the following steps:
Step 2, calculating actual excitation direct current I based on no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Based on the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q And a direct axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Step 3, calculating excitation electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor has a rotor turn-to-turn short-circuit fault, and giving an alarm after delaying; before the monitoring function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
Preferably, step 1 comprises:
step 1.1, collecting stator side parameters, excitation parameters and motor parameters of the salient pole synchronous motor; wherein, stator side parameter includes: the three-phase voltage at the machine end and the three-phase current at the machine end; the excitation parameters include: exciting to change three-phase current at the low-voltage side; the motor parameters include: quadrature axis synchronous reactance, direct axis synchronous reactance;
step 1.2, calculating according to the collected generator-end three-phase voltage to obtain a generator-end phase voltage positive sequence component
Calculating according to the collected three-phase current to obtain the positive sequence component of the current of the generator end phase
Calculating to obtain actual excitation direct current I according to the collected excitation variable low-voltage side three-phase current f1 。
Preferably, in step 1.2, the actual exciting direct current I is calculated by using the three-phase current at the low-voltage side of the excitation transformer according to the following relation f1 ：
I f1 ＝(|IE A |+|IE B |+|IE C |)/2
In the formula, IE A 、IE B 、IE C The measured excitation low-voltage side three-phase alternating currents are measured.
And eliminating errors caused by the peak of the sampling point at the commutation moment through filtering processing.
Preferably, step 2 comprises:
step 2.1, inputting no-load characteristic fitting enabling when performing a no-load characteristic test on an engineering site;
step 2.2, fitting the no-load electromotive force E by using a fixed value conversion module on the premise of enabling the no-load characteristic fitting 0 According to the actual exciting DC current I f1 Of varying characteristics, i.e. I f1 The amplitude is reduced from the maximum value to zero, and the corresponding positive sequence component of the terminal phase voltage is recorded every 5 percent reduction
An amplitude value;
step 2.3, fitting an empty load characteristic function E by using the data recorded in the step 2.2 0 ＝f(I f1 )；
And 2.4, ending the no-load characteristic test, and exiting the no-load characteristic fitting enable.
And (4) displaying a curve corresponding to the no-load characteristic function through a recording middle node, and verifying the accuracy by using the no-load characteristic test data recorded on site.
Preferably, the actual induced field electromotive force in the stator winding of the salient pole synchronous motor in step 2
Satisfies the following relation:
in the formula (I), the compound is shown in the specification,
X d is a direct-axis synchronous reactance, comprising: the unsaturated value of the direct-axis synchronous reactance and the sectional saturated value of the direct-axis synchronous reactance,
X q is a quadrature-axis synchronous reactance, and is,
Current of straight-axis armature
Quadrature axis armature current
Positive sequence component of current of terminal phase
Satisfies the following relation:
I d ＝Isinψ
I q ＝Icosψ
in the formula (I), the compound is shown in the specification,
i is the positive sequence component of terminal phase current
The effective value of (a) of (b),
I d 、I q respectively, direct axis armature current
Effective value of (a), quadrature axis armature current
The effective value of (a) of (b),
psi is an internal power factor angle, and the positive sequence component of the terminal phase voltage is obtained according to the geometric relation
Positive sequence component of current of terminal phase
Calculated, the following relational expression is satisfied:
in the formula (I), the compound is shown in the specification,
as external power factor angle, as positive sequence component of terminal phase voltage
Positive sequence component of current of terminal phase
The measured phase difference therebetween.
Excitation electromotive force for calculating actual induction in stator winding of salient pole synchronous motor
Among the parameters (A) and (B), because the cross-axis corresponding air gap is very large, the magnetic circuit is not saturated, and the cross-axis synchronous reactance X is q Directly adopting field-provided parameters as fixed value input; direct axis synchronous reactance X d Considering the saturation effect of a magnetic circuit, the direct-axis synchronous reactance X is automatically switched and adopted according to the position of the grid-connected circuit breaker, the load current and the terminal voltage d Unsaturated or segment saturated values.
The invention also provides a salient pole synchronous motor fault monitoring device based on the double reaction theory, the monitoring device is configured in the hardware of the motor protection device, and the monitoring device comprises: the monitoring data acquisition module and the fault monitoring module are connected with the monitoring data acquisition module;
the monitoring data acquisition module is used for obtaining the fault monitoring data of the salient pole synchronous motor, and comprises: terminal phase voltage positive sequence component
Positive sequence component of terminal phase current
Actual exciting DC current I f1 Quadrature axis synchronous reactance X q Straight-axis synchronous reactance X d ；
A fault monitoring module comprising: an excitation electromotive force calculating unit and a short-circuit fault monitoring unit;
an excitation electromotive force calculation unit for calculating an actual excitation direct current I based on the no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Based on the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q And a direct axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Short-circuit fault monitoring unit for calculating exciting electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short circuit degree fixed value sigma, the salient pole synchronous motor is judged to be generatedThe rotor turn-to-turn short circuit fault is delayed and then is alarmed; before the monitoring function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
Compared with the prior art, the salient pole synchronous motor fault monitoring method and device based on the double reaction theory can be used for hydropower stations and pumped storage power stations, and can realize on-line monitoring of rotor turn-to-turn short circuit faults of salient pole synchronous motors such as hydraulic generators or generating motors. The method adopts the three-phase alternating current on the low-voltage side of the excitation transformer originally used for excitation protection, which is collected by the device, to calculate and obtain the actual direct-current component I of the excitation current f1 The excitation direct current is directly measured and led into the device without modifying the primary and secondary circuits and the device alternating current plug-in unit, so that the modification work of an engineering field is reduced, and the engineering practice is easy; and filtering processing is added in the algorithm for calculating the direct current component by the alternating current component, so that errors caused by sampling point peaks at the commutation moment are eliminated, and the calculation result is more accurate. According to the method, the device software is used for automatically recording each measurement quantity in the no-load test, real-time calculation is carried out, the no-load characteristic function which can be directly used for subsequent calculation is accurately fitted, the fitted no-load characteristic curve can be displayed through the recording middle node, the test data recorded on site is used for checking accuracy, and the accuracy of fault judgment is guaranteed. If the measured no-load characteristic test data is input into the device in a fixed value mode by adopting a traditional method, because the no-load characteristic curve changes along with the saturation degree of a magnetic circuit and comprises a linear section and a nonlinear section, at least dozens of groups of fixed values are required to be added to ensure the accuracy of fitting the no-load characteristic curve, and the field test data generally records a primary value and needs to be converted to be used for a secondary protection device, so that the fixed value setting calculation and the workload of field engineering personnel are increased. Calculating actual induced excitation electromotive force E 'in stator winding' 0 In the process, the double reaction theory is adopted for analysis and calculation according to the structural characteristics of the rotor of the salient pole synchronous motor, so that the method is more targeted; calculating parameters and selecting positive sequence components to avoid the influence of other faults on protection and misjudgment; the saturation degree of the magnetic circuit under different working conditions is consideredThe protection precision is higher due to the influence on the value of the synchronous reactance.
Drawings
FIG. 1 is a flow chart of a fault monitoring method of a salient pole synchronous motor based on a double reaction theory in the invention;
fig. 2 is a waveform diagram of a fault characteristic when a rotor turn-to-turn short circuit fault occurs in the embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. The embodiments described herein are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art without inventive step, are within the scope of protection of the present invention.
On one hand, the invention provides a salient pole synchronous motor fault monitoring method based on a double reaction theory, as shown in figure 1, comprising the following steps:
Specifically, step 1 comprises:
step 1.1, collecting stator side parameters, excitation parameters and motor parameters of a salient pole synchronous motor; wherein, stator side parameter includes: the three-phase voltage at the machine end and the three-phase current at the machine end; the excitation parameters include: exciting to change three-phase current at the low-voltage side; the motor parameters include: quadrature axis synchronous reactance, direct axis synchronous reactance.
Step 1.2, calculating according to the collected generator-end three-phase voltage to obtain a generator-end phase voltage positive sequenceComponent(s) of
Calculating according to the collected three-phase current to obtain the positive sequence component of the current of the generator end phase
Calculating to obtain actual excitation direct current I according to the collected excitation variable low-voltage side three-phase current f1 。
The method adopts the three-phase alternating current on the low-voltage side of the excitation transformer originally used for excitation protection, which is collected by the device, to calculate and obtain the actual direct-current component I of the excitation current f1 And the excitation direct current is directly measured and led into the device without modifying the primary and secondary circuits and the device alternating current plug-in unit, so that the modification work of an engineering field is reduced, and the engineering practice is easy.
Specifically, in step 1.2, the actual excitation direct current I is calculated by using the excitation-to-low-voltage-side three-phase current according to the following relational expression f1 ：
I f1 ＝(|IE A |+|IE B |+|IE C |)/2
In the formula, IE A 、IE B 、IE C The measured excitation low-voltage side three-phase alternating currents respectively;
and the error caused by the peak of the sampling point at the commutation moment is eliminated through filtering processing. The filtering processing is added in the algorithm for calculating the direct current component from the alternating current component, so that the error caused by the peak of the sampling point at the commutation moment is eliminated, and the calculation result is more accurate.
Step 2, calculating actual excitation direct current I based on no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Based on the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal current
Quadrature axis synchronous reactance X q Direct-axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Specifically, step 2 comprises:
step 2.1, inputting no-load characteristic fitting enabling when performing a no-load characteristic test on an engineering site;
step 2.2, fitting the no-load electromotive force E by using a fixed value conversion module on the premise of enabling the no-load characteristic fitting 0 According to the actual exciting DC current I f1 Of varying characteristics, i.e. I f1 The amplitude is reduced from the maximum value to zero, and the corresponding positive sequence component of the terminal phase voltage is recorded every 5 percent reduction
An amplitude value;
step 2.3, fitting an empty load characteristic function E by using the data recorded in the step 2.2 0 ＝f(I f1 )；
And 2.4, ending the no-load characteristic test, and exiting the no-load characteristic fitting enable.
In this embodiment, a curve corresponding to the no-load characteristic function is displayed through the recording intermediate node, and accuracy is verified by using the no-load characteristic test data recorded on site. According to the method, the device software is used for automatically recording each measurement quantity during the no-load test, real-time calculation is carried out, the no-load characteristic function which can be directly used for subsequent calculation is accurately fitted, the fitted no-load characteristic curve can be displayed through the recording middle node, the test data recorded on site is used for checking the accuracy, and the accuracy of fault judgment is guaranteed. If the measured no-load characteristic test data is input into the device in a fixed value mode by adopting a traditional method, because the no-load characteristic curve changes along with the saturation degree of a magnetic circuit and comprises a linear section and a nonlinear section, at least dozens of groups of fixed values are required to be added to ensure the accuracy of fitting the no-load characteristic curve, and the field test data generally records a primary value and needs to be converted to be used for a secondary protection device, so that the fixed value setting calculation and the workload of field engineering personnel are increased.
Specifically, in step 2, the excitation electromotive force E 'actually induced in the stator winding of the salient pole synchronous motor is calculated' 0 According to the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q Direct-axis synchronous reactance X d Calculating excitation induction electromotive force E' 0 The following relational expression is satisfied:
in the formula (I), the compound is shown in the specification,
X d is a direct-axis synchronous reactance, comprising: the unsaturated value of the direct-axis synchronous reactance and the sectional saturated value of the direct-axis synchronous reactance,
X q is a quadrature-axis synchronous reactance, and is,
current of straight-axis armature
Quadrature axis armature current
Positive sequence component of current of terminal phase
Satisfies the following relation:
I d ＝Isinψ
I q ＝Icosψ
in the formula (I), the compound is shown in the specification,
i is the positive sequence component of terminal phase current
The effective value of (a) of (b),
I d 、I q respectively, current of straight-axis armature
Effective value of (a), quadrature axis armature current
The effective value of (a) of (b),
psi is an internal power factor angle, and the positive sequence component of the terminal phase voltage is obtained according to the geometric relation
Positive sequence component of current of terminal phase
Calculated, the following relational expression is satisfied:
in the formula (I), the compound is shown in the specification,
as external power factor angle, as terminalPhase voltage positive sequence component
Positive sequence component of current of terminal phase
The measured phase difference therebetween.
The embodiment calculates the actual induced excitation electromotive force in the stator winding
In time, the double reaction theory is adopted for analysis and calculation according to the structural characteristics of the rotor of the salient pole synchronous motor, so that the method is more targeted; calculating parameters and selecting positive sequence components to avoid the influence of other faults on protection and misjudgment; the influence of the saturation degree of the magnetic circuit on the value of the synchronous reactance under different working conditions is considered, and the protection precision is higher.
In this embodiment, in the parameter for calculating the actual induced field electromotive force in the stator winding, since the quadrature axis corresponds to a large air gap, the magnetic circuit is not saturated, and the quadrature axis synchronous reactance X is q Directly adopting field-provided parameters as fixed value input; direct axis synchronous reactance X d Considering the magnetic circuit saturation effect, the direct-axis synchronous reactance X is automatically switched according to the position of the grid-connected circuit breaker, the load current and the terminal voltage d Unsaturated or segment saturated values.
Step 3, calculating excitation electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short-circuit degree fixed value sigma, the rotor turn-to-turn short circuit fault of the salient pole synchronous motor is judged to occur,and alarming after time delay. In the present embodiment, as shown in fig. 2, the solid line represents E 0 The dotted line represents
The salient pole synchronous motor normally operates at 0-5 s, E 0 And
the sizes are basically the same, the waveforms are overlapped, the 5 th s begins to generate the rotor turn-to-turn short circuit fault, the short circuit degree is more and more serious along with the time, E 0 Gradually increase, E 0 And
the deviation of (c) increases with the degree of short circuit. Before the monitoring function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
The invention also provides a salient pole synchronous motor fault monitoring device based on the double reaction theory, wherein the monitoring device is configured in the hardware of the motor protection device and comprises the following components: the monitoring data acquisition module and the fault monitoring module are connected with the monitoring data acquisition module;
the monitoring data acquisition module is used for obtaining the fault monitoring data of the salient pole synchronous motor, and comprises: terminal phase voltage positive sequence component
Positive sequence component of terminal current
Actual exciting DC current I f1 Quadrature axis synchronous reactance X q Direct axis synchronous reactance X d ；
A fault monitoring module comprising: an excitation electromotive force calculating unit and a short-circuit fault monitoring unit;
an excitation electromotive force calculation unit for calculating an actual excitation direct current I based on the no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Electromagnetic relation and double-reverse based on salient pole synchronous motorIt should be theorized that the terminal phase voltage positive sequence component is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q And a direct axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Short-circuit fault monitoring unit for calculating exciting electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor has a rotor turn-to-turn short-circuit fault, and giving an alarm after delaying; before the monitoring function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
The present disclosure may be systems, methods, and/or computer program products. The computer program product may include a computer-readable storage medium having computer-readable program instructions embodied thereon for causing a processor to implement various aspects of the present disclosure.
The computer readable storage medium may be a tangible device that can hold and store the instructions for use by the instruction execution device. The computer readable storage medium may be, for example, but not limited to, an electronic memory device, a magnetic memory device, an optical memory device, an electromagnetic memory device, a semiconductor memory device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a Static Random Access Memory (SRAM), a portable compact disc read-only memory (CD-ROM), a Digital Versatile Disc (DVD), a memory stick, a floppy disk, a mechanical coding device, such as punch cards or in-groove projection structures having instructions stored thereon, and any suitable combination of the foregoing. Computer-readable storage media as used herein is not to be construed as transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission medium (e.g., optical pulses through a fiber optic cable), or electrical signals transmitted through electrical wires.
The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a respective computing/processing device, or to an external computer or external storage device over a network, such as the internet, a local area network, a wide area network, and/or a wireless network. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. The network adapter card or network interface in each computing/processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in a computer-readable storage medium in the respective computing/processing device.
Computer program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction Set Architecture (ISA) instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider). In some embodiments, the electronic circuitry that can execute the computer-readable program instructions implements aspects of the present disclosure by utilizing the state information of the computer-readable program instructions to personalize the electronic circuitry, such as a programmable logic circuit, a Field Programmable Gate Array (FPGA), or a Programmable Logic Array (PLA).
Various aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer-readable program instructions.
These computer-readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer-readable program instructions may also be stored in a computer-readable storage medium that can direct a computer, programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer-readable medium storing the instructions comprises an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer, other programmable apparatus or other devices implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (10)
1. A salient pole synchronous motor fault monitoring method based on double reaction theory is characterized in that,
the method comprises the following steps:
step 1, acquiring fault monitoring data of a salient pole synchronous motor, comprising the following steps of: terminal phase voltage positive sequence component
Positive sequence component of terminal phase current
Actual exciting DC current I f1 Quadrature axis synchronous reactance X q Direct axis synchronous reactance X d ；
Step 2, calculating actual excitation direct current I based on no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Based on the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q And a direct axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Step 3, calculating excitation electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor has a rotor turn-to-turn short-circuit fault, and giving an alarm after delaying; wherein at the supervisionBefore the testing function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
2. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 1,
the step 1 comprises the following steps:
step 1.1, collecting stator side parameters, excitation parameters and motor parameters of the salient pole synchronous motor; wherein, stator side parameter includes: the three-phase voltage at the machine end and the three-phase current at the machine end; the excitation parameters include: exciting to change three-phase current at the low-voltage side; the motor parameters include: quadrature axis synchronous reactance, direct axis synchronous reactance;
step 1.2, calculating according to the collected generator-end three-phase voltage to obtain a generator-end phase voltage positive sequence component
Calculating according to the collected three-phase current to obtain the positive sequence component of the current of the generator end phase
Calculating to obtain actual excitation direct current I according to the collected excitation variable low-voltage side three-phase current f1 。
3. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 2,
in step 1.2, the actual excitation direct current I is calculated by utilizing the three-phase current of the excitation variable low-voltage side according to the following relational expression f1 ：
I f1 ＝(|IE A |+|IE B |+|IE C |)/2
In the formula, IE A 、IE B 、IE C The measured excitation low-voltage side three-phase alternating currents are measured.
4. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 3,
and eliminating errors caused by the peak of the sampling point at the commutation moment through filtering processing.
5. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 1,
the step 2 comprises the following steps:
step 2.1, inputting no-load characteristic fitting enabling when performing a no-load characteristic test on an engineering site;
step 2.2, fitting the no-load electromotive force E by using a fixed value conversion module on the premise of enabling the no-load characteristic fitting 0 According to the actual exciting DC current I f1 Of varying characteristics, i.e. I f1 The amplitude is reduced from the maximum value to zero, and the corresponding positive sequence component of the terminal phase voltage is recorded every 5 percent reduction
An amplitude value;
step 2.3, fitting an empty load characteristic function E by using the data recorded in the step 2.2 0 ＝f(I f1 )；
And 2.4, ending the no-load characteristic test, and exiting the no-load characteristic fitting enable.
6. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 5,
and (4) displaying a curve corresponding to the no-load characteristic function through a recording middle node, and verifying the accuracy by using the no-load characteristic test data recorded on site.
7. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 1,
step 2, exciting electromotive force actually induced in stator winding of salient pole synchronous motor
Satisfies the following relation:
in the formula (I), the compound is shown in the specification,
X d is a direct-axis synchronous reactance, comprising: the unsaturated value of the direct-axis synchronous reactance and the sectional saturated value of the direct-axis synchronous reactance,
X q is a quadrature-axis synchronous reactance, and is,
8. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 7,
direct axis armature current
Quadrature axis armature current
Positive sequence component of current of terminal phase
Satisfies the following relation:
I d ＝Isinψ
I q ＝Icosψ
in the formula (I), the compound is shown in the specification,
i is the positive sequence component of terminal phase current
The effective value of (a) of (b),
I d 、I q respectively, direct axis armature current
Effective value of (a), quadrature axis armature current
The effective value of (a) of (b),
psi is an internal power factor angle, and the positive sequence component of the terminal phase voltage is obtained according to the geometric relation
Positive sequence component of current of terminal phase
Calculated, the following relational expression is satisfied:
in the formula (I), the compound is shown in the specification,
as external power factor angle, as positive sequence component of terminal phase voltage
Positive sequence component of current of terminal phase
The measured phase difference therebetween.
9. The double reaction theory-based salient pole synchronous motor fault monitoring method according to claim 7,
excitation electromotive force for calculating actual induction in stator winding of salient pole synchronous motor
Among the parameters (A) and (B), because the cross-axis corresponding air gap is very large, the magnetic circuit is not saturated, and the cross-axis synchronous reactance X is q Directly adopting field-provided parameters as fixed value input; direct axis synchronous reactance X d Considering the magnetic circuit saturation effect, the direct-axis synchronous reactance X is automatically switched according to the position of the grid-connected circuit breaker, the load current and the terminal voltage d Unsaturated or segment saturated values.
10. A double reaction theory based salient pole synchronous motor fault monitoring device using the method of any one of claims 1 to 9, the monitoring device is configured in motor protection device hardware,
the monitoring device includes: the monitoring data acquisition module and the fault monitoring module are connected with the monitoring data acquisition module;
the monitoring data acquisition module is used for obtaining the fault monitoring data of the salient pole synchronous motor, and comprises: terminal phase voltage positive sequence component
Positive sequence component of terminal current
Actual exciting DC current I f1 Quadrature axis synchronous reactance X q Straight-axis synchronous reactance X d ；
A fault monitoring module comprising: an excitation electromotive force calculating unit and a short-circuit fault monitoring unit;
excitationAn electromotive force calculating unit for calculating an actual exciting direct current I based on the no-load characteristic function f1 Corresponding field electromotive force E 0 (ii) a Based on the electromagnetic relation and double reaction theory of the salient pole synchronous motor, the positive sequence component of the terminal phase voltage is utilized
Positive sequence component of terminal phase current
Quadrature axis synchronous reactance X q And a direct axis synchronous reactance X d Calculating the actual induced field electromotive force in the stator winding
Short-circuit fault monitoring unit for calculating exciting electromotive force E 0 Exciting electromotive force actually induced in stator winding
The difference ratio between
If the difference ratio is less than or equal to the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor normally operates; if it is
If the value is larger than the short-circuit degree fixed value sigma, judging that the salient pole synchronous motor has a rotor turn-to-turn short-circuit fault, and giving an alarm after delaying; before the monitoring function is enabled, the short circuit degree fixed value sigma is adjusted according to the normal running state of the actual motor and the requirement of a user on monitoring sensitivity.
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