A method for modeling ground fault of pumped storage power generation motor stator winding
By establishing a modeling method for grounding faults in the stator windings of pumped storage generator motors, the accuracy problem of simulation models for grounding faults in synchronous motor windings was solved, enabling clear simulation and diagnosis of different types of grounding faults.
Patent Information
- Application Number
- CN202610806938.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-05
- Publication Date
- 2026-08-25
AI Technical Summary
Existing simulation models for synchronous motor winding grounding faults are difficult to accurately reflect the stator winding grounding fault process of pumped storage generator motors, especially when weak initial characteristic signals are masked, which can easily lead to unit damage.
A modeling method for stator winding grounding faults in pumped storage generator motors is established. By defining the relationship between current and flux linkage, the phase windings are divided into multiple branches, each branch consisting of multiple coils connected in series. Combining the state equations of electromagnetic field and temperature field, single-phase, two-phase grounding short circuits and two-phase interphase short circuits are simulated, and simulation operation models for specific fault types are established.
It can more clearly reflect the changes in voltage, current and temperature after a stator winding grounding fault, and provides a fast and accurate mathematical model for motor design and fault diagnosis.
Smart Images
Figure CN122632136A_ABST
Abstract
Description
Technical Field
[0001] This invention specifically relates to a modeling method for grounding faults in the stator winding of a pumped storage generator motor, belonging to the field of modeling or simulation technology for motor control purposes (H02P6 / 34). Background Technology
[0002] Pumped-storage generators (PSGs) are structurally salient-pole electrically excited synchronous motors. Due to their large size, complex operating conditions, and frequent switching between pumping and power generation, they are prone to stator winding grounding faults. These faults initially manifest as weak characteristic signals such as slight unbalanced current or voltage distortion, but these are often masked by mechanical vibration, electromagnetic interference, and noise, making them difficult to accurately identify using traditional detection methods. If not addressed promptly, these faults can easily escalate into multi-phase grounding or inter-turn short circuits, causing serious damage to the unit and threatening the safe operation of the power station. Therefore, it is crucial to study the mechanism of stator winding grounding faults in PSGs and to propose a suitable mathematical model for stator grounding faults in PSGs.
[0003] Common simulation models for synchronous motor winding grounding faults include transient simulation models based on Transient Network Analyzer (TNA), quasi-distributed capacitance parameter models, and phase coordinate methods. TNA transient simulation models often use lumped parameters; however, the motor windings are a single unit, so only grounding faults at the generator terminals can be considered. Furthermore, in this model, the stator winding capacitance to ground is often equivalent to a lumped parameter capacitance, rather than a distributed parameter. Compared to TNA transient simulation models, quasi-distributed capacitance parameter models, while accurately reflecting the relationships and dynamic processes of various physical quantities in the actual generator stator, require separate discussion of the fundamental and third harmonic models. To obtain the actual synthesized effect, the fundamental and third harmonic zero-sequence voltages must be superimposed. This separation-then-synthesis simulation often differs significantly from actual operating conditions. Summary of the Invention
[0004] The technical problem to be solved by this invention is: how to establish a mathematical model that can accurately and effectively reflect the stator winding grounding fault process of a pumped storage generator motor.
[0005] To solve the above-mentioned technical problems, the technical solution proposed by this invention is: a modeling method for grounding faults in the stator winding of a pumped-storage generator motor, comprising the following steps:
[0006] Step 1: It is stipulated that the stator circuit of the pumped storage power generator produces a negative flux linkage with a positive current, and the rotor circuit produces a positive flux linkage with a positive current; it is stipulated that each phase winding of the three-phase winding of the pumped storage power generator has m branches, and each branch is composed of n coils connected in series.
[0007] Step 2: Establish a normal operation model for the pumped-storage generator under normal conditions. The normal operation model includes the electromagnetic field state equation and the temperature field state equation of the pumped-storage generator under normal conditions, as detailed below:
[0008] Step 2.1: Establish the electromagnetic field state equation of the pumped storage power generator under normal conditions as shown in the following equation.
[0009]
[0010] In the formula, It is the inductance matrix between the stator and rotor of the pumped storage power generator; It is the terminal-neutral point inductance matrix of the pumped storage power generator; It is the stator winding-to-ground capacitance of the pumped storage power generator; It is the terminal-neutral point capacitor matrix of the pumped storage power generator; It is the stator winding current and excitation current matrix of the pumped storage power generator; This is the terminal-neutral point current matrix of the pumped storage generator motor. It is the stator winding node voltage matrix of the pumped storage power generator; It is the terminal-neutral point voltage matrix of the pumped storage power generator; It is a differential operator; It is the stator-rotor winding resistance matrix of the pumped storage power generator; It is the resistance matrix at the generator terminals and neutral point of the pumped storage power generator; It is the resistance temperature correction coefficient of the stator winding of the pumped storage power generator; , , , These are the branch association matrices for the first, second, third, and fourth nodes, respectively. It is the conductance matrix of the pumped storage power generator under normal conditions; It is the external power supply matrix of the pumped storage generator motor;
[0011] Step 2.2: The temperature field equation under normal conditions of the pumped storage power generator is established as shown in the following equation.
[0012]
[0013] In the formula, This is the temperature matrix of the stator windings of the pumped-storage generator motor. It is the node-branch correlation matrix; It is the density of the stator winding material. It is specific heat capacity; This refers to the operating time after the pumped storage generator motor fails. It is the thermal conductivity stiffness matrix;
[0014] Step 3: Classify the grounding faults of the stator winding of the pumped storage generator into single-phase grounding faults, two-phase grounding short-circuit faults, and two-phase short-circuit faults.
[0015] Obtain the simulated single-phase ground fault conductance matrix of the stator winding of the pumped storage generator motor when a single-phase ground fault occurs. As shown in the following formula,
[0016]
[0017] In the formula, It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase A of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase A of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A grounding fault caused by a single-phase grounding fault in phase A of the specified sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase B of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase B of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the B-phase ground fault transition resistance generated when a single-phase B-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase C of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in the C-phase of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault caused by a single-phase ground fault in phase C of the specified sub-winding;
[0018] The simulated single-phase ground fault conductance matrix Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped storage generator under a single-phase ground fault is obtained, as shown in the following formula.
[0019] ;
[0020] Obtain the simulated two-phase ground fault conductance matrix of the stator winding of the pumped storage generator motor when a two-phase ground fault occurs. As shown in the following formula,
[0021]
[0022] In the formula, It is the number of branches before the faulty branch on phase A when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the ground fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault generated on phase A ground fault when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase B when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the B-phase ground short circuit fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of the B-phase ground fault generated on the B-phase ground fault phase when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase C when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the C-phase ground short-circuit fault phase and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the C-phase ground fault transition resistance generated on the C-phase ground fault phase when a two-phase ground fault occurs in the sub-winding;
[0023] The simulated two-phase-to-ground short-circuit fault conductance matrix Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped-storage generator under a two-phase-to-ground short-circuit fault is obtained, as shown in the following formula.
[0024] ;
[0025] Obtain the simulated two-phase short-circuit fault conductance matrix of the stator winding of the pumped-storage generator when a two-phase short-circuit fault occurs. As shown in the following formula,
[0026]
[0027] In the formula, It is the number of branches before the fault branch on phase A when a two-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase A and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the phase-to-phase short-circuit fault transition resistance generated when a two-phase phase-to-phase short-circuit fault occurs in the sub-winding; It is the number of branches before the fault branch on phase B when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase B and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is the number of branches before the fault branch on the C-phase phase when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase C and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0;
[0028] The conductance matrix of the simulated two-phase interphase short-circuit fault Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped-storage generator under a two-phase short-circuit fault is obtained, as shown in the following formula.
[0029] ;
[0030] Step 4: Obtain the specific fault type and location of the pumped storage generator motor for which stator winding grounding fault modeling is to be performed. Select the simulation operation model corresponding to the fault type established in Step 3 according to the specific fault type. Substitute the specific fault location into the simulation operation model to complete the modeling of the pumped storage generator motor stator winding grounding fault.
[0031] Furthermore, the electromagnetic field state equation of the pumped-storage power generator under normal conditions... The specific content is shown in the following formula.
[0032]
[0033] In the formula, It is the self-inductance of phase A winding; It is the self-inductance of phase B winding; It is the self-inductance of the C-phase winding; It is the self-inductance of the excitation winding; and It is the mutual inductance between phase A winding and phase B winding; and It is the mutual inductance between phase A winding and phase C winding; It is the mutual inductance between phase A winding and excitation winding; It is the mutual inductance between the B-phase winding and the excitation winding; It is the mutual inductance between the C-phase winding and the excitation winding.
[0034] The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula.
[0035]
[0036] In the formula, It is the inductance of the camera-end winding of generator A; For the inductance of the camera-end winding of generator B; For the inductance of the generator C-side camera winding; It is a neutral point grounding inductor.
[0037] The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula.
[0038]
[0039] In the formula, It is the capacitor at camera A; It is the capacitor at the B camera end; It is the capacitor at the C-side of the camera; It is a neutral point capacitor.
[0040] The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula.
[0041]
[0042] In the formula, Let be the capacitance to ground of a coil in phase A winding; Here is the capacitance to ground of a coil in phase B winding; This is the capacitance to ground of a coil in the C-phase winding.
[0043] The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula.
[0044]
[0045] In the formula, It is the resistance of the A-phase extreme winding; It is the resistance of the B-phase terminal winding; It is the resistance of the C-phase extreme winding; It is the neutral point grounding resistance.
[0046] The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula.
[0047]
[0048] In the formula, It is the resistance of each rod in phase A winding; It is the resistance of each rod in phase B winding; It is the resistance of each rod in phase B winding; It is the resistance of the excitation winding.
[0049] The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula.
[0050]
[0051] In the formula, It is the voltage of the excitation winding; , It is the system line voltage.
[0052] The formula for calculating the resistance temperature correction factor h in M is shown below.
[0053]
[0054] In the formula, It is the temperature coefficient of the winding material of the pumped storage power generator.
[0055] Furthermore, the aforementioned In The calculation formula is shown in the following equation.
[0056]
[0057] In the formula, , and These are the ground capacitances at the A-phase, B-phase, and C-phase terminals of the pumped storage power generator motor, respectively. , and These are the equivalent capacitances of phases A, B, and C of the pumped storage generator motor from the generator terminals to the low-voltage windings of the step-up transformer. It is the capacitance to ground of the A-phase coil in the stator A-phase winding of the pumped storage power generator; It is the ground capacitance of the stator A-phase winding of the pumped storage generator motor; It is the capacitance to ground of the B-phase coil in the stator B-phase winding of the pumped storage generator motor; It is the ground capacitance of the stator B-phase winding of the pumped storage generator motor; It is the C-phase coil-to-ground capacitance in the C-phase winding of the stator of the pumped storage power generator; It is the ground capacitance of the stator C-phase winding of the pumped storage generator motor.
[0058] Furthermore, the calculation formula for the parameters in M is as follows:
[0059] The first in the stator winding of the pumped storage generator motor coil and The mutual inductance of coil # is:
[0060]
[0061] In the formula, , ; This is the effective length of the air gap; This refers to the effective length of the stator core. For stator coils and Number of turns; The mechanical angle of the stator slot pitch. This refers to the number of stator slots in the motor. for The slot coefficient of the polar harmonic, The stator slot pitch is an electrical angle. for The short-pitch coefficient of the coil for polar harmonics, This is the short-pitch angle of the coil;
[0062] The first in the stator winding of the pumped storage generator motor The self-inductance of coil #1:
[0063]
[0064] The self-inductance of the excitation winding in the pumped storage generator motor is:
[0065]
[0066] In the formula, These are the number of turns in the excitation winding and the number of parallel branches in the excitation winding, respectively. This is a constant term for the air gap permeability.
[0067] The first in the stator winding of the pumped storage generator motor The mutual inductance between the coil and the excitation winding is:
[0068]
[0069] In the formula, The harmonic order of the magnetomotive force is... ; The permeability of the excitation section; The rotor position angle, This refers to the motor's rotational speed. for The initial position angle of the rotor at that time.
[0070] Furthermore, the constant term of the air gap permeability coefficient and the permeability of the excitation section The calculation formula is shown in the following equation.
[0071]
[0072]
[0073] In the formula, It is the vacuum permeability; It is the distance from the air gap axis The length of the air gap at that location.
[0074] The beneficial effects of this invention are as follows: This invention provides a modeling method for stator winding grounding faults in pumped-storage generator motors, which can more clearly reflect the changes in various physical quantities such as voltage, current, and temperature after different types of grounding faults occur in the stator windings of the pumped-storage generator motor, and more accurately simulate the actual situation under different types of grounding faults. This invention provides pumped-storage power station motor designers and maintenance personnel with a convenient and quick mathematical model for calculating and analyzing generator motors, and provides a fast and accurate research method for stator winding grounding fault characteristic analysis, fault prevention, and diagnosis. Attached Figure Description
[0075] Figure 1 This is a flowchart of the method proposed in the embodiments of the present invention;
[0076] Figure 2 This is an equivalent circuit model diagram of the pumped storage power generation motor in an embodiment of the present invention;
[0077] Figure 3 This is a schematic diagram of a single-phase ground fault occurring in the stator winding of a pumped storage generator motor in an embodiment of the present invention.
[0078] Figure 4 This is a schematic diagram of a two-phase ground fault occurring in the stator winding of a pumped storage power generator in an embodiment of the present invention.
[0079] Figure 5 This is a schematic diagram of a two-phase short-circuit fault occurring in the stator winding of a pumped-storage generator motor in an embodiment of the present invention. Detailed Implementation
[0080] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the modeling method for stator winding grounding faults in a pumped-storage generator according to the present invention.
[0081] Example
[0082] The modeling method in this embodiment, such as Figure 1 As shown, it includes the following steps:
[0083] Step 1: It is stipulated that the stator circuit of the pumped storage generator motor generates a negative flux linkage with a positive current, and the rotor circuit generates a positive flux linkage with a positive current; it is stipulated that each phase winding of the three-phase winding of the pumped storage generator motor has m branches, and each branch is composed of n coils connected in series.
[0084] Step 2: Establish a normal operation model for the pumped-storage generator motor under normal conditions. The normal operation model includes the electromagnetic field state equation and the temperature field state equation under normal conditions, as detailed below:
[0085] Step 2.1: Establish the electromagnetic field state equation of the pumped storage power generator under normal conditions, as shown in the following equation.
[0086]
[0087] In the formula, It is the inductance matrix between the stator and rotor of the pumped storage generator motor; It is the terminal-neutral point inductance matrix of the pumped storage generator motor; It is the stator winding-to-ground capacitance of the pumped storage generator motor; It is the terminal-neutral point capacitor matrix of the pumped storage power generator; It is the stator winding current and excitation current matrix of the pumped storage generator motor; It is the terminal-neutral point current matrix of the pumped storage generator motor. It is the stator winding node voltage matrix of the pumped storage generator motor; It is the terminal-neutral point voltage matrix of the pumped storage power generator; It is a differential operator; It is the stator-rotor winding resistance matrix of a pumped storage power generator; It is the resistance matrix at the generator terminals and neutral point of the pumped storage power generator; It is the resistance temperature correction factor for the stator winding of the pumped storage generator motor; , , , These are the branch association matrices for the first, second, third, and fourth nodes, respectively. It is the conductance matrix of the pumped storage generator motor under normal conditions; It is an external power supply matrix for pumped storage generator motors;
[0088] Step 2.2: Establish the temperature field equation under normal conditions for the pumped storage power generator, as shown in the following equation.
[0089]
[0090] In the formula, It is the temperature matrix of the stator windings of the pumped-storage generator. It is the node-branch correlation matrix; It is the density of the stator winding material. It is specific heat capacity; This refers to the operating time after a pumped-storage generator motor fails. It is the thermal conductivity stiffness matrix;
[0091] Step 3: The grounding faults of the stator windings of the pumped storage generator motor are classified into single-phase grounding faults, two-phase grounding short-circuit faults, and two-phase short-circuit faults.
[0092] Obtain the simulated single-phase ground fault conductance matrix for a pumped-storage generator stator winding experiencing a single-phase ground fault. As shown in the following formula,
[0093]
[0094] In the formula, It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase A of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase A of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A grounding fault caused by a single-phase grounding fault in phase A of the specified sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase B of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase B of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the B-phase ground fault transition resistance generated when a single-phase B-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase C of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in the C-phase of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault caused by a single-phase ground fault in phase C of the specified sub-winding;
[0095] The conductance matrix for simulating a single-phase ground fault Replace the normal operation model of the pumped storage generator motor under normal conditions. The simulated operating model of the stator winding of the pumped storage generator under a single-phase ground fault is obtained, as shown in the following equation.
[0096] ;
[0097] Obtain the simulated two-phase ground fault conductance matrix of a pumped-storage generator stator winding experiencing a two-phase ground fault. As shown in the following formula,
[0098]
[0099] In the formula, It is the number of branches before the faulty branch on phase A when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the ground fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault generated on phase A ground fault when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase B when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the B-phase ground short circuit fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of the B-phase ground fault generated on the B-phase ground fault phase when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase C when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the C-phase ground short-circuit fault phase and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the C-phase ground fault transition resistance generated on the C-phase ground fault phase when a two-phase ground fault occurs in the sub-winding;
[0100] The conductance matrix for simulating a two-phase-to-ground short-circuit fault will be used. Replace the normal operation model of the pumped storage generator motor under normal conditions. The simulated operating model of the stator winding of the pumped-storage generator under a two-phase-to-ground short-circuit fault is obtained, as shown in the following formula.
[0101] ;
[0102] To obtain the simulated two-phase short-circuit fault conductance matrix of a pumped-storage generator stator winding experiencing a two-phase short-circuit fault. As shown in the following formula,
[0103]
[0104] In the formula, It is the number of branches before the fault branch on phase A when a two-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase A and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the phase-to-phase short-circuit fault transition resistance generated when a two-phase phase-to-phase short-circuit fault occurs in the sub-winding; It is the number of branches before the fault branch on phase B when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase B and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is the number of branches before the fault branch on the C-phase phase when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase C and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0;
[0105] The conductance matrix for simulating a two-phase inter-phase short-circuit fault will be used. Replace the normal operation model of the pumped storage generator motor under normal conditions. The simulated operating model of the stator winding of the pumped-storage generator under a two-phase short-circuit fault is obtained, as shown in the following equation.
[0106] ;
[0107] Step 4: Obtain the specific fault type and location of the pumped storage generator motor for which stator winding grounding fault modeling is to be performed. Select the corresponding simulation operation model established in Step 3 based on the specific fault type, and substitute the specific fault location into the simulation operation model to complete the modeling of the pumped storage generator motor stator winding grounding fault.
[0108] The following section models a stator winding grounding fault for a specific pumped-storage generator motor. The equivalent circuit model of the pumped-storage generator motor is shown below. Figure 2 As shown, in this embodiment, the number of branches is (2); the number of coils in each branch is (2);
[0109] This embodiment demonstrates and models three types of grounding faults respectively.
[0110] 1) such as Figure 3 As shown, a single-phase ground fault occurred in the pumped-storage generator motor, in which...
[0111] Assume a single-phase ground fault occurs in the first coil of the first branch of phase A, and the transition resistance is... .
[0112] The electromagnetic field state equation of a pumped-storage generator motor under normal conditions is:
[0113]
[0114] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0115]
[0116] In the electromagnetic field state equation, the stator and rotor inductance matrices for
[0117]
[0118] In the electromagnetic field state equation The expression is
[0119]
[0120] In the electromagnetic field state equation The expression is
[0121]
[0122] In the electromagnetic field state equation The expression is
[0123]
[0124] The electromagnetic field state equation described The expression is
[0125]
[0126] In the electromagnetic field state equation The expression is
[0127]
[0128] In The calculation formula is
[0129]
[0130] In the temperature field state equation, the winding temperature matrix is:
[0131]
[0132] The fault conductance matrix is
[0133]
[0134] The electromagnetic field state equation under fault conditions of pumped storage generator motor is:
[0135]
[0136] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0137]
[0138] 2) such as Figure 4 As shown, a two-phase ground fault occurred in the pumped storage generator motor, in which...
[0139] Assume a single-phase ground fault occurs in the first coil of the first branch of phase A, and the transition resistance of phase A is... The transition resistance of phase B is .
[0140] The electromagnetic field state equation of a pumped-storage generator motor under normal conditions is:
[0141]
[0142] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0143]
[0144] In the electromagnetic field state equation, the stator and rotor inductance matrices for
[0145]
[0146] In the electromagnetic field state equation The expression is
[0147]
[0148] In the electromagnetic field state equation The expression is
[0149]
[0150] In the electromagnetic field state equation The expression is
[0151]
[0152] The electromagnetic field state equation described The expression is
[0153]
[0154] In the electromagnetic field state equation The expression is
[0155]
[0156] In The calculation formula is
[0157]
[0158] In the temperature field state equation, the winding temperature matrix is:
[0159]
[0160] The fault conductance matrix is
[0161]
[0162] The electromagnetic field state equation under fault conditions of pumped storage generator motor is:
[0163]
[0164] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0165]
[0166] 3) such as Figure 5 As shown, a two-phase short-circuit fault occurred in the pumped-storage generator motor, in which...
[0167] Assume a phase-to-phase short circuit fault occurs between the first coil of the second branch of phase A and the first coil of the first branch of phase B, and the transition resistance is... .
[0168] The electromagnetic field state equation of a pumped-storage generator motor under normal conditions is:
[0169]
[0170] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0171]
[0172] In the electromagnetic field state equation, the stator and rotor inductance matrices for
[0173]
[0174] In the electromagnetic field state equation The expression is
[0175]
[0176] In the electromagnetic field state equation The expression is
[0177]
[0178] In the electromagnetic field state equation The expression is
[0179]
[0180] The electromagnetic field state equation described The expression is
[0181]
[0182] In the electromagnetic field state equation The expression is
[0183]
[0184] In The calculation formula is
[0185]
[0186] In the temperature field state equation, the winding temperature matrix is:
[0187]
[0188] The fault conductance matrix is
[0189]
[0190] The electromagnetic field state equation under fault conditions of pumped storage generator motor is:
[0191]
[0192] The temperature field equation for a pumped-storage generator motor under normal conditions is:
[0193]
Claims
1. A modeling method for stator winding grounding faults in a pumped-storage generator motor, characterized in that: Includes the following steps: Step 1: Specify that the stator circuit of the pumped storage generator motor generates a negative flux linkage with a positive current, and the rotor circuit generates a positive flux linkage with a positive current. The pumped storage generator motor is specified to have m branches in each phase winding of the three phase winding, and each branch is composed of n coils connected in series. Step 2: Establish a normal operation model for the pumped-storage generator under normal conditions. The normal operation model includes the electromagnetic field state equation and temperature field state equation of the pumped-storage generator under normal conditions, as detailed below: Step 2.1: Establish the electromagnetic field state equation of the pumped-storage generator motor under normal conditions, as shown in the following equation. In the formula, It is the inductance matrix between the stator and rotor of the pumped storage power generator; It is the terminal-neutral point inductance matrix of the pumped storage power generator; It is the stator winding-to-ground capacitance of the pumped storage power generator; It is the terminal-neutral point capacitor matrix of the pumped storage power generator; It is the stator winding current and excitation current matrix of the pumped storage power generator; This is the terminal-neutral point current matrix of the pumped storage generator motor. It is the stator winding node voltage matrix of the pumped storage power generator; It is the terminal-neutral point voltage matrix of the pumped storage power generator; It is a differential operator; It is the stator-rotor winding resistance matrix of the pumped storage power generator; It is the resistance matrix at the generator terminals and neutral point of the pumped storage power generator; It is the resistance temperature correction coefficient of the stator winding of the pumped storage power generator; , , , These are the branch association matrices for the first, second, third, and fourth nodes, respectively. It is the conductance matrix of the pumped storage generator motor under normal conditions; It is the external power supply matrix of the pumped storage generator motor; Step 2.2: Establish the temperature field equation for the pumped-storage generator motor under normal conditions, as shown in the following equation. In the formula, This is the temperature matrix of the stator windings of the pumped-storage generator motor. It is the node-branch correlation matrix; It is the density of the stator winding material. It is specific heat capacity; This is the operating time after the pumped storage generator motor fails; It is the thermal conductivity stiffness matrix; Step 3: Classify the grounding faults of the stator winding of the pumped storage generator into single-phase grounding faults, two-phase grounding short-circuit faults, and two-phase short-circuit faults. Obtain the simulated single-phase ground fault conductance matrix of the stator winding of the pumped storage generator motor when a single-phase ground fault occurs. As shown in the following formula, In the formula, It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase A of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase A of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A grounding fault caused by a single-phase grounding fault in phase A of the specified sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase B of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in phase B of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the B-phase ground fault transition resistance generated when a single-phase B-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch when a single-phase ground fault occurs in phase C of the stator winding. and These are the location of the fault branch and the location of the fault coil on the fault branch when a single-phase ground fault occurs in the C-phase of the stator winding. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault caused by a single-phase ground fault in phase C of the specified sub-winding; The simulated single-phase ground fault conductance matrix Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped storage generator under a single-phase ground fault is obtained, as shown in the following formula. ； Obtain the simulated two-phase ground fault conductance matrix of the stator winding of the pumped storage generator motor when a two-phase ground fault occurs. As shown in the following formula, In the formula, It is the number of branches before the faulty branch on phase A when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the ground fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of phase A ground fault generated on phase A ground fault when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase B when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the B-phase ground short circuit fault and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the transition resistance of the B-phase ground fault generated on the B-phase ground fault phase when a two-phase ground fault occurs in the sub-winding; It is the number of branches before the faulty branch on phase C when a two-phase-to-ground short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the C-phase ground short-circuit fault phase and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the C-phase ground fault transition resistance generated on the C-phase ground fault phase when a two-phase ground fault occurs in the sub-winding; The simulated two-phase-to-ground short-circuit fault conductance matrix Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped-storage generator under a two-phase-to-ground short-circuit fault is obtained, as shown in the following formula. ； Obtain the simulated two-phase short-circuit fault conductance matrix of the stator winding of the pumped-storage generator when a two-phase short-circuit fault occurs. As shown in the following formula, In the formula, It is the number of branches before the fault branch on phase A when a two-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase A and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It refers to the phase-to-phase short-circuit fault transition resistance generated when a two-phase phase-to-phase short-circuit fault occurs in the sub-winding; It is the number of branches before the fault branch on phase B when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase B and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is the number of branches before the fault branch on the C-phase phase when a two-phase phase-to-phase short-circuit fault occurs in the stator winding. and These are the location of the fault branch on the phase with the phase-to-phase short circuit fault in phase C and the location of the fault coil on the fault branch, respectively. It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; It is a 3mn-order square matrix, where except for the first... The first in the row The elements of the column are Except for the elements, all other elements are 0; The conductance matrix of the simulated two-phase interphase short-circuit fault Replace the normal operation model of the pumped storage power generator under normal conditions. The simulated operating model of the stator winding of the pumped storage generator under a two-phase short-circuit fault is obtained, as shown in the following formula. ； Step 4: Obtain the specific fault type and location of the pumped storage generator motor for which stator winding grounding fault modeling is to be performed. Select the simulation operation model corresponding to the fault type established in Step 3 according to the specific fault type. Substitute the specific fault location into the simulation operation model to complete the modeling of the pumped storage generator motor stator winding grounding fault.
2. The modeling method for stator winding grounding faults of pumped storage generator motors according to claim 1, characterized in that: The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula. In the formula, It is the self-inductance of the A-phase winding of the pumped storage generator motor; It is the self-inductance of the B-phase winding of the pumped storage generator motor; It is the self-inductance of the C-phase winding of the pumped storage generator motor; It is the self-inductance of the excitation winding of the pumped storage generator motor; and It is the mutual inductance between the A-phase winding and the B-phase winding of the pumped storage power generator; and It is the mutual inductance between the A-phase winding and the C-phase winding of the pumped storage generator motor; It is the mutual inductance between the A-phase winding and the excitation winding of the pumped storage generator motor; It is the mutual inductance between the B-phase winding and the excitation winding of the pumped storage generator motor. It is the mutual inductance between the C-phase winding and the excitation winding of the pumped storage generator motor; The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula. In the formula, It is the inductance of the camera-end winding of the pumped storage power generator; It is the inductance of the camera-end winding of the pumped storage power generator; It is the inductance of the generator C camera terminal winding of the pumped storage power generator motor; It is the neutral point grounding inductance of the pumped storage generator motor; The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula. In the formula, It is the A-camera terminal capacitor of the pumped storage power generator motor; It is the B-camera terminal capacitor of the pumped storage power generator motor; It is the C-camera terminal capacitor of the pumped storage power generator motor; It is the neutral point capacitor of the pumped storage power generation motor; The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula. In the formula, It is the capacitance to ground of a coil of phase A winding of the pumped storage power generator; It is the capacitance to ground of a coil of phase B winding of the pumped storage power generator. It is the capacitance to ground of a coil of the C-phase winding of the pumped storage power generator; The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula. In the formula, It is the resistance of the A-phase extreme winding of the pumped storage power generator; It is the resistance of the B-phase extreme winding of the pumped storage power generator motor; It is the C-phase extreme winding resistance of the pumped storage power generator motor; It is the neutral point grounding resistance of the pumped storage power generator motor; The electromagnetic field state equation of the pumped storage power generator under normal conditions is described in the following. The specific content is shown in the following formula. In the formula, It is the resistance of each bar in the A-phase winding of the pumped storage power generator; It is the resistance of each bar in the B-phase winding of the pumped storage power generator; It is the resistance of each bar in the C-phase winding of the pumped storage power generator; It is the excitation winding resistance of the pumped storage power generator motor; The electromagnetic field state equation of the pumped storage power generator under normal conditions is as follows: The specific content is shown in the following formula. In the formula, It is the excitation winding voltage of the pumped storage power generator motor; , It is the line voltage of the pumped storage power generator motor; The formula for calculating the resistance temperature correction factor h in M is shown below. In the formula, It is the temperature coefficient of the winding material of the pumped storage power generator.
3. The modeling method for stator winding grounding faults of pumped storage generator motors according to claim 2, characterized in that: The In The calculation formula is shown in the following equation. In the formula, , and These are the ground capacitances at the A-phase, B-phase, and C-phase terminals of the pumped storage power generator, respectively. , and These are the equivalent capacitances of phases A, B, and C of the pumped storage generator motor from the generator terminals to the low-voltage windings of the step-up transformer. It is the capacitance to ground of the A-phase coil in the stator A-phase winding of the pumped storage generator motor; It is the ground capacitance of the stator A-phase winding of the pumped storage generator motor; It is the B-phase coil-to-ground capacitance in the B-phase winding of the stator of the pumped storage generator motor; It is the ground capacitance of the stator B-phase winding of the pumped storage generator motor; It is the C-phase coil-to-ground capacitance in the C-phase winding of the stator of the pumped storage generator motor; It is the ground capacitance of the stator C-phase winding of the pumped storage generator motor.
4. The modeling method for stator winding grounding faults of pumped storage generator motors according to claim 2 is characterized in that: The formulas for calculating the parameters in M are as follows: The first in the stator winding of the pumped storage generator motor coil and The mutual inductance of coil # is: In the formula, , ; This is the effective length of the air gap; This refers to the effective length of the stator core. For stator coils and Number of turns; The mechanical angle of the stator slot pitch. This refers to the number of stator slots in the motor. for The slot coefficient of the polar harmonic, The stator slot pitch is an electrical angle. for The short-pitch coefficient of the coil for polar harmonics, This is the short-pitch angle of the coil; The first in the stator winding of the pumped storage generator motor The self-inductance of coil #1: The self-inductance of the excitation winding in the pumped storage generator motor is: In the formula, These are the number of turns in the excitation winding and the number of parallel branches in the excitation winding, respectively. This is a constant term for the air gap permeability. The first in the stator winding of the pumped storage generator motor The mutual inductance between the coil and the excitation winding is: In the formula, The harmonic order of the magnetomotive force. ; is the permeability of the excitation section; The rotor position angle, This refers to the motor's rotational speed. for The initial position angle of the rotor at that time.
5. The modeling method for stator winding grounding faults of pumped storage generator motors according to claim 4, characterized in that: The constant term of the air gap permeability and the permeability of the excitation section The calculation formula is shown in the following equation. In the formula, It is the vacuum permeability; It is the distance from the air gap axis The length of the air gap at that location.