A generator distributed parameter test device and test method thereof

Abstract

The present invention belongs to the technical field of generator distributed parameter testing, and specifically proposes a generator distributed parameter testing device and a testing method thereof, the device comprising a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor and a variable frequency power supply; the stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles are sequentially different by a fixed angle, and the head end and the tail end of each coil are connected to the control box; the control box stores a plurality of coil connection methods, and after the control box completes the connection of the head end and the tail end of each coil according to the required coil connection method based on the test requirements, the control box adjusts the grounding impedance, the capacitance to ground, and the number of magnetic poles to obtain the voltage of the neutral point and three outlets, the voltage parameters of the head end of each coil and the current parameters of each coil to ground, and the device of the present invention can more accurately simulate the distribution of the neutral point grounding impedance, the coil phase, the coil capacitance to ground and the changes in the winding voltage and the capacitance current to ground.

Description

Technical Field

[0001] The present invention belongs to the technical field of generator distributed parameter testing, and in particular relates to a generator distributed parameter testing device and a testing method thereof. Background Art

[0002] In the design, manufacture, renovation and transformation of large generators, the power, voltage, speed, and structural dimensions of different application conditions are different, and the winding structure parameters of the generator are also different. When designing and selecting, it is necessary to select parameters according to the actual application conditions. Some parameters are selected within a certain range according to the site conditions. Therefore, there may be certain differences between the selected parameters and the actual needs of the site. Some differences may cause deviations in the final generator performance parameters. In order to minimize the deviation between design and manufacture and the final product, simulation tests and model parameter tests are required. At present, simulation tests and model tests are mainly based on centralized parameter tests, which cannot fully verify the influence of distributed parameters in the generator winding design on the generator performance indicators; there may be model parameter deviations in simulation analysis, and physical model verification must be carried out to make up for the shortcomings of simulation analysis. In commercial generators, there is no shortage of neutral point potential drift and machine-end voltage imbalance caused by winding distributed parameters. In order to better analyze the influence of winding distributed parameters on generator performance indicators, there is an urgent need for a test device that can carry out distributed parameters to facilitate the analysis and verification of the causes of generator failures. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, the first object of the present invention is to provide a generator distributed parameter test device to more accurately simulate the distributed parameters when the neutral point grounding impedance, coil phase, and coil-to-ground capacitance change.

[0005] The second object of the present invention is to provide a generator distributed parameter test method.

[0006] To achieve the above-mentioned purpose, the first aspect of the present invention proposes a generator distributed parameter test device, including a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor and a variable frequency power supply, wherein the variable frequency power supply is connected to the dynamic model generator via the variable frequency drive motor, the excitation power supply is connected to the dynamic model generator, and the control box is respectively controlled and connected to the dynamic model generator, the neutral point grounding device, and the capacitor configuration device;

[0007] The stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles are sequentially different by a fixed angle, and the head end and the tail end of each coil are connected to the control box;

[0008] The control box stores a variety of coil connection methods. The control box is used to complete the connection of the head end and the tail end of each coil according to the required coil connection method based on test requirements to achieve the distribution of coils with different phases in the winding, control the neutral point grounding device to adjust the grounding impedance of the dynamic model generator to the set grounding impedance and connect the neutral point of the stator winding, control the capacitor configuration device to adjust the capacitance of each coil to the ground to achieve different capacitance distributions of the winding, control the rotor loop of the dynamic model generator to make the fixed angle between adjacent coils equal to the preset verification phase angle, control the neutral point and three outlets of the stator winding, and the head end of any coil to connect to the channel of the oscilloscope of the control box according to test requirements, adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding and the voltage parameters of the head end of each coil.

[0009] In the generator distributed parameter test device provided in the first aspect of the present invention, the dynamic model generator adopts a low-voltage salient pole generator. When the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 2, the fixed angle is 10 degrees; when the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 4, the fixed angle is 20 degrees.

[0010] In the generator distributed parameter test device provided in the first aspect of the present invention, the rotor circuit of the dynamic model generator includes a first rotor pole coil, a first switch, a second rotor pole coil, a third rotor pole coil, a third switch and a fourth rotor pole coil connected in series in sequence. The first switch is connected in series with the second rotor pole coil and then connected in parallel with the second switch. The third switch is connected in series with the fourth rotor pole coil and then connected in parallel with the fourth switch. The control box adjusts the number of poles by controlling the on and off of the first switch, the second switch, the third switch and the fourth switch.

[0011] In the generator distributed parameter test device provided in the first aspect of the present invention, the multiple coil connection methods include a three-phase branch coil phase symmetrical distribution wiring method, a three-phase branch coil phase asymmetrical distribution wiring method, a three-phase two-branch coil phase symmetrical distribution wiring method, and a three-phase two-branch coil phase asymmetrical distribution wiring method.

[0012] In the generator distributed parameter test device provided in the first aspect of the present invention, the neutral point grounding device includes an adjustable inductance coil, an adjustable resistor, an access exit switch, a direct grounding switch and a wiring terminal. The wiring terminal is grounded via the access exit switch, the adjustable resistor and the inductance coil. One end of the direct grounding switch is connected to the wiring terminal, and the other end of the direct grounding switch is grounded.

[0013] In the generator distributed parameter test device provided in the first aspect of the present invention, the capacitor configuration device includes a plurality of capacitor configuration units, the number of the capacitor configuration units is consistent with the number of coils of the stator winding, each capacitor configuration unit matches a single coil of the stator winding, the input end of each capacitor configuration unit is connected to the head end of the corresponding stator winding coil, the output end of each capacitor configuration unit is grounded, and three branches are connected in parallel between the input end and the output end of each capacitor configuration unit, each branch includes a capacitor configuration switch and an AC capacitor connected in series, and the control box adjusts the capacitance of each stator winding coil to ground by controlling the on and off of each capacitor configuration switch.

[0014] In the generator distributed parameter test device provided in the first aspect of the present invention, each capacitor configuration unit also includes a current transformer, and the grounding end of the capacitor configuration unit is grounded after passing through the current transformer. The control box is also used to connect the current transformer to the channel of the oscilloscope of the control box according to the test requirements to obtain the current parameters of each coil to ground.

[0015] To achieve the above-mentioned purpose, the second aspect of the present invention provides a generator distributed parameter test method based on the generator distributed parameter test device provided in the first aspect, comprising:

[0016] Based on the test requirements, the control box completes the connection between the head and tail ends of each coil in the stator winding of the dynamic model generator according to the required coil connection method to achieve the distribution of coils of different phases in the winding;

[0017] Control the neutral point grounding device to adjust the grounding impedance of the dynamic generator to the set grounding impedance and connect the neutral point of the stator winding;

[0018] The control capacitance configuration device adjusts the capacitance of each coil in the stator winding to the ground to achieve different capacitance distribution of the winding;

[0019] Controlling the rotor circuit of the dynamic mode generator so that the fixed angle between adjacent coils is equal to a preset verification phase angle;

[0020] The neutral point and three outlets of the control stator winding, the head end of any coil, and the current transformer of the capacitor configuration device are connected to the channel of the oscilloscope of the control box according to the test requirements;

[0021] Adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding, the voltage parameters of the first end of each coil, and the current parameters of each coil to ground.

[0022] In the generator distributed parameter test method provided in the second aspect of the present invention, the control capacitor configuration device adjusts the capacitance of each coil in the stator winding to the ground, including: the control box controls the on and off of each capacitor configuration switch to achieve the adjustment of the capacitance of each stator winding coil to the ground.

[0023] In the generator distributed parameter test method provided in the second aspect of the present invention, the rotor circuit of the dynamic model generator is controlled so that the fixed angle between adjacent coils is equal to the preset verification phase angle, including: the control box controls the on and off of the first switch, the second switch, the third switch and the fourth switch in the rotor circuit based on the on-off rules corresponding to the preset verification phase angle to achieve adjustment of the number of magnetic poles, so that each coil of the stator winding is sequentially differentiated by the verification phase angle.

[0024] The invention provides a generator distributed parameter test device and a test method thereof. The test device comprises a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor and a variable frequency power supply. The variable frequency power supply is connected to the dynamic model generator via the variable frequency drive motor, the excitation power supply is connected to the dynamic model generator, and the control box is respectively controlled and connected to the dynamic model generator, the neutral point grounding device and the capacitor configuration device; the stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles differ in sequence by a fixed angle, and the head end and the tail end of each coil are connected to the control box; the control box stores a plurality of coil connection modes, and the control box is used to complete the head end and the tail end of each coil according to the required coil connection mode based on the test requirements. The invention relates to a method for controlling the distribution of coils of different phases in the winding, controlling the neutral point grounding device to adjust the grounding impedance of the dynamic model generator to the set grounding impedance and connect the neutral point of the stator winding, controlling the capacitor configuration device to adjust the capacitance of each coil to the ground to realize different capacitance distribution of the winding, controlling the rotor loop of the dynamic model generator to make the fixed angle between adjacent coils equal to the preset verification phase angle, controlling the neutral point and three outlets of the stator winding, and the head end of any coil to be connected to the channel of the oscilloscope of the control box according to the test requirements, adjusting the parameters of the variable frequency drive motor, controlling the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding, and the voltage parameters of the head end of each coil. In this case, the dynamic model generator, the neutral point grounding device, the capacitor configuration device, the control box, the excitation power supply, the variable frequency drive motor and the variable frequency power supply are integrated. During the test, the connection between the head end and the tail end of each coil is completed according to the required coil connection method based on the test requirements. The control box adjusts the grounding impedance and the capacitance to ground through the neutral point grounding device and the capacitor configuration device. The control box adjusts the fixed phase angle of the coil by controlling the rotor loop of the dynamic model generator, thereby obtaining the voltage parameters of the neutral point and the three outlets and the voltage parameters of the head end of each coil under different conditions. Compared with the existing simulation analysis, the device of the present invention is a physical model test, so the distributed parameters obtained for the changes in the neutral point grounding impedance, phase, and capacitance to ground are more accurate.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A block diagram of a generator distributed parameter test device provided by an embodiment of the present invention;

[0028] Figure 2A schematic diagram of a stator winding provided in an embodiment of the present invention;

[0029] Figure 3 A stator circuit diagram of a dynamic mode generator provided by an embodiment of the present invention when the coil phase angle is equal to 20°;

[0030] FIG4 (a) is a three-phase voltage vector diagram of the first three-phase branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0031] FIG4( b ) is a three-phase voltage vector diagram of a second three-phase branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0032] FIG4 (c) is a three-phase voltage vector diagram of a third three-phase branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0033] FIG. 5 (a) is a three-phase voltage vector diagram of a first three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0034] FIG5( b ) is a three-phase voltage vector diagram of a second three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0035] FIG5( c ) is a three-phase voltage vector diagram of a third three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0036] FIG5( d ) is a three-phase voltage vector diagram of a fourth three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0037] FIG5( e ) is a three-phase voltage vector diagram of a fifth three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0038] FIG5( f ) is a three-phase voltage vector diagram of a sixth three-phase branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0039] FIG6 (a) is a three-phase voltage vector diagram of the first three-phase two-branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0040] FIG6 (b) is a three-phase voltage vector diagram of the second three-phase two-branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0041] FIG6 (c) is a three-phase voltage vector diagram of the third three-phase two-branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0042] FIG6 (d) is a three-phase voltage vector diagram of the fourth three-phase two-branch coil phase symmetrically distributed connection provided by an embodiment of the present invention;

[0043] FIG. 7 (a) is a three-phase voltage vector diagram of the first three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0044] FIG. 7( b ) is a three-phase voltage vector diagram of the second three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0045] FIG. 7 ( c ) is a three-phase voltage vector diagram of the third three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0046] FIG. 7( d ) is a three-phase voltage vector diagram of a fourth three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention;

[0047] Figure 8 A rotor circuit diagram of a dynamic mode generator provided by an embodiment of the present invention;

[0048] Fig. 9 A circuit diagram of a capacitor configuration unit provided in an embodiment of the present invention;

[0049] Fig.10 A circuit diagram of a neutral point grounding device provided by an embodiment of the present invention;

[0050] Fig.11 The present invention provides a flow chart of a generator distributed parameter test method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the embodiments of the present invention. Instead, they are merely examples of devices and methods consistent with some aspects of the embodiments of the present invention as detailed in the appended claims.

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0053] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. It should also be understood that the term "and / or" used in the present invention refers to and includes any or all possible combinations of one or more associated listed items.

[0054] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0055] The present invention proposes a generator distributed parameter test device and a test method thereof, so as to more accurately simulate the distributed parameters when the neutral point grounding impedance, coil phase and phase distribution, ground capacitance and capacitance distribution change, as well as the voltage parameters of the outlet, neutral point, and each coil node, and the ground capacitance current parameters under these parameters.

[0056] In an embodiment of the present invention, Figure 1 The block diagram of a generator distributed parameter test device provided by an embodiment of the present invention is shown in FIG. The generator distributed parameter test device in the present invention may be referred to as a test device for short. Figure 1 As shown, the generator distributed parameter test device includes a dynamic model generator 1, a neutral point grounding device 2, a capacitor configuration device 3, a control box 4, an excitation power supply 5, a variable frequency drive motor 6 and a variable frequency power supply 7. The variable frequency power supply 7 is connected to the dynamic model generator 1 via the variable frequency drive motor 6, the excitation power supply 5 is connected to the dynamic model generator 1, and the control box 4 is respectively controlled and connected to the dynamic model generator 1, the neutral point grounding device 2, and the capacitor configuration device 3.

[0057] In this embodiment, in order to meet the test requirements, the dynamic mode generator 1 can use a low-voltage salient pole generator. The structural parameters of the low-voltage salient pole generator used include, for example: rated voltage 0-400V adjustable, rated frequency 50Hz, maximum power 1.2kW, current 21A, speed 1500 rpm (maximum speed 3000 rpm); stator parameters: 3-phase, double-layer winding, number of stator slots Z=36, number of slots per pole per phase q=3, pitch Y=9, electrical angle between coils (i.e. fixed angle) 20°, 36 coil groups are led out at the head and tail ends respectively; rotor parameters: number of magnetic poles 2P=4 (adjustable to 2P=2), adjustable speed n=0-3000 rpm, excitation voltage DC 0-36V, excitation current DC 0-5A adjustable.

[0058] In this embodiment, the dynamic model generator has a unique stator winding connection. Specifically, the stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles are sequentially different by a fixed angle, and the head end and tail end of each coil are connected to the control box. When the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 2, the fixed angle is 10 degrees; when the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 4, the fixed angle is 20 degrees. The number of magnetic poles is related to the rotor circuit (described later).

[0059] Take the coil quantity of 36 as an example, Figure 2 A schematic diagram of a stator winding provided in an embodiment of the present invention is shown in FIG. Figure 2As shown, there are 36 coils from left to right. The tail end of the first coil is x1 and the head end is a1; the tail end of the second coil is x2 and the head end is a2; the tail end of the third coil is x3 and the head end is a3; the tail end of the fourth coil is z1 and the head end is c1; the tail end of the fifth coil is z2 and the head end is c2; the tail end of the sixth coil is z3 and the head end is c3; the tail end of the seventh coil is y1 and the head end is b1; the tail end of the eighth coil is y2 and the head end is b2; the tail end of the ninth coil is y3 and the head end is b3 ; The tail end of the 10th coil is x4 and the head end is a4; the tail end of the 11th coil is x5 and the head end is a5; the tail end of the 12th coil is x6 and the head end is a6; the tail end of the 13th coil is z4 and the head end is c4; the tail end of the 14th coil is z5 and the head end is c5; the tail end of the 15th coil is z6 and the head end is c6; the tail end of the 16th coil is y4 and the head end is b4; the tail end of the 17th coil is y5 and the head end is b5; the tail end of the 18th coil is y6 and the head end is b6; the tail end of the 19th coil is y6 and the head end is b6; the tail end of the 19th coil is y5 and the head end is b5; the tail end of the 18th coil is y6 and the head end is b6; the tail end of the 19th coil is y5 and the head end is b5; the tail end of the 19 ... The tail end of the 20th coil is x7 and the head end is a7; the tail end of the 20th coil is x8 and the head end is a8; the tail end of the 21st coil is x9 and the head end is a9; the tail end of the 22nd coil is z7 and the head end is c7; the tail end of the 23rd coil is z8 and the head end is c8; the tail end of the 24th coil is z9 and the head end is c9; the tail end of the 25th coil is y7 and the head end is b7; the tail end of the 26th coil is y8 and the head end is b8; the tail end of the 27th coil is y9 and the head end is b9; the tail end of the 28th coil is x 10. The head end is a10; the tail end of the 29th coil is x11, and the head end is a11; the tail end of the 30th coil is x12, and the head end is a12; the tail end of the 31st coil is z10, and the head end is c10; the tail end of the 32nd coil is z11, and the head end is c11; the tail end of the 33rd coil is z12, and the head end is c12; the tail end of the 34th coil is y10, and the head end is b10; the tail end of the 35th coil is y11, and the head end is b11; the tail end of the 36th coil is y12, and the head end is b12. Among them, the head end of each coil is the port where the current of the coil flows out, and the tail end is the port where the current of the coil flows in.

[0060] Take the stator winding as an example, which consists of 36 coils with phase angles that differ by 20 degrees (that is, the fixed angles between adjacent coils differ by 20 degrees, also known as the coil phase angle θ=20°). Figure 3 The stator circuit diagram of the dynamic mode generator provided by the embodiment of the present invention when the coil phase angle is equal to 20°. Figure 3As shown, θ=20°, the head and tail ends of each coil are arranged in phase according to x1-a1, x2-a2, x3-a3......x10-a10, x11-a11, x12-a12; y1-b1, y2-b2, y3-b3......y10-b10, y11-b11, y12-b12; z1-c1, z2-c2, z3-c3......z10-c10, z11-c11, z12-c12. Figure 3 In the three regions, the 1st and 3rd rows of each column in each region have the same phase, the 2nd and 4th rows have the same phase, the coils with a phase difference of 20° in each pole phase group are arranged in the same row, and the same column between the three regions differs by 60° successively. Among them, A, B, C, X, Y, and Z are the connection terminals of the corresponding regions. For example, in the area where terminal A is located, the potentials of rows 1 and 3 are E∠0, E∠20 and E∠40, the potentials of rows 2 and 4 are E∠180, E∠200 and E∠220, the potentials of rows 1 and 3 are E∠120, E∠140 and E∠160, the potentials of rows 2 and 4 are E∠300, E∠320 and E∠340, the potentials of rows 1 and 3 are E∠60, E∠80 and E∠100, the potentials of rows 2 and 4 are E∠240, E∠260 and E∠280. The potential phase distribution required for the test can be achieved by combining the 36 coils in series and parallel.

[0061] In this embodiment, the series and parallel combination between each coil is a coil connection method. In this embodiment, there are multiple coil connection methods. From the direction of the coil angle, the multiple coil connection methods include a three-phase branch coil phase symmetrical distribution wiring method, a three-phase branch coil phase asymmetrical distribution wiring method, a three-phase two-branch coil phase symmetrical distribution wiring method, and a three-phase two-branch coil phase asymmetrical distribution wiring method.

[0062] In this embodiment, the required number of branches per phase, phase distribution of each branch coil and three-phase voltage vector diagram are achieved by selecting the series or parallel combination of the head and tail terminals of the coil (that is, selecting different wiring methods).

[0063] Taking 17 coil connection methods as an example, the 17 coil connection methods include 3 three-phase branch coil phase symmetrical distribution wiring methods, 6 three-phase branch coil phase asymmetrical distribution wiring methods, 4 three-phase two-branch coil phase symmetrical distribution wiring methods, and 4 three-phase two-branch coil phase asymmetrical distribution wiring methods.

[0064] The three types of three-phase branch coil phase symmetrical distribution wiring methods are: (1) A-a1-x1-a2-x2-a3-x3-a4-x4-a5-x5-a6-x6-a7-x7-a8-x8-a9-x9-a10-x10-a11-x11-a12-x12-X; B-b1-y1-b2-y2-b3-y3-b4-y4-b5 -y5-b6-y6-b7-y7-b8-y8-b9-y9-b10-y10-b11-y11-b12-y12-Y;C-c1-z1-c2-z2- c3-z3-c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z. (2) A-a1-x1-a4-x4-a7-x7-a10-x10-a2-x2-a5-x5-a8-x8-a11-x11-a3-x3 -a6-x6-a9-x9-a12-x12-X;B-b1-y1-b4-y4-b7-y7-b10-y10-b2-y2-b5-y5 -b8-y8-b11-y11-b3-y3-b6-y6-b9-y9-b12-y12-Y;C-c1-z1-c4-z4-c7-z7 -c10-z10-c2-z2-c5-z5-c8-z8-c11-z11-c3-z3-c6-z6-c9-z9-c12-z12-Z. (3) A-a1-x1-a2-x2-a3-x3-a6-x6-a5-x5-a4-x4-a7-x7-a8-x8-a9-x9-a12 -x12-a11-x11-a10-x10-X;B-b1-y1-b2-y2-b3-y3-b6-y6-b5-y5-b4-y4-b 7-y7-b8-y8-b9-y9-b12-y12-b11-y11-b10-y10-Y;C-c1-z1-c2-z2-c3-z3 -c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z.

[0065] Figure 4 (a) is a three-phase voltage vector diagram of the first three-phase branch coil phase symmetrically distributed wiring provided by an embodiment of the present invention; Figure 4 (b) is a three-phase voltage vector diagram of the second three-phase branch coil phase symmetrically distributed wiring provided by an embodiment of the present invention; Figure 4 (c) is a three-phase voltage vector diagram of the third three-phase branch coil phase symmetrically distributed wiring provided by an embodiment of the present invention. Figure 3The coil terminals (i.e., the head and tail ends) in the three three-phase branch coil phase symmetrical distribution wiring methods are connected according to the above three wiring methods, and the three terminals X, Y, and Z are connected together to obtain the neutral point, thereby realizing the three-phase voltage vector diagram of the three-phase branch coil phase symmetrical distribution shown in Figures 4 (a), 4 (b), and 4 (c), respectively. The intersection of the three phases in Figure 4 (a) is the neutral point after the three terminals X, Y, and Z are connected, and the 12 vectors from the neutral point to point A are the voltage vectors of the 12 coils from terminal X to terminal A in the corresponding wiring method. Figures 4 (b) and 4 (c) can refer to the relevant description of Figure 4 (a).

[0066] The six three-phase branch coil phase asymmetric distribution wiring methods are: (1) A-a3-x3-a2-x2-a1-x1-a6-x6-a5-x5-a4-x4-a9-x9-a8-x8-a7-x7-a12-x12-a11-x11-a10-x10-X; B-b1-y1-b2-y2-b3-y3-b4-y4-b 5-y5-b6-y6-b7-y7-b8-y8-b9-y9-b10-y10-b11-y11-b12-y12-Y;C-c1-z1-c2-z2 -c3-z3-c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z. (2) A-a1-x1-a4-x4-a7-x7-a10-x10-a2-x2-a5-x5-a8-x8-a11-x11-a3-x3 -a6-x6-a9-x9-a12-x12-X;B-b1-y1-b2-y2-b3-y3-b4-y4-b5-y5-b6-y6-b 7-y7-b8-y8-b9-y9-b10-y10-b11-y11-b12-y12-Y;C-c1-z1-c2-z2-c3-z3 -c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z. (3) A-a1-x1-a4-x4-a7-x7-a10-x10-a2-x2-a5-x5-a8-x8-a11-x11-a3-x3 -a6-x6-a9-x9-a12-x12-X;B-b1-y1-b4-y4-b7-y7-b10-y10-b2-y2-b5-y5 -b8-y8-b11-y11-b3-y3-b6-y6-b9-y9-b12-y12-Y;C-c3-z3-c6-z6-c9-z9 -c12-z12-c2-z2-c5-z5-c8-z8-c11-z11-c1-z1-c4-z4-c7-z7-c10-z10-Z.<h2 style=";text-align:left;direction:ltr">(4) A-a3-x3-a2-x2-a1-x1-a6-x6-a5-x5-a4-x4-a9-x9-a8-x8-a7-x7-a12-x12-a11-x11-a10-x10-X;B-b1-y1-b4-y4-b7-y7-b10-y10-b2-y2-b5-y5-b8-y8-b11-y11-b3-y3-b6-y6-b9-y9-b12-y12-Y;C-c1-z1-c4-z4-c7-z7 -c10-z10-c2-z2-c5-z5-c8-z8-c11-z11-c3-z3-c6-z6-c9-z9-c12-z12-Z。(5)A-a3-x3-a2-x2-a1-x1-a4-x4-a5-x5-a6-x6-a9-x9-a8-x8-a7-x7-a10-x10-a11-x11-a12-x12-X;B-b1-y1-b2-y2-b3-y3-b6-y6-b5-y5-b4-y4-b 7-y7-b8-y8-b9-y9-b12-y12-b11-y11-b10-y10-Y;C-c1-z1-c2-z2-c3-z3-c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z。(6)A-a1-x1-a4-x4-a7-x7-a10-x10-a2-x2-a5-x5-a8-x8-a11-x11-a3-x3 -a6-x6-a9-x9-a12-x12-X;B-b1-y1-b2-y2-b3-y3-b6-y6-b5-y5-b4-y4-b7-y7-b8-y8-b9-y9-b12-y12-b11-y11-b10-y10-Y;C-c1-z1-c2-z2-c3-z3-c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z。<h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">

[0067] Figure 5 (a) is a three-phase voltage vector diagram of the first type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention; Figure 5 (b) is a three-phase voltage vector diagram of the second type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention; Figure 5 (c) is a three-phase voltage vector diagram of the third type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention; Figure 5 (d) is a three-phase voltage vector diagram of the fourth type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention; Figure 5 (e) is a three-phase voltage vector diagram of the fifth type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention; Figure 5 (f) is a three-phase voltage vector diagram of the sixth type of three-phase branch coil phase asymmetric distribution connection provided in an embodiment of the present invention. Comparison Figure 3 The coil terminals (i.e., the head and tail ends) in the three-phase branch coil are connected according to the above 6 three-phase branch coil phase asymmetric distribution wiring methods, and the three terminals X, Y, and Z are connected together to obtain the neutral point, thereby respectively realizing the three-phase branch coil phase asymmetric distribution wiring three-phase voltage vector diagram shown in Figures 5 (a) to 5 (f). The intersection of the three phases in Figure 5 (a) is the neutral point after the three terminals X, Y, and Z are connected, and the 12 vectors from the neutral point to point A are the voltage vectors of the 12 coils from terminal X to terminal A in the corresponding wiring method. Figures 5 (b) to 5 (f) can refer to the relevant description of Figure 5 (a).

[0068] Four types of three-phase two-branch coil phase symmetrical distribution wiring methods are shown in Table 1.

[0069] Table 1 Three-phase two-branch coil phase symmetrical distribution wiring table

[0070]

[0071] Among them, Table 1 lists four three-phase two-branch coil phase symmetrical distribution wiring methods. Taking the first type (1) as an example, each row is a branch. In the two rows corresponding to terminal A, the six coils in each row are connected in series to form a branch. The two branches are connected in parallel to obtain two branches of phase A. The other two phases can refer to the description of the two branches of phase A. The other three situations can refer to the description of the first type (1).

[0072] Figure 6 (a) is a three-phase voltage vector diagram of the first three-phase two-branch coil phase-symmetrically distributed wiring provided by an embodiment of the present invention; Figure 6 (b) is a three-phase voltage vector diagram of the second three-phase two-branch coil phase-symmetrically distributed wiring provided by an embodiment of the present invention; Figure 6 (c) is a three-phase voltage vector diagram of the third three-phase two-branch coil phase-symmetrically distributed wiring provided by an embodiment of the present invention; Figure 6 (d) is a three-phase voltage vector diagram of the fourth three-phase two-branch coil phase-symmetrically distributed wiring provided by an embodiment of the present invention. Comparison Figure 3Each coil terminal (i.e., the head end and the tail end) in the three-phase two-branch coil is connected according to the above four three-phase two-branch coil phase symmetrical distribution wiring methods, and the three terminals X, Y, and Z are connected together to obtain the neutral point, thereby respectively realizing the three-phase voltage vector diagram of the three-phase two-branch coil phase symmetrical distribution wiring shown in Figures 6 (a) to 6 (d). The intersection of the three phases in Figure 6 (a) is the neutral point after the three terminals X, Y, and Z are connected, and the two groups of vectors from the neutral point to point A (6 vectors in each group) are the voltage vectors of the two rows of coils from terminal X to terminal A in the corresponding wiring method. Figures 6 (b) to 6 (d) can refer to the relevant description of Figure 6 (a).

[0073] Four types of three-phase two-branch coil phase asymmetric distribution wiring methods are shown in Table 2. The four situations in Table 2 can refer to the relevant descriptions in Table 1.

[0074] Table 2 Three-phase two-branch coil phase asymmetric distribution wiring table

[0075]

[0076] Figure 7 (a) is a three-phase voltage vector diagram of the first three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention; Figure 7 (b) is a three-phase voltage vector diagram of the second three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention; Figure 7 (c) is a three-phase voltage vector diagram of the third three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention; Figure 7 (d) is a three-phase voltage vector diagram of the fourth three-phase two-branch coil phase asymmetric distribution connection provided by an embodiment of the present invention. Comparison Figure 3 The coil terminals (i.e., the head and tail ends) in the three-phase two-branch coil are connected according to the above four three-phase two-branch coil phase asymmetric distribution wiring methods, and the three terminals X, Y, and Z are connected together to obtain the neutral point, thereby respectively realizing the three-phase voltage vector diagrams of the three-phase two-branch coil phase asymmetric distribution wiring shown in Figures 7 (a) to 7 (d). The intersection of the three phases in Figure 7 (a) is the neutral point after the three terminals X, Y, and Z are connected, and the two groups of vectors from the neutral point to point A (6 vectors in each group) are the voltage vectors of the two rows of coils from terminal X to terminal A in the corresponding wiring method. Figures 7 (b) to 7 (d) can refer to the relevant description of Figure 7 (a).

[0077] In the embodiment of the present invention, changing the number of magnetic poles can also verify a smaller coil phase angle distribution. The number of magnetic poles is related to the rotor circuit.

[0078] Specifically, Figure 8 The rotor circuit diagram of the dynamic mode generator provided by the embodiment of the present invention. Figure 8As shown, the rotor circuit of the dynamic mode generator includes a first rotor pole coil P1, a first switch K1, a second rotor pole coil P2, a third rotor pole coil P3, a third switch K3 and a fourth rotor pole coil P4 connected in series in sequence. The first switch K1 is connected in series with the second rotor pole coil P2 and then connected in parallel with the second switch K2. The third switch K3 is connected in series with the fourth rotor pole coil P4 and then connected in parallel with the fourth switch K4. If is the rotor current, and Uf:DC is the rotor input voltage.

[0079] The control box 4 adjusts the number of magnetic poles by controlling the on and off of the first switch K1, the second switch K2, the third switch K3 and the fourth switch K4. Figure 3 As shown, if the control box 4 controls the first switch K1 to be closed, the second switch K2 to be opened, the third switch K3 to be closed, and the fourth switch K4 to be opened, the number of magnetic poles is 2P=4, and the coil phase angle θ=20°; if the control box 4 controls the first switch K1 to be opened, the second switch K2 to be closed, the third switch K3 to be opened, and the fourth switch K4 to be closed, the number of magnetic poles is 2P=2, and the coil phase angle θ=10°. P is the number of magnetic pole pairs. Thus, the switching of the coil phase angles of 10° and 20° is realized to meet the simulation needs of generators with different phase angles.

[0080] In the embodiment of the present invention, changing the capacitance can also verify the influence of different capacitance distributions to the ground, and combining the change of the series and parallel connection of the coils can also verify the cross-influence of the phase distribution and the capacitance distribution. The change of the capacitance to the ground is achieved by controlling the capacitance configuration device 3 through the control box 4.

[0081] Specifically, in this embodiment, the capacitor configuration device 3 includes a plurality of capacitor configuration units, the number of which is consistent with the number of coils of the stator winding, each capacitor configuration unit matches a single coil of the stator winding, and the input end of each capacitor configuration unit is connected to the head end of the corresponding coil of the stator winding. Figure 3 As shown, the capacitor configuration device 3 includes, for example, 36 capacitor configuration units. Each capacitor configuration unit matches a single coil of a stator winding, and the input end of each capacitor configuration unit is connected to the tail end of the corresponding coil of the stator winding. The output capacitance of each capacitor configuration unit is the capacitance to ground of the corresponding coil.

[0082] The circuit structure in each capacitor configuration unit is the same. Fig. 9 FIG. 1 is a circuit diagram of a capacitor configuration unit provided in an embodiment of the present invention. Fig. 9As shown, the input end of the capacitor configuration unit is M, and the input end M is used to connect the head end of the coil of the corresponding stator winding, and the output end N of the capacitor configuration unit is grounded. The input end M and the output end N of the capacitor configuration unit include three branches connected in parallel, each branch includes a capacitor configuration switch and an AC capacitor connected in series, specifically, the first branch is obtained by connecting the first capacitor configuration switch k011 and the first AC capacitor c011 in series, the second branch is obtained by connecting the second capacitor configuration switch k012 and the second AC capacitor c012 in series, and the third branch is obtained by connecting the third capacitor configuration switch k013 and the third AC capacitor c013 in series. The control box 4 adjusts the capacitance of the coil of each stator winding to the ground by controlling the on and off of each capacitor configuration switch.

[0083] For example, the three branches of the capacitor configuration unit are three 1000V AC capacitors, c011=0.05μF, c012=0.1μF, c013=0.2μF. By controlling the on and off of the capacitor configuration switches of the three branches, a 0μF-0.35μF capacitor output with a step size of 0.05μF is achieved, so that the required capacitor is configured to the coil to achieve the setting of the coil-to-ground capacitance. The capacitor configuration switch can be a panel button switch, or it can be automatically controlled by a control box.

[0084] Taking the capacitance Ca1 of the a1-x1 coil in phase A as an example, in the capacitance configuration unit connected to the a1-x1 coil, when k011 is closed, k012 is disconnected, and k013 is disconnected, Ca1=0.05μF, when k011 is disconnected, k012 is closed, and k013 is disconnected, Ca1=0.1μF, when k011 is closed, k012 is closed, and k013 is disconnected, Ca1=0.15μF, when k011 is disconnected, k012 is disconnected, and k013 is closed, Ca1=0.2μF, when k011 is closed, k012 is disconnected, and k013 is closed, Ca1=0.25μF, when k011 is disconnected, k012 is closed, and k013 is closed, Ca1=0.3μF, when k011 is closed, k012 is closed, and k013 is closed, Ca1=0.35μF.

[0085] In this embodiment, for each wiring mode, by adjusting the capacitance value of each coil in each branch of the three phases under the wiring mode, different capacitance distributions of the entire stator winding can be achieved. When each coil selects the same capacitance, it is a uniform distribution, and when each coil selects a different capacitance, it is an uneven distribution. Taking the phase symmetrical distribution wiring of a three-phase branch coil in Figure 4 (b) as an example, the branch capacitance is configured to be a uniform distribution phase capacitance Ca=Cb=Cc=1.2μF, where Ca is the capacitance of phase A in the three phases, Cb is the capacitance of phase B in the three phases, and Cc is the capacitance of phase C in the three phases. The configuration method is that the capacitance to ground of the 36 coils of the three phases is 0.1μF, that is, the capacitance to ground of the 12 coils of phase A, Ca1 to Ca12, the capacitance to ground of the 12 coils of phase B, Cb1 to Cb12, and the capacitance to ground of the 12 coils of phase C, Cc1 to Cc12, are all set to 0.1μF, and the total capacitance to ground of the 12 coils of each phase is 1.2μF; still taking the phase symmetrical distribution wiring of the three-phase branch coil in Figure 4 (b) as an example, the configuration The branch capacitance is unevenly distributed, and the capacitance gradually increases from the neutral point to the head end. The phase capacitance Ca=Cb=Cc=1.2μF. The configuration method is that the capacitance to ground of phase A Ca1 to Ca4 is set to 0.05μF, the capacitance to ground of Ca5 to Ca8 is set to 0.1μF, and the capacitance to ground of Ca9 to Ca12 is set to 0.15μF. The capacitance to ground of the coils is not completely equal. The total capacitance to ground of 12 coils in each phase is equal to 1.2μF, that is, the capacitance to ground is unevenly distributed. Using the present invention with reference to the above settings, various uniform and uneven distributions of the total capacitance to ground of 4.2μF per phase can be achieved.

[0086] In this embodiment, if Fig. 9 As shown, the capacitor configuration unit further includes a current transformer CT, and the output terminal N of the capacitor configuration unit is grounded via the current transformer CT. The accuracy of the current transformer CT may be, for example, 1 μA. The capacitance current of each coil to ground is measured via the current transformer CT.

[0087] In this embodiment, the neutral point grounding device is used to match the test low-voltage salient pole generator to adjust the neutral point grounding impedance of the generator. The neutral point grounding device 2 includes an adjustable inductor, an adjustable resistor, an access and exit switch, a direct grounding switch and a wiring terminal. The wiring terminal is grounded through the access and exit switch, the adjustable resistor and the inductor, one end of the direct grounding switch is connected to the wiring terminal, and the other end of the direct grounding switch is grounded.

[0088] Fig.10 The circuit diagram of the neutral point grounding device provided by the embodiment of the present invention is shown in FIG. Fig.10As shown, the neutral point grounding device is composed of an adjustable inductor coil L, an adjustable resistor Rv, an access exit switch ka, a direct grounding switch kb, and a terminal T. The terminal T is grounded through the access exit switch ka, the adjustable resistor Rv and the adjustable inductor coil L. One end of the direct grounding switch kb is connected to the terminal T, and the other end of the direct grounding switch is grounded. The impedance size can be adjusted in the range of 0-500Ω. The neutral point grounding state of the generator with different resistance values ​​can be achieved by adjusting the resistance. The neutral point grounding device also includes a current transformer CT0, and the adjustable inductor coil L is grounded through the current transformer CT0.

[0089] In this embodiment, the excitation power supply is a controllable DC excitation power supply, which is used for the rotor excitation of the above-mentioned low-voltage salient pole generator. The excitation voltage is DC0-220V, the excitation current is DC0-5A, and the excitation voltage and current are adjustable.

[0090] In this embodiment, the speed range of the variable frequency drive motor is 0-3000 rpm, and the speed is adjusted by variable frequency speed regulation to drive the generator to the speed required for the test. For example, when 2P=4, the frequency is 50HZ, and the speed of the drive motor is n=1500. When 2P=2, the frequency is 50HZ, and the speed of the drive motor is n=3000.

[0091] In this embodiment, the variable frequency power supply is controlled by the control box to supply power to the variable frequency drive motor.

[0092] In this embodiment, the control box 4 stores a plurality of coil connection modes, such as the 17 coil connection modes mentioned above.

[0093] In this embodiment, the control box 4 is used to complete the connection of the head end and the tail end of each coil according to the required coil connection method based on the test requirements to realize the distribution of coils of different phases in the winding, control the neutral point grounding device to adjust the grounding impedance of the dynamic model generator to the set grounding impedance and connect the neutral point of the stator winding, control the capacitor configuration device to adjust the capacitance of each coil to the ground to realize different capacitance distribution of the winding, control the rotor loop of the dynamic model generator so that the fixed angle between adjacent coils is equal to the preset verification phase angle, control the neutral point and three outlets of the stator winding, the head end of any coil, and the current transformer to connect to the channel of the oscilloscope of the control box according to the test requirements, adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding, the voltage parameters of the head end of each coil, and the current parameters of each coil to the ground.

[0094] Among them, the test requirements may be to test the voltages of the neutral point and three outlets under different coil phase angles, to test the voltages of the neutral point and three outlets under different winding capacitance distributions, etc.

[0095] The test device of the present invention is used to test and verify the influence of the distributed parameter coil phase distribution and the ground capacitance distribution on the neutral point potential drift and the output ground voltage of a 18kV three-phase 1 branch generator with a uniform distribution of the winding phase capacitance of 1.2μF, 3 slots per pole and per phase, a slot pitch angle of 20°, a uniform phase distribution of the three-phase coil, a generator idling residual voltage of 110V, a neutral point grounding transformer high resistance grounding resistance of 475Ω, and a reactance of 0.5Ω. The test steps are as follows:

[0096] 11) Complete the stator winding connection of the dynamic generator according to the winding phase distribution diagram that needs to be verified. Compare the above 17 connection methods and vector diagrams and adopt the three-phase branch coil phase symmetrical distribution connection in Figure 4 (a) A-a1-x1-a2-x2-a3-x3-a4-x4-a5-x5-a6-x6-a7-x7-a8-x8-a9-x9-a10-x10-a11-x11-a12-x12-X, B-b1-y1 -b2-y2-b3-y3-b4-y4-b5-y5-b6-y6-b7-y7-b8-y8-b9-y9-b10-y10-b11-y11-b12-y12-Y,C-c 1-z1-c2-z2-c3-z3-c4-z4-c5-z5-c6-z6-c7-z7-c8-z8-c9-z9-c10-z10-c11-z11-c12-z12-Z;

[0097] 12) Verify the neutral point grounding method and parameters of the generator as needed, adjust the adjustable resistance and adjustable inductance of the neutral point grounding device to the required grounding impedance value. For example, if the neutral point is high-resistance grounded Z=475+0.5i, then L=0.0016H, Rv=475, connect the terminals TXYZ in sequence, close the switch ka and disconnect kb;

[0098] 13) Set the ground capacitance value according to the winding ground capacitance parameters of the generator to be verified. If the capacitance distribution is uniform, the phase capacitance is 1.2μF and the coil capacitance is 0.1μF. It should be noted that the single coil of this test device has a ground capacitance of 5pF, which is negligible compared to the capacitance parameters to be verified. Adjust the ground capacitance of each coil. Take Ca1 as an example, close k012 and disconnect k011 and k013. The capacitance settings of the remaining coils are consistent with Ca1.

[0099] 14) Verify that the phase angle is 20°, adjust the rotor circuit 2P=4, k1 closed, k2 open, k3 closed, k4 open;

[0100] 15) Connect the winding outlets A, B, C and neutral point T to channels 1-4 of the oscilloscope to monitor the amplitude and phase of the voltage parameters at each point;

[0101] 16) According to the above test parameters, the frequency is 50Hz, 2P=4, and the speed is 1500 rpm; start the variable frequency drive motor and adjust the speed to 1500 rpm;

[0102] 17) According to the above test parameters, the generator idling residual voltage is 110V; start the controllable DC excitation power supply, through Figure 8 Connect the positive and negative terminals of Uf to the DC excitation current, gradually adjust the current, and observe the output voltages A, B, and C through an oscilloscope. When the voltage to ground reaches 110V, it stabilizes and keeps the excitation current unchanged.

[0103] 18) Use an oscilloscope to measure and record the voltage amplitude and phase of the outlet A, B, and C to the ground, and the neutral point voltage amplitude and phase, to obtain the voltage data measured by this test device, so as to facilitate the subsequent analysis of the three-phase voltage balance, the neutral point voltage, and the impact of the capacitor and coil phase distribution on the voltage through the measured voltage data.

[0104] Take a large 18kV generator stator winding structure, 720 slots, 80 poles, 3-phase 4-branch 1 / 4 wave winding, integer slot-pole phase group is 3, slot pitch angle is 20°, that is, the electrical angle between two adjacent slots is 20°, relative capacitance is 1.8μF, neutral point grounding transformer high resistance grounding, reactance 0.75Ω resistance 475Ω. During operation, there is an unbalanced voltage at the outlet relative to the ground, the highest voltage and the lowest voltage phase difference is nearly 1kV, the neutral point potential drift problem, and the residual voltage A, B, C of the generator idling operation are 108V, 116V, 112V respectively. The present invention verifies and analyzes the parameters and fault phenomena of the generator. Specifically including:

[0105] 21) Select the test connection according to the structural parameters of the generator, for example, the test connection corresponding to the three-phase branch coil phase asymmetric distribution connection three-phase voltage vector diagram shown in Figure 5 (c) mentioned above, A-a1-x1-a4-x4-a7-x7-a10-x10-a2-x2-a5-x5-a8-x8-a11-x11-a3-x3-a6-x6-a9-x9-a12-x12-X, B-b1-y1- b4-y4-b7-y7-b10-y10-b2-y2-b5-y5-b8-y8-b11-y11-b3-y3-b6-y6-b9-y9-b12-y12-Y,C-c3 -z3-c6-z6-c9-z9-c12-z12-c2-z2-c5-z5-c8-z8-c11-z11-c1-z1-c4-z4-c7-z7-c10-z10-Z;

[0106] 22) Verify the neutral point grounding method and parameters of the generator as needed, adjust the adjustable resistance and adjustable inductance of the neutral point grounding device to the required grounding impedance value and connect it to the neutral point of the stator winding, reactance 0.75Ω resistance 475Ω, L=0.75 / 314=0.0024H, Rv=475, connect the terminals TXYZ in sequence, close the switch ka and disconnect kb;

[0107] 23) Verify the generator winding-to-ground capacitance parameters as needed and set the ground capacitance value. The capacitance distribution is evenly distributed at 1.8 / 12=0.15μF. Adjust the ground capacitance of each coil. Take Ca1 as an example, close k012, close k011, and disconnect k013. The capacitance settings of the remaining coils are consistent with Ca1.

[0108] 24) Verify that the phase angle is 20°, adjust the rotor circuit 2P=4, k1 closed, k2 open, k3 closed, k4 open;

[0109] 25) Carry out the influence of the phase distribution of the distributed parameter coil and the distribution of the capacitance to ground on the neutral point potential drift and the voltage at the outlet to the ground according to the test requirements (i.e. adjust the coil phase angle, capacitance to ground, ground resistance, etc. according to the test requirements), connect the winding outlet A, B, C and the neutral point T to the oscilloscope channels 1-4, and monitor the voltage phase at each point;

[0110] 26) According to the above test parameters, the frequency is 50Hz, 2P=4, and the speed is 1500 rpm; start the variable frequency drive motor and adjust the speed to 1500 rpm;

[0111] 27) According to the above test parameters, the generator idling residual voltage B phase is 116V; start the controllable DC excitation power supply, through Figure 8 Connect the positive and negative terminals of Uf to the DC excitation current, gradually adjust the current, and observe the output voltages of the three terminals A, B, and C through an oscilloscope. When the voltage of B reaches 116V, stabilize and keep the excitation current unchanged.

[0112] 28) The voltage phases of the three outlets A, B, and C to the ground and the neutral point voltage were measured and recorded using an oscilloscope. Phase A is 105V, phase B is 116V, phase C is 110V, and the neutral point voltage is 7V. The three-phase unbalanced voltage phenomenon is consistent with the real machine. The fault is the influence of the coil phase distribution on the outlet voltage.

[0113] The following is an embodiment of the method of the present invention. For details not disclosed in the embodiment of the method of the present invention, please refer to the embodiment of the device of the present invention. The method embodiment of the present invention proposes a generator distributed parameter test method. The generator distributed parameter test method uses the generator distributed parameter test device of the above device embodiment.

[0114] Fig.11The present invention provides a flow chart of a generator distributed parameter test method according to an embodiment of the present invention.

[0115] like Fig.11 As shown, the generator distributed parameter test method includes:

[0116] Step S101, based on the test requirements, the control box completes the connection of the head end and the tail end of each coil in the stator winding of the dynamic mode generator according to the required coil connection method to achieve the distribution of coils of different phases in the winding;

[0117] Step S102, controlling the neutral point grounding device to adjust the grounding impedance of the dynamic mode generator to a set grounding impedance and connect the neutral point of the stator winding;

[0118] Step S103, controlling the capacitance configuration device to adjust the capacitance of each coil in the stator winding to the ground to achieve different capacitance distributions of the windings;

[0119] Step S104, controlling the rotor loop of the dynamic mode generator so that the fixed angle between adjacent coils is equal to a preset verification phase angle;

[0120] Step S105, controlling the neutral point and three outlets of the stator winding, the head end of any coil, and the current transformer of the capacitor configuration device to be connected to the channel of the oscilloscope of the control box according to the test requirements;

[0121] Step S106, adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic mode generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding, the voltage parameters of the first end of each coil, and the current parameters of each coil to ground.

[0122] In step S103, the capacitor configuration device is controlled to adjust the capacitance of each coil in the stator winding to ground, including: the control box controls the on and off of each capacitor configuration switch to achieve the adjustment of the capacitance of each coil of the stator winding to ground.

[0123] In step S104, the rotor circuit of the dynamic model generator is controlled so that the fixed angle between adjacent coils is equal to the preset verification phase angle, including: the control box controls the on and off of the first switch, the second switch, the third switch and the fourth switch in the rotor circuit based on the on-off rules corresponding to the preset verification phase angle to adjust the number of magnetic poles, so that each coil of the stator winding is sequentially phase-differenced by the verification phase angle.

[0124] It should be noted that the aforementioned explanation of the embodiment of the generator distributed parameter test device is also applicable to the generator distributed parameter test method of this embodiment, which will not be repeated here.

[0125] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0126] In the generator distributed parameter test device and test method of the embodiment of the present invention, the test device includes a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor and a variable frequency power supply. The variable frequency power supply is connected to the dynamic model generator via the variable frequency drive motor, the excitation power supply is connected to the dynamic model generator, and the control box is respectively controlled and connected with the dynamic model generator, the neutral point grounding device, and the capacitor configuration device; the stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles differ by a fixed angle in sequence, and the head and tail ends of each coil are connected to the control box; the control box stores a plurality of coil connection methods, and the control box is used to complete the head and tail ends of each coil according to the required coil connection method based on the test requirements. to achieve the distribution of coils with different phases in the winding, control the neutral point grounding device to adjust the grounding impedance of the dynamic model generator to the set grounding impedance and connect the neutral point of the stator winding, control the capacitor configuration device to adjust the capacitance of each coil to the ground to achieve different capacitance distributions of the winding, control the rotor loop of the dynamic model generator to make the fixed angle between adjacent coils equal to the preset verification phase angle, control the neutral point and three outlets of the stator winding, and the head end of any coil to connect to the channel of the oscilloscope of the control box according to the test requirements, adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding and the voltage parameters of the head end of each coil. In this case, the dynamic model generator, the neutral point grounding device, the capacitor configuration device, the control box, the excitation power supply, the variable frequency drive motor and the variable frequency power supply are integrated. During the test, the connection between the head end and the tail end of each coil is completed according to the required coil connection method based on the test requirements. The control box adjusts the grounding impedance and the capacitance to ground through the neutral point grounding device and the capacitor configuration device. The control box adjusts the phase angle by controlling the rotor loop of the dynamic model generator, thereby obtaining the voltage parameters of the neutral point and the three outlets, the voltage parameters of the head end of each coil under different conditions, etc. Compared with the existing simulation analysis, the device of the present invention is a physical model test, so the distributed parameters obtained for the changes in the neutral point grounding impedance, phase, and capacitance to ground are more accurate and reliable.

[0127] The device and method of the present invention are used to study and analyze the influence of the phase distribution of the distributed parameter coil and the ground capacitance distribution on the motor voltage of a large generator. The present invention comprises a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor, a variable frequency power supply, and a test wiring, parameter configuration, and a test process for the distributed parameter research proposed on the basis of the device. The present invention is different from simulation analysis, and the physical model test can make up for the shortcomings of simulation analysis. The stator coil, branch, phase wiring method and the ground capacitance and neutral point grounding impedance parameter configuration method of the present invention can be used to carry out the test research and analysis of the generator winding distributed parameter capacitance and the winding coil phase distribution on the generator neutral point potential, the generator output voltage, the branch voltage, the winding capacitance current, and the branch circulating current. The device and method of the present invention can be used to carry out the research on the terminal voltage imbalance and the neutral point potential drift of large generators. Compared with simulation calculation and real machine test, the method of the present invention is used to study the distributed parameters of the generator, which has high reliability, low safety risk, low cost, and is easy to promote and apply. The present invention can solve the test verification and analysis of the influence of the distributed parameters in the generator winding structure parameters on the electrical performance of the generator. The process of the present invention is a typical distributed parameter verification process. Through the device and method of the present invention, at least the listed 17 types of wiring coil phase distribution parameters can be verified. Changing the number of magnetic poles can also verify the distribution of smaller coil phase angles. Changing the capacitance can also verify the influence of different ground capacitance distributions, as well as the cross-influence of phase distribution and capacitance distribution. Using this device, the changes in coil voltage amplitude, phase, and capacitance current during voltage synthesis can be measured through the reserved wiring terminals and CT, and the influence of distributed parameters on the motor can be studied.

[0128] Compared with the prior art, the beneficial effects are as follows: currently, in the design, test and fault analysis of large-scale generator stators, concentrated parameter analysis and calculation are mainly used. In the past experience, distributed parameters are relatively uniform and equivalent to concentrated parameter analysis and calculation, which can meet the requirements. As the capacity, voltage and specifications of large-scale generators increase, the uniformity of distributed parameters deteriorates. The error of concentrated parameter calculation is large and cannot meet the requirements. Many large-scale hydroelectric generators in China have problems of neutral point potential drift and export voltage imbalance caused by distributed parameters. In addition to theoretical analysis and simulation calculation using distributed parameters, corresponding physical models need to be used for experimental verification. At present, the industry has begun to use distributed parameters to study large-scale generator problems, but there is a lack of test devices for experimental verification of generator distributed parameters. The present invention is a generator distributed parameter test device and test method, which are used to verify the influence of winding coil phase distribution and ground capacitance distribution on motor neutral point potential and terminal voltage; the device and method have been used in the study of voltage imbalance at the export of a large-scale generator, and can simulate voltage imbalance through distributed parameters, and verify its cause, treatment method and effect. The present invention is helpful to promote technological progress in the industry and solve industry problems.

[0129] The accompanying drawings show schematic diagrams of structures according to the disclosed embodiments of the present invention. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0130] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and the present invention is not limited here.

[0131] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A generator distributed parameter test device, characterized in that: It includes a dynamic model generator, a neutral point grounding device, a capacitor configuration device, a control box, an excitation power supply, a variable frequency drive motor and a variable frequency power supply, wherein the variable frequency power supply is connected to the dynamic model generator via the variable frequency drive motor, the excitation power supply is connected to the dynamic model generator, and the control box is respectively controlled and connected to the dynamic model generator, the neutral point grounding device and the capacitor configuration device; The stator winding of the dynamic model generator is composed of a plurality of coils whose phase angles are sequentially different by a fixed angle, and the head end and the tail end of each coil are connected to the control box; The control box stores a variety of coil connection methods. The control box is used to complete the connection of the head end and the tail end of each coil according to the required coil connection method based on test requirements to achieve the distribution of coils with different phases in the winding, control the neutral point grounding device to adjust the grounding impedance of the dynamic model generator to the set grounding impedance and connect the neutral point of the stator winding, control the capacitor configuration device to adjust the capacitance of each coil to the ground to achieve different capacitance distributions of the winding, control the rotor loop of the dynamic model generator to make the fixed angle between adjacent coils equal to the preset verification phase angle, control the neutral point and three outlets of the stator winding, and the head end of any coil to connect to the channel of the oscilloscope of the control box according to test requirements, adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding and the voltage parameters of the head end of each coil.

2. The generator distributed parameter test device according to claim 1, characterized in that: The dynamic model generator adopts a low-voltage salient pole generator. When the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 2, the fixed angle is 10 degrees; when the number of coils of the stator winding of the dynamic model generator is 36 and the number of magnetic poles is 4, the fixed angle is 20 degrees.

3. The generator distributed parameter test device according to claim 1, characterized in that: The rotor circuit of the dynamic model generator includes a first rotor pole coil, a first switch, a second rotor pole coil, a third rotor pole coil, a third switch and a fourth rotor pole coil which are connected in series in sequence. The first switch is connected in series with the second rotor pole coil and then connected in parallel with the second switch. The third switch is connected in series with the fourth rotor pole coil and then connected in parallel with the fourth switch. The control box adjusts the number of poles by controlling the on and off of the first switch, the second switch, the third switch and the fourth switch.

4. The generator distributed parameter test device according to claim 1, characterized in that: The multiple coil connection methods include a three-phase one-branch coil phase symmetrical distribution wiring method, a three-phase one-branch coil phase asymmetrical distribution wiring method, a three-phase two-branch coil phase symmetrical distribution wiring method, and a three-phase two-branch coil phase asymmetrical distribution wiring method.

5. The generator distributed parameter test device according to claim 1, characterized in that: The neutral point grounding device includes an adjustable inductor, an adjustable resistor, an access / exit switch, a direct grounding switch and a wiring terminal. The wiring terminal is grounded via the access / exit switch, the adjustable resistor and the inductor. One end of the direct grounding switch is connected to the wiring terminal, and the other end of the direct grounding switch is grounded.

6. The generator distributed parameter test device according to claim 1, characterized in that: The capacitor configuration device includes multiple capacitor configuration units, the number of capacitor configuration units is consistent with the number of coils of the stator winding, each capacitor configuration unit matches a single coil of the stator winding, the input end of each capacitor configuration unit is connected to the head end of the corresponding coil of the stator winding, the output end of each capacitor configuration unit is grounded, and three branches are connected in parallel between the input end and the output end of each capacitor configuration unit, each branch includes a capacitor configuration switch and an AC capacitor connected in series, and the control box controls the on and off of each capacitor configuration switch to achieve the adjustment of the ground capacitance of each stator winding coil.

7. The generator distributed parameter test device according to claim 6, characterized in that: Each capacitor configuration unit also includes a current transformer, and the grounding end of the capacitor configuration unit is grounded after passing through the current transformer. The control box is also used to connect the current transformer to the channel of the oscilloscope of the control box according to test requirements to obtain the current parameters of each coil to ground.

8. A generator distributed parameter test method based on the generator distributed parameter test device according to any one of claims 1 to 7, characterized in that: include: Based on the test requirements, the control box completes the connection between the head and tail ends of each coil in the stator winding of the dynamic model generator according to the required coil connection method to achieve the distribution of coils of different phases in the winding; Control the neutral point grounding device to adjust the grounding impedance of the dynamic generator to the set grounding impedance and connect the neutral point of the stator winding; The control capacitance configuration device adjusts the capacitance of each coil in the stator winding to the ground to achieve different capacitance distribution of the winding; Controlling the rotor circuit of the dynamic mode generator so that the fixed angle between adjacent coils is equal to a preset verification phase angle; The neutral point and three outlets of the control stator winding, the head end of any coil, and the current transformer of the capacitor configuration device are connected to the channel of the oscilloscope of the control box according to the test requirements; Adjust the parameters of the variable frequency drive motor, control the starting excitation power supply and the variable frequency power supply to make the dynamic model generator run, so as to obtain the voltage parameters of the neutral point and three outlets of the stator winding, the voltage parameters of the first end of each coil, and the current parameters of each coil to ground.

9. The generator distributed parameter test method according to claim 8, characterized in that: The control capacitance configuration device adjusts the capacitance of each coil in the stator winding to the ground, including: The control box adjusts the capacitance of the coil of each stator winding to the ground by controlling the on and off of each capacitor configuration switch.

10. The generator distributed parameter test method according to claim 8, characterized in that: The step of controlling the rotor circuit of the dynamic mode generator so that the fixed angle between adjacent coils is equal to a preset verification phase angle comprises: The control box controls the on and off of the first switch, the second switch, the third switch and the fourth switch in the rotor circuit based on the on and off rules corresponding to the preset verification phase angle to adjust the number of magnetic poles, so that each coil of the stator winding is sequentially phase-differenced by the verification phase angle.

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