JP3407529B2 - Two-pole turbine generator and its rotor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbine generator and its rotor, and more particularly to a two-pole turbine generator using a massive iron core and its cylindrical rotor.

[0002]

2. Description of the Related Art A conventional cylindrical rotor of a turbine generator is provided with a field winding for exciting the generator by receiving a direct current power source from an exciting power source in the rotor. The rotor is made of a single steel ingot and is composed of a magnetic pole portion and a non-magnetic pole portion. The non-magnetic pole portion is provided with slots for inserting a plurality of windings in a circumferential direction in a massive rotor iron core at equal intervals, and teeth are provided between the slots. A field winding is provided in the slot, and the rotor winding inserted in the upper portion of the field winding holds the field winding.

In the large-capacity machine, in the cylindrical rotor of the turbine generator described above, the size of the magnetic pole portion where no slot is provided, that is, the angle θ between the slots closest to the magnetic pole portion with the magnetic pole portion as a boundary. Is generally selected so that the magnetic flux in the gap approaches a sine wave so that the voltage waveform of the generator becomes good. On the other hand, at this time, in order to obtain the field magnetomotive force necessary for exciting the generator, for example, JP-A-49-45
As described in Japanese Patent Publication No. 307, the required depth of field is adjusted so that the cross section of the field winding is adjusted by adjusting the depth and width of the slot so as not to exceed the predetermined temperature rise limit of the field winding. I try to secure the magnetomotive force.

[0004]

In the above conventional technique, the angle θ between the slots closest to the magnetic pole portion (hereinafter referred to as the magnetic pole angle θ) is a sinusoidal wave distribution of the gap magnetic flux of the generator when no load is applied. It is selected to be the closest value, 2
For polar machines, θ = 60 ° is selected. In FIG. 6, the horizontal axis is the magnetic pole angle θ, and the waveform deviation rate kw of the terminal voltage under no load, that is, the maximum difference between the instantaneous value of a wave containing a harmonic component and the instantaneous value of a sine wave equivalent to the wave. An example is shown in which the vertical axis represents the numerical value kw expressed as a percentage with respect to the peak value of the equivalent sine wave. Here, the waveform deviation rate kw of the terminal voltage increases as the waveform moves away from the sine wave, and becomes minimum at a magnetic pole angle θ of 60 ° as can be seen from FIG. 6.

However, even if the magnetic pole angle θ is 60 ° and becomes the closest to the sinusoidal magnetic flux distribution when there is no load, the waveform deviation rate is not the minimum when the generator is actually loaded and operated. It was found by the inventor. Also, even if the magnetic pole angle θ is set to 60 °, the field magnetomotive force required to excite the generator is not always minimized under load, and the temperature rise and loss of the field winding must not be minimized. I understood.

A first object of the present invention is to reduce the waveform deviation rate under load to improve the quality of power supply and to reduce the required field current under load, and a two-pole turbine generator and its rotor. To provide.

A second object of the present invention is to obtain a two-pole turbine generator having the same size and a large output.

A third object of the present invention is to provide a two-pole turbine generator capable of reducing the capacity of an exciter for exciting a field and a rotor thereof.

[0009]

In order to achieve the above object, a two-pole turbine generator of the present invention comprises a stator and a rotor supported by a bearing with a gap from the stator. In a two-pole turbine generator, the rotor has a massive rotor core having a magnetic pole portion, a plurality of winding insertion slots other than the magnetic pole portion, and teeth formed between the slots, and the winding insertion core. Field winding inserted in the slot,
A wedge for holding the field winding, wherein an angle between the winding insertion slots closest to the magnetic pole portion is θ,
When the number of slots for winding insertion is Nr, θ is 65
Within the range of ° ≦ θ <75 ° and Nr is Nr = 20 + 4 m
It is characterized in that it is configured to have a relationship of (m = 1, 2, 3). Further, when the angle between the winding insertion slots closest to the magnetic pole portion is θ and the number of the winding insertion slots is Nr, θ is in the range of 75 ° ≦ θ <80 ° and Nr is Nr = 16 + 4 m. (M = 1,2,3)
It is characterized in that it is configured to have the relationship of.

Further, the rotor is a massive rotor iron core having a magnetic pole portion, a plurality of winding insertion slots provided at equal intervals other than the magnetic pole portion, and teeth formed between the slots. In a rotor of a two-pole turbine generator equipped with a field winding inserted in the winding insertion slot and a wedge for holding the field winding, the winding is inserted near the magnetic pole part. When θ is the angle between slots and Nr is the number of slots for winding insertion, θ is in the range of 65 ° ≦ θ <75 ° and Nr is Nr = 20 + 4 m (m = 1, 2, 3). It is characterized in that it is configured to have. Further, when the angle between the winding insertion slots closest to the magnetic pole portion is θ and the number of the winding insertion slots is Nr, θ is in the range of 75 ° ≦ θ <80 ° and Nr is Nr =
It is characterized in that it is configured to have a relationship of 16 + 4 m (m = 1, 2, 3).

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. 1 is a cross-sectional view of a rotor of a two-pole turbine generator of this embodiment, FIG. 2 is a cross-sectional view of a two-pole turbine generator of this embodiment, and FIG. FIG. 4 is a diagram showing the relationship of the terminal voltage waveform deviation rate kw,
FIG. 5 is a diagram showing the relationship between the magnetic pole angle θ and the required field magnetomotive force ATf under load, and FIG. 5 is a diagram showing the magnetic pole angle and the selection range of the number of slots in the present embodiment. Here, FIGS. 1 and 2 show only one of the two poles, and in the following description, the central axis 12 of the magnetic pole portion 6 will be referred to as a straight axis.

As shown in FIG. 2, the turbine generator of this embodiment is mainly composed of a stator 1 and a rotor 2 bearing-supported (not shown) so as to have the stator 1 and a gap 11. . The stator 1 is provided with a stator slot 3 in a laminated iron core, and the stator slot 3 is provided with an armature winding 4. As the armature winding 4, a hexagonal copper wire formed into a hexagonal coil is used, and in order to hold the armature winding 4, a stator wedge 5 is inserted into the opening of the stator slot 3. Has been done.

The rotor 2 of the turbine generator is made of a single steel ingot to have mechanical strength, and the magnetic pole portion 6
And a non-magnetic pole portion are formed. Rotor 2 for non-pole
Rotor slots 7 for inserting a plurality of windings are provided at equal intervals in the circumferential direction, and teeth 8 are provided between the slots 7. A field winding 9 is provided in the slot 7, and a rotor wedge 10 is inserted in the upper portion of the field winding 9, that is, on the side of the stator to hold the field winding 9. The field winding 9 is formed by flattening a bare copper strip to insulate the layers. With this configuration, by exciting the field winding 9,
A magnetic flux can be generated in the direction of. Here, a plurality of slots 7 are installed, and the slots 9
Each of the slots 7 up to 0 ° apart is attached to the magnetic pole portion 6
Sn, Sr, ..., Snr in order of increasing distance from the nearest, the number Nr of slots 7 is Nr = 4 × nr because it is a two-pole machine. In addition, as shown in FIG. 1, at least the depth of the slot S1 closest to the magnetic pole portion 6 is set to be equal to or less than the depth of the other slots, and the gap between the bottom portions of the slots S1 closest to the magnetic pole portion 6 is widened. Saturation may be relaxed.

In the present embodiment, in the rotor 2 shown in FIG. 1, the angle θ of the magnetic pole portion 6, that is, the angle θ between the slots S1 centered on the straight axis 12 and the number Nr of slots 7 for winding insertion. In the range of 65 ° ≦ θ <75 ° and Nr = 20
+ 4m (where m = 1, 2, 3), or 75 ° ≤
In the range of θ <80 ° and Nr = 16 + 4 m (here, m
= 1,2,3).

The basis for such selection will be described below. In this description, the magnetic pole angle θ is examined in the range of 40 ° to 90 °, and the number of slots Nr is 16,2.
It was set to 0, 24, 28, 32, 36. Here, the number of slots Nr is set to be a multiple of 4 because a rotor that is symmetrical with respect to the magnetic poles in a two-pole machine is considered.

FIG. 3, which shows the relationship between the magnetic pole angle θ and the terminal voltage waveform deviation rate kw under load, is intended for a 100 MVA class two-pole turbine generator, and the delay of the rated power factor is 0.9 p.
An example is shown for u. At this time, the field winding,
The size of the slots is selected and designed so that the mechanical strength of the rotor can be satisfied under the conditions of the magnetic pole angle θ and the number of slots Nr. Also, the reciprocal of the unit method display of the synchronous reactance of the generator is the short-circuit ratio, and when designing a generator, in general, it is necessary to balance the stability of the power system to which the generator is connected with the generator's physique. Since it is necessary to maintain the short-circuit ratio at a certain value, the comparison is performed under the condition that the synchronous reactances of the generators are the same in any design.

Here, the number of slots Nr = 24 indicated by black dots in FIG. 3 and the magnetic pole angle θ = 40, 60, 7
The 5 points of 0, 80, 90 degrees are the points measured by a small model with a similar cross section to a 100 MAV class two-pole turbine generator, and the other white points are the points when the load is calculated from these measured points. Is the terminal voltage waveform deviation rate kw. Figure 3
As can be seen from the above, no matter which slot number Nr is selected, the terminal voltage waveform deviation rate kw under load can be reduced within the range of the magnetic pole angle θ of about 65 ° to 80 °. This result is
The magnetic flux angle θ is 60 ° under no load, and the terminal voltage waveform deviation rate kw is the smallest, which is different from the conventional result. However, since the current flowing through the armature winding 4 causes an armature reaction when loaded, the magnetic flux density Of the gap in the gap 1
This is because the magnetic flux density distribution at 1 is significantly different from that at no load. The value of the waveform deviation rate kw also changes depending on the number of slots Nr. If the magnetic pole angle θ is the same, kw becomes smaller as the number of slots increases. This is because as the number of slots Nr is larger, the winding components are distributed and arranged, so that the harmonic components included in the gap magnetic flux density distribution are reduced.

In the conventional turbine generator, the magnetic pole angle θ is 6
About 0 ° and the number of slots Nr is selected to 24, 28, or 32. In FIG. 3, the magnetic pole angle θ = 60
3 and the case where Nr = 32 out of Nr = 24, 28, 32 is indicated by an X mark in FIG. 3, but in the case of no load,
The waveform deviation rate kw becomes the smallest at the conventional magnetic pole angle θ = 60 °. It is the portion within the shaded area in FIG. 3 that the waveform deviation rate kw can be made smaller than the point indicated by the cross mark.

FIG. 4 shows the relationship between the magnetic pole angle θ and the required field magnetomotive force ATf at the time of loading, but shows the case where comparison is made under the same conditions as in FIG. Here, the five points with the number of slots Nr = 24 and the magnetic pole angles θ = 40, 60, 70, 80, 90 ° indicated by the black dots in FIG. 4 are two poles of 100 MAV class as in FIG. The required field magnetomotive force measured by a small model having a cross section similar to that of the turbine generator is converted into the field magnetomotive force of a 100 MAV class two-pole turbine generator, and other white points are those points. It is the required field magnetomotive force ATf under load estimated from Figure 4
As shown in FIG. 5, no matter which slot number Nr is selected, the required field magnetomotive force ATf at the time of load is small in the range of the magnetic pole angle θ of about 65 ° to 80 °.

That is, it can be seen that the required field magnetomotive force ATf at the time of load is not minimum at the magnetic pole angle θ = 60 ° at which the terminal voltage waveform deviation rate kw becomes the smallest under no load. The reason why the required field magnetomotive force ATf under load is small in the range where the magnetic pole angle θ is about 65 ° to 80 ° is as follows. In the region where the magnetic pole angle is small, increasing the magnetic pole angle θ reduces the magnetic saturation of the magnetic pole portion 6 and reduces ATf. In the region where the magnetic pole angle is large, the magnetic pole angle becomes large and the magnetic saturation of the magnetic pole portion 6 is alleviated,
This is because the synchronous reactance increases, so that the radial length of the gap 11 must be increased in order to maintain the synchronous reactance at the same value, and the magnetic resistance of the gap 11 increases. Therefore, the magnetic pole angle θ is 65 ° to 8
The required field magnetomotive force ATf under load can be minimized near 0 °. Further, the value of the required field magnetomotive force ATf is
The number of slots Nr also changes, and if the magnetic pole angle θ is the same, the smaller the number of slots, the more the ATf can be reduced. This means that the smaller the number of slots Nr, the more slots 7
Of the leakage magnetic flux passing between the tips of the teeth 8 on the gap 11 and the inner diameter side of the stator 1 without interlinking with the armature winding 4 because the opening width of the tooth 7 increases and the width-direction magnetic resistance on the upper side of the slot 7 increases. This is because the total magnetic flux passing through the rotor 2 is reduced and the magnetic saturation of the rotor 2 is alleviated due to the decrease of the.

In FIG. 4, the magnetic pole angle .theta.
= 60 ° and Nr = 24, 28, 32, a point indicated by a cross in FIG. 4 is a case where the field magnetomotive force ATf at the time of load becomes the smallest, and Nr = 24. ing.
The field magnetomotive force ATf at the time of loading can be made smaller than the point of this X mark in the portion in the shaded area in FIG.

FIG. 5 is a diagram showing a selection range of the magnetic pole angle and the number of slots in the present embodiment. In FIG. 4, a region where the waveform deviation rate kw under load can be reduced as compared with the current machine shown in FIG. It shows a region where the field magnetomotive force ATf under load can be reduced as compared with the current machine shown. Also, as far as the numerical values in the shaded areas in FIGS. 3 and 4 are concerned, in the range in which θ changes by about 5 °, the numerical values of the waveform deviation rate kw and the field magnetomotive force ATf do not significantly change, so in FIG. , The magnetic pole angle θ is shown at 5 ° intervals. As shown in FIG. 5, 65 ° ≦ θ <75 ° and Nr = 20 + 4 m (here, m = 1, 2, 3), or 75 ° ≦ θ <80 ° and Nr = 16 + 4 m (here, m = 1, 2, 3), the waveform deviation rate kw and the required magnetomotive force A when the load is higher than that of the current machine in a region satisfying any of the relations.
Tf can be reduced.

As described above, by selecting a range in which the magnetic pole angle and the waveform deviation rate can be reduced, the waveform of the terminal voltage at the time of load is improved, the quality of the supplied power is improved, and the field at the time of load is improved. The current can be reduced. As a result, it is possible to improve the generator efficiency and reduce the temperature rise of the field winding by reducing the copper loss of the field winding.

In the present embodiment, the analysis result of the 100 MVA class generator is described. In addition to this, based on the measurement result of the similarity model of the 100 MVA class generator, 200 MVA is obtained.
It was confirmed that the same results as in this example were obtained even when the estimation of the class, 700 MVA class, and 1000 MVA class machines was performed. On the other hand, even if the power factor is estimated to fall within the range of 0.8 pu to 1.0 pu, it has been confirmed that the same result is obtained.

Further, as described in, for example, Japanese Patent Publication No. 60-34340, when the rotor 2 is constructed by inserting a damper bar between the field winding 9 and the rotor wedge 10. Also, the configuration of the present embodiment described above can be applied, and the same effect can be obtained.

[0026]

As described above, according to the present invention, it is possible to improve the quality of the supplied power by improving the waveform of the terminal voltage when the load is applied and to reduce the field current when the load is applied. . As a result, it is possible to improve the generator efficiency and reduce the temperature rise of the field winding by reducing the copper loss of the field winding. Further, there is an effect that a turbine generator having the same physical structure and a large output can be obtained. In addition, the capacity of the exciter for exciting the field can be reduced, and the entire power generation system can be economically and compactly constructed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a rotor of a two-pole turbine generator showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the two-pole turbine generator of this embodiment.

FIG. 3 is a diagram showing a relationship between a magnetic pole angle and a waveform deviation rate under load.

FIG. 4 is a diagram showing a relationship between a magnetic pole angle and a field magnetomotive force under load.

FIG. 5 is a diagram showing a relationship between a magnetic pole angle and the number of slots showing the range of the present embodiment.

FIG. 6 is a diagram showing a relationship between a magnetic pole angle and an unloaded waveform deviation rate.

[Explanation of symbols]

2 ... Rotor, 6 ... Magnetic pole part, 7 ... Rotor slot, 8 ... Rotor teeth, 9 ... Field winding, 10 ... Rotor wedge.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Takahashi 7-2-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi, Ltd. Electric Power & Electric Development Division (72) Haruo Obaragi Omika-cho, Hitachi-shi, Ibaraki 7-2-1, Hitachi Ltd., Electric Power & Electric Machinery Development Headquarters (72) Inventor Shinichi Yukai 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Miyagawa Ieda 3-1, 1-1 Sachimachi, Hitachi, Ibaraki Hitachi Ltd., Hitachi factory (72) Inventor Yasuomi Yagi 3-1-1, Sachimachi, Hitachi, Ibaraki Hitachi, Ltd. (56) Reference References JP-A-4-21338 (JP, A) JP-A-6-14502 (JP, A) JP-A-7-95752 (JP, A) JP-A-6-178480 (J , A) JP Akira 50-26011 (JP, A) JP flat 3-261340 (JP, A) (58 ) investigated the field (Int.Cl. ^7, DB name) H02K 1/26 H02K 19/26

Claims (6)

(57) [Claims] 1. A two-pole turbine generator comprising a stator and a rotor supported by bearings with a gap from the stator, wherein the rotor comprises a magnetic pole part and a plurality of parts other than the magnetic pole part. A lumped rotor core having winding insertion slots and teeth formed between the slots, a field winding inserted in the winding insertion slot, and a wedge for holding the field winding. When the angle between the winding insertion slots closest to the magnetic pole portion is θ and the number of the winding insertion slots is Nr, θ is in the range of 65 ° ≦ θ <75 ° and Nr. Is configured so as to have a relationship of Nr = 20 + 4 m (m = 1, 2, 3), a two-pole turbine generator. 2. A two-pole turbine generator comprising a stator and a rotor supported by bearings with a gap from the stator, wherein the rotor comprises a magnetic pole part and a plurality of parts other than the magnetic pole part. A lumped rotor core having winding insertion slots and teeth formed between the slots, a field winding inserted in the winding insertion slot, and a wedge for holding the field winding. When the angle between the winding insertion slots closest to the magnetic pole portion is θ and the number of the winding insertion slots is Nr, θ is in the range of 75 ° ≦ θ <80 ° and Nr. Is configured so as to have a relationship of Nr = 16 + 4 m (m = 1, 2, 3), a two-pole turbine generator. 3. A mass rotor core having a magnetic pole portion, a plurality of winding insertion slots provided at equal intervals other than the magnetic pole portion, and teeth formed between the slots, and the winding insertion core. In a rotor of a two-pole turbine generator including a field winding inserted in a slot and a wedge for holding the field winding, an angle between the winding insertion slots closest to the magnetic pole portion is θ. , Θ is in the range of 65 ° ≦ θ <75 ° and Nr is Nr =
A rotor for a two-pole turbine generator, characterized in that it is configured to have a relationship of 20 + 4 m (m = 1, 2, 3). 4. A lump rotor core having a magnetic pole portion, a plurality of winding insertion slots provided at equal intervals other than the magnetic pole portion, and teeth formed between the slots, and the winding insertion core. In a rotor of a two-pole turbine generator including a field winding inserted in a slot and a wedge for holding the field winding, an angle between the winding insertion slots closest to the magnetic pole portion is θ. When the number of slots for winding insertion is Nr, θ is in the range of 75 ° ≦ θ <80 ° and Nr is Nr =
A rotor for a two-pole turbine generator, which is configured to have a relationship of 16 + 4 m (m = 1, 2, 3). 5. The generator is 100 MVA class to 1000.
The two-pole turbine generator according to claim 1 or 2, which is in the MVA class range. 6. A rotor for a two-pole turbine generator according to claim 3, wherein a damper bar is mounted between the field winding and the rotor wedge.