JPS6250913A - Invalid electric power adjusting device - Google Patents

Abstract

PURPOSE:To adjust the smooth invalid electric power simply and to eliminate the necessity of the maintenance almost by turning and positioning relatively the winding type rotor and the stator of the shifting device. CONSTITUTION:Switches S1-Sn and S1'-Sn' are all opened, so that a delay invalid electric power adjusting device 6 can obtain the maximum delay invalid electric powe, the rotational angle of a winding rotor 1 of a phase shifter M is adjusted to 180 deg. by a worm 5 to a stator 2. Next, switches S1' and S1 are inputted. At such a time, since the invalid electric power obtained by a capaci tor C1 and the delay invalid electric power obtained by the device 6 are equal, the total invalid electric power comes to be zero. Next, so that the invalid electric power obtained by the device 6 can come to be small, a rotational angle theta of the rotor 1 is decreased, the rotational angle theta is brought to 0 deg. and the switch S1' is opened. In the same way hereinafter, capacitors C2-Cn are proceeded and the invalid electric power is obtained. Thus, the total capacity of the phase shifter M and a transformer T can be decreased to 1/n of the capacitor K.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reactive power adjustment device that can arbitrarily adjust reactive power.

BACKGROUND ART Devices for adjusting reactive power include conventional devices such as synchronous phase modifiers, devices using an accelerator and a capacitor, and lagging reactive power adjusting devices using thyristors. However, since the synchronous phase modifier is a type of synchronous motor and a rotating machine, it has drawbacks such as a complicated starting device, time-consuming maintenance and inspection, and a large amount of noise. Furthermore, the method using the reactor and capacitor described above has the drawback that it is not possible to smoothly adjust the reactive power, and the changeover switch is worn out.

That is, since the reactor adjusts the reactive power by changing the number of turns of the winding by switching the tap, the reactive power is adjusted stepwise by this tap switching, and smooth adjustment is not possible. Furthermore, since the reactive power is adjusted by changing the number of capacitors that are turned on and off, the adjustment becomes stepwise.

In addition, a delayed reactive power adjustment device using a thyristor uses a thyristor to control the current flowing through a reactor, and allows smooth adjustment of reactive power, but has the disadvantage that harmonics are generated, which adversely affects the power supply.

Problems to be Solved by the Invention The object of the present invention is to improve the drawbacks of the above-mentioned prior art and provide a reactive power adjustment device that can smoothly adjust reactive power and requires almost no maintenance.

Means for Solving the Problems The present invention has a phase shifter and a transformer each comprising a wire-wound rotor and a stator, and the wire-wound rotor and stator of the phase shifter are each wound with a wire. Connect the terminals of the windings wound around the wire-wound rotor to the secondary terminals of the transformer, and connect the primary terminals of the transformer and the terminals of the windings wound around the stator. The wire-wound rotor and the stator were connected in parallel to a power source so that they could be rotated and positioned relative to each other.

By rotating and positioning either the working wire-wound rotor or the stator, reactive power can be varied and controlled in accordance with the amount of rotation.

Embodiment FIG. 1 shows an embodiment of the reactive power adjustment device of the present invention. The reactive power adjustment device is composed of a phase shifter M and a three-phase transformer T. Furthermore, terminals A, B, and C of the capacitor wired in three phases are connected to a three-phase AC power source A, B, and C.

The phase shifter M is composed of a wire-wound rotor 1 and a stator 2, a worm gear 4 is fixed to the rotor shaft 3 of the wire-wound rotor 1, and a worm 5 is meshed with the worm gear 4, By rotating the worm 5, the wire-wound rotor 1 can be rotated, and its stationary position relative to the stator 2 can be controlled. The stator 2 is provided with a three-phase primary winding, and terminals A and B thereof.

C is connected to a three-phase AC power supply, and the wire-wound rotor 1 is provided with a three-phase secondary winding, and its terminals a and b.

C is connected to secondary side terminals a, b, c of three-phase transformer T,
Primary terminals A, B, and C of the three-phase transformer T are connected to three-phase AC power supplies A, B, and C. J5, the three-phase winding of the wire-wound rotor 1 of the phase shifter M may be used as the primary winding, and the three-phase winding of the stator 2 may be used as the secondary winding. Furthermore, in the above embodiment,
Although the wire-wound rotor 1 of the phase shifter M can be rotated with respect to the stator 2, the stator 2 may be rotated with respect to the wire-wound rotor 1 conversely. Further, although the worm 5 and the worm gear 4 are used as means for relatively rotating the wire-wound rotor 1 or the stator 2, other configurations may be used.

Therefore, in this embodiment having the above configuration, the position of the wire-wound rotor 1 of the phase shifter M is rotated by the worm 5 and then stopped at a position rotated by an electrical angle θ, and the reactive power in this state is analyzed. do.

The voltage induced in the a phase of the three-phase winding of the wire-wound rotor 1 is 61
The induced voltage on the secondary side a-phase of the transformer T is 62.

The transformation ratio of the transformer T is 3 of the wire-wound rotor 1.
The voltage is selected so that the absolute value of the voltage a1 induced in the a-phase of the phase winding is equal to the absolute value of the induced voltage e2 in the secondary a-phase of the transformer T.

Now, assuming that the induced voltage δ2 is 62-E, the induced voltage 61 on the winding side becomes 6=E6JO since the position of the wire-wound rotor 1 has rotated by θ in electrical angle.

Now, if the sum of the leakage impedances for one phase of the winding of the wire-wound rotor 1 and the secondary winding of the transformer T is 7, the resistance valve is r, and the reactance is X, then the wire-wound rotor 1
The current I flowing from the a-phase terminal of the three-phase winding to the a-phase terminal on the secondary side of the transformer T is expressed by the following equation (1).

Zr + jx r + jx −= <
1) Therefore, if the conjugate of the current I is set to ■, then the reactive power QX due to the reactance X is expressed by the following equation (2).

E(εJθ−1) E(ε−Jo−1〉 Qx = x Il = x −−−□r + jx
r −jx εJθε−Jo−εJθ−ε−Jθ+1= X EQ
.

r'+x' 2-(CO3θ+j sinθ) -(cosθ-j
sinθ)2-(1-cosθ)=X EQ◆-1111-1.

r'+x' EQ 1 =□・□・2 (1-cosθ) X (r/x)2+1
(2) As can be seen from equation (2), by changing the position θ of the wire-wound rotor 1 of the phase shifter M, the reactive power Qx can be changed.

This relationship is illustrated in FIG. 2. That is,
If we take the position θ of the wire-wound rotor 1 on the horizontal axis and the reactive power on the vertical axis, then the reactive power due to the reactance
It becomes a curve of x.

Next, if the A-phase reactive power in the capacitor is Qc, this is leading reactive power, and since it is unrelated to the position θ of the wire-wound rotor 1, it becomes the straight line of QC in FIG. Therefore, the sum of Qx and Qc becomes the curve (Qx +Qc) in FIG.

As can be seen from the curve (QX +QC) in FIG. 2, the A-phase reactive power (Q
X +QC) can be changed from leading reactive power to lagging reactive power by changing the position θ of the wire-wound rotor 1 of the phase shifter M from 0 degrees to 180 degrees.

In the above explanation, only the A phase is considered, but the same applies to the B and C phases. Also, in the above explanation,
The reactive power due to the leakage reactance and excitation impedance of the stator 2 of the phase shifter M and the primary side of the transformer T is omitted - this is to simplify the explanation, and the actual reactive power is It will be included.

Next, a description will be given of adjusting the voltage at the receiving end using the reactive power adjusting device of the present invention.

As shown in Fig. 3, the voltage at the sending end is VS, the impedance of the line 1 is (R+j

Here, the reactive power adjusting device of the present invention is connected to the power receiving end in parallel with the load, so that the reactive power Q of the power receiving end can be adjusted by the reactive power adjusting device of the present invention.

Assuming that the current flowing through the line 1 is ti, this is expressed by the following equation (3).

i = (V s - ψ R + jX) ...
- As for (3), the receiving end voltage is set to Vr = Vrε-Jδ. Here, δ is the phase difference angle of the lightning pressure at the transmission and reception terminals.

Using the above equation (3), the complex power at the receiving end is expressed as follows.

Vs　Vr　,E-1δ-VrQ =□　　　　　・・・・・・(4)−jX When formula (4) is rearranged, it becomes formula (5).

(Pj Q) (P-j X) =Vs Vr e-
Jδ−Vr2 (5) Since the real part and the imaginary part on both sides of equation (5) are equal, the following equation (6) holds true.

RP1XQ+Vr' = Vr Vs cos δRQ-
XP=−Vr Vs sin δ (6) When the sum of the squares of the two equations in equation (6) is taken, the following equation is obtained.

(RP1XQ+Vr2)' + (RQ-XP)=y
r! 2ysQ...”
(7) Now, suppose that the reactive power Q at the receiving end is increased to (Q + ΔQ) by the reactive power adjustment device of the present invention.If the variation in the voltage at the receiving end in this case is Δ■r, this is expressed by the following equation. It becomes like this.

ΔVr = (6Vr / 8Q) ΔQ (8
) By calculating the partial differential (8Vr/6Q) from equation (1) and substituting it into equation (8), the following equation is obtained.

Z'Q + XVr2 ΔVr= −1−−−−−−−−−−−−・ΔQVr
(2XQ+2RP+2Vr'-Vs 2)...
...(9) t, : z = fr1TX7 As seen from equation (9), the coefficient of ΔQ is negative. Therefore, if the reactive power at the receiving end is increased by ΔQ using the reactive power adjustment device of the present invention, the receiving end voltage Vr will be reduced by Δvr. Conversely, when the reactive power at the receiving end is reduced by the reactive power adjustment device of the present invention, the receiving end voltage Vr increases by ΔVr.

In this way, the reactive power adjusting device of the present invention can adjust the receiving end voltage by changing the position θ of the wire-wound rotor.

Next, a method for reducing the wording of the reactive power adjustment device of the present invention will be described. Generally, many loads have a lagging power factor, so in order to compensate for the lagging reactive power, the reactive power adjustment device is often operated in leading phase mode. In such a case, the capacity of the reactive power adjustment device of the present invention can be reduced.

The method will be explained below.

The capacitor K shown in FIG. 1 is divided into an arbitrary number n of banks, and as shown in FIG.
2.83...Connect to the power supply via Sn. Note that the n capacitors C+, C2, and C2 of each bank are
The capacitances of C3...Cn are all made equal.

Furthermore, the delayed reactive power adjusting device 6 consisting only of the phase shifter M and the transformer T shown in FIG.
+ ' , 82 ' + Sa ' ++msn ' to the capacitors C1, C of each bank of n
2, C3......Connect in parallel to Cn, and connect the capacity of the delayed reactive power adjustment device 6 to one bank of capacitor IJ-C.
be equal to the capacity of I.

First, a case will be described in which the advanced reactive power is gradually increased from zero. Switch S1.82.

S3...Sn and switch S+', 82'
, 83'...Sn' are all left open.

The rotation angle of the wire-wound rotor 1 of the phase shifter M in Fig. 1 is set to 18 so that the delayed reactive power adjustment 1@6 obtains the maximum delayed reactive power.
Adjust to 0 degrees.

Next, the switch 81' in FIG. 4 is turned on, and then the switch S1 is turned on. In this state, capacitor C1
Since the lead reactive power taken by the lag reactive power and the lag reactive power taken by the lag reactive power adjusting device 6 are equal, their total reactive power becomes zero. Next, the rotation angle θ of the wire-wound rotor 1 of the phase shifter M is decreased to bring the rotation angle θ to zero degrees so that the delayed reactive power taken by the delayed reactive power adjustment device 6 is reduced. Then, the switch 81' is opened.

By doing this, the reactive power taken from the power supply starts from zero and progresses to the advanced reactive power taken by the capacitor C1, which increases the reactive power smoothly. Thereafter, following the same procedure, the capacitors C2, C3, . . . are turned on and reactive power is taken.

The above has explained the case where the advanced reactive power is gradually increased from zero, but if it is desired to decrease the reactive power conversely, the following operation is performed. Switch S1, 82.83
...3n are all turned on, and switch S1' is turned on.
, 82', S3'--...Sn' are all released. That is, an operation will be described in which the reactive power adjusting device of the present invention is brought into a state in which the maximum advanced reactive power is taken from the power source, and from this state, the reactive power is gradually decreased. First, the rotation angle θ of the wire-wound rotor 1 of the phase shift WM is adjusted to zero degrees so that the delayed reactive power taken by the delayed reactive power adjusting device 6 becomes small. Then, switch S+' is turned on. Then, the rotation angle of the wire-wound rotor 1 of the phase shifter M is increased to 180 degrees so that the delayed reactive power taken by the delayed reactive power adjusting device 6 becomes larger.

Then, SL is opened. Then, 81' is opened.

By doing this, the lead reactive power taken from the power supply is gradually reduced, and only the lead reactive power part taken by the capacitor C1 is reduced.

Following the same procedure, capacitors C2, C3...O
The leading reactive power taken by n is reduced.

In this way, the wording of the delayed reactive power adjustment device 6 can be reduced. That is, the phase shifter M shown in FIG.
and the total capacitance of the transformer T is 1/n of the capacitance of the capacitor.
can be reduced to

Although the above embodiment has been explained using a three-phase example, a phase shifter,
The transformer may be single-phase and used in a single-phase power supply.

Effects of the Invention As described above, the present invention makes it possible to easily and smoothly adjust the reactive power by simply rotating and positioning the wire-wound rotor and stator of the phase shifter relative to each other, thereby reducing the voltage at the receiving end. allows for easy adjustment.

And since no switches are used, there is less wear and tear and maintenance is easy.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of one embodiment of the present invention, Fig. 2 is a diagram showing the relationship between reactive power and the position of the wire-wound rotor according to the same embodiment, and Fig. 3 is an explanatory diagram of adjustment of receiving end voltage. , FIG. 4 is a diagram showing a method of reducing the capacity of the reactive power adjustment device. DESCRIPTION OF SYMBOLS 1... Wire-wound rotor, 2... Stator, 3... Rotor shaft, 4... Worm gear, 5... Worm, 6...
... Reactive power adjustment device, M, ... Phase shifter, T... Transformer, K... Capacitor, C1-Cn... Capacitor, 81-3n. S+'~Sn'...Switch.

Claims (9)

[Claims] (1) It has a phase shifter and a transformer consisting of a wire-wound rotor and a stator, and the wire-wound rotor and stator of the phase shifter are each wound with a winding, and the wire-wound rotor is wound with a winding. The terminals of the wound winding and the secondary terminal of the transformer are connected, and
The next terminal and the terminal of the winding wound on the stator are connected to a power source in parallel, and the rotor has means for relatively rotating and positioning either the wire-wound rotor or the stator. Power regulator. (2) The reactive power adjusting device according to claim 1, wherein a capacitor is connected in parallel with the reactive power adjusting device. (3) A plurality of capacitors are each connected to a power supply in parallel via a first switch, and the reactive power adjustment device is connected in parallel to each of the plurality of capacitors via a plurality of second switches. A reactive power adjustment device according to claim 1. (4) Claims 1 and 2, in which the winding wound around the stator is the primary winding, and the winding around the wire-wound rotor is the secondary winding. Or the reactive power adjustment device according to item 3. (5) Claims 1 and 2, in which the winding wound around the stator is a secondary winding, and the winding around the wire-wound rotor is a primary winding. Or the reactive power adjustment device according to item 3. (6) Claims 1, 2, and 3, wherein the rotating and positioning means fixes the stator and rotates and positions the wire-wound rotor relative to the stator. , the reactive power adjustment device according to item 4 or 5. (7) The rotating and positioning means fixes the wire-wound rotor and is capable of rotationally positioning the stator with respect to the wire-wound rotor.
5. The reactive power adjustment device according to item 4, item 5, or item 5. (8) Each of the above-mentioned windings and transformers are single-phase and connected to a single-phase power source. The reactive power adjustment device according to item 7. (9) Each of the windings and the transformer is three-phase, and is connected to a three-phase power source. The reactive power adjustment device according to item 7.