JP2800471B2 - Reactive power compensator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactive power compensator.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional reactive power compensator. In this circuit, as shown in FIG. 1, a DC reactor 2 is connected to a DC circuit in a three-phase full-wave rectifier circuit 1 using a self-extinguishing semiconductor element, which is a main converter. The reactive power compensator controls the reactive power that the device attempts to compensate by controlling the conduction phase angle of a three-phase full-wave rectifier circuit using a self-extinguishing semiconductor device.

[0003]

In the case of the reactive power compensating device shown in FIG. 4 in which delayed reactive power is generated by the device and the leading reactive power generated in the power supply system is compensated,
The conduction phase angle of the three-phase full-wave rectifier circuit 1 using the self-extinguishing type semiconductor rectifier element serving as the main converter is set to (90-ε) ° to (210).
−ε) When the amount of reactive power to be compensated is adjusted by changing ε as °, and the reactive power is advanced by the device to compensate for the delayed reactive power generated in the power supply system, the main converter and The conduction phase angle of the three-phase full-wave rectifier circuit 1 by the self-extinguishing type semiconductor rectifier is (ε-210) °.
The reactive power amount to be compensated is adjusted by changing ε as 〜 (ε−90) °.
Is applied with a DC voltage. However, in this device, the only elements that suppress the current flowing through the DC reactor 2 are the resistance on the wiring and the internal resistance of the DC reactor 2, so that the conduction phase angles (90−ε) ° to (210−ε) ° and (ε− There is a problem that it is difficult to obtain stable characteristics because the amount of reactive power to be compensated changes greatly only by changing ε in a small amount in the range of 210) ° to (ε−90) °. Therefore, the present invention is intended to easily obtain stable characteristics in a reactive power compensator.

[0004]

According to a first aspect of the present invention, there is provided a DC auxiliary device comprising a transformer and a three-phase full-wave thyristor rectifier circuit, the output voltage of which is adjustable in series with a DC reactor of a conventional reactive power compensator. The power supply circuit is connected, the conduction phase angle of the three-phase full-wave rectifier circuit of the self-extinguishing type semiconductor element as the main converter is made constant, and the firing phase angle of the three-phase full-wave thyristor rectifier circuit of the DC auxiliary power supply circuit is set. Change. Claim 2
In the present invention, a double connection rectifier circuit using a self-extinguishing semiconductor device is used as the main converter in the first embodiment. According to a third aspect of the present invention, a tap is provided on the DC side of the inter-phase reactor of the double connection rectifier circuit with an inter-phase reactor by a self-extinguishing semiconductor device as the main converter in the first aspect of the invention, and the self-extinguishing is performed on the tap. A rectifier circuit to which a type semiconductor element is connected is used. It is needless to say that a thyristor in this specification includes a GTO, an SI thyristor, and the like.

[0005]

According to the first aspect of the present invention, by using the means, it is possible to control the amount of reactive power to be compensated only by changing the firing phase angle of the three-phase bridge thyristor rectifier circuit of the DC auxiliary power supply circuit. Possible and easily obtain stable characteristics. Further, the DC auxiliary power supply circuit is also for compensating for the electric loss generated in the device, and its capacity may be sufficiently smaller than the amount of reactive power to be compensated by the device. According to the second aspect of the present invention, the harmonic current generated by the main converter in the first aspect can be reduced. According to the third aspect, the harmonic current generated by the main converter in the second aspect can be further reduced.

[0006]

FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a three-phase full-wave rectifier circuit using a self-extinguishing semiconductor device;
Is a DC reactor, 3 is a transformer, and 4 is a three-phase full-wave thyristor rectifier circuit. The circuit configuration is different from that of the conventional reactive power compensator shown in FIG.
And a DC auxiliary power supply circuit comprising a transformer 3 and a three-phase full-wave thyristor rectifier circuit 4 in series. In this device, the conduction phase angle of the three-phase full-wave rectifier circuit 1 using a self-extinguishing type semiconductor device is fixed, and the three-phase full-wave thyristor rectifier circuit 4
The amount of reactive power to be compensated is adjusted by adjusting the firing phase angle of. FIG. 2 shows another embodiment of the reactive power compensator of the present invention, in which a double connection rectifier circuit using a self-extinguishing semiconductor device is used as a main converter. In FIG. 2, 2 is a DC reactor, 3 is a transformer, 4 is a three-phase full-wave thyristor rectifier circuit, 5 is a primary winding of a transformer, 6 and 7 are secondary windings of a transformer, and 8 and 9 are self windings. A three-phase full-wave rectifier circuit 10 using an arc-extinguishing semiconductor device is an inter-phase reactor. As a circuit configuration, in the reactive power compensator according to claim 1 shown in FIG. 1, a three-phase full-wave rectifier circuit 1 including a self-extinguishing type semiconductor element as a main converter includes a primary winding 5, a secondary winding Line 6, 2
A three-phase full-wave rectifier circuit composed of a transformer composed of a secondary winding 7 and a self-extinguishing semiconductor element 8 A three-phase full-wave rectifier circuit 9 composed of a self-extinguishing semiconductor element and a self-extinguishing semiconductor element composed of an interphase reactor 10 It uses a double connection rectifier circuit. FIG. 3 shows still another embodiment of the reactive power compensator according to the present invention, wherein a tap is provided on the DC side of the interphase reactor of a double connection rectifier circuit with an interphase reactor as a main converter by a self-extinguishing semiconductor device. This is an embodiment in the case where a rectifier circuit to which an arc-extinguishing type semiconductor element is connected is used. In FIG. 3, 2 is a DC reactor, 3 is a transformer, 4 is a three-phase full-wave thyristor rectifier circuit, 5 is a primary winding of a transformer, 6 and 7 are secondary windings of a transformer, and 8 and 9 are Three-phase full-wave rectifier circuit with self-extinguishing semiconductor element, 11 is a tapped interphase reactor, 1
Reference numeral 2 denotes a self-extinguishing type semiconductor element. As the circuit configuration,
In the reactive power compensator according to claim 1 shown in FIG. 1, a three-phase full-wave rectifier circuit 1 comprising a self-extinguishing type semiconductor element as a main converter comprises a primary winding 5, a secondary winding 6, and a secondary winding. A three-phase full-wave rectifier circuit 9 using a transformer composed of a winding 7 and a self-extinguishing type semiconductor element 8;
Interphase reactor 11 with tap, self-extinguishing type semiconductor element 1
This embodiment uses a double connection rectifier circuit composed of two self-extinguishing semiconductor elements.

[0007]

According to the first aspect of the present invention, stable and highly accurate reactive power compensation can be easily performed as compared with the conventional reactive power compensator. According to the second aspect of the present invention, stable and highly accurate reactive power can be easily compensated when a double connection rectifier circuit using a self-extinguishing semiconductor element is used for the main converter in the first aspect of the invention. is there. According to a third aspect of the present invention, in the first aspect of the present invention, a tap is provided on the DC side of the interphase reactor of the double connection thyristor rectifier circuit with the interphase reactor in the main converter, and a thyristor is connected to the tap. In such a case, stable and highly accurate reactive power compensation can be easily performed.

[Brief description of the drawings]

FIG. 1 is an embodiment of the present invention.

FIG. 2 is an embodiment of the present invention.

FIG. 3 is an embodiment of the present invention.

FIG. 4 shows an example of a conventional reactive power compensator.

[Explanation of symbols]

1, 8, 9 Three-phase full-wave rectifier circuit with self-extinguishing semiconductor element 2 DC reactor 3 Transformer 4 Three-phase full-wave thyristor rectifier circuit 5 Primary winding of transformer 6, 7 Secondary winding of transformer DESCRIPTION OF SYMBOLS 10 Interphase reactor 11 Tapped interphase reactor 12 Self-extinguishing type semiconductor element

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-363707 (JP, A) JP-A-59-2222079 (JP, A) JP-A-56-33717 (JP, A) JP-A-51- 119956 (JP, A) JP-A-55-125082 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G05F 1/70 H02J 3/18

Claims (3)

(57) [Claims] 1. A three-phase full-wave rectifier circuit comprising a self-extinguishing semiconductor device as a main converter, a DC reactor connected to a DC circuit section of the main converter, and a series connection to the DC reactor. A DC auxiliary power supply circuit, comprising a transformer and a three-phase full-wave thyristor rectifier circuit, which regulates the amount of reactive power compensated by the device by controlling the output voltage while keeping the conduction phase angle of the main converter constant. And a reactive power compensating device comprising: 2. The reactive power compensator according to claim 1, wherein a double connection rectifier circuit using a self-extinguishing semiconductor device is used as the main converter. 3. A rectifier circuit as a main converter, wherein a tap is provided on the DC side of the interphase reactor of the double connection rectifier circuit with an interphase reactor using a self-extinguishing semiconductor element, and the self-extinguishing semiconductor element is connected to the tap. The reactive power compensator according to claim 1, wherein: