JP3526170B2 - Reactive power adjustment device - 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 adjusting device which is connected to a power system and is used for voltage stabilization and reactive power adjustment.

[0002]

2. Description of the Related Art In recent years, a reactive power adjusting device has been used to stabilize the voltage of a power system and reduce the power loss of electric wires. Conventionally, this type of reactive power adjusting device has generally been configured as shown in FIG. The configuration will be described below. FIG. 4 shows an example of the configuration of a conventional reactive power adjusting device. In FIG. 4, 1 is a first reactor, 20 is a second reactor, and 21 is a capacitor, which are connected in series. A thyristor 4 is formed at a connection point between the first reactor 1 and the second reactor 20.

The reactive power adjusting device having this structure is provided with a switch 5
It is connected to a three-phase power system such as a distribution line via the phase control of the firing angle of the thyristor 4 to control the reactive power amount of the reactive power adjusting device. Depending on the voltage of the three-phase power system, a transformer may be provided between the switch 5 and this reactive power adjusting device. Further, the harmonic current distortion generated by controlling the firing angle of the thyristor 4 in phase is
Outflow from the inside of the reactive power adjusting device to the power system such as a distribution line via the switch 5 is suppressed.

[0004]

However, this conventional reactive power adjusting device has not been provided with means for absorbing harmonic voltage distortion of the power system such as a distribution line. In general, the harmonic voltage distortion in the three-phase power system is the largest in the fifth harmonic voltage distortion, and is the seventh, eleventh, etc. below.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a reactive power adjusting device capable of stabilizing the voltage of a power system and adjusting the reactive power as well as improving harmonic voltage distortion included in the power system.

[0006]

According to a first aspect of the present invention, there is provided a reactive power regulating device comprising a first reactor connected to a power system, a reactor and a capacitor, and a fifth reactor connected in series to the first reactor. An internal fifth harmonic filter that absorbs current distortion of the next harmonic, and an internal seventh harmonic that is composed of a reactor and a capacitor and is connected in series to the first reactor to absorb the current distortion of the seventh harmonic. A wave filter and a thyristor connected in parallel to the internal fifth-order harmonic filter and the internal seventh-order harmonic filter to control reactive power by controlling the phase.
Basic of the capacitor of the internal fifth harmonic filter
For the wave capacity, the internal fifth-order harmonic filter
Basic with reactor and the first reactor added
When the wave capacity is 6% or more, the first reactor and the internal fifth-order harmonic filter generate delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system, and the first reactor.
The reactor and the internal seventh harmonic filter connected in series to this reactor constitute a fifth harmonic filter as seen from the power system.

According to the reactive power control apparatus of the first aspect, the advance reactive power to the delayed reactive power can be controlled by phase-controlling the firing angle of the thyristor. Further, the harmonic current distortion in the reactive power control device generated by the phase control by the thyristor is the fifth harmonic filter and the seventh harmonic filter.
It is absorbed by the second harmonic filter. Further, it becomes possible to absorb the fifth harmonic existing in the power system through the first reactor by the internal seventh harmonic filter configured inside the reactive power adjusting device. In addition, since the circuit formed by the first reactor, the reactor 2 of the internal fifth-order harmonic filter and the capacitor 3 is delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system as seen from the power system, It has the effect of absorbing the second harmonic voltage without expanding it. In this way, the effect of absorbing the harmonic distortion of the power system while preventing the harmonics generated by the phase control by the thyristor from being absorbed by the harmonic filter configured inside the reactive power regulator and flowing out to the power system As a result, it is possible to provide a reactive power adjustment device that exerts a great effect on the quality improvement of the power system.

According to a second aspect of the present invention, in the reactive power control apparatus according to the first aspect, the reactor and the capacitor are connected in series to the first reactor and are connected in parallel to the thyristor so that the 11th harmonic current distortion occurs. It has an internal 11th-order harmonic filter that absorbs, and constitutes a 7th-order harmonic filter as seen from the power system, with the first reactor and the internal 11th-order harmonic filter connected in series with this. is there.

According to the reactive power control apparatus of the second aspect, in addition to the same effect as that of the first aspect, the eleventh aspect of the reactive power control apparatus generated by the phase control by the thyristor.
The next harmonic current distortion is absorbed by the internal 11th harmonic filter, and the 7th harmonic existing in the power system is first absorbed.
It becomes possible to absorb by the internal 11th harmonic filter configured inside the reactive power adjusting device through the reactor.

According to a third aspect of the present invention, in the reactive power control apparatus according to the second aspect, the reactor and the capacitor are connected in series to the first reactor and are connected in parallel to the thyristor so that the thirteenth harmonic current distortion occurs. And an internal 13th-order harmonic filter that absorbs, and the 1st reactor and the internal 13th-order harmonic filter connected in series to the 1st reactor constitute an 11th-order harmonic filter viewed from a power system. It is a thing.

According to the reactive power control apparatus of the third aspect, in addition to the same effect as that of the second aspect, the thirteenth aspect of the reactive power control apparatus which is generated by the phase control by the thyristor.
The next harmonic current distortion is absorbed by the 13th harmonic filter, and the 11th harmonic existing in the power system is formed by the internal 13th harmonic filter configured inside the reactive power regulator through the first reactor. It becomes possible to absorb.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the reactive power adjusting device includes a first reactor 1 connected to a three-phase power system via a switch 5, a reactor 2 and a capacitor 3 in series with the first reactor 1. Internal 5th harmonic filter 15 connected to absorb current distortion of 5th harmonic
An internal seventh harmonic filter 16 configured by a reactor 7 and a capacitor 8 connected in series to the first reactor 1 to absorb current distortion of the seventh harmonic, an internal fifth harmonic filter 15 and Internal 7th harmonic filter 16
, And a thyristor 4 which is connected in parallel between the three phases to control the reactive power by controlling the phase.

Further, the first reactor 1 and the internal fifth-order harmonic filter 15 are configured so as to be delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system. Specifically, the fundamental wave capacity obtained by adding the reactor 2 and the first reactor 1 of the internal fifth-order harmonic filter 15 to the fundamental wave capacity of the capacitor 3 of the internal fifth-order harmonic filter 15 is 6%. That's it. That is, the impedance of the circuit formed by connecting the reactor and the capacitor in series is represented by 2πfL- (1 / 2πfC), where f is the frequency of the alternating current applied to this circuit. If this value is> 0, the circuit will be delayed reactive power.

When 2πfL = (6/100) × (1 / 2πfC) at the fundamental frequency, the impedance of this circuit when a frequency five times the fundamental frequency is applied to this circuit is 2π (5f) L- {. 1 / 2π (5f) C}. Substituting the previous equation into this equation, 5 × (6/100) × (1 / 2πfC) − {1 / 2π
(5f) C} = (1/10) × (1 / 2πfC)> 0, which results in delayed reactive power.

In this embodiment, a fifth-order harmonic filter viewed from the electric power system is formed by the first reactor 1 and the reactor 7 and the capacitor 8 of the internal seventh-order harmonic filter 16 connected in series to the first reactor 1. I am configuring. The operation of this reactive power adjusting device will be described. This reactive power adjusting device is used for reactive power or voltage adjustment in a three-phase power system, and by controlling the firing angle of the thyristor 4 in phase, the reactive power is delayed from the reactive power. Power can be controlled. Further, by controlling the phase of the thyristor 4, the harmonic current distortion generated in the reactive power regulator is absorbed by the internal harmonic filters 15 and 16 described above, so that the switch 5 which is turned on when the reactive power regulator is operated. To prevent harmonic current from flowing into the power system.

On the other hand, the fifth harmonic existing in the power system is
Through the first reactor 1, it can be absorbed by the seventh harmonic filter 16 configured inside the reactive power adjusting device. Furthermore, as seen from the electric power system, the first reactor 1,
In addition, the circuit formed by the reactor 2 and the capacitor 3 of the internal fifth-order harmonic filter 5 becomes delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system, and absorbs the fifth-order harmonic voltage without expanding it. .

As a result, the reactive power adjusting apparatus can absorb the fifth harmonic distortion of the power system in addition to stabilizing the voltage of the power system and adjusting the reactive power. A second embodiment of this invention is shown in FIG. That is, this reactive power adjusting device in the first embodiment is composed of the reactor 9 and the capacitor 10 and is connected in series to the first reactor 1 and connected in parallel to the thyristor 4 to generate the 11th harmonic. An internal 11th-order harmonic filter 17 that absorbs current distortion is added, and the reactor 9 and the capacitor 10 of the internal reactor 11 and the internal 11th-order harmonic filter 17 connected in series with the first reactor 1 are connected to the power system. It is composed of the 7th harmonic filter.

According to this embodiment, the 11th-order harmonic current distortion in the reactive power control device generated by the phase control by the thyristor 4 is absorbed by the internal 11th-order harmonic filter 17, and the power is reduced. It becomes possible to absorb the 7th harmonic existing in the system through the first reactor 1 by the reactor 9 and the capacitor 10 of the 11th harmonic filter 17 configured inside the reactive power adjusting device.

Others are the same as those in the first embodiment. A third embodiment of the present invention is shown in FIG. That is, this reactive power adjusting device in the second embodiment is composed of the reactor 11 and the capacitor 12 and is connected in series to the first reactor 1 and in parallel to the thyristor 4 so as to generate the 13th harmonic wave. An internal 13th-order harmonic filter 18 that absorbs current distortion is added, and the 11th-order harmonic filter viewed from the power system by the first reactor 1 and the internal 13th-order harmonic filter 18 connected in series to this Is configured.

According to this embodiment, the thirteenth harmonic current distortion in the reactive power controller generated by the phase control by the thyristor 4 is the thirteenth harmonic filter 18.
And the 11th harmonic existing in the power system may be absorbed by the reactor 11 and the capacitor 12 of the internal 13th harmonic filter 18 formed inside the reactive power adjusting device through the first reactor 1. It will be possible.

Others are the same as those in the second embodiment.

[0022]

According to the reactive power control apparatus of the first aspect, it is possible to control from advanced reactive power to delayed reactive power by controlling the firing angle of the thyristor in phase. Further, the harmonic current distortion in the reactive power control device generated by the phase control by the thyristor is the fifth harmonic filter and the seventh harmonic filter.
It is absorbed by the second harmonic filter. Further, it becomes possible to absorb the fifth harmonic existing in the power system through the first reactor by the internal seventh harmonic filter configured inside the reactive power adjusting device. In addition, since the circuit formed by the first reactor, the reactor 2 of the internal fifth-order harmonic filter and the capacitor 3 is delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system as seen from the power system, It has the effect of absorbing the second harmonic voltage without expanding it. In this way, the effect of absorbing the harmonic distortion of the power system while preventing the harmonics generated by the phase control by the thyristor from being absorbed by the harmonic filter configured inside the reactive power regulator and flowing out to the power system As a result, it is possible to provide a reactive power adjustment device that exerts a great effect on the quality improvement of the power system.

According to the reactive power control apparatus of the second aspect, in addition to the same effect as the first aspect, the eleventh reactive power control apparatus in the reactive power control apparatus which is generated by the phase control by the thyristor.
The next harmonic current distortion is absorbed by the internal 11th harmonic filter, and the 7th harmonic existing in the power system is first absorbed.
It becomes possible to absorb by the internal 11th harmonic filter configured inside the reactive power adjusting device through the reactor.

According to the reactive power control apparatus of the third aspect, in addition to the same effect as that of the second aspect, the thirteenth element in the reactive power control apparatus which is generated by the phase control by the thyristor.
The next harmonic current distortion is absorbed by the 13th harmonic filter, and the 11th harmonic existing in the power system is formed by the internal 13th harmonic filter configured inside the reactive power regulator through the first reactor. It becomes possible to absorb.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a configuration of a three-phase reactive power regulator according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a configuration of a three-phase reactive power regulator according to a second embodiment.

FIG. 3 is a circuit configuration diagram showing a configuration of a three-phase reactive power regulator according to a third embodiment.

FIG. 4 is a circuit configuration diagram showing a configuration of a conventional three-phase reactive power regulator.

[Explanation of symbols]

1 first reactor 2 reactor 3 capacitors 4 Thyristor 5 switch 7 reactor 8 capacitors 9 reactor 10 capacitors 11 reactor 12 capacitors 15 Internal fifth harmonic filter 16 Internal 7th harmonic filter 17 Internal 11th harmonic filter 18 Internal 13th harmonic filter

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G05F 1/70 H02J 3/18 H03H 7/01

Claims (3)

(57) [Claims] 1. An internal fifth harmonic wave which is composed of a first reactor connected to a power system, a reactor and a capacitor, and which is connected in series to the first reactor and absorbs current distortion of the fifth harmonic wave. A filter, an internal 7th harmonic filter, which is composed of a reactor and a capacitor, is connected in series to the 1st reactor and absorbs current distortion of the 7th harmonic, the internal 5th harmonic filter and the internal And a thyristor connected in parallel to the seventh harmonic filter to control the reactive power by controlling the phase,
Basic of the capacitor of the internal fifth harmonic filter
For the wave capacity, the internal fifth-order harmonic filter
Basic with reactor and the first reactor added
When the wave capacity is 6% or more, the first reactor and the internal fifth-order harmonic filter generate delayed reactive power with respect to the fifth-order harmonic voltage distortion of the power system, and the first reactor.
And the internal seventh harmonic filter connected in series to the reactor to form a fifth harmonic filter as seen from the power system. 2. An internal 11th-harmonic filter, which comprises a reactor and a capacitor, is connected in series with the first reactor and is connected in parallel with a thyristor, and absorbs current distortion of the 11th harmonic, The reactive power adjusting apparatus according to claim 1, wherein the first reactor and the internal eleventh harmonic filter connected in series to the first reactor constitute a seventh harmonic filter viewed from a power system. 3. An internal 13th-order harmonic filter, which is composed of a reactor and a capacitor, is connected in series with the first reactor and is connected in parallel with a thyristor, and absorbs current distortion of the 13th-order harmonic, The reactive power adjusting device according to claim 2, wherein the first reactor and the internal 13th harmonic filter connected in series to the first reactor constitute an 11th harmonic filter as viewed from a power system.