KR20070004152A - Neutral line current reduction using single phase active power filter in three-phase four-wire power system - Google Patents

Neutral line current reduction using single phase active power filter in three-phase four-wire power system Download PDF

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KR20070004152A
KR20070004152A KR1020050059506A KR20050059506A KR20070004152A KR 20070004152 A KR20070004152 A KR 20070004152A KR 1020050059506 A KR1020050059506 A KR 1020050059506A KR 20050059506 A KR20050059506 A KR 20050059506A KR 20070004152 A KR20070004152 A KR 20070004152A
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phase
neutral
power
current
neutral line
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민준기
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민준기
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
    • H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
    • H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

A neutral line current reduction of three-phase four-wire power system using an active filter for a single power is provided to reduce power energy in a load by decreasing a current on a neutral line. An active filter for a power includes a neutral line(12), phase lines(11a,11b,11c), nonlinear loads(13a,13b,13c), a single transformer(14), an inverter(15), and a capacitor(16). The single transformer(14) is connected to a phase line of the neutral line(12) and three phase lines(11a,11b,11c). The inverter(15) of an H-bridge is connected to an inductor(15) from the transformer(14). The capacitor(16) operates as constant voltage source according to a switching operation of the inverter(15) of the H-bridge. The inverter(15) of the H-bridge outputs a compensation signal for compensating a neutral line current.

Description

단상 전력용 능동 필터를 이용한 3상 4선식 전력회로의 중선선 전류 저감{Neutral line current reduction using single phase active power filter in three-phase four-wire power system}Neutral line current reduction using single phase active power filter in three-phase four-wire power system}

도 1은 본 발명에 따른 전력용 능동 필터 장치의 회로구성을 나타낸 도면.1 is a view showing a circuit configuration of an active filter device for power according to the present invention.

10 : 3상전원10: 3-phase power

11a, 11b, 11c : 위상선11a, 11b, 11c: phase line

12 : 중성선12: neutral wire

13a, 13b, 13c : 비선형 부하13a, 13b, 13c: nonlinear load

14 : 단상 변압기14: single phase transformer

15 : H브리지 인버터15: H bridge inverter

16 : 캐패시터16: capacitor

본 발명은 3상 4선식 전력시스템에 대해 적용되는 전력용 능동 필터에 관한 것으로, 보다 상세하게는 3상 4선식 전력시스템의 비선형 부하에서 발생하는 기본파 및 3차 고조파 전류에 의한 중성선 전류의 과도한 증가를 효과적으로 억제하기 위한 전력용 능동 필터 장치에 관한 것이다.The present invention relates to an active filter for power applied to a three-phase four-wire power system, and more particularly to the excessive of the neutral current due to the fundamental and third harmonic currents generated from the nonlinear load of the three-phase four-wire power system. An active filter device for power for effectively suppressing the increase.

일반적으로, 건물 내부와 외부에 설치되는 각종 부하에 전력을 공급하기 위한 시스템으로 3상 4선식 전력시스템이 적용되고 있는 바, 이러한 3상 4선식의 전력시스템은 실내의 냉방과 난방을 위해 설치되는 공기조화기나, 냉동기구, 조명기구, 컴퓨터 및 서버장치, UPS 등과 같은 민감한 전력조건을 요구하는 여러 가지 전력부하에 분배 할 수 있도록 되어 있다.In general, a three-phase four-wire power system is applied as a system for supplying power to various loads installed inside and outside the building. Such three-phase four-wire power system is installed for cooling and heating indoors. It can be distributed to various power loads that require sensitive power conditions such as air conditioners, refrigeration appliances, lighting fixtures, computers and server devices, and UPS.

한편, 이러한 3상 4선식 전력시스템에서는 중성선에 비선형 부하를 포함하는 여러 가지 부하에서 발생되는 고조파 전류와 부하의 불평형으로 발생하는 불평형 전류가 흐르게 된다. 과도한 중성선 전류는 다른 부하의 이상동작이나 동작불능 등의 원인이 되는 것은 물론, 전력시스템 자체에서 전력 선로의 단선이나 과열 등이 발생되고, 심하게는 변압기 내부 권선의 절연파괴를 유발하여 심각한 손상을 가할 수 있는 가능성이 상존하게 된다.On the other hand, in the three-phase four-wire power system, harmonic currents generated by various loads including nonlinear loads and neutral currents flow in neutral lines. Excessive neutral line current may cause abnormal operation or inoperability of other loads, as well as disconnection or overheating of the power line in the power system itself, and severely induce insulation breakdown of the internal winding of the transformer, which may cause serious damage. The possibility exists.

그러한 종래의 문제점을 해결하기 위해, 비선형 부하에 대해 각각 중성선을 분리하여 사용할 수 있도록 하거나, 중성선의 설비 용량을 증가시키거나, 각 위상별로 전력용 능동필터를 설치하거나, Zig-Zag 변압기를 설치하여 중성선 전류의 과도한 증가를 막고 있다.In order to solve such a conventional problem, it is possible to separate the neutral wire for each non-linear load, increase the capacity of the neutral wire, install an active filter for each phase, or install a Zig-Zag transformer It prevents excessive increase in neutral current.

그러나, 이러한 전력시스템에 있어서 중성선에 흐르게 되는 고조파 전류를 제거하기 위한 수단의 경우에는 각 비선형 부하에 정상적인 전력을 공급하기 위해서 부가적인 장치가 추가되어야 할 뿐만 아니라, 전력공급을 위한 작동효율이 저하하고, 전력선의 설비용량을 증가하게 하거나, 각 상별로 전력용 능동필터 시스템을 설치하게 되면 시스템의 가격을 상승시키는 요인이 되고 Zia-Zag 변압기를 설치하게되면 크기와 무게가 과도하게 증가한다는 문제점이 있다.However, in such a power system, the means for eliminating harmonic currents flowing to the neutral line requires not only additional devices to supply normal power to each nonlinear load, but also to reduce the operating efficiency for power supply. Increasing the capacity of the power line or installing active filter system for each phase increases the price of the system, and installing Zia-Zag transformer causes excessive increase in size and weight. .

따라서, 본 발명은 상기한 종래의 사정을 감안하여 이루어진 것으로, 그 목적은 3상 4선식 전력시스템의 중성선에 흐르게 되는 고조파 전류를 단상 H브리지 인버터를 이용하여 전력용 능동 필터로 동작하게 함으로써 보상 고조파 전류 주입으로 효과적으로 저감하는 전력용 능동 필터 장치를 제공하는 것이다.Accordingly, the present invention has been made in view of the above-described conventional circumstances, and its object is to compensate harmonics by operating a harmonic current flowing through the neutral line of a three-phase four-wire power system as an active filter for power using a single-phase H bridge inverter. It is to provide an active filter device for power that is effectively reduced by current injection.

상기한 목적을 달성하기 위해 본 발명에 따르면, 부하에 전력을 공급하는 3상 전원의 중성선으로 흐르게 되는 중성선 전류를 저감하기 위한 장치에 있어서, 설치된 상과 중성선을 입력으로 하는 단상 변압기;와 상기 단상 변압기에서 인버터 입력단 사이에 있는 인덕터;와 상기 인덕터와 연결되는 전력용 능동 필터 동작을 하는 H브리지 인버터;와 H브리지 인버터에 연결되는 정전압원으로 동작하는 캐패시터;로 구성되어 H브리지 인버터의 출력전류를 H브리지 인버터가 설치된 상과 중성선에 보상 전류를 공급하는 전력용 능동 필터 장치가 제공된다.According to the present invention for achieving the above object, in the device for reducing the neutral current flowing to the neutral wire of the three-phase power supply for powering the load, a single-phase transformer having the installed phase and the neutral wire; and the single phase An inductor between the inverter input terminal and an H-bridge inverter for active power filter operation connected to the inductor; and a capacitor for operating as a constant voltage source connected to the H-bridge inverter. An active filter device for power supplying a compensating current to a phase and a neutral wire in which an H bridge inverter is installed is provided.

이하, 상기한 바와 같이 구성된 본 발명에 대해 첨부도면을 참조하여 상세히 설명한다.Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

도 1은 본 발명에 따른 전력용 능동 필터 장치의 회로구성을 나타낸 도면이다. a,b,c상으로 이루어진 3상 전원(10)이 각 위상선 (11a),(11b),(11c)과 중성선(12)을 이용하여 비선형 부하(13a),(13b),(13c)로 전력을 공급하며, 3상전원(10)에서 위상선(11a),(11b),(11c)을 통하여 부하(13a),(13b),(13c)로 입력된 전류는 중성선(12)로 출력된다. 이때, 중성선(12)으로 출력되는 전류에서는 비선형부하(13a),(13b),(13c)에 의해서 발생되는 고조파 전류가 포함된다. 전력용 능동필터가 연결된 a상(11a)과 중성선(12)으로 중성선 전류를 저감하기 위한 보상 전류는 직류 전압원으로 동작하는 캐패시터(16)로부터 전원을 공급받아 H브리지 인버터(15)의 스위칭 동작으로 인해 필터 인덕터를 거쳐 출력 단상 변압기(14)를 거쳐 주입된다.1 is a diagram showing a circuit configuration of an active filter device for power according to the present invention. A three-phase power supply 10 composed of a, b, and c phases uses non-linear loads 13a, 13b, and 13c by using the phase lines 11a, 11b, 11c, and the neutral wire 12, respectively. Power from the three-phase power supply 10, and the currents input to the loads 13a, 13b, and 13c through the phase lines 11a, 11b, and 11c to the neutral line 12. Is output. At this time, the current output to the neutral line 12 includes harmonic currents generated by the nonlinear loads 13a, 13b, and 13c. The compensation current for reducing the neutral current to the a phase 11a and the neutral wire 12 to which the power active filter is connected is supplied from a capacitor 16 which operates as a direct current voltage source to the switching operation of the H bridge inverter 15. It is injected via the filter inductor through the output single-phase transformer (14).

Figure 112005035982343-PAT00001
상기한 수학식1에 따르면,중성선 전류(iN)는 각 상의 전류의 합(iA+iB+iC)으로 표현되며, 비선형 평형 또는 비선형 불평형 부하(13a),(13b),(13c)에서 발생된 고조파 전류는 중성선을 통하여 흐르게 된다.
Figure 112005035982343-PAT00001
According to Equation 1, the neutral current i N is represented by the sum of the currents in each phase i A + i B + i C , and the nonlinear balanced or nonlinear unbalanced loads 13a, 13b, and 13c. The harmonic current generated in the) flows through the neutral line.

Figure 112005035982343-PAT00002
고조파는 기본 주파수에 대해 정수배의 주파수를 가지는 주기 파형 또는 양의 정현파 성분으로 정의되므로, 상기한 수학식2에 따라, 고조파 전류를 표현하기위한 파라미터로 사용되는 전류 THD를 계산할 수 있다.상기한 바와 같이 이루어진 본 발명에 따르면, 3상 4선식 전력 시스템에서 다이오드 브리지 회로로 구성된 3상 불평형 비선형 부하(13a),(13b),(13c)에 대해 중성선(12)을 통해 고조파 전류가 흐르게 되는 경우에, 도 2a, 2b, 2c에서 (13a),(13b),(13c)에 고조파 전류가 흐르게 되어 수학식1과 같이 중성선(12)에 도 2d와 같은 중성선(12) 전류가 흐르게 된다. 도 2d와 같이 중성선(12)에 흐르는 고조파 전류를 주파수 스펙트럼 상태로 보면 도 2e와 같다. 본 발명에 따른 전력용 능동 필터의 동작에 의해 중성선(12)에 흐르는 전류는 도 2f와 같고 주파수 스펙트럼으로 보면 도 2g와 같다.
Figure 112005035982343-PAT00002
Since harmonics are defined as periodic waveforms or positive sinusoidal components having integer multiples of the fundamental frequency, the current THD used as a parameter for expressing harmonic currents can be calculated according to Equation 2 above. According to the present invention, a harmonic current flows through the neutral wire 12 to the three-phase unbalanced nonlinear loads 13a, 13b, and 13c constituted by a diode bridge circuit in a three-phase four-wire power system. In FIGS. 2A, 2B, and 2C, harmonic currents flow through (13a), (13b), and (13c), and the neutral line 12 current as shown in FIG. 2d flows through the neutral line 12 as shown in Equation (1). As shown in FIG. 2D, the harmonic current flowing through the neutral line 12 is as shown in FIG. 2E. The current flowing in the neutral line 12 by the operation of the power active filter according to the present invention is as shown in Figure 2f and in the frequency spectrum as shown in Figure 2g.

본 발명에 따른 적용 중성선 전류 저감 예Application Neutral Current Reduction Example According to the Present Invention 중성선 전류 고조파 차수Neutral Current Harmonic Order 본 발명에 따른 전력용 능동필터 설치전의 중성선 전류( iSN )Neutral current (iSN) before installing active filter for power according to the present invention 본 발명에 따른 전력용 능동필터 설치후의 중성선 전류( iSN )Neutral current (iSN) after installation of an active filter for power according to the invention 기본파( i1 )Fundamental wave (i1) 28.1628.16 8.478.47 제 3차 고조파( i3 )3rd harmonic (i3) 51.8551.85 15.8815.88 제 5차 고조파( i5 )5th harmonic (i5) 10.110.1 7.487.48 제 7차 고조파( i7 )7th harmonic (i7) 2.492.49 2.412.41 제 9차 고조파( i9 )9th harmonic (i9) 1.541.54 2.482.48 제 11차 고조파( i11 )11th harmonic (i11) 1.221.22 1.151.15 제 13차 고조파( i13 )13th harmonic (i13) 0.780.78 0.470.47 총 고조파Total harmonic 96.0496.04 38.3438.34

여기서, 본 발명에 따른 전력용 능동필터의 설치전의 중성선(12) 전류 총합은 94.06[A]인 반면 설치후 중성선(12) 전류의 총합은 38.34[A]로서, 중성선(12)에 흐르는 전류가 설치전에 비하여 60.4[%]가 줄어들어, 전력에너지의 저감이 가능하고, 3상 4선식 전력시스템의 중성선 설비용량 감소가 가능하게 되는 것이다.Here, the total current of the neutral wire 12 before installation of the power active filter according to the present invention is 94.06 [A], while the total of the neutral wire 12 current after installation is 38.34 [A], and the current flowing through the neutral wire 12 is 60.4 [%] is reduced compared to before installation, it is possible to reduce the power energy, and to reduce the neutral capacity of the three-phase four-wire power system.

상기한 실시예를 갖는 본 발명은 그 실시양태에 구애받지 않고 그 요지를 벗어나지 않는 한도 내에서 얼마든지 다양하게 변형하여 실시할 수 있음은 물론이다.It is a matter of course that the present invention having the above-described embodiments can be variously modified without departing from the gist of the present invention without departing from the gist thereof.

이상과 같이 본 발명에 따르면, 다양한 부하에 전력을 공급하는 3상 4선식 전력 시스템에 단상 전력용 능동 필터를 적용하여 중성선에 흐르는 전류를 감소시킴에 따라 부하에서 사용되는 전력에너지의 대폭적인 절감이 가능하고, 기존의 3상 4선식 전력용 능동 필터와 Zig-Zag 변압기를 사용하는 방식에 대해 부피와 무게가 줄어든 저가격대의 전력용 능동 필터를 적용할 수 있음에 따라 원가절감이 가능하다는 효과를 갖게 된다.As described above, according to the present invention, by applying an active filter for single-phase power to a three-phase four-wire power system that supplies power to various loads, a significant reduction in power energy used in the load is reduced by reducing the current flowing through the neutral wire. In addition, it is possible to reduce the cost by applying a low cost power active filter with reduced volume and weight to the existing three-phase four-wire active filter and Zig-Zag transformer. Will have

Claims (3)

3상 4선식 전력시스템에서 위상선(11a)(11b)(11c)과 중성선(12)을 이용하여 전력을 공급하고 비선형 부하(13a)(13b)(13c)에 의해 발생되는 고조파 전류를 보상하여 중성선(12) 전류를 저감하기위한 장치에 있어서,In a three-phase four-wire power system, power is supplied using the phase lines 11a, 11b, 11c and the neutral wire 12 to compensate for the harmonic currents generated by the nonlinear loads 13a, 13b, 13c. In the device for reducing the neutral 12 current, 상기 중성선(12)과 (11a)(11b)(11c)중의 한 위상선과 연결된 단상변압기(14);와,A single phase transformer 14 connected to one of the neutral lines 12 and 11a, 11b, and 11c; 변압기(14)에서 인덕터로 연결된 H브리지 인버터(15);와,An H-bridge inverter 15 connected to the inductor from the transformer 14; H브리지 인버터(15)의 스위칭 동작에 따라 정전압원으로 동작하는 캐패시터(16);를 사용하며 중성선 전류를 보상하기 위한 보상신호를 출력하는 H브리지 인버터(15);로 구성되어 인버터(16)의 출력전류가 단상변압기(14)를 통과하여 (11a)(11b)(11c)중의 한 위상선에 연결되어 고조파 전류를 보상하여 중성선 전류를 저감하는 것을 특징으로하는 전력용 능동 필터 장치.A capacitor 16 operating as a constant voltage source according to the switching operation of the H bridge inverter 15; and an H bridge inverter 15 for outputting a compensation signal for compensating the neutral current. An active filter device for power, characterized in that an output current passes through a single phase transformer (14) and is connected to one of the phase lines of (11a) (11b) (11c) to compensate for harmonic currents to reduce the neutral current. 제 1항에 있어서, 상기 H브리지 인버터는 상기 중성선 전류의 기본파 성분과 3고조파 성분을 보상하도록 하는 것을 특징으로 하는 전력용 능동 필터 장치.2. The active filter device as claimed in claim 1, wherein the H bridge inverter compensates for fundamental and three harmonic components of the neutral current. 제 1항에 있어서, 상기 단상 변압기가 (11a)(11b)(11c)중의 두 위상선과 연결되어 고조파 전류 저감을 특징으로 하는 전력용 능동 필터 장치.2. The active filter device as claimed in claim 1, wherein said single-phase transformer is connected to two phase lines of (11a) (11b) (11c) to reduce harmonic currents.
KR1020050059506A 2005-07-04 2005-07-04 Neutral line current reduction using single phase active power filter in three-phase four-wire power system KR20070004152A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110121774A1 (en) * 2008-05-15 2011-05-26 Merstech Inc. Alternating voltage control apparatus
CN110071510A (en) * 2019-04-25 2019-07-30 西南交通大学 Single-phase hybrid active electric filter and its control method based on UPQC
CN110649618A (en) * 2018-06-27 2020-01-03 施耐德电气美国股份有限公司 Neutral current-limiting adjustable active power filter
CN111293695A (en) * 2020-03-18 2020-06-16 山东华天电气有限公司 Angle-type chain-type active power filter based on optical fiber serial control and control method

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110121774A1 (en) * 2008-05-15 2011-05-26 Merstech Inc. Alternating voltage control apparatus
US8384333B2 (en) * 2008-05-15 2013-02-26 Merstech, Inc. Alternating voltage control apparatus
CN110649618A (en) * 2018-06-27 2020-01-03 施耐德电气美国股份有限公司 Neutral current-limiting adjustable active power filter
CN110071510A (en) * 2019-04-25 2019-07-30 西南交通大学 Single-phase hybrid active electric filter and its control method based on UPQC
CN111293695A (en) * 2020-03-18 2020-06-16 山东华天电气有限公司 Angle-type chain-type active power filter based on optical fiber serial control and control method
CN111293695B (en) * 2020-03-18 2021-10-26 山东华天电气有限公司 Angle-type chain-type active power filter based on optical fiber serial control and control method

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