CN109962478B - A low pass filter device - Google Patents
A low pass filter device Download PDFInfo
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- CN109962478B CN109962478B CN201910205403.2A CN201910205403A CN109962478B CN 109962478 B CN109962478 B CN 109962478B CN 201910205403 A CN201910205403 A CN 201910205403A CN 109962478 B CN109962478 B CN 109962478B
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- pass filter
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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
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- 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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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
Abstract
The invention discloses a low-pass filter device which comprises an input terminal, a capacitor, an output terminal, a metal shell, a first reactor, a second reactor and a third reactor, wherein the output terminal is positioned on one side of the metal shell, the input terminal is connected with a current transformer through a wire secondary loop, the capacitor, the first reactor, the second reactor and the third reactor form a low-pass filter loop in a series-parallel connection mode, and the output terminal is positioned on the other side of the metal shell and is connected with a receiving module through a wire. The device eliminates the influence of the higher harmonic current on the sampling through the filtering performance of the low-pass filter, filters the higher harmonic current through a hardware mode, ensures that the sampling is protected from the influence of the higher harmonic current, has no influence on the size of the fundamental current, and ensures the sampling precision.
Description
Technical Field
The invention relates to the technical field of high-voltage flexible alternating current transmission systems, in particular to a low-pass filter device for a sampling loop of a serial flexible alternating current transmission system.
Background
With the development of economy, the electric load is continuously increased, and higher requirements are put on the transmission capacity of the power grid. In particular, there is an increasing demand for power flow control, voltage control and short-circuit current control of power systems, and thus flexible ac transmission (Flexible AC Transmission Systems, FACTS) devices are increasingly used in power systems.
FACTS can be classified into a series device, a parallel device, and a series-parallel device according to the manner of connection to the power grid.
The currently applied series flexible alternating current transmission device comprises a series compensation device and a series resonance type fault current limiting device, and the schematic diagram of the series compensation device and the series resonance type fault current limiting device is shown in figure 1. In the figure, 31 is a bus bar on one side of a power transmission line, 36 is a bus bar on the other side of the power transmission line, 32 is a line switch on one side of the power transmission line, 35 is a line switch on the other side of the power transmission line, 33 is the power transmission line, and 34 is a mounted serial device. Because the device is connected in series in the circuit, the insulation requirement on the ground is consistent with the insulation requirement on the circuit on the ground, and in order to reduce the engineering cost, the series device is arranged on an insulation platform of a steel structure, and the insulation platform is fixed by a post insulator and a cable-stayed insulator. Therefore, the series device has no electrical connection with the ground, the insulation requirement is met by the post insulator and the cable-stayed insulator, and the device only needs to consider the insulation requirement on the insulation platform, so that the insulation level of the series device is greatly reduced.
Considering that the serial flexible alternating current transmission devices are connected in series in a circuit, in order to ensure normal operation of main equipment, overvoltage protection equipment needs to be configured, corresponding secondary protection needs to be configured for the primary main equipment, further corresponding electric quantities on an insulation platform need to be collected, and the electric quantities are transmitted to a ground protection device to serve as a basis for logic judgment of the protection device.
For the series compensation device, the matched secondary protection comprises capacitor unbalance protection, and a certain domestic series compensation device generates capacitor unbalance protection action in the running process of the peripheral system after direct current and SVG are added, so that the series compensation device exits. During subsequent fault analysis, the abnormal phenomenon of the capacitor unit of the series compensation device is not found, but the unbalanced current power frequency component of the capacitor is found to be very small during wave recording analysis, and the higher harmonic wave has very large content. Because the algorithm adopted by the secondary control protection device matched with the series compensation device is a root mean square algorithm and is sensitive to higher harmonic waves, the protection misoperation is caused. Considering that the manufacturer has no after-sale technical support in China, the influence of higher harmonic current on protection cannot be eliminated through upgrading software, and a filtering device adopted in a power system in the past generally filters voltage signals.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a low-pass filter device.
The low-pass filter device is realized by the following technical scheme that the low-pass filter device comprises an input terminal, a capacitor, an output terminal, a metal shell, a first reactor, a second reactor and a third reactor, wherein the input terminal is positioned on one side of the metal shell, the input terminal is connected with a current transformer for collecting primary loop current through a wire secondary loop, the output terminal is positioned on the other side of the metal shell, a receiving module is connected through a wire, one end of the first reactor is connected with one side of the input terminal, the other end of the first reactor is connected with one end of the second reactor, the other end of the second reactor is connected with the output terminal on the side, the capacitor is connected with the other side of the output terminal through a wire, the capacitor is connected with one end of the third reactor, the other end of the third reactor is connected onto the first reactor and the second reactor, and the capacitor, the first reactor, the second reactor and the third reactor form a low-pass filter loop.
The first reactor forms a first branch, the second reactor forms a second branch, the third reactor and the capacitor are connected in series to form a third branch, and the reactor and the capacitor form a low-pass filter loop in a series-parallel connection mode.
The low-pass filter loop adopts a low-pass network of elliptic function, and the cut-off frequency of the low-pass filter loop is 400Hz.
The low-pass filter loop is connected into the sampling loop in series. The low-pass filter circuit is connected in series, so that higher harmonic current can be filtered.
The current transformer is a through type current transformer.
Compared with the prior art, the device has the advantages that the influence of the higher harmonic current on sampling is eliminated through the filtering performance of the low-pass filter, the device is suitable for a current sampling loop in an electric power system, the higher harmonic current is filtered through a hardware mode, the sampling is protected from being influenced by the higher harmonic current, the size of the fundamental current is not influenced, and the sampling precision is ensured.
Drawings
Fig. 1 is a schematic structural diagram of an existing serial flexible ac transmission device connected to a power system;
FIG. 2 is a schematic diagram of a low-pass filter according to the present invention;
Fig. 3 is a schematic diagram of a low-pass filter according to the present invention connected to a sampling loop.
The reference numerals in the figure mean 1, a low-pass filter, 11, a first reactor, 12, a second reactor, 13, a third reactor, 14, a capacitor, 15, an input terminal, 16, an output terminal, 17, a metal shell, 21, a first capacitor bank branch, 22, a second capacitor bank branch, 23, a first through type current transformer, 24, a second through type current transformer, 25, a sampling device, 31, a bus bar at one side of a power transmission line, 32, a line switch at one side of the power transmission line, 33, a power transmission line, 34, a series type device installed, 35, a line switch at the other side of the power transmission line, 36, and a bus bar at the other side of the power transmission line.
Detailed Description
The present invention will be described in further detail with reference to the drawings and detailed description.
Examples
Referring to fig. 2, a low-pass filter device comprises an input terminal 15, a capacitor 14, an output terminal 16, a metal shell 17, a first reactor 11, a second reactor 12 and a third reactor 13, wherein the input terminal 15 is positioned on one side of the metal shell 17, the input terminal 15 is connected with a current transformer for collecting the current of a primary loop through a wire secondary loop, the output terminal 16 is positioned on the other side of the metal shell 17 and is connected with a receiving module through a wire, one end of the first reactor 11 is connected with one side of the input terminal 15, the other end of the first reactor is connected with one end of the second reactor 12, the other end of the second reactor 12 is connected with one end of the output terminal 16 on the side, the capacitor 14 is connected with the other side of the input terminal 15 through a wire, one end of the capacitor 14 is connected with one end of the third reactor 13 in series, the other end of the third reactor 13 is connected with the first reactor 11 and the second reactor 12, and the capacitor 14 is connected with the first reactor 11, the second reactor 12 and the third reactor 13 in series-parallel connection mode to form a low-pass filter loop.
The first reactor 11 forms a first branch, the second reactor 12 forms a second branch, the third reactor 13 and the capacitor 14 are connected in series to form a third branch, and the reactors and the capacitor 14 form a low-pass filter loop in a series-parallel mode.
The low-pass filter loop adopts a low-pass network of elliptic functions, and the cut-off frequency of the low-pass network is 400Hz.
The low-pass filter loop is connected into the sampling loop in series. The low-pass filter circuit is connected in series, so that higher harmonic current can be filtered.
The current transformer is a through type current transformer.
In this embodiment, the receiving module is a conventional technology, and does not perform expansion analysis.
Referring to fig. 3, in use, the low-pass filter 1 is connected in series to the secondary terminals of the first and second pass current transformers 23, 24, the first capacitor bank branch 21 and the first pass current transformer 23 are connected in series to form a first branch, the second capacitor bank branch 22 and the second pass current transformer 24 are connected in series to form a second branch, the first branch and the second branch are connected in parallel, and the other end of the low-pass filter 1 is connected to a sampling loop of the sampling device 25. When higher harmonic components appear in unbalanced current of the capacitor 14, the higher harmonic current can be filtered out by the low-pass filter 1. The cut-off frequency selected in the application example is 400Hz, and the filter requirement of the higher harmonic current in the example can be met. If there are other requirements on the cut-off frequency, this can be achieved by modifying the reactor, the capacitor 14 of the filter loop.
The device provided by the device can effectively filter out the higher harmonic current component generated in the capacitor bank, ensure the readiness of protection sampling and ensure that the series compensation device keeps normal operation.
The foregoing detailed description is directed to embodiments of the invention which are not intended to limit the scope of the invention, but rather to cover all modifications and variations within the scope of the invention.
Claims (2)
1. A low-pass filter device is characterized by comprising an input terminal, a capacitor, an output terminal, a metal shell, a first reactor, a second reactor and a third reactor, wherein the input terminal is positioned on one side of the metal shell, a current transformer used for collecting primary loop current is connected to the input terminal through a wire secondary loop, the output terminal is positioned on the other side of the metal shell, a receiving module is connected to the output terminal through a wire, one end of the first reactor is connected with one side of the input terminal, the other end of the first reactor is connected with one end of the second reactor, the other end of the second reactor is connected with the output terminal of the side, the capacitor is connected with one end of the third reactor through a wire, the other end of the third reactor is connected onto a connecting wire of the first reactor and the second reactor, the capacitor and the second reactor form a low-pass filter loop, one end of the first reactor is connected with the first reactor, the second reactor and the third reactor form a low-pass filter loop, one end of the first reactor is connected with the second reactor through a series connection type of the low-pass filter, the second reactor is connected with the second reactor through a first branch of the low-pass filter, and the second reactor is connected with the second branch of the second reactor through the first branch, and the second branch of the low-pass filter is connected with the second branch of the second reactor through the first branch through the low-pass filter through the first branch, the low-pass filter through the first branch through the second branch, the low-pass filter through the current filter.
2. The low-pass filter device according to claim 1, wherein the low-pass filter circuit uses a low-pass network of elliptic functions with a cut-off frequency of 400Hz.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910205403.2A CN109962478B (en) | 2019-03-18 | 2019-03-18 | A low pass filter device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910205403.2A CN109962478B (en) | 2019-03-18 | 2019-03-18 | A low pass filter device |
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| Publication Number | Publication Date |
|---|---|
| CN109962478A CN109962478A (en) | 2019-07-02 |
| CN109962478B true CN109962478B (en) | 2025-01-21 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910205403.2A Active CN109962478B (en) | 2019-03-18 | 2019-03-18 | A low pass filter device |
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Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111447727B (en) * | 2020-04-01 | 2021-04-27 | 南京国电南自维美德自动化有限公司 | Secondary circuit anti-interference circuit board device |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201584892U (en) * | 2009-11-26 | 2010-09-15 | 广州市高澜水技术有限公司 | Series connection filter |
| CN209709690U (en) * | 2019-03-18 | 2019-11-29 | 中国南方电网有限责任公司超高压输电公司百色局 | A kind of low-pass filtering device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5921738B2 (en) * | 2015-03-11 | 2016-05-24 | 三菱電機株式会社 | Filter device and electric vehicle drive control device |
| CN204835532U (en) * | 2015-07-30 | 2015-12-02 | 江苏默顿电气有限公司 | Parallelly connected type active power filter device |
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2019
- 2019-03-18 CN CN201910205403.2A patent/CN109962478B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201584892U (en) * | 2009-11-26 | 2010-09-15 | 广州市高澜水技术有限公司 | Series connection filter |
| CN209709690U (en) * | 2019-03-18 | 2019-11-29 | 中国南方电网有限责任公司超高压输电公司百色局 | A kind of low-pass filtering device |
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| CN109962478A (en) | 2019-07-02 |
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Effective date of registration: 20211105 Address after: 533000 Baise Bureau of UHV company, No. 69 Yinglong Road, Youjiang District, Baise City, Guangxi Zhuang Autonomous Region (next to Zhuzhou bridge) Applicant after: CSG EHV TRANSMISSION COMPANY BOSE BUREAU Address before: 533000 Baise Bureau of UHV company, No. 69 Yinglong Road, Youjiang District, Baise City, Guangxi Zhuang Autonomous Region (next to Zhuzhou bridge) Applicant before: CSG EHV TRANSMISSION COMPANY BOSE BUREAU Applicant before: NR ENGINEERING Co.,Ltd. |
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