CN111969564A - Fuse-free capacitor bank unbalance protection device and method - Google Patents
Fuse-free capacitor bank unbalance protection device and method Download PDFInfo
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- CN111969564A CN111969564A CN202011009901.9A CN202011009901A CN111969564A CN 111969564 A CN111969564 A CN 111969564A CN 202011009901 A CN202011009901 A CN 202011009901A CN 111969564 A CN111969564 A CN 111969564A
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- detection module
- fuse
- capacitor bank
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/16—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for capacitors
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0038—Details of emergency protective circuit arrangements concerning the connection of the detecting means, e.g. for reducing their number
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
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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
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1807—Arrangements for adjusting, eliminating or compensating reactive power in networks using series compensators
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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
- Y02E40/30—Reactive power compensation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Artificial Intelligence (AREA)
- Evolutionary Computation (AREA)
- Protection Of Static Devices (AREA)
Abstract
The invention provides an unbalance protection device and method for a fuse-free capacitor bank, which comprises the fuse-free capacitor bank; a current detection unit connected to the fuse-less capacitor bank; the sampling unit is connected with the current detection unit; an arithmetic unit connected to the sampling unit; and a logic judgment unit connected with the arithmetic unit; by the method, the influence of higher harmonic current on the unbalanced protection can be reduced, and the unbalanced protection action of the capacitor is higher in accuracy.
Description
Technical Field
The invention relates to the technical field of high-voltage flexible alternating current transmission, in particular to an unbalance protection device and method for a fuse-free capacitor bank.
Background
The series flexible ac transmission device currently used includes a series compensation device and a series resonance type fault current limiting device. Because the device is connected in series in the line, the insulation requirement of the device to the ground is consistent with the insulation requirement of the line to the ground, and in order to reduce the construction cost, the series device is installed on an insulation platform of a steel structure, and the insulation platform is fixed by a post insulator and a diagonal insulator. Therefore, the series connection device is not in electrical connection with the ground, the insulation requirement is met by the post insulator and the cable-stayed insulator, the device only needs to consider the insulation requirement on the insulation platform, and the insulation level of the series connection device is greatly reduced. Although the capacitor unbalance protection action in the running process of a part of series compensation devices after the direct current and the SVG are added to the peripheral system causes the series compensation devices to exit, the capacitor unbalance protection misoperation problem still exists. It is desirable to provide a solution to improve the accuracy of the capacitor imbalance protection action.
Disclosure of Invention
The invention aims to provide an unbalance protection device and method of a fuse-free capacitor bank, which are used for realizing the technical effect of improving the accuracy of unbalance protection action of a capacitor.
In a first aspect, the present invention provides a fuse-less capacitor bank imbalance protection apparatus, comprising a fuse-less capacitor bank; a current detection unit connected to the fuse-less capacitor bank; the sampling unit is connected with the current detection unit; an arithmetic unit connected to the sampling unit; and a logic judgment unit connected with the arithmetic unit; the fuseless capacitor bank comprises a first fuseless capacitor module and a second fuseless capacitor module connected in parallel; the current detection unit comprises a first current detection module, a second current detection module and a third current detection module; the first current detection module is arranged on a branch where the first fuse-free capacitor module is arranged; the second current detection module is arranged on a branch where the second fuse-free capacitor module is arranged; the first end of the first current detection module is in short circuit with the second end of the second current detection module, and the second end of the first current detection module is in short circuit with the first end of the second current detection module; the third current detection module is arranged on a main circuit after the first fuse-free capacitor module and the second fuse-free capacitor module are connected in parallel; the operation unit is used for acquiring a first current value output by the first current detection module and the second current detection module in parallel and a second current value output by the third current detection module, which are transmitted by the sampling unit; calculating an unbalanced current effective value of the fuse-free capacitor bank according to the first current value; calculating the current effective value of the fuse-free capacitor bank according to the second current value; and the logic judgment unit is used for judging whether the capacitor unbalance protection needs to act according to the ratio of the unbalance current effective value to the current effective value and a preset fixed value.
Further, the first current detection module, the second current detection module and the third current detection module are all open type current transformers.
Furthermore, the sampling unit comprises a first connecting terminal, a second connecting terminal, a third connecting terminal, a fourth connecting terminal, a fifth connecting terminal and a sixth connecting terminal; the first connecting terminal is in short circuit with the second connecting terminal; the third connecting terminal is in short circuit with the fourth connecting terminal; the first end of the first current detection module is connected with the first wiring terminal; the second end of the first current detection module is connected with the third wiring terminal; the second end of the second current detection module is connected with the second wiring terminal; the first end of the second current detection module is connected with the fourth wiring terminal; the first end of the third current detection module is connected with the fifth wiring terminal; and the second end of the third current detection module is connected with the sixth wiring terminal.
Further, the first current detection module and the second current detection module are open type current transformers with excitation characteristic curve deviation not exceeding 2%.
Further, the sampling unit comprises a low-pass filtering module, and the cut-off frequency of the low-pass filtering module is 380 Hz.
Further, the operation unit calculates the unbalanced current effective value and the current effective value respectively by using a fundamental wave effective value algorithm.
In a second aspect, the present invention provides a method for protecting an unbalance of a fuseless capacitor bank, which is applied to the unbalance protection device of the fuseless capacitor bank, and includes: acquiring an unbalanced current value and a current value of the fuse-free capacitor bank; calculating an unbalanced current effective value corresponding to the unbalanced current value and a current effective value corresponding to the current value through a fundamental wave effective value algorithm; and judging whether the capacitor unbalance protection needs to act or not according to the ratio of the unbalance current effective value to the current effective value and a preset fixed value.
The beneficial effects that the invention can realize are as follows: the device and the method for protecting the unbalance of the fuse-free capacitor bank can reduce the influence of higher harmonic current on the unbalance protection, so that the accuracy of the unbalance protection action of the capacitor is higher.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic diagram of a series flexible ac power transmission device connected to a power system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an unbalance protection apparatus without a fuse capacitor bank according to an embodiment of the present invention;
FIG. 3 is a logic diagram of capacitor imbalance protection provided by an embodiment of the present invention;
fig. 4 is a schematic diagram of a connection manner of a sampling unit according to an embodiment of the present invention;
fig. 5 is a schematic flow chart of a method for protecting an unbalance of a capacitor bank without a fuse according to an embodiment of the present invention.
Icon: 10-fuse-less capacitor bank imbalance protection; 100-a fuseless capacitor bank; 110-a first fuseless capacitor module; 120-a second fuseless capacitor module; 200-a current detection unit; 210-a first current detection module; 220-a second current detection module; 230-a third current detection module; 300-a sampling unit; 310-a low-pass filtering module; 400-an arithmetic unit; 500-a logic judgment unit; 600-fiber signal column; 700-post insulator; 800-stayed insulators; 900-insulating platform.
Detailed Description
The technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present invention, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
Referring to fig. 1, fig. 2 and fig. 3, fig. 1 is a schematic diagram of a series flexible ac power transmission device accessing a power system according to an embodiment of the present invention, and fig. 2 is a schematic diagram of a structure of a fuse-free capacitor bank imbalance protection device according to an embodiment of the present invention; fig. 3 is a logic diagram of capacitor imbalance protection according to an embodiment of the present invention.
As shown in fig. 1, the structure of a series flexible ac power transmission device currently used includes busbars a1 and a2 on both sides of a power transmission line; a line switch K1 connected with the bus A1 and a line switch K2 connected with the bus A2; and an inductor L1 and a series-type device C disposed between K1 and K2. However, since the devices are connected in series to the line, the requirement for insulation to ground is consistent with the requirement for insulation to ground, and in order to reduce the construction cost, the series devices are mounted on a steel-structured insulation platform 900, which is further fixed by post insulators 700 and diagonal tension insulators 800. Therefore, the series connection device is not in electrical connection with the ground, the insulation requirement is met by the post insulator 700 and the cable-stayed insulator 800, the device only needs to consider the insulation requirement on an insulation platform, and the insulation level of the series connection device is greatly reduced. Therefore, the embodiment of the invention provides a scheme for improving the accuracy of the unbalanced protection action of the capacitor.
In one embodiment, the present invention provides a fuse-less capacitor bank imbalance protection device 10 comprising a fuse-less capacitor bank 100; a current detection unit 200 connected to the fuse-less capacitor bank 100; a sampling unit 300 connected to the current detection unit 200; an arithmetic unit 400 connected to the sampling unit 300; and a logic judgment unit 500 connected to the arithmetic unit 400.
The fuseless capacitor bank 100 includes a first fuseless capacitor module 110 and a second fuseless capacitor module 120 in parallel.
The current detection unit 200 includes a first current detection module 210, a second current detection module 220, and a third current detection module 230; the first current detection module 210 is disposed on the branch where the first non-fuse capacitor module 110 is located; the second current detection module 220 is disposed on the branch where the second fuseless capacitor module 120 is located; the first end of the first current detection module 210 is short-circuited with the second end of the second current detection module 220, and the second end of the first current detection module 210 is short-circuited with the first end of the second current detection module 220; the third current detection module 230 is disposed on the main path after the first non-fuse capacitor module 110 and the second non-fuse capacitor module 120 are connected in parallel.
The operation unit 400 is configured to obtain a first current value output by the first current detection module 210 and the second current detection module 220 in parallel and a second current value output by the third current detection module 230, which are transmitted by the sampling unit 300; calculating an unbalanced current effective value of the fuse-free capacitor bank according to the first current value; and calculating the effective current value of the fuse-free capacitor bank according to the second current value. The sampling unit 300 may be connected to the operation unit 400 through the optical fiber signal column 600.
The logic determining unit 500 is configured to determine whether the capacitor unbalance protection needs to be performed according to a ratio of the unbalanced current effective value to the current effective value and a preset fixed value.
Referring to fig. 4, fig. 4 is a schematic diagram of a connection manner of a sampling unit according to an embodiment of the present invention.
In one embodiment, the first current detecting module 210, the second current detecting module 220, and the third current detecting module 230 are all open-type current transformers. The sampling unit 300 includes a first connection terminal b1, a second connection terminal b2, a third connection terminal b3, a fourth connection terminal b4, a fifth connection terminal b5, and a sixth connection terminal b 6; the first connection terminal b1 is short-circuited with the second connection terminal b 2; the third connection terminal b3 is short-circuited with the fourth connection terminal b 4; a first end of the first current detection module 210 is connected to the first connection terminal b 1; the second end of the first current detection module 210 is connected to the third connection terminal b 3; a second end of the second current detection module 220 is connected to a second connection terminal b 2; a first end of the second current detection module 220 is connected to a fourth connection terminal b 4; a first end of the third current detection module 230 is connected to a fifth connection terminal b 5; the second end of the third current detection module 230 is connected to a sixth connection terminal b 6.
Further, in order to ensure that the unbalanced current of the fuse-free capacitor bank still maintains a certain precision after the unbalanced current is transmitted twice, the first current detection module 210 and the second current detection module 220 may select an open-type current transformer whose excitation characteristic curve deviation does not exceed 2%.
In one embodiment, in order to filter the effect of higher harmonic currents from the source, the sampling unit 300 further includes a low-pass filtering module 310, and the cut-off frequency of the low-pass filtering module 310 is 380 Hz.
In one embodiment, the operation unit 400 calculates the unbalanced current effective value and the current effective value, respectively, using a fundamental effective value algorithm.
Referring to fig. 5, fig. 5 is a schematic flow chart illustrating a method for protecting an unbalance of a capacitor bank without a fuse according to an embodiment of the present invention.
In an embodiment, the present invention further provides a method for protecting an unbalance of a fuseless capacitor bank, which is applied to the device for protecting an unbalance of a fuseless capacitor bank, and the specific contents are as follows.
Step S101, obtains the unbalanced current value and the current value of the fuse-less capacitor bank.
The sampling unit can acquire the unbalanced current value and the current value of the fuse-free capacitor bank through the current detection unit.
And S102, calculating an unbalanced current effective value corresponding to the unbalanced current value and a current effective value corresponding to the current value through a fundamental wave effective value algorithm.
The sampling unit can send the unbalanced current value and the current value of the fuse-free capacitor bank to the operation unit after acquiring the unbalanced current value and the current value, and the operation unit further calculates the unbalanced current effective value corresponding to the unbalanced current value and the current effective value corresponding to the current value through a fundamental wave effective value algorithm.
And step S103, judging whether the capacitor unbalance protection needs to be operated or not according to the ratio of the unbalance current effective value to the current effective value and a preset fixed value.
After the unbalanced current effective value and the current effective value are obtained, the logic judgment unit can judge whether the capacitor unbalanced protection needs to act or not according to the ratio of the unbalanced current effective value to the current effective value and a preset fixed value. Specifically, if the unbalanced current effective value/current effective value > a preset constant value, the capacitor unbalanced protection is activated, otherwise the capacitor unbalanced protection is not activated.
To sum up, the embodiments of the present invention provide an apparatus and a method for protecting an unbalance of a fuse-less capacitor bank, including a fuse-less capacitor bank; a current detection unit connected to the fuse-less capacitor bank; the sampling unit is connected with the current detection unit; an arithmetic unit connected to the sampling unit; and a logic judgment unit connected with the arithmetic unit; by the method, the influence of higher harmonic current on the unbalanced protection can be reduced, and the unbalanced protection action of the capacitor is higher in accuracy.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (7)
1. A fuseless capacitor bank imbalance protection device, comprising: a fuse-less capacitor bank; a current detection unit connected to the fuse-less capacitor bank; the sampling unit is connected with the current detection unit; an arithmetic unit connected to the sampling unit; and a logic judgment unit connected with the arithmetic unit;
the fuseless capacitor bank comprises a first fuseless capacitor module and a second fuseless capacitor module connected in parallel;
the current detection unit comprises a first current detection module, a second current detection module and a third current detection module; the first current detection module is arranged on a branch where the first fuse-free capacitor module is arranged; the second current detection module is arranged on a branch where the second fuse-free capacitor module is arranged; the first end of the first current detection module is in short circuit with the second end of the second current detection module, and the second end of the first current detection module is in short circuit with the first end of the second current detection module; the third current detection module is arranged on a main circuit after the first fuse-free capacitor module and the second fuse-free capacitor module are connected in parallel;
the operation unit is used for acquiring a first current value output by the first current detection module and the second current detection module in parallel and a second current value output by the third current detection module, which are transmitted by the sampling unit; calculating an unbalanced current effective value of the fuse-free capacitor bank according to the first current value; calculating the current effective value of the fuse-free capacitor bank according to the second current value;
and the logic judgment unit is used for judging whether the capacitor unbalance protection needs to act according to the ratio of the unbalance current effective value to the current effective value and a preset fixed value.
2. The fuseless capacitor bank imbalance protection device of claim 1, wherein the first current detection module, the second current detection module, and the third current detection module are open-ended current transformers.
3. The fuseless capacitor bank imbalance protection device of claim 2, wherein the sampling unit comprises a first terminal, a second terminal, a third terminal, a fourth terminal, a fifth terminal, and a sixth terminal; the first connecting terminal is in short circuit with the second connecting terminal; the third connecting terminal is in short circuit with the fourth connecting terminal; the first end of the first current detection module is connected with the first wiring terminal; the second end of the first current detection module is connected with the third wiring terminal; the second end of the second current detection module is connected with the second wiring terminal; the first end of the second current detection module is connected with the fourth wiring terminal; the first end of the third current detection module is connected with the fifth wiring terminal; and the second end of the third current detection module is connected with the sixth wiring terminal.
4. The device of claim 2, wherein the first current detection module and the second current detection module are open-ended current transformers with excitation characteristic curves that deviate by no more than 2%.
5. The fuseless capacitor bank imbalance protection device of claim 1, wherein the sampling unit comprises a low pass filtering block having a cutoff frequency of 380 Hz.
6. The fuseless capacitor bank unbalance protection device according to claim 1, wherein the operation unit calculates the unbalance current effective value and the current effective value respectively using a fundamental effective value algorithm.
7. A method for protecting an unbalance of a fuseless capacitor bank, applied to the unbalance protection device of a fuseless capacitor bank as claimed in any one of claims 1 to 6, comprising:
acquiring an unbalanced current value and a current value of the fuse-free capacitor bank;
calculating an unbalanced current effective value corresponding to the unbalanced current value and a current effective value corresponding to the current value through a fundamental wave effective value algorithm;
and judging whether the capacitor unbalance protection needs to act or not according to the ratio of the unbalance current effective value to the current effective value and a preset fixed value.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011009901.9A CN111969564A (en) | 2020-09-23 | 2020-09-23 | Fuse-free capacitor bank unbalance protection device and method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011009901.9A CN111969564A (en) | 2020-09-23 | 2020-09-23 | Fuse-free capacitor bank unbalance protection device and method |
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| CN111969564A true CN111969564A (en) | 2020-11-20 |
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| CN202011009901.9A Pending CN111969564A (en) | 2020-09-23 | 2020-09-23 | Fuse-free capacitor bank unbalance protection device and method |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA724305A (en) * | 1965-12-21 | M. Minder Peter | Capacitor bank protective means having unbalance current compensation | |
| CN101170254A (en) * | 2007-09-21 | 2008-04-30 | 四川电力试验研究院 | Unbalanced protection method and device for high-voltage serial connection compensation capacitor group |
| CN101777755A (en) * | 2010-02-02 | 2010-07-14 | 南方电网技术研究中心 | High-voltage capacitor imbalance protecting method for high-voltage DC transmission system |
| CN104076197A (en) * | 2014-07-14 | 2014-10-01 | 国家电网公司 | Unbalanced current testing device and method for capacitor bank |
-
2020
- 2020-09-23 CN CN202011009901.9A patent/CN111969564A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA724305A (en) * | 1965-12-21 | M. Minder Peter | Capacitor bank protective means having unbalance current compensation | |
| CN101170254A (en) * | 2007-09-21 | 2008-04-30 | 四川电力试验研究院 | Unbalanced protection method and device for high-voltage serial connection compensation capacitor group |
| CN101777755A (en) * | 2010-02-02 | 2010-07-14 | 南方电网技术研究中心 | High-voltage capacitor imbalance protecting method for high-voltage DC transmission system |
| CN104076197A (en) * | 2014-07-14 | 2014-10-01 | 国家电网公司 | Unbalanced current testing device and method for capacitor bank |
Non-Patent Citations (1)
| Title |
|---|
| 张江等: "基波有效值快速算法在电压波动与闪变中的应用", 《四川电力技术》 * |
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Application publication date: 20201120 |