CN108767815B - Automatic bypass resonance elimination device of electromagnetic voltage transformer - Google Patents
Automatic bypass resonance elimination device of electromagnetic voltage transformer Download PDFInfo
- Publication number
- CN108767815B CN108767815B CN201810785444.9A CN201810785444A CN108767815B CN 108767815 B CN108767815 B CN 108767815B CN 201810785444 A CN201810785444 A CN 201810785444A CN 108767815 B CN108767815 B CN 108767815B
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- China
- Prior art keywords
- voltage transformer
- electromagnetic voltage
- bypass
- fuse
- silicon controlled
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- 230000008030 elimination Effects 0.000 title claims abstract description 15
- 238000003379 elimination reaction Methods 0.000 title claims abstract description 15
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 19
- 239000010703 silicon Substances 0.000 claims abstract description 19
- 239000013307 optical fiber Substances 0.000 claims abstract 2
- 239000003990 capacitor Substances 0.000 abstract description 6
- 230000005350 ferromagnetic resonance Effects 0.000 abstract description 5
- 230000006378 damage Effects 0.000 abstract description 3
- 230000008018 melting Effects 0.000 abstract description 2
- 238000002844 melting Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 description 3
- 239000000835 fiber Substances 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
Classifications
-
- 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
- H02H7/04—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 transformers
- H02H7/05—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 transformers for capacitive voltage transformers, e.g. against resonant conditions
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Supply And Distribution Of Alternating Current (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses an automatic bypass resonance elimination device of an electromagnetic voltage transformer, which comprises an electromagnetic voltage transformer PT, a fuse FU, a bypass resistor R and two silicon controlled rectifiers SCR, wherein the bypass resistor R is connected with the two silicon controlled rectifiers SCR in series and then is connected with the electromagnetic voltage transformer PT and a circuit connected with the fuse FU in series in parallel, one end of the parallel fuse FU connected with the bypass resistor R is connected with one phase of a power system, the tail end of the other end of the electromagnetic voltage transformer PT is connected with the ground, and a current transformer CT is arranged on a connecting line; the secondary of the current transformer CT is connected with a light emitting diode LED, light emitted by the light emitting diode LED is transmitted to a photodiode LCR through an optical fiber, one end of the photodiode LCR is connected with the gate electrode of the silicon controlled rectifier SCR, and the other end of the photodiode LCR is connected with the anode of the silicon controlled rectifier SCR after being connected with a current limiting resistor r in series. The invention can effectively inhibit the charge and discharge flow of the capacitor to the ground when the ferromagnetic resonance and bypass single-phase grounding disappear, and solve the problems of frequency melting and frequency destruction of the voltage transformer and the fuse.
Description
Technical Field
The invention belongs to the technical field of power distribution network protection, and particularly relates to an automatic bypass device for charging and discharging current of a capacitor to ground flowing through a PT.
Background
Electromagnetic voltage transformers (PT) and fuses of the power distribution network frequently destroy phenomena, so that the operation and maintenance cost is increased, and serious threats are caused to safe and stable operation of the power grid and equipment.
Expert scholars at home and abroad have conducted a great deal of research on ferromagnetic resonance, and developed corresponding devices, and also achieved certain effects in the system operation. These detuning measures fall into two main categories: the primary neutral point is connected with a harmonic elimination resistor (a SiC primary harmonic elimination device) and the secondary opening angle is connected with a microcomputer harmonic elimination device (a secondary harmonic elimination device). Practice proves that most of ferromagnetic resonance can be eliminated by the conventional SiC primary harmonic eliminator, however, the voltage measurement accuracy is affected by the SiC primary harmonic eliminator, the problem of lifting the voltage at the tail end of the PT is solved, and even the tail end insulation breakdown of the semi-insulating PT is caused, so that serious potential safety hazards are formed. The secondary harmonic elimination devices take the opening angle voltage as a criterion, the result can be calculated only by data in a certain time period, and the action delay is longer and is more than 100 ms; when the single-phase grounding disappears, because of voltage abrupt change, the charging and discharging current of the system to the ground capacitor only flows through the PT primary loop, and when intermittent grounding frequently happens, the PT fuse is not only triggered to be fused, even the PT is burnt out, but the secondary resonance elimination device cannot continuously act, and basically does not act on the intermittent grounding. According to statistics of a national power grid, neutral points on the medium voltage distribution network side of a transformer substation are connected in a non-grounding mode, ferromagnetic resonance frequently occurs, an electromagnetic voltage transformer and a fuse thereof are subjected to frequent fusion and frequent destruction, a large amount of labor is wasted, and safe and reliable operation of the medium voltage distribution network is seriously affected.
Disclosure of Invention
The invention aims to overcome the defects and provide the automatic bypass resonance elimination device of the electromagnetic voltage transformer, which has a simple, rapid and efficient structure.
In order to solve the technical problems, the automatic bypass resonance elimination device of the electromagnetic voltage transformer comprises an electromagnetic voltage transformer PT, a fuse FU, a bypass resistor R and two silicon controlled rectifiers SCR, wherein the bypass resistor R is connected with the two silicon controlled rectifiers SCR in series and then is connected with the electromagnetic voltage transformer PT and a circuit connected with the fuse FU in series, one end of the parallel fuse FU connected with the bypass resistor R is connected with one phase of a power system, the tail end of the parallel electromagnetic voltage transformer PT is connected with the ground, and a current transformer CT is arranged on a connecting line of the electromagnetic voltage transformer PT and the ground; the secondary of current transformer CT connects emitting diode LED, the light that emitting diode LED sent is transmitted to photodiode LCR through optic fibre, photodiode LCR one end with the gate of silicon controlled rectifier SCR is connected, the other end concatenates current limiting resistor r back with the positive pole of silicon controlled rectifier SCR.
Preferably, the bypass resistor R has a value of 50kΩ -200kΩ.
The invention has the beneficial effects that: the invention has simple and reliable structure, can effectively inhibit the charge and discharge current of the system to the ground capacitor when the ferromagnetic resonance and bypass single-phase grounding disappear, and solves the problems of frequency melting and frequency destruction of the electromagnetic voltage transformer and the fuse thereof.
Drawings
Fig. 1 is a schematic diagram of the composition of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples.
The invention relates to an automatic bypass resonance elimination device of an electromagnetic voltage transformer, which comprises an electromagnetic voltage transformer PT, a fuse FU, a bypass resistor R and two silicon controlled rectifiers SCR, wherein the bypass resistor R is connected with the two silicon controlled rectifiers SCR in series, then is connected with the electromagnetic voltage transformer PT and a circuit connected with the fuse FU in series in parallel, one end of the parallel fuse FU connected with the bypass resistor R is connected with one phase of a power system, the tail end of the parallel electromagnetic voltage transformer PT is connected with the ground, and a current transformer CT is arranged on a connecting line of the electromagnetic voltage transformer PT and the ground; the secondary of current transformer CT connects emitting diode LED, the light that emitting diode LED sent is transmitted to photodiode LCR through optic fibre, photodiode LCR one end with the gate of silicon controlled rectifier SCR is connected, the other end concatenates current limiting resistor r back with the positive pole of silicon controlled rectifier SCR.
Preferably, the bypass resistor R has a value of 50kΩ -200kΩ.
Examples: the three-phase circuit of the automatic bypass resonance elimination device of the electromagnetic voltage transformer is completely symmetrical, and referring to fig. 1, a circuit inside a dotted line frame in the figure is a three-phase shared circuit, and a circuit outside the dotted line frame is a three-phase independent circuit.
The invention is a charge-discharge current automatic bypass device of a capacitor to ground flowing through PT, a bypass resistor R is connected in series with two anti-parallel thyristors SCR, then is connected in parallel with an electromagnetic voltage transformer PT and a circuit after the fuse FU is connected in series, one end of the circuit fuse FU connected in parallel with a current limiting resistor R is connected into one phase of a power system, the tail end of the electromagnetic voltage transformer PT at the other end is connected with the ground after being connected in parallel, and a current transformer CT is arranged on a connecting wire; the secondary of current transformer CT connects the luminescent diode LED, the light that LED sent is transmitted to the photodiode LCR through the optic fibre, one end of photodiode LCR is connected with gate pole of the silicon controlled rectifier SCR, another end connects in series the current-limiting resistor r, connect with positive pole of SCR.
Under normal conditions, the exciting current of the electromagnetic voltage transformer PT is very small, the secondary output of the current transformer CT is insufficient to drive the light emitting diode LED, the photodiode LCR is not conducted, and the silicon controlled rectifier SCR is in an off state; when the system is intermittently grounded or ferroresonance and the like, the electromagnetic voltage transformer PT is used for enabling a large saturated exciting current or charging and discharging current of a system capacitor to the ground to flow, secondary current of the current transformer CT drives the light-emitting diode LED to emit light, the light-emitting diode LCR is triggered to be conducted by illumination, the silicon controlled rectifier SCR is conducted within a period of a few us (microseconds), the bypass resistor R is immediately put into operation, strong damping is formed, the ferroresonance is effectively restrained, current of the electromagnetic voltage transformer PT is induced, and the ferroresonance and fuse fusing are avoided.
The above disclosed examples are only intended to help illustrate the invention, the preferred examples do not recite all details, nor limit the invention to only the specific embodiments described. It will be apparent from the disclosure of the present invention that numerous modifications and variations can be made thereto, and the embodiments selected and described in detail herein are chosen to best explain the principles of the invention and the practical application, thereby enabling others skilled in the art to best understand and utilize the invention and as long as the foregoing construction is employed.
Claims (2)
1. The automatic bypass resonance elimination device of the electromagnetic voltage transformer comprises an electromagnetic voltage transformer PT, a fuse FU, a bypass resistor R and two silicon controlled rectifiers SCR, and is characterized in that the bypass resistor R is connected with the two silicon controlled rectifiers SCR in series, then is connected with the electromagnetic voltage transformer PT and a circuit connected with the fuse FU in series, one end of the parallel fuse FU connected with the bypass resistor R is connected into one phase of a power system, the other end of the parallel fuse FU is connected with the tail end of the electromagnetic voltage transformer PT and is connected with the ground, and a current transformer CT is arranged on a connecting line of the electromagnetic voltage transformer PT and the ground; the secondary side of the current transformer CT is connected with a light emitting diode LED, light emitted by the light emitting diode LED is transmitted to a photodiode LCR through an optical fiber, one end of the photodiode LCR is connected with a gate electrode of the silicon controlled rectifier SCR, and the other end of the photodiode LCR is connected with an anode of the silicon controlled rectifier SCR after being connected with a current limiting resistor r in series.
2. The automatic bypass harmonic elimination device for electromagnetic voltage transformer according to claim 1, wherein the bypass resistor R has a value between 50kΩ and 200kΩ.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810785444.9A CN108767815B (en) | 2018-07-17 | 2018-07-17 | Automatic bypass resonance elimination device of electromagnetic voltage transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810785444.9A CN108767815B (en) | 2018-07-17 | 2018-07-17 | Automatic bypass resonance elimination device of electromagnetic voltage transformer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108767815A CN108767815A (en) | 2018-11-06 |
| CN108767815B true CN108767815B (en) | 2024-02-02 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810785444.9A Active CN108767815B (en) | 2018-07-17 | 2018-07-17 | Automatic bypass resonance elimination device of electromagnetic voltage transformer |
Country Status (1)
| Country | Link |
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| CN (1) | CN108767815B (en) |
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| CN2133967Y (en) * | 1992-05-07 | 1993-05-19 | 河北省电力试验研究所 | Resonant suppressor for bus voltage mutual-inductor |
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2018
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| CN203376375U (en) * | 2013-06-07 | 2014-01-01 | 国家电网公司 | Graded insulation electromagnetic type PT primary side current monitoring device |
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| CN104377680A (en) * | 2014-11-21 | 2015-02-25 | 国家电网公司 | Secondary alternating-current resonance elimination device used for electromagnetic type voltage transformer |
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| Publication number | Publication date |
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| CN108767815A (en) | 2018-11-06 |
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