CN106602516B - PT secondary resonance elimination device and harmonic elimination method - Google Patents
PT secondary resonance elimination device and harmonic elimination method Download PDFInfo
- Publication number
- CN106602516B CN106602516B CN201611036810.8A CN201611036810A CN106602516B CN 106602516 B CN106602516 B CN 106602516B CN 201611036810 A CN201611036810 A CN 201611036810A CN 106602516 B CN106602516 B CN 106602516B
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- ground resistance
- voltage
- circuit
- harmonic elimination
- exciting current
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Classifications
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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
- H02H7/04—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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
- H01F27/343—Preventing or reducing surge voltages; oscillations
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F38/00—Adaptations of transformers or inductances for specific applications or functions
- H01F38/20—Instruments transformers
- H01F38/22—Instruments transformers for single phase ac
- H01F38/24—Voltage transformers
- H01F38/26—Constructions
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses a kind of PT secondary resonance elimination device and harmonic elimination methods, the device includes ground resistance R and harmonic elimination control device, the common end of the one end ground resistance R connection PT secondary winding, the ground resistance R other end connects one end of PT open-triangular winding and ground connection, harmonic elimination control device is converted to exciting current by detecting the voltage at the both ends ground resistance R, and is compared with setting value, when PT exciting current is greater than the set value, ferromagnetic resonance occurs for judgement, starts harmonic elimination circuit.The present invention judges whether PT occurs ferromagnetic resonance by detection PT exciting current, it is easy to detect, accuracy of judgement, the present invention are converted into PT exciting current by detecting the voltage of ground resistance, and element is few, it is easily installed, signal detection is accurate, which is preferably 1 ohm hereinafter, compared with a harmonic elimination resistance of the resistance value greater than 1000 ohm, the measurement accuracy of PT, tail end insulation significantly improve, suitable with PT neutral-point solid ground.
Description
Technical field
The invention belongs to technical field of power systems, and in particular to a kind of secondary resonance elimination device.
Background technique
Conventional secondary resonance elimination device is with PT(voltage transformer) angle voltage (residual voltage) is open for criterion, according to its width
Value and harmonic component judge whether generation ferromagnetic resonance, this judgment method has three: first, require to carry out in Fu greatly
Leaf calculates, it is contemplated that Subharmonic Resonance, the sampling calculating time is longer, acts delay time generally all in 100ms；In practical application by
Various in the producer of PT, kind model, excitation property, impedance operator difference are very big, and amplitude, the frequency of resonance are also aobvious with regard to difference
Write, and many Ferroresonance Process be not it is very stable, often there is large error in the calculating based on Fourier, misdeems
Accidentally, the problems such as harmonic elimination tripping；Second, system direct-to-ground capacitance charging and discharging currents often cause the impact of PT when single-phase earthing disappears
PT fuse blows, and during this, the amplitude of voltage signal is often especially small, it is difficult to detect；Third cannot accurately identify
Industrial frequency resonance.
Summary of the invention
Accurate judgement ferromagnetic resonance and the two of harmonic elimination can be carried out the technical problem to be solved by the invention is to provide a kind of
Secondary harmonic elimination apparatus.
In order to solve the above technical problems, the technical scheme adopted by the invention is that:
A kind of PT secondary resonance elimination device, the device include ground resistance R and harmonic elimination control device, the ground resistance R
One end connects the common end of PT secondary winding, and the ground resistance R other end connects one end of PT open-triangular winding and ground connection, described
Harmonic elimination control device includes voltage detecting circuit, central processor circuit, the harmonic elimination circuit for detecting ground resistance R both end voltage,
The wherein input of the output connection central processor circuit of voltage detecting circuit, the output connection harmonic elimination electricity of central processor circuit
The input on road, the voltage signal at the both ends ground resistance R that voltage detecting circuit will test are sent into central processor circuit, center
Voltage signal is converted to PT exciting current and compared with setting value by processor circuit, when PT exciting current is greater than the set value,
It controls harmonic elimination circuit and connects progress harmonic elimination.
Further, the voltage detecting circuit further includes three-phase phase voltage detection circuit and zero sequence voltage detection electricity
Road.
Further, the resistance value of the ground resistance R is 0.1~10 ohm.
Preferably, the resistance value of the ground resistance R is 1 ohm or less.
A kind of PT harmonic elimination method, method includes the following steps:
A, PT exciting current detects,
B, the PT exciting current that step A is detected is compared with setting value, when PT exciting current is greater than the set value,
Ferromagnetic resonance occurs for judgement, starts harmonic elimination circuit, and it is PT capacity and 1.9 times two that the setting value, which is the limit current output of PT,
The ratio of secondary winding voltage rating.
The detection of PT exciting current is realized by detecting the voltage at the both ends ground resistance R in the step A, PT excitation electricity
Stream be converted by the voltage at the both ends ground resistance R Lai, the one end the ground resistance R connect PT secondary winding common end,
The ground resistance R other end connects one end of PT open-triangular winding and ground connection.
By adopting the above-described technical solution, the technological progress achieved by the present invention is:
The present invention judges whether PT occurs ferromagnetic resonance, easy to detect, accuracy of judgement, sheet by detection PT exciting current
Invention is converted into PT exciting current by detecting the voltage of ground resistance, compared with using CT detection mode, can really reflect
Input signal comprising optional frequency component and DC component is not influenced, signal detection by PT electric current Severe distortion when resonance
Accurately, element is few, is easily installed, which is generally 0.1~10 ohm, preferably 1 ohm 1 hereinafter, big with resistance value
It is compared in 1000 ohm of a harmonic elimination resistance, the measurement accuracy of PT, tail end insulation significantly improve, straight with PT neutral point
Earth Phase is connect to work as.
Detailed description of the invention
Fig. 1 is the principle of the present invention figure.
Specific embodiment
The present invention is described in further details below with reference to embodiment:
In the power system, cause PT fuse since system direct-to-ground capacitance charging and discharging currents are easy when single-phase earthing disappears
Fusing, so cause fuse blows, be because occur on PT amplitude is especially high, pulsewidth significantly beyond normal power frequency excitation
Electric current, since voltage signal magnitude at this time is especially small, it is difficult to detect, therefore as PT iron occurs for the present invention with PT exciting current
The criterion of magnetic resonance.
The present invention is from the basic mechanism of PT resonance, as long as ferromagnetic resonance occurs for PT, PT is magnetic saturation state certainly,
If affirmative does not have PT resonance without magnetic saturation, simultaneously as the saturation exciting current amplitude of PT is much higher than normal excitation electricity
Stream, hundred times of difference or more convenient for detection and guarantee accurate identify.Therefore use PT exciting current detection method, can be convenient and
Quick discrimination ferromagnetic resonance effectively avoids PT fuse blows.
As shown in Figure 1, secondary resonance elimination device of the present invention includes ground resistance R and harmonic elimination control device, the ground connection electricity
The common end of the one end R connection PT secondary winding is hindered, the ground resistance R other end connects one end of PT open-triangular winding and ground connection,
The harmonic elimination control device includes the voltage detecting circuit for detecting ground resistance R both end voltage, central processor circuit, harmonic elimination electricity
Road wherein further includes three-phase phase voltage detection circuit and zero sequence voltage detection circuit in voltage detecting circuit.The voltage inspection
The input of the output connection central processor circuit of slowdown monitoring circuit, the input of the output connection harmonic elimination circuit of central processor circuit,
The voltage signal at the both ends ground resistance R that voltage detecting circuit will test is sent into central processor circuit, central processing unit electricity
Voltage signal is converted to PT exciting current and compared with setting value by road, when PT exciting current is greater than the set value, controls harmonic elimination
Circuit, which is connected, carries out harmonic elimination.The setting value is the limit current output of PT, is PT capacity and 1.9 times of secondary winding voltage ratings
Ratio.
In the power system, it is generally the case that the detection of electric current uses CT (current transformer), and the present invention is using ground connection electricity
R is hindered to detect, and not only avoids the complicated installation question of CT, solves CT and be unable to accurate delivery ultra-low frequency signal, cannot transmit
The problem of DC component, simultaneously because the resistance value of ground resistance R is generally 0.1~10 ohm, preferably 1 ohm of the present invention with
Under, compared with a harmonic elimination resistance of the resistance value greater than 1000 ohm, the measurement accuracy of PT, tail end insulation significantly improve,
Suitable with PT neutral-point solid ground, resistance is small, can also simplify detection circuit structure, avoid the overtension due to acquisition and
Design bleeder circuit.
PT secondary resonance elimination device of the invention based on PT exciting current judge, harmonic elimination method the following steps are included:
A, PT exciting current detects,
B, the PT exciting current that step A is detected is compared with setting value, when PT exciting current is greater than the set value,
Ferromagnetic resonance occurs for judgement, starts harmonic elimination circuit, and it is PT capacity and 1.9 times two that the setting value, which is the limit current output of PT,
The ratio of secondary winding voltage rating.
The detection of PT exciting current is realized by detecting the voltage at the both ends ground resistance R in the step A, PT excitation electricity
Stream be converted by the voltage at the both ends ground resistance R Lai, the one end the ground resistance R connect PT secondary winding common end,
The ground resistance R other end connects one end of PT open-triangular winding and ground connection.
Claims (4)
1. a kind of PT secondary resonance elimination device, it is characterised in that: the device includes ground resistance R and harmonic elimination control device, described
The one end ground resistance R connects the common end of PT secondary winding, and the ground resistance R other end connects one end of PT open-triangular winding simultaneously
Ground connection, the harmonic elimination control device include detect the voltage detecting circuit of ground resistance R both end voltage, central processor circuit,
Harmonic elimination circuit, the wherein input of the output connection central processor circuit of voltage detecting circuit, the output of central processor circuit
The input of harmonic elimination circuit is connected, the voltage signal at the both ends ground resistance R that voltage detecting circuit will test is sent into central processing
Device circuit, voltage signal is converted to PT exciting current and compared with setting value by central processor circuit, when PT exciting current is big
When setting value, control harmonic elimination circuit, which is connected, carries out harmonic elimination；
PT harmonic elimination method the following steps are included:
A, PT exciting current detects, and the detection of PT exciting current is realized by detecting the voltage at the both ends ground resistance R, and PT is encouraged
Magnetoelectricity stream be converted by the voltage at the both ends ground resistance R Lai, the one end the ground resistance R connect PT secondary winding it is public
End, the ground resistance R other end connect one end of PT open-triangular winding and ground connection；
B, the PT exciting current that step A is detected is compared with setting value, when PT exciting current is greater than the set value, judgement
Occur ferromagnetic resonance, start harmonic elimination circuit, the setting value be PT limit current output, be PT capacity and 1.9 times it is secondary around
The ratio of group voltage rating.
2. PT secondary resonance elimination device according to claim 1, it is characterised in that: the voltage detecting circuit further includes three-phase
Phase voltage detection circuit and zero sequence voltage detection circuit.
3. according to claim 1 or 2 described in any item PT secondary resonance elimination devices, it is characterised in that: the resistance of the ground resistance R
Value is 0.1~10 ohm.
4. PT secondary resonance elimination device according to claim 1 or 2, it is characterised in that: the resistance value of the ground resistance R is 1
Ohm or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611036810.8A CN106602516B (en) | 2016-11-23 | 2016-11-23 | PT secondary resonance elimination device and harmonic elimination method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201611036810.8A CN106602516B (en) | 2016-11-23 | 2016-11-23 | PT secondary resonance elimination device and harmonic elimination method |
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| Publication Number | Publication Date |
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| CN106602516A CN106602516A (en) | 2017-04-26 |
| CN106602516B true CN106602516B (en) | 2019-02-26 |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107332219A (en) * | 2017-07-10 | 2017-11-07 | 合肥东玖电气有限公司 | A kind of harmonic elimination system for microcomputer |
| CN107171302A (en) * | 2017-07-10 | 2017-09-15 | 合肥东玖电气有限公司 | A kind of new microcomputer harmonic elimination device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101009429A (en) * | 2006-01-16 | 2007-08-01 | 林苏 | Harmony and arc elimination method of the neutral point non-valid grounding power grid and its integrated protection device |
| CN103743935A (en) * | 2013-12-27 | 2014-04-23 | 神华集团有限责任公司 | Method for measuring system capacitance current in power supply system in coalmine production |
| CN105449651A (en) * | 2015-10-12 | 2016-03-30 | 国家电网公司 | Controllable resonance suppression device for distribution network |
| CN206340959U (en) * | 2016-11-23 | 2017-07-18 | 苏州立旭智能电气有限公司 | PT secondary resonance elimination devices |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7804198B2 (en) * | 2007-02-15 | 2010-09-28 | Harmonics Holdings, Inc. | Electrical harmonic suppression system and enclosure for the same |
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2016
- 2016-11-23 CN CN201611036810.8A patent/CN106602516B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101009429A (en) * | 2006-01-16 | 2007-08-01 | 林苏 | Harmony and arc elimination method of the neutral point non-valid grounding power grid and its integrated protection device |
| CN103743935A (en) * | 2013-12-27 | 2014-04-23 | 神华集团有限责任公司 | Method for measuring system capacitance current in power supply system in coalmine production |
| CN105449651A (en) * | 2015-10-12 | 2016-03-30 | 国家电网公司 | Controllable resonance suppression device for distribution network |
| CN206340959U (en) * | 2016-11-23 | 2017-07-18 | 苏州立旭智能电气有限公司 | PT secondary resonance elimination devices |
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| CN106602516A (en) | 2017-04-26 |
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Effective date of registration: 20211008 Address after: No.226 Xiangjiang Road, East Development Zone, Shijiazhuang, Hebei 050000 Patentee after: HEBEI XUHUI ELECTRIC Co.,Ltd. Address before: 215123 1-b602, creative industrial park, No. 328, Xinghu street, Suzhou Industrial Park, Suzhou, Jiangsu Patentee before: SUZHOU LIXU INTELLIGENT ELECTRIC Co.,Ltd. |
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