CN201118203Y - Device for suppressing transformer noise arousing from dc magnetic bias - Google Patents
Device for suppressing transformer noise arousing from dc magnetic bias Download PDFInfo
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- CN201118203Y CN201118203Y CNU2007200762138U CN200720076213U CN201118203Y CN 201118203 Y CN201118203 Y CN 201118203Y CN U2007200762138 U CNU2007200762138 U CN U2007200762138U CN 200720076213 U CN200720076213 U CN 200720076213U CN 201118203 Y CN201118203 Y CN 201118203Y
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- diode
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- neutral point
- transformer
- earth electrode
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Abstract
The utility model relates to a device for inhibiting direct current magnetic bias to cause the noise of a transformer, belonging to the field of emergency protection circuit devices, which comprises a blocking unit and a one-time system failure protection unit and is characterized in that the blocking unit comprises a first electrolytic capacitor, a second electrolytic capacitor, a first protection diode and a second protection diode; wherein, the first electrolytic capacitor is connected with the second electrolytic capacitor in series by the mode of reversed polarity, the anodes and the cathodes of the first electrolytic capacitor and the second electrolytic capacitor are respectively connected with the first protection diode and the second protection diode in parallel by the mode of reversed polarity, and the serially connected electrolytic capacitors and the corresponding protection diodes are connected between the neutral point and the grounding electrode of the transformer; the one-time system failure protection unit comprises a first unidirectional over-voltage protection loop and a second unidirectional over-voltage protection loop which are connected in series reversely, wherein, each unidirectional over-voltage protection loop comprises n diodes which are connected in series equidirectionally and sequentially; the first unidirectional over-voltage protection loop and the second unidirectional over-voltage protection loop are connected between the neutral point and the grounding electrode of the transformer after being reversely shunt-wounded; the device can be wildly used in the field of power transmission and transformation.
Description
Technical field
The utility model belongs to emergency protective circuit device field, relates in particular to a kind of emergency protective circuit device that is used to suppress the transformer neutral point direct current.
Background technology
Along with the construction of China's electrical network, increasing DC power transmission line (also being called high voltage direct current transmission) puts into operation, has played very positive effect in regional interconnection of power system.
When DC transmission system one pole the earth operation (also being called asymmetric operation), the face of land can produce DC voltage difference, and same result also may be caused (as dc electrolysis etc.) by DC earthing in the industrial production.
Because the DC potential difference of the earth, when the transformer of transmission line two ends all adopts the mode of neutral ground, the earth direct current differential pressure produces D.C. magnetic biasing by neutral ground to transformer, produce magnetic biasing after the AC transformer neutral point stack DC component, cause magnetic saturation, in AC system, produce harmonic wave, vibration, noise, had a strong impact on the safe and stable operation of AC system.The tangible consequence of wherein bringing is that transformer noise increases greatly, and through measuring, the mean value of transformer noise is greater than 75 decibels, when serious even up to 90 decibels.
Because transformer is generally very near from the residential block in the urban distribution network now, the increase greatly of transformer noise often causes very big social concern, produces many adverse effects.
Simultaneously, the existence of D.C. magnetic biasing phenomenon also makes the loss of transformer self obviously increase, and is unfavorable for efficiency of transmission energy-saving and cost-reducing and the raising transmission line.
Domestic have research to the DC source that produces in the 220KV transformer neutral point ground connection operational mode more, carried out many theory analysises and on-the-spot actual measurement.Because 220KV transformer station span is longer relatively, relatively large at the direct current epd that then long distance produces, therefore constitute DC loop easily.The potential difference maximum that shows 220KV transformer station neutral ground two ends according to more domestic test report data can reach between 40V～50V, and maximum direct current can reach about 30A.
In order effectively to reduce direct current, some local employings mode such as series resistor or electric capacity in the neutral ground loop solves the transformer bias that direct current causes both at home and abroad;
2 units of the subordinate of Quebec, CAN power office, electric power research institute IREQ and TransEnergie company played joint research and development in 1993 and suppress the neutral point direct current current device, and it is used for limiting HVDC (High Voltage Direct Current) transmission system flows into AC network when adopting the earth echo plex mode direct current.Its operation principle is to insert little capacitive reactance at transformer neutral point, when the system failure with its bypass.
Domestic have " the principle emulation of transformer DC magnetic bias " to study, and analyzes imperial certainly mechanism that transformer bears the external forced direct current, and having illustrated direct current one pole earth current is the source of D.C. magnetic biasing, has proposed to alleviate some operation measures of transformer vibration.
Concluding from practical application gets up to have following three kinds of modes to solve DC component:
1) at transformer neutral point dress small resistor, with the size of restriction direct current.
2) series capacitor on transformer neutral point, blocking-up direct current, failure condition are used the thyristor bypass down.
3) inject the DC potential that the counter current method is offset transformer neutral point at the transformer periphery, to reduce neutral point direct current.
The said method solution cuts both ways, and first method simply should be gone, but not thorough, effect is relevant with epd, if epd is bigger, earth resistance is subjected to system's restriction to be had in the time of should not increasing, and effect is just poor.Second method is a kind of method that suppresses more completely, but because the use in the controls such as triggering of thyristor protection loop has brought decline and some uncertain factors of reliability.Feasible on the third theoretical method, the practical application more complicated is difficult to accomplish ideal state, moreover the direct current that injects has brought other problem again.
The utility model content
Technical problem to be solved in the utility model provides a kind of device that suppresses voltage transformer noise caused by DC magnetic biasing, it is in the ascending change procedure of whole centre-point earth electric current, guaranteed the continuity of grounded circuit every the reliable nonlinear characteristic of straight assembly, complicated control loop and thyristor components and parts have been avoided, built-in auto by pass guarantees every perfectly safe every straight assembly directly, do not change existing network system structural parameters, when normal operation, DC component thoroughly can be cut off again simultaneously.
The technical solution of the utility model is: a kind of device that suppresses voltage transformer noise caused by DC magnetic biasing is provided; comprise be arranged between transformer neutral point and the earth electrode every straight unit and primary system error protection unit; it is characterized in that: describedly comprise first electrochemical capacitor every straight unit; second electrochemical capacitor; the first protection diode and the second protection diode; wherein; first and second electrochemical capacitor reversed polarity serial connection; at first and second electrochemical capacitors just; the negative pole two ends; respectively with the reversed polarity mode and connect first and second the protection diodes; electrochemical capacitor after the serial connection and corresponding protection diode thereof; be connected between transformer neutral point and the earth electrode, constitute one complete every straight unit.
Above-mentioned is the capacitive characteristic every straight unit under nominal situation, when increasing, neutral point current is the capacitance-resistance characteristic, breaking down at primary system is resistance characteristic when causing current surge, and can ignore state along with its resistance value of increase of fault current sharply drops to.
Described primary system error protection unit comprises the first and second unidirectional overvoltage protection loops of two reverse parallel connections; each unidirectional overvoltage protection loop comprises n (n 〉=2) diode; each diode is series connection successively in the same way; behind the first and second unidirectional overvoltage protection loop reverse parallel connections; be connected between transformer neutral point and the earth electrode, constitute a complete primary system error protection unit.
Above-mentioned primary system error protection unit automatic short-circuit under the extreme case of reverse breakdown directly will be every straight unit short circuit excision, makes the direct ground connection of transformer neutral point.
Concrete, the negative pole of its first and second electrochemical capacitor connects, and the positive pole of first and second electrochemical capacitors is connected with earth electrode with transformer neutral point respectively.
The positive and negative electrode of first and second electrochemical capacitors respectively with first and second the protection diodes negative, positive extremely corresponding connection.
The positive pole of the 1st diode in the first unidirectional overvoltage protection loop is connected with transformer neutral point, and the negative pole of n diode is connected with earth electrode.
The negative pole of the 1st diode in the second unidirectional overvoltage protection loop is connected with transformer neutral point, and the positive pole of n diode is connected with earth electrode.
Further, between transformer neutral point and earth electrode, an auto by pass switch can be set also, be used for described out of service, with the neutral-point solid ground of transformer every straight unit and/or primary system error protection unit.
Between the positive pole and earth electrode of n the diode in the second unidirectional overvoltage protection loop, the actuation coil of a by-pass switch can be set also.
Compared with the prior art, the utility model has the advantages that:
1. in electric capacity two ends reversed polarity and connect diode, utilize the characteristic of diode nonlinear area, operational mode and failure condition have been taken into account, rationally be provided with breakover point, neither influence has the system parameters of protective relaying device now, can not change the various operating modes of original primary system again, also reach the goal of the invention that reduces transformer noise;
2. with two polarity electrochemical capacitor reversed polarity serial connection is arranged, again and connect the composition mode of pair of diodes, the Capacity Ratio tradition connection of electric capacity is doubled, and the volume that exchanges big electric capacity can be significantly reduced, and also can ensure the safety in operation of electrochemical capacitor simultaneously;
3. utilize the series circuit of a plurality of device for high-power power electronic diodes to constitute the primary system faulty channel, circuit structure is succinct, has avoided complicated control loop and thyristor components and parts, can reduce its manufacturing/use cost and maintenance workload greatly;
4. the pressure drop of diode series connection is greater than face of land voltage difference, so will have only very little leakage current to flow through under the normal condition, element does not almost have caloric value, compole is short under failure condition because during short circuit current, and electric current is subjected to the restriction of transformer short-circuit impedance and the effect of by-pass switch, so need not diode is carried out radiating treatment, also help dwindling the volume of whole device;
5. this device is not owing to there is control loop, and circuit structure is simple, the maintenance issues that do not exist in service.Selected components and parts are power electronic device commonly used, stable performance, and the reliability height is not even if certain components and parts generation problem in service can produce serious consequence yet.
Description of drawings
Fig. 1 is an equivalent electric circuit topological diagram of the present utility model;
Fig. 2 is the electrical block diagram of the utility model every straight unit.
Embodiment
Below in conjunction with accompanying drawing the utility model is described further.
Among Fig. 1; the utility model be included in be arranged in parallel between transformer neutral point O (or O ') and the earth electrode Q (or Q ') every straight unit 1 (or 1 ') and primary system error protection unit 2 (or 2 '); its innovation and creation point is; with two electrochemical capacitor reversed polarity serial connections that polarity is arranged; two ends at each electrochemical capacitor; in the reversed polarity mode and connect a diode (concrete connected mode see Fig. 2); the capacity that capacitances in series such as elimination causes in the protection electric capacity effect that reduces by half; utilize the nonlinear resistance property of diode, constitute one complete have good communication channel every straight unit 1 (or 1 ').
In other words; it comprises first electrochemical capacitor, second electrochemical capacitor, the first protection diode and the second protection diode every straight unit; its first and second electrochemical capacitors reversed polarity serial connection; positive and negative electrode two ends at first and second electrochemical capacitors; respectively with the reversed polarity mode and connect first and second the protection diodes; electrochemical capacitor after the serial connection and corresponding protection diode thereof are connected between transformer neutral point and the earth electrode, constitute one complete every straight unit.
Be the capacitive characteristic every straight unit under nominal situation, be the capacitance-resistance characteristic when neutral point current increases, breaking down at primary system is resistance characteristic when causing current surge, and can ignore state along with its resistance value of increase of fault current sharply drops to.
In addition; second innovation and creation point of the present invention is; its primary system error protection unit comprises the first unidirectional overvoltage protection loop 2-1 (or 2-1 ') and the second unidirectional overvoltage protection loop 2-2 (or 2-2 ') of two reverse parallel connections; each unidirectional overvoltage protection loop comprises n (n 〉=2) diode; each diode is series connection successively in the same way; behind the first and second unidirectional overvoltage protection loop reverse parallel connections; be connected between transformer neutral point and the earth electrode, constitute a complete primary system error protection unit 2 (or 2 ').
As seen from the figure, the positive pole of the 1st diode in the first unidirectional overvoltage protection loop is connected with transformer neutral point, and the negative pole of n diode is connected with earth electrode; The negative pole of the 1st diode in the second unidirectional overvoltage protection loop is connected with transformer neutral point, and the positive pole of n diode is connected with earth electrode.
The automatic short-circuit under the extreme case of reverse breakdown of primary system error protection unit directly will be every straight unit short circuit excision, makes the direct ground connection of transformer neutral point.
Further, between transformer neutral point and earth electrode, an auto by pass switch 4 (or 4 ') can be set also, be used for making it out of service, with the neutral-point solid ground of transformer every straight unit and/or the excision of primary system error protection unit.
Further, in order to obtain better effect, also can be in unidirectional overvoltage protection loop, a certain road the actuation coil of (among the figure be example with 2-2) serial connection one by-pass switch, the output signal of overcurrent actuation coil is used to start the closed ON Action of described by-pass switch.Be example with the second unidirectional overvoltage protection loop 2-2 among the figure, between the positive pole and earth electrode of n the diode in the described second unidirectional overvoltage protection loop, be provided with the actuation coil 2-3 (or 2-3 ') of by-pass switch.
Adopt technique scheme, in the ascending change procedure of whole centre-point earth electric current, guaranteed the continuity of grounded circuit every the reliable nonlinear characteristic of straight assembly, complicated control loop and thyristor components and parts have been avoided, built-in auto by pass guarantees every perfectly safe every straight assembly directly, do not change the structural parameters of existing network system, when normal operation, DC component thoroughly can be cut off simultaneously.
During real work:
1. the earth direct current I
ZProduce voltage drop (peak of testing this voltage according to reality can reach between 40V～50V) above the electric resistance of soil Z between two transformer centre-point earth;
2. centre-point earth two terminal voltages at resistance Z constitute the loop by transformer centre-point earth line and overhead wire, make transformer produce magnetic bias;
3. grounded circuit series connection electric power heavy-duty diode, utilize the nonlinear resistance principle of diode, with the reasonable constituent components that cooperates of capacitor, little electric current passes through electric capacity, big electric current constitutes the good result that extremely simple isolated DC electric current guarantees communication channel by diode; Simultaneously, because heavy-duty diode bears the advantage of big current work characteristic in short-term, the component element long period reliability of operation is high.
In case short circuit current is by neutral ground, in short-term, pass through diode circuit, (4～10mS) directly just with neutral-point solid ground, even if grounding shunt neutral point short circuit current is all by diode circuit, to device also not influence for the intrinsic closing time of process by-pass switch.
Among Fig. 2; with two electrochemical capacitor C1 and C2 reversed polarity serial connections that polarity is arranged; two ends at each electrochemical capacitor; in the reversed polarity mode and meet a diode D1 and D2; utilize the nonlinear resistance property of diode; the capacity that capacitances in series such as elimination causes in the protection electric capacity effect that reduces by half, constituted one complete have good communication channel every straight unit.
Particularly; it comprises the first electrochemical capacitor C1, the second electrochemical capacitor C2, the first protection diode D1 and the second protection diode D2 every straight unit; wherein; first and second electrochemical capacitor reversed polarity serial connection; positive and negative electrode two ends at first and second electrochemical capacitors; respectively with the reversed polarity mode and connect first and second the protection diodes, electrochemical capacitor after the serial connection and corresponding protection diode thereof are connected between transformer neutral point and the earth electrode.
Particularly; the negative pole of first and second electrochemical capacitors connects; the positive pole of first and second electrochemical capacitors is connected with earth electrode with transformer neutral point respectively, the positive and negative electrode of first and second electrochemical capacitors respectively with first and second the protection diodes negative, positive extremely corresponding connection.
Because the nonlinear resistance property of diode, under nominal situation, be the capacitive characteristic every straight unit, be the capacitance-resistance characteristic when neutral point current increases, breaking down at primary system is resistance characteristic when causing current surge, and along with its resistance value of increase of fault current sharply descends.
To sum up, this device does not generate heat owing in service, the electric capacity miniaturization, and whole volume is very little, is no more than 1 cube volume, can be placed near the transformer nearby, so long as the transformer noise that D.C. magnetic biasing causes all can use this this method to carry out the elimination of noise.
Be noted that enumerating of above-mentioned execution mode, only be in order to help to understand better the technical solution of the utility model, and should do not regard qualification as technical solutions of the utility model.
Those of ordinary skill in the art; after understanding and having grasped innovation intention of the present utility model and mentality of designing; need not through creative work; fully can be on the basis of the utility model technique scheme; derive various that be equal to or have the deformation program of identical function, and these sex change schemes also should belong to the scope that the utility model is asked for protection.
The utility model can be widely used in defeated, the power transformation field of electric power system.
Claims (7)
1. device that suppresses voltage transformer noise caused by DC magnetic biasing, comprise be arranged between transformer neutral point and the earth electrode every straight unit and primary system error protection unit, it is characterized in that:
Describedly comprise first electrochemical capacitor, second electrochemical capacitor, the first protection diode and the second protection diode every straight unit, wherein, first and second electrochemical capacitor reversed polarity serial connection, positive and negative electrode two ends at first and second electrochemical capacitors, respectively with the reversed polarity mode and connect first and second the protection diodes, electrochemical capacitor after the serial connection and corresponding protection diode thereof are connected between transformer neutral point and the earth electrode, constitute one complete every straight unit;
Described primary system error protection unit comprises the first and second unidirectional overvoltage protection loops of two reverse parallel connections; each unidirectional overvoltage protection loop comprises n (n 〉=2) diode; each diode is series connection successively in the same way; behind the first and second unidirectional overvoltage protection loop reverse parallel connections; be connected between transformer neutral point and the earth electrode, constitute a complete primary system error protection unit.
2. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 1, it is characterized in that the negative pole of described first and second electrochemical capacitors connects, the positive pole of first and second electrochemical capacitors is connected with earth electrode with transformer neutral point respectively.
3. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 1, the positive and negative electrode that it is characterized in that described first and second electrochemical capacitors respectively with the negative, positive extremely corresponding connection of the first and second protection diodes.
4. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 1, it is characterized in that the positive pole of the 1st diode in the described first unidirectional overvoltage protection loop is connected with transformer neutral point, the negative pole of n diode is connected with earth electrode.
5. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 1, it is characterized in that the negative pole of the 1st diode in the described second unidirectional overvoltage protection loop is connected with transformer neutral point, the positive pole of n diode is connected with earth electrode.
6. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 1, it is characterized in that between described transformer neutral point and earth electrode, an auto by pass switch is set.
7. according to the device of the described inhibition voltage transformer noise caused by DC magnetic biasing of claim 6, it is characterized in that between the positive pole and earth electrode of n the diode in the described second unidirectional overvoltage protection loop, the actuation coil of a by-pass switch being set.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200762138U CN201118203Y (en) | 2007-11-15 | 2007-11-15 | Device for suppressing transformer noise arousing from dc magnetic bias |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2007200762138U CN201118203Y (en) | 2007-11-15 | 2007-11-15 | Device for suppressing transformer noise arousing from dc magnetic bias |
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| Publication Number | Publication Date |
|---|---|
| CN201118203Y true CN201118203Y (en) | 2008-09-17 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2007200762138U Expired - Lifetime CN201118203Y (en) | 2007-11-15 | 2007-11-15 | Device for suppressing transformer noise arousing from dc magnetic bias |
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| CN (1) | CN201118203Y (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102709881A (en) * | 2012-03-15 | 2012-10-03 | 东北电力科学研究院有限公司 | Device utilizing adjustable resistance method to curb DC of neutral point of transformer |
| CN102832607A (en) * | 2011-06-15 | 2012-12-19 | 西门子公司 | Quick bypass device |
-
2007
- 2007-11-15 CN CNU2007200762138U patent/CN201118203Y/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102832607A (en) * | 2011-06-15 | 2012-12-19 | 西门子公司 | Quick bypass device |
| CN102709881A (en) * | 2012-03-15 | 2012-10-03 | 东北电力科学研究院有限公司 | Device utilizing adjustable resistance method to curb DC of neutral point of transformer |
| CN102709881B (en) * | 2012-03-15 | 2015-04-22 | 东北电力科学研究院有限公司 | Device utilizing adjustable resistance method to curb DC of neutral point of transformer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: SHANGHAI ELECTRIC POWER CORP. Free format text: FORMER OWNER: SHANGHAI ULTRA-HV TRANSMISSION + DISTRIBUTION COMPANY, SHANGHAI ELECTRIC POWER C Effective date: 20110519 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| COR | Change of bibliographic data |
Free format text: CORRECT: ADDRESS; FROM: 200063 NO. 600, WUNING ROAD, PUTUO DISTRICT, SHANGHAI TO: 200122 NO. 1122, YUANSHEN ROAD, SHANGHAI |
|
| TR01 | Transfer of patent right |
Effective date of registration: 20110519 Address after: 200122, 1122 deep road, Shanghai Patentee after: Shanghai Electric Power Corporation Address before: 200063 No. 600, Wuning Road, Shanghai, Putuo District Patentee before: Shanghai Ultra-HV Transmission & Distribution Company, Shanghai Electric Power C |
|
| CX01 | Expiry of patent term |
Granted publication date: 20080917 |