CN203278211U - Transformer excitation inrush current eliminating device - Google Patents
Transformer excitation inrush current eliminating device Download PDFInfo
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- CN203278211U CN203278211U CN 201320276187 CN201320276187U CN203278211U CN 203278211 U CN203278211 U CN 203278211U CN 201320276187 CN201320276187 CN 201320276187 CN 201320276187 U CN201320276187 U CN 201320276187U CN 203278211 U CN203278211 U CN 203278211U
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Abstract
The utility model provides a transformer excitation inrush current eliminating device. By using the switch performance of each thyristor in a thyristor component, three thyristors which are in antiparallel connection are connected in series with a three-phase power supply. By adjusting the size of the thyristor conduction angle, the opening degree of each thyristor is changed. The size of the output voltage of the output side of the power supply is changed. Voltage reduction starting is directly carried out on a load such as the primary side of a transformer. A low initial voltage is output to the transformer when starting is carried out, and then the voltage is enabled to rise to a rated voltage according to a set slope. Excitation inrush current produced by direct no-load starting of the transformer is reduced and eliminated. Tripping of a superior switch cabinet, which is caused by excitation inrush current, is avoided. The transformer is prevented from the damage of the current impact. The device can be used for motor soft starting and realizes the design of multi function integration.
Description
Technical field
The utility model relates to a kind of transformer excitation flow cancellation element.
Background technology
When power transformer drops into electrical network at idle-loaded switching-on, because the nonlinear characteristic of the saturated and core material of transformer core magnetic flux can produce the sizable magnetizing inrush current of amplitude (being generally 6-8 transformer rated current doubly), the generation reason of magnetizing inrush current and endanger as follows:
For three-phase system, transformer can only have a phase (for example A phase) to close a floodgate under no-voltage, and in addition two-phase B and C equal 86.6% of maximal phase voltage at the instantaneous voltage that closes a floodgate, and one for just, and one for bearing.In like manner, if during the last separating brake of transformer, remanent magnetism in A phase iron core equal with the close corresponding value of maximum magnetic flux and polarity and same nominal voltage under the magnetic flux of gained is opposite usually, so B phase and C mutually the remanent magnetism in iron core will equal and close half the corresponding value of every phase normal magnetic flux, and polarity is opposite with remanent magnetism in A phase iron core.So; the impulse current of three-phase is unequal; in the time of also can not adopting the method for best closing phase angle to make Transformer Close, three-phase enters stable state simultaneously; always there is two-phase that impulse current is arranged; thereby produce huge magnetizing inrush current at the transformer primary side, the transformer excitation flow peak value is up to 10-25 transformer rated current doubly, and huge magnetizing inrush current can cause the transformer differential protection misoperation; cause simultaneously winding deformation, thereby reduce transformer life.In addition, magnetizing inrush current contains a plurality of harmonic componentss and DC component, can reduce the power system power supply quality, and the high order harmonic component in shoving simultaneously has extremely strong destruction to the responsive power electronic device that is connected in electric power system.
The measure that solves at present transformer excitation flow mainly contains following two classes: hide measure and braking measure; wherein; hide measure and mainly contain the identification transformer excitation flow, adjust the manner of execution of relay protection device, allow to pass into transformer in the situation that magnetizing inrush current occurs.Braking measure has: (1) external control, i.e. magnetizing inrush current when the power transformer outside takes some remedial measures to cut down idle-loaded switching-on; As series resistance, control the threephase switch closing time, at the step down side shunt capacitor etc.; (2) internal control, namely by analyzing the excitation principle of transformer core, the internal structure that changes Transformer Winding is cut down magnetizing inrush current.Above method all can not well be eliminated in practice, especially eliminates the magnetizing inrush current in whole three-phases loop.
The utility model content
For solving the thoroughly problem of the magnetizing inrush current in eliminating transformer three-phase loop of prior art, a kind of transformer excitation flow cancellation element is proposed, its concrete technical scheme is as follows:
A kind of transformer excitation flow cancellation element, comprising: synchrotrans are connected on power supply and from mains side and obtain voltage signal; Current transducer is connected on power supply and from mains side and obtains current signal; Silicon controlled component is connected between power supply and load, and the controllable silicon that is connected by the three-phase inverse parallel forms; Trigger module is connected between the output and silicon controlled component of main control module; Main control module sends triggering signal according to above-mentioned voltage and current signal and triggers silicon controlled component by trigger module, and then adjusts in silicon controlled component each silicon controlled angle of flow and control the voltage that power supply outlet side output linearity increases.
The utility model also comprises further: the first overvoltage protective module is connected in described silicon controlled component between each silicon controlled controlled stage and negative electrode, is composed in series by some piezo-resistances.
The utility model also comprises further: the second overvoltage protective module is connected in described silicon controlled component between each silicon controlled anode and negative electrode, is composed in series by electric capacity and resistance.
The utility model also comprises further: the current signal that the current temperature detection module detects described current transducer be converted to light signal by Optical Fiber Transmission to described main control module.
Further, be connected with load switch or reactor between described reactor and described load.
Further, described load is transformer or motor.
Compared with prior art advantage of the present utility model and good effect are as follows:
the utility model transformer excitation flow cancellation element (as calling soft starter in the following text) utilizes each silicon controlled switch performance in silicon controlled component, the controllable silicon in serial connection that will be connected by three groups of inverse parallels is on three phase mains, change silicon controlled degree of opening by the size of regulating thyristor operating angle, thereby change the size of power supply outlet side output voltage, realization is carried out direct reduced voltage starting to load such as transformer primary side, during starting, transformer is exported a very low initial voltage, then allow voltage rise to rated voltage according to the slope of setting, thereby reduce and the magnetizing inrush current that produces of the direct starting under no load of eliminating transformer, avoid magnetizing inrush current to cause the tripping operation of higher level's switch cubicle, protection transformer itself is not subjected to the injury of rush of current.
After reading by reference to the accompanying drawings embodiment of the present utility model, other characteristics of the present utility model and advantage will become clearer.
Description of drawings
Fig. 1 is the utility model embodiment electrical schematic diagram;
Fig. 2 is the silicon controlled component partial circuit schematic diagram with overvoltage protection;
Direct starting transformer and soft initiator starting transformer experimental system circuit diagram under Fig. 3 rated voltage;
Fig. 4 is directly input voltage, curent change figure after starting transformer under rated voltage;
Fig. 5 is by soft initiator starting transformer, input current and soft initiator output voltage variation diagram under rated voltage.
Embodiment
Find in the utility model implementation procedure: the size of transformer excitation flow, character depend on 5 principal elements: size and the initial phase angle of voltage when 1) closing a floodgate; 2) remanent magnetism of transformer core; 3) internal structure of transformer; 4) capacity of transformer; 5) resistance value of closing circuit; 6) size of electric power system.The the 2nd to 4 is determined by transformer itself, can not change; The the 1st and the 5th can change from the outside.The utility model realize principle just be based on the 1st and the 5th.
Below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
With reference to figure 1, the present embodiment soft initiator comprises: synchrotrans TG, current transducer TM, silicon controlled component, trigger module and main control module.
Described synchrotrans TG is connected on three phase mains and from mains side and obtains voltage signal, and high tension voltage is converted to 120V AC low voltage voltage, and it is the detecting element that power panel (follow-up introduction) detects supply voltage.Described current transducer TM also is connected on three phase mains and from mains side and obtains current signal.Described silicon controlled component is connected between power supply and load, can be according to different voltage and currents, high-voltage thyristor is matched, and carry out inverse parallel and be assembled in radiator, the present embodiment silicon controlled component is comprised of the controllable silicon SCR that three groups of inverse parallels connect, and the present embodiment load can be transformer or motor.
Described trigger module is connected between the output and silicon controlled component of main control module, is the module of carrying out trigger command, according to the triggering signal that power panel sends, carries out the power supply supply by using pulse transformer TP, and controllable silicon SCR is triggered control.Described main control module comprises a block power supply plate and a CPU board, and external input signal directly or indirectly is connected to power panel, and external signal is converted to the electronic circuit signal, and carries out communication with CPU board.CPU board Storage controlling program, customer parameter, monitor data etc. are also made trigger command accordingly, carry out defencive function.This main control module sends triggering signal according to above-mentioned voltage and current signal and triggers silicon controlled component by trigger module, and then adjusts in silicon controlled component each silicon controlled angle of flow and control the voltage that power supply outlet side output linearity increases.
Impact and damage in order to make controllable silicon avoid overvoltage; avoiding overvoltage impacts and damages; with reference to figure 2; the present embodiment also comprises the first overvoltage protective module MOV plate and the second overvoltage protective module DV/DT plate; the MOV plate is connected between the controlled stage G and negative electrode K of each controllable silicon SCR in described silicon controlled component; be composed in series by some piezo-resistance RT; the serial number amount depends on system voltage; due to the over-voltage breakdown effect of piezo-resistance RT, thereby can discharge to be applied to and control utmost point G and the direct too high voltages of negative electrode K.The DV/DT plate is connected in described silicon controlled component between each silicon controlled anode A and negative electrode K; be composed in series by high-voltage capacitance C and high-power resistance R; capacitor C voltage depends on system voltage; resistance R resistance and capacity depend on rated current; the principle that it mainly utilizes capacitance voltage C not suddenly change, protection controllable silicon anode and cathode is not subjected to the injury of too high voltages.
In order to reduce the interference of signal transmission, also comprise a current temperature detection module, its input connects current transducer TM, output connects the power panel of main control module by optical fiber, its effect is that the current signal that current transducer detects is converted to light signal, and the temperature signal that the detector unit on radiator for thyristors is detected is converted to light signal.
When the present embodiment is controlled many different loads, can be connected a load switch between the output of described silicon controlled component and described load; In order to suppress peak current, the present embodiment is linked reactor between the output of described control silicon assembly and load switch, can effectively protect controllable silicon not to be damaged.Certainly also can be connected separately load switch or independent linked reactor between the output of silicon controlled component and load.
The control power supply of the present embodiment is provided by the control transformer TC that is connected on main control module, described control transformer TC is 120V AC voltage with different control voltage transitions, control power supply as device, the output of described control transformer TC also connects trigger module by a pulse transformer TP, this pulse transformer TP becomes 28V voltage with 120V voltage, trigger power supply as silicon controlled, and adopt the mode of building to encapsulate, lead-out wire is the high-voltage line of withstand voltage 40kV DC.
The present embodiment principle is as follows: the user can be input to load parameter and start-up parameters in soft initiator in advance, selects corresponding load by the load switch, and selection result is fed back to main control module; By the external command element, initiating signal is transferred to master control borad, and according to the fiber-optic signal of current temperature detection module transmission, the voltage signal of synchrotrans transmission, sends triggering signal according to the parameter of input to trigger module; Trigger module triggers silicon controlled component according to triggering signal control impuls transformer; Controllable silicon carries out copped wave according to triggering signal to power supply, controls the size of output voltage; Under the constraint of setting curve, control linear the increasing of output voltage of silicon controlled component.
Come current/voltage variation in two kinds of situations of comparative illustration below by direct starting transformer under rated voltage and in the experiment by the soft initiator starting transformer under rated voltage.
With reference to figure 3, this experimental system comprises: 6.3kV power supply, soft initiator, 3 6.3kV 400kW motor (M1, M2, M3), 1 6300kVA 6.3kV/35kV transformer T, 5 power supply switch cabinets (VCU09, VCU01, VCU02, VCU03, VCBU03), in experiment, across-the-line starting transformer under rated voltage, input voltage, curent change are as shown in Figure 4, in figure, the numeral in left side is the effective value of phase voltage and electric current, and the top is phase voltage, and the below is current value; Abscissa is time shaft.Test 3 times, what choose the starting current maximum is experimental result, C phase current 480A, A phase 433A, B phase 365A during starting, started rear 4.7 seconds, the time point of second vertical line in figure namely, the three-phase electricity flow valuve tends to balance, and is stabilized in 7.5A left and right (no-load transformer electric current).In starting process, voltage is steady, without abnormal, and UAB:400V, UBC:400V, UCA:400V.
Under rated voltage by the soft starter starting transformer, the variation of input current and soft starter output voltage as shown in Figure 5, in figure, the numeral in left side is the effective value of phase voltage and electric current, the top is phase voltage, the below is current value, abscissa is time shaft; Totally 22 seconds from start to end, article one vertical line was the starting time, and the effective writing time of the right side of line after for starting, second vertical line is the soft start concluding time; Actual measurement voltage curve and soft starter setting curve are basic identical; Be current curve close to the mild curve that rises of axis of abscissas, in starting process without any impact phenomenon, approximately 7.5A, namely no-load current value of effective value after proceed-to-send.Under the same terms, other 2 experimental results are same as described above.
Experiment shows: by the soft starter starting transformer, current peak is reduced to the rank of no-load current from thousands of amperes of theoretical value, has realized without the starting of excitation surge, and has all obtained identical result at many experiments after this.Meanwhile, this equipment has been realized the soft start of 3 middle voltage electromotors, and the 300A of starting current from across-the-line starting dropped in 150A, has avoided across-the-line starting to cause the line voltage fluctuation.
the above, it is only preferred embodiment of the present utility model, be not to be the utility model to be done the restriction of other form, the equivalent embodiment that any those skilled in the art may utilize the technology contents of above-mentioned announcement to be changed or be modified as equivalent variations is applied to the liquid that there is similar requirement in other field, the control of gas, but every technical solutions of the utility model content that do not break away from, any simple modification that foundation technical spirit of the present utility model is done above embodiment, equivalent variations and remodeling, the protection range that still belongs to technical solutions of the utility model.
Claims (10)
1. transformer excitation flow cancellation element is characterized in that comprising:
Synchrotrans are connected on power supply and from mains side and obtain voltage signal;
Current transducer is connected on power supply and from mains side and obtains current signal;
Silicon controlled component is connected between power supply and load, and the controllable silicon that is connected by the three-phase inverse parallel forms;
Trigger module is connected between the output and silicon controlled component of main control module;
Main control module sends triggering signal according to above-mentioned voltage and current signal and triggers silicon controlled component by trigger module, and then adjusts in silicon controlled component each silicon controlled angle of flow and control the voltage that power supply outlet side output linearity increases.
2. transformer excitation flow cancellation element according to claim 1 characterized by further comprising:
The first overvoltage protective module is connected in described silicon controlled component between each silicon controlled controlled stage and negative electrode, is composed in series by some piezo-resistances.
3. transformer excitation flow cancellation element according to claim 2 characterized by further comprising:
The second overvoltage protective module is connected in described silicon controlled component between each silicon controlled anode and negative electrode, is composed in series by electric capacity and resistance.
4. transformer excitation flow cancellation element according to claim 3 characterized by further comprising:
The current signal that the current temperature detection module detects described current transducer be converted to light signal by Optical Fiber Transmission to described main control module.
5. transformer excitation flow cancellation element according to claim 4, is characterized in that: be connected with reactor between the output of described silicon controlled component and described load.
6. transformer excitation flow cancellation element according to claim 4, is characterized in that: be connected with the load switch between described reactor and described load.
7. transformer excitation flow cancellation element according to claim 5, it is characterized in that: described load is transformer.
8. transformer excitation flow cancellation element according to claim 5, it is characterized in that: described load is motor.
9. transformer excitation flow cancellation element according to claim 6, it is characterized in that: described load is transformer.
10. transformer excitation flow cancellation element according to claim 6, it is characterized in that: described load is motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320276187 CN203278211U (en) | 2013-05-10 | 2013-05-10 | Transformer excitation inrush current eliminating device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320276187 CN203278211U (en) | 2013-05-10 | 2013-05-10 | Transformer excitation inrush current eliminating device |
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| CN203278211U true CN203278211U (en) | 2013-11-06 |
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| CN 201320276187 Expired - Fee Related CN203278211U (en) | 2013-05-10 | 2013-05-10 | Transformer excitation inrush current eliminating device |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103715654A (en) * | 2014-01-10 | 2014-04-09 | 国家电网公司 | Method for restraining magnetizing inrush currents |
| CN104836202A (en) * | 2015-05-20 | 2015-08-12 | 三峡大学 | Static circuit breaker used for eliminating closing excitation surge current of transformer |
| CN105226610A (en) * | 2015-10-26 | 2016-01-06 | 三峡大学 | A kind of Transformer Close magnetizing inrush current arrester |
| CN108390377A (en) * | 2018-04-25 | 2018-08-10 | 深圳市禾望电气股份有限公司 | A kind of shore-based power supply system and the method for reducing excitation surge current |
-
2013
- 2013-05-10 CN CN 201320276187 patent/CN203278211U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103715654A (en) * | 2014-01-10 | 2014-04-09 | 国家电网公司 | Method for restraining magnetizing inrush currents |
| CN103715654B (en) * | 2014-01-10 | 2016-03-23 | 国家电网公司 | A kind of suppressing method of magnetizing inrush current |
| CN104836202A (en) * | 2015-05-20 | 2015-08-12 | 三峡大学 | Static circuit breaker used for eliminating closing excitation surge current of transformer |
| CN105226610A (en) * | 2015-10-26 | 2016-01-06 | 三峡大学 | A kind of Transformer Close magnetizing inrush current arrester |
| CN105226610B (en) * | 2015-10-26 | 2017-11-24 | 三峡大学 | A kind of Transformer Close excitation surge current arrester |
| CN108390377A (en) * | 2018-04-25 | 2018-08-10 | 深圳市禾望电气股份有限公司 | A kind of shore-based power supply system and the method for reducing excitation surge current |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C53 | Correction of patent of invention or patent application | ||
| CB03 | Change of inventor or designer information |
Inventor after: Wang Liang Inventor after: Lin Yang Inventor after: Liu Shuwei Inventor after: Zhang Guorong Inventor after: Yao Changlong Inventor after: Chen Aizhen Inventor after: Song Ke Inventor before: Wang Liang |
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131106 |