CN203278214U - Novel multifunctional electric power electronic current-limiting system - Google Patents
Novel multifunctional electric power electronic current-limiting system Download PDFInfo
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- CN203278214U CN203278214U CN 201320315255 CN201320315255U CN203278214U CN 203278214 U CN203278214 U CN 203278214U CN 201320315255 CN201320315255 CN 201320315255 CN 201320315255 U CN201320315255 U CN 201320315255U CN 203278214 U CN203278214 U CN 203278214U
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Abstract
The utility model discloses a novel multifunctional electric power electronic current-limiting system. A PWM voltage stabilization module is merged into a 10kV electrical network through a parallel transformer Tb in a parallel way. A three-single-phase DVR module achieves energy supplying through the direct current side of the common PWM voltage stabilization module. Thyristor branches are set between each inversion unit output point of the three-single-phase DVR module and an output filter reactor. The thyristor branches are connected with two DVR module inversion unit output points. The DVR output is merged between an electrical network and a load in a serial way through a series transformer and meanwhile connected with a small capacitor C filter branch in a parallel way on the secondary side of the series transformer. The system which can compensate voltage fluctuation improves the electrical network system power supply reliability and stability. The system further stabilizes load voltages and ensures the normal running of equipment on user sides. The system which limits short-circuit currents enhances the safety of the electrical network system and power supply equipment and further protects the safety of user equipment. The time period when the electrical network bears a large short-circuit current from a short-circuit fault generation point to a relay protection motion starting point is shortened. The safety of the electrical network is improved.
Description
Technical field
The utility model belongs to the power technology field, relates in particular to a kind of Multifunction power electronics current limiting system.
Background technology
Electric power is main energy sources and the economic lifeline of country, guarantees that safety, high-quality electric power supplies with the economic development that not only concerns country and the people's quality of life, also maintains social stability and national security.And in recent years along with the continuous expansion of electrical network scale and the complexity day by day of structure, certainly will cause the continuous increase of Power System Shortcuts electric current.When being short-circuited fault, the short circuit current of thousands of ampere can burn electric, causes being subjected to mechanical stress between conductor and is out of shape, and causes simultaneously voltage drop, power changes in distribution, the serious threat power network safety operation.Simultaneously, various nonlinear-loads and impact load constantly network, and have caused in system the quality of voltage such as voltage fluctuation, flickering problem day by day serious, more affect the normal operation of the sensitiveness load of the stable operation of electrical network and networking.Existing technical scheme has series reactor on bus.
The shortcoming of prior art is as follows:
1, the long-term series connection on the line, loss is large, causes the ample resources loss;
2, current-limiting reactor when the non-fault of system, leaves unused in electrical network for a long time, and utilance is low;
3, the current-limiting reactor design difficulty is large, need to consider simultaneously the loss between current limitation effect and the non-age at failure of electrical network; The large current limliting of reactance value is effective, but required idle and meritorious energy also large (itself has resistance reactance); Reactance value is little, and current limitation effect is difficult to reach;
4, only can realize the failure current limit function, can not compensate for power quality problem.
The utility model content
The utility model provides a kind of Multifunction power electronics current limiting system, can realize the multi-functional topological structure, control method of current limliting and voltage fluctuation compensation and for the logic control mode of different faults type.
The utility model embodiment is achieved in that a kind of Multifunction power electronics current limiting system, and described power electronic system mainly is comprised of PWM Voltage stabilizing module, three single-phase DVR modules, thyristor branch road three parts; The PWM Voltage stabilizing module is by shunt transformer T
bIncorporate the 10kV electrical network into, three single-phase DVR modules realize Power supply by the DC side that shares the PWM Voltage stabilizing module, set up the thyristor branch road between each inversion unit output point of three single-phase DVR modules and output filtering reactor, the thyristor branch road connects two output points of DVR module inversion unit, the output of DVR seals between electrical network and load by series transformer, simultaneously at series transformer secondary side little capacitor C filter branch in parallel.
Further, the connected mode of PWM Voltage stabilizing module: inductance is connected to respectively on insulated gate bipolar transistor IGBT successively, and dc bus capacitor is connected in parallel on the two ends of insulated gate bipolar transistor IGBT;
Further, the connected mode of three single-phase DVR modules: the insulated gate bipolar transistor IGBT of three single-phase DVR is connected in parallel on respectively the two ends of dc bus capacitor successively;
Further, the connected mode of thyristor branch road: thyristor branch road 3 is connected between each inversion unit output point of single-phase DVR and output filtering reactor, is shorted to another output of DVR inversion unit by bidirectional thyristor.
The Multifunction power electronics current limiting system that the utility model provides, but the bucking voltage fluctuation improves network system power supply reliability, stability; Steady load voltage is guaranteed the normal operation of user side equipment; Limiting short-circuit current, the fail safe that improves network system and power supply unit; Limiting short-circuit current, the safety of protection subscriber equipment; Shorten short trouble and occur to the time that between the relaying protection action, electrical network bears short circuit current, improve electric network security.
Description of drawings
Fig. 1 is the topological structure of the Multifunction power electronics current limiting system that provides of the utility model embodiment;
Fig. 2 is the schematic diagram of the Voltage stabilizing module control procedure that provides of the utility model embodiment;
Fig. 3 is the single-phase voltage compensation that provides of the utility model embodiment and the schematic diagram of pattern switching controls process;
Fig. 4 is that the short trouble that provides of the utility model embodiment detects the schematic diagram with identifying;
Fig. 5 is the schematic diagram of the course of action of the short circuit generation timer that provides of the utility model embodiment;
Fig. 6 is the schematic diagram of current limliting logic corresponding to the different short-circuit-type that provide of the utility model embodiment.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with embodiment, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
Fig. 1 is the topological structure of the Multifunction power electronics current limiting system that the utility model proposes.Mainly formed by PWM Voltage stabilizing module 1, three single-phase DVR modules 2, thyristor branch road 3 three parts.PWM Voltage stabilizing module 1 is by shunt transformer T
bIncorporate the 10kV electrical network into, three single-phase DVR modules 2 realize Power supply by the DC side that shares PWM Voltage stabilizing module 1, set up thyristor branch road 3 between each inversion unit output point of three single-phase DVR modules 2 and output filtering reactor, at series transformer secondary little capacitor C filter branch in parallel, series transformer is connected between electrical network and load.
The DC side of three-phase H bridge PWM Voltage stabilizing module 1 realizes the Power supply to three single-phase DVR modules 2;
Three single-phase DVR modules 2, every phase DVR detects respectively the phase voltage of each phase, and control DVR compensates the change in voltage of each phase, makes phase voltage be stabilized in the standard value of setting;
The connected mode of PWM Voltage stabilizing module 1: inductance is connected to respectively on insulated gate bipolar transistor IGBT successively, and dc bus capacitor is connected in parallel on the two ends of insulated gate bipolar transistor IGBT;
The connected mode of three single-phase DVR modules 2: the insulated gate bipolar transistor IGBT of three single-phase DVR is connected in parallel on respectively the two ends of dc bus capacitor successively;
The connected mode of thyristor branch road 3: thyristor branch road 3 is connected between each inversion unit output point of single-phase DVR and output filtering reactor, is shorted to another output of DVR inversion unit by bidirectional thyristor.
Fig. 2 is the control procedure of PWM Voltage stabilizing module.The dc voltage standard value
With the actual dc voltage value U that detects
dcMake it poor, its difference through after pi regulator with three-phase voltage with after the sinusoidal quantity sin of homophase multiplies each other frequently with the actual electric current of voltage regulation that detects do poor, its difference is carried out triangular modulation through after pi regulator, the pwm control signal that modulation obtains is sent into the H bridge of Voltage stabilizing module after overdrive circuit, then the output current signal of the H bridge of Voltage stabilizing module is the actual electric current of voltage regulation that detects, then before feeding back to for the second time pi regulator.
Fig. 3 is single-phase voltage compensation and pattern switching controls process.The stability criterion voltage of setting is
With the actual mains side voltage that detects be U
sDiffer from, its difference multiply by after 1/k to be done poorly with the secondary side bucking voltage of the actual output of DVR, carries out triangular modulation through after pi regulator, and the signal that obtains after modulation is connected to the input with door, simultaneously current i
slSend into thyristor through the fault detect rear portion after overdriving, a part is connected to another input with door through lock modules, is connected to the input of inverter bridge with the output of door after overdriving.
Applicable electric power system is the 10kv isolated neutral system, and the device topological structure mainly is comprised of three parts: PWM Voltage stabilizing module, three single-phase DVR modules, thyristor branch road.Its operation principle is: shunt transformer T
b10kV voltage is reduced to 400V line voltage, PWM Voltage stabilizing module by three-phase H bridge with DC-side Voltage Stabilization at 800V, three single-phase DVR structures are connected in parallel on dc bus capacitor two ends, every phase DVR detects respectively the phase voltage of each phase, when voltage fluctuation being detected, should fluctuate part as instruction, and control DVR compensates the change in voltage of each phase, makes load place phase voltage be stabilized in the standard value of setting.When short trouble occured, when thyristor was shorted to the secondary side of series transformer with the DVR outputting inductance, the no-load voltage ratio of establishing series transformer was k, and the impedance of outputting inductance is Z, and the secondary side equivalence is k to the impedance of primary side
2Z is so suitably select the no-load voltage ratio k of series transformer to control with short-circuit current limitation within the specific limits.
Adopt voltage and current double closed-loop PI to control to the PWM Voltage stabilizing module, the dc voltage standard value
With the actual dc voltage value U that detects
dcIt is poor to do, and its difference is through multiplying each other as the needed electric current of voltage regulation of PWM Voltage stabilizing module with the sinusoidal quantity s in of three-phase voltage with the frequency homophase after pi regulator
With the actual electric current of voltage regulation i that detects
wa, i
wb, i
wcIt is poor to do, and its difference carries out through after pi regulator the control signal that triangle wave obtains three brachium pontis of Voltage stabilizing module.
Every phase DVR voltage compensation in three single-phase DVR modules adopts voltage close loop PI to control, and the stability criterion voltage of setting is
The actual mains side voltage that detects is U
s, the no-load voltage ratio of series transformer is k, standard value
With actual value U
sDifference multiply by 1/k and be only DVR in the idea output of Circuit Fault on Secondary Transformer, this idea output is as voltage fluctuation instruction U
ref, U
refVoltage U with the actual compensation output of DVR secondary side
cDifference through carrying out triangle wave after pi regulator, obtain the control signal of DVR inverter bridge.When detecting this and mutually short circuit current arranged, this phase fault detection module provides high level, after being converted into low level through lock modules, the DVR working pulse is blocked, this high level is controlled the thyristor conducting simultaneously, the DVR out put reactor is shorted to the series transformer secondary side carries out current limliting.
As shown in Figure 4, i
slBe the transient current on the circuit that detects; i
opBe the operating value of short circuit current, namely think when the instantaneous absolute value of line current is double the fault that is short-circuited during greater than this value; i
reBe short circuit operating current return value, namely the calculating amplitude of line current is double when being worth less than this, thinks that short trouble eliminates.When normal, network system is working properly, there is no short circuit current, and trigger set Q is low level.After short trouble occurs, the instantaneous absolute value of line taking road electric current relatively, as the operating value i of instantaneous absolute value greater than short circuit current
op, and time-delay delay1 i after the time
slInstantaneous absolute value still greater than i
opValue, S1 is high level, and is set to low level in the rest-set flip-flop initial Q that powers on, after short circuit occurs, S is high level.i
slAfter multiplying each other with the first-harmonic sine and cosine of twice amplitude, obtain DC component through after low-pass filtering
Calculate
Root-mean-square value just obtained current i
slAmplitude I
m, I
mGreater than short circuit operating current return value i
reForm low level, and time-delay delay2 I after the time
mStill greater than short circuit operating current return value, S2 obtains low level, and Q is through delay3 time-delay and S2 signal phase and the low level that forms R.S is high level, and R is low level, and trigger output this moment Q becomes high level, and this high level signal converts low level to DVR pulse blocking through locking on the one hand, controls on the other hand this phase thyristor conducting and carries out short circuit current limitation.After short trouble is eliminated, the amplitude I that calculates
mForm high level signal less than short circuit operating current return value, time-delay and time-delay delay2 I after the time
mStill less than short circuit operating current return value, making S2 is high level, and Q is in high level when short circuit, and R is high level.I after short trouble disappears
slInstantaneous absolute value always less than i
op, S1 is low level, making S is low level.S is low level, and R is high level, rest-set flip-flop again set Q be low level, locking signal disappears, DVR reworks, the thyristor Continuity signal disappears, and bears back-pressure and turn-offs.Delay1, delay2, delay3 is set to respectively 50us, 10us, 5ms, the setting of delay1 is to have the burr of current mode in electrical network, occurs just the instantaneous absolute value of double judgement is judged as short circuit during greater than the current limliting operating value, and the setting of delay2 is just to calculate short trouble for double judgement amplitude less than current limliting action return value to disappear; The setting of delay3 is the time of quality of power supply compensating coefficient that switches to from limited current state; Delay1, delay2, delay3 can set flexibly according to the actual electric network situation.Simultaneously owing to usually adopting at present computer numerical control (CNC), computational speed is fast, can arrange to the instantaneous absolute value of line current continuous n time greater than i
opThink that short trouble occurs, calculate I m time continuously
mLess than i
reThink and the short trouble elimination can n be set flexibly, the size of m according to controlling needs.
As Fig. 5, shown in Figure 6, dissimilar short circuit malfunction correspondence different current limliting manner of execution.When single-phase shorted to earth occured in system, the line voltage between Three-phase Power Systems was still symmetrical, and system can continue operation with an earth point, and current-limiting apparatus is failure to actuate.When system's generation phase fault or alternate ground short circuit, device detects short circuit current, the DVR working pulse of controlling fault phase blocks, fault phase DVR does not work, after locking pulse 10us, with the thyristor conducting of fault phase, the DVR outputting inductance is by the secondary side of short circuit at series transformer, outputting inductance equivalence is carried out current limliting to the impedance of primary side as the current-limiting impedance of circuit, keep simultaneously healthy phases can continuous service at the quality of voltage compensating coefficient.When system's generation three-phase shortcircuit or three relative ground circuits, after device detects the three-phase shortcircuit electric current, block the working pulse of three-phase DVR, after time-delay 10us, control three-phase thyristor D1, D2, D3 is conducting, the DVR outputting inductance of three-phase all is shorted to the secondary side of series transformer, and inductance carries out current limliting by the series transformer equivalence to the impedance of primary side.When electrical network mutually or a few when breaking down mutually, this time that enters mutually the current limliting attitude only is the us level, protect action and be generally 0.5s-1s to time limit of completion system tripping operation and continue, protect in the time of moving so continue in wait, greatly shortened the time that short circuit current bears in system.
When network system is short-circuited fault usually, continue to protect and complete tripping operation, fault restores electricity after getting rid of again, and the preciseness of the utility model in order to realize controlling, added the Failure elimination self-recovering function, in case namely electrical network does not cut off the power supply, short trouble disappears automatically, short trouble of the present utility model detects identification module can control the excision current-limit mode automatically, returns to quality of power supply compensation model.
The above is only preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of doing within spirit of the present utility model and principle, be equal to and replace and improvement etc., within all should being included in protection range of the present utility model.
Claims (4)
1. a Multifunction power electronics current limiting system, is characterized in that, described power electronic system mainly is comprised of PWM Voltage stabilizing module, three single-phase DVR modules, thyristor branch road three parts; The PWM Voltage stabilizing module is connected to the grid by shunt transformer, three single-phase DVR modules realize Power supply by the DC side that shares the PWM Voltage stabilizing module, set up the thyristor branch road between each inversion unit output point of three single-phase DVR modules and output filtering reactor, the thyristor branch road connects two output points of DVR module inversion unit, the output of DVR seals between electrical network and load by series transformer, simultaneously at series transformer secondary side little capacitor C filter branch in parallel.
2. Multifunction power electronics current limiting system as claimed in claim 1, it is characterized in that, the connected mode of PWM Voltage stabilizing module: inductance is connected to respectively on insulated gate bipolar transistor IGBT successively, and dc bus capacitor is connected in parallel on the two ends of insulated gate bipolar transistor IGBT.
3. Multifunction power electronics current limiting system as claimed in claim 1, it is characterized in that the connected mode of three single-phase DVR modules: the insulated gate bipolar transistor IGBT of three single-phase DVR is connected in parallel on respectively the two ends of dc bus capacitor successively.
4. Multifunction power electronics current limiting system as claimed in claim 1, it is characterized in that, the connected mode of thyristor branch road: the thyristor branch road is connected between each inversion unit output point of single-phase DVR and output filtering reactor, is shorted to another output of DVR inversion unit by bidirectional thyristor.
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| CN 201320315255 CN203278214U (en) | 2013-06-04 | 2013-06-04 | Novel multifunctional electric power electronic current-limiting system |
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| CN 201320315255 CN203278214U (en) | 2013-06-04 | 2013-06-04 | Novel multifunctional electric power electronic current-limiting system |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280789A (en) * | 2013-06-04 | 2013-09-04 | 湖南大学 | Novel multifunctional power electronic current-limiting system and control method thereof |
| CN106786643A (en) * | 2016-12-16 | 2017-05-31 | 湖南大学 | Fault current active control type current limiting system and its control method |
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2013
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103280789A (en) * | 2013-06-04 | 2013-09-04 | 湖南大学 | Novel multifunctional power electronic current-limiting system and control method thereof |
| CN103280789B (en) * | 2013-06-04 | 2017-02-08 | 湖南大学 | Novel multifunctional power electronic current-limiting system and control method thereof |
| CN106786643A (en) * | 2016-12-16 | 2017-05-31 | 湖南大学 | Fault current active control type current limiting system and its control method |
| CN106786643B (en) * | 2016-12-16 | 2019-03-26 | 湖南大学 | Fault current active control type current limiting system and its control method |
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| C14 | Grant of patent or utility model | ||
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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 Termination date: 20160604 |