CN100367595C - Static exciter inrush current inhibition method and apparatus - Google Patents
Static exciter inrush current inhibition method and apparatus Download PDFInfo
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- CN100367595C CN100367595C CNB2004100152087A CN200410015208A CN100367595C CN 100367595 C CN100367595 C CN 100367595C CN B2004100152087 A CNB2004100152087 A CN B2004100152087A CN 200410015208 A CN200410015208 A CN 200410015208A CN 100367595 C CN100367595 C CN 100367595C
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Abstract
The present invention discloses a suppressing method and a device for excitation surges of a transformer, and a technical problem to be solved is to eliminate the excitation surges generated by the arrangement of the transformer. The present invention uses the following steps: (1), a power supply is switched on; (2), a real-time period value of voltage at the power supply side of the transformer is detected; (3), time of unit phase angles is calculated; (4), time for executing switch-on and switch-off is calculated when the phase angle is in angles which are integral multiples of 90 DEG; (5), switch-on and switch-off orders are transmitted; (6), the switch-on and switch-off orders are executed. The power supply side of the transformer of the suppressing device for excitation surges of a transformer is connected with a circuit breaker, the switch-on and switch-off control end of the circuit breaker is connected with the output end of a surge suppressing device comprising a measuring circuit and an operational circuit, and the input end of the measuring circuit receives input signals of any phase voltage of three-phase power supply voltage. Compared with the prior art, power can be timely and accurately input to the transformer when the phase angle of the power supply voltage is 90 DEG or 270 DEG, the excitation surges are eliminated, and the reliability of the relay protection action of the power transformer is improved.
Description
Technical field
The present invention relates to a kind of restraining device of power transformer excitation surge current.
Background technology
Magnetizing inrush current is to be applied to when voltage on the elementary or secondary winding of power transformer is uprushed to produce.It can bring following consequence: 1, cause system voltage to descend significantly in short-term, influence the operate as normal of other electric equipments in the system; 2, cause the power transformer protective relaying maloperation, the input transformer is failed repeatedly, drop into failure as lose the back in working power, mean and cause large-area power-cuts for the stand-by power supply transformer that is in cold standby state.For magnetizing inrush current, take both at home and abroad to occur behind the magnetizing inrush current to reduce the probability of protective relaying maloperation so far with hardware or its feature of certain algorithm identified and the measure avoided always.For example with fast saturated current transformer, secondary harmonic brake principle, interval angle principle, waveform symmetry principle, small wave converting method, neural net method, magnetic flux characteristic method of identification, equivalent circuit parameter differential method, based on algorithm, the difference of transformer circuit equation works are arranged, based on the multicriteria method of fuzzy logic etc.These principles and algorithm all can not solve the problem that magnetizing inrush current causes transformer overcurrent protection and differential protection malfunction effectively, this in the world still one fail the difficult problem that thoroughly solves.
Summary of the invention
The restraining device that the purpose of this invention is to provide a kind of transformer excitation flow; the technical problem that solves is to eliminate the air-drop transformer to produce excessive magnetizing inrush current and cause declining to a great extent of power system voltage; magnetizing inrush current when the inhibition transformer load lead-out wire short trouble excision back voltage that produces is uprushed; thereby avoided transformer that protective relaying maloperation is excised by mistake, eliminated the phenomenon of air-drop transformer failure.
The present invention is by the following technical solutions: a kind of restraining device of transformer excitation flow, the transformer frequency response side is connected with circuit breaker, the combined floodgate of described circuit breaker, separating brake control end connect the output of the inhibitor of shoving, the inhibitor of shoving comprises measuring circuit and computing circuit, and the input of measuring circuit receives the arbitrary phase voltage input signal in the three-phase mains voltage; Described measuring circuit and computing circuit adopt single-chip microcomputer, the input of single-chip microcomputer is connected with the transformer height to three-winding transformer, in, three voltage signal inputs of low-pressure side with the famous prime minister, the transformer height, in, the auxiliary contact of low-pressure side circuit breaker three-phase, three sides that send the outside are closed circuit breaker and are divided the switching value signal input part of circuit breaker, three high, in, low-pressure side breaker closing classification selector switch amount signal input part, three locking height, in, the downside breaker open operation, the switching value signal input part that closes a floodgate, a distant place reset switch amount signal input part; The output of single-chip microcomputer is connected with the transformer high, medium and low voltage side circuit breaker phase-splitting energization control signal output that 9 photoelectricity are isolated the output of MOSFET relay, 9 photoelectricity are isolated the transformer high, medium and low voltage side circuit breaker phase-splitting separating brake control signal output ends of MOSFET relay output, device alarm switch amount signal output part is with the communication interface of host computer.
Measuring circuit of the present invention be connected with control circuit breaker three-phase phase-splitting operating mechanism and three-phase simultaneously operating mechanism parts and execution unit be set.
Single-chip microcomputer of the present invention adopts SOC C8051F series monolithic, and photoelectricity is isolated the MOSFET relay and adopted the high-power photoelectricity of AQZ164B02 type to isolate the MOS relay, or APV1122 type photoelectricity is isolated the combination of mosfet driver and high-power MOSFET relay.
The present invention compared with prior art, be that 90 degree or 270 drop into power supply to transformer when spending timely and accurately at the phase angle of supply voltage, thoroughly eliminate magnetizing inrush current, thereby the magnetizing inrush current method of hiding that will continue to use many decades becomes inhibition magnetizing inrush current method, corrected and thought to be the technology prejudice that 90 degree or 270 degree can not drop at the phase angle originally always, thoroughly finished the history that unloaded transformer puts into operation and fails.For electric power system, no longer, the air-drop transformer causes declining to a great extent of power system voltage because of producing excessive magnetizing inrush current.Magnetizing inrush current when the transformer load lead-out wire short trouble excision back voltage that produces is uprushed is suppressed; avoided transformer that the protection malfunction is excised by mistake; increase substantially the reliable in action of power transformer relaying protection, and improve excision fault speed.
Description of drawings
Fig. 1 is the schematic diagram of transformer.
Fig. 2 is the circuit block diagram of the restraining device of transformer excitation flow of the present invention.
Fig. 3 is the schematic diagram of the inhibition method of transformer excitation flow of the present invention.
Fig. 4 is the flow chart of the inhibition method of transformer excitation flow of the present invention.
Fig. 5 is that the inhibition method combined floodgate of transformer excitation flow of the present invention interrupts flow chart.
Fig. 6 is that the inhibition method separating brake of transformer excitation flow of the present invention interrupts flow chart.
Fig. 7 is the connection layout of the restraining device of transformer excitation flow of the present invention.
Fig. 8 is the application drawing of the inhibition method of transformer excitation flow of the present invention.
Fig. 9 is the connection layout of the restraining device embodiment of transformer excitation flow of the present invention.
Figure 10 is the schematic diagram of the inhibition method embodiment of transformer excitation flow of the present invention.
Embodiment
Below in conjunction with accompanying drawing and exemplifying embodiment the present invention is described in further detail.
As shown in Figure 1, N
1And N
2Be respectively the number of turn of primary and secondary winding, u
1For being applied to the alternating voltage on the elementary winding, when closing, K switch will produce current i
1, and alternating flux Φ appears in iron core.The transformer secondary output winding will produce induced voltage U
2
u
1Can describe by following formula:
u
1＝√2U
1Sin(ωt+α)--(1)
Voltage U when α is t=0 in the formula
1Initial phase, the equation below t 〉=0 interval can be write out:
i
1R
1+N
1dΦ/dt＝√2U
1Sin(ωt+α)--(2)
R in the formula
1Be the resistance of elementary winding, as negligible resistance R
1, then following formula can be reduced to:
N
1dΦ/dt＝√2U
1Sin(ωt+α)--(3)
Finding the solution the differential equation gets:
Φ＝-√2U
1/ωN
1cos(ωt+α)+C--(4)
Integral constant c is determined by initial condition, according to the magnetic linkage conservation principle, considers that the preceding magnetic flux of no-load transformer combined floodgate is 0, so can obtain:
C=√ 2U
1/ ω N
1Cos α gets C substitution (4) formula:
Φ＝-√2U
1/ωN
1〔cosα-cos(ωt+α)〕--(5)
Make Φ m=√ 2U
1/ ω N
1Be the maximum of stable state magnetic flux, then (5) formula can be rewritten as:
Φ＝Φm〔cosα-cos(ωt+α)〕--(6)
Be not difficult to find out, when dropping into power supply or supply voltage and uprush, as α=pi/2, then
Φ＝Φm?cos(ωt+π/2)＝ΦmSinωt --(7)
Promptly the magnetic flux of transformer directly enters stable state alternating flux Φ mSin ω t, transformer primary current i at this moment
1Do not have transient process, just do not have magnetizing inrush current.
When dropping into power supply or supply voltage and uprush, promptly during t=0, as α=0 °, then
Φ＝Φm〔1-cosωt〕＝Φm-Φmcosωt＝Φ’+Φ”--(8)
In the magnetic flux of transformer a constant flux component Φ m and a stable state alternating flux component-Φ mcos ω t have appearred promptly at this moment.The maximum Φ max of magnetic flux Φ can reach 2 times of steady-state component maximum Φ m, promptly
Φmax＝2Φm --(9)
To cause supersaturation unshakable in one's determination like this, thereby exciting current is significantly increased, can reach more than 100 times of normal operation no-load current sometimes, Here it is magnetizing inrush current, it will cause protective relaying maloperation, make the failure of transformer input.As load side outlet short circuit occurs in the transformer running, voltage sharply descends, and after the protected excision of short circuit, voltage gos up again rapidly, equally also can produce magnetizing inrush current.Constant flux component Φ ' and the alternating flux component Φ that occur this moment " cause the magnetic circuit supersaturation, and Φ ' can't the progress of disease to secondary, make the primary and secondary current imbalance, cause differential protection malfunction and excise transformer, cause the serious consequence of power failure.
Past is though people have recognized that as dropping into power supply in phase angle α=90 of supply voltage ° or during α=270 °, can avoid magnetizing inrush current to occur.Limited by technical conditions, at first need accurate Calculation α=90 ° or α=270 ° to take place, and must before α=90 ° or α=270 ° arrival, be equivalent to mains switch closing time t when
cThe moment send the order of closing a floodgate, to guarantee switch closure in α=90 ° or during α=270 °, power up to transformer.Secondly, the numerical value instability of the intrinsic closing time of mains switch was subjected to factor affecting such as operating power voltage, mechanical structure in the past, added the intermediate link of carrying out closing operation, and for example the operate time of auxiliary relay is also unstable.The moment that will go to catch α=90 ° or α=270 ° like this may.Although this is a method of effecting a permanent cure of fundamentally eliminating magnetizing inrush current, people have to abandon, and the various features of walking to utilize magnetizing inrush current to be different from normal current are hidden the magnetizing inrush current influence, yet still do not have last full plan so far.
Be familiar with the inertia of things based on people, the no one removes to make inquiries the measure that suppresses magnetizing inrush current, the pocket in " hiding " circle that does not stop again in decades.And in microcomputer and electronic technology in recent years the progress of advancing by leaps and bounds has appearred in fact, can from the blind alley of " hiding ", jump out fully.Realize the complete or inhibition partly of magnetizing inrush current, the road that the present invention follows " inhibition " produces.The theoretical foundation that realizes " inhibition " is exactly to allow the opportunity of dropping into transformer frequency response, or the opportunity of excision transformer fault drop on just the moment of transformer frequency response initial phase angle α=90 ° or α=270 °, this can realize fully that for single-phase transformer or the three-phase transformer with phase-splitting operating breaker magnetizing inrush current is near zero level.Three-phase transformer for same time-division of three-phase, closing operation can be zero with the magnetizing inrush current inhibition of a phase then, and two-phase cuts down about 20% in addition.Be noted that influenced by magnetizing inrush current causes malfunction for tranformer protection, the power failure consequence is worst should to be that voltage is the above system of 220KV or 500KV, because of the power breakdown spread area of these systems is extremely wide.And their circuit breaker all can be operated in phase-splitting just, provides most important hardware to guarantee for suppressing magnetizing inrush current.
Occasion for three-phase phase-splitting operation; in order to eliminate magnetizing inrush current; need pursue and close a floodgate mutually or separating brake; phase difference is 120 ° between the three-phase voltage; be that every phase closing time is divided into the promptly about 6.7ms of T/3 mutually; three-phase is finished combined floodgate or the opening time difference is the promptly about 13.3ms of 2/3T; that is to say in 13.3ms and open-phase operation will occur; but this can not cause existing generator; transformer or circuit relay protection error action of device; because of of short duration open-phase operation is avoided in the general time-delay of using 1～4 second of these protections; and exciting surge suppressor only causes 13.3 milliseconds open-phase operation, therefore, can not produce any adverse consequences.
For the three-phase occasion process calculating of divide-shut brake simultaneously, close a floodgate when catching arbitrary phase power phase angle and be 90 ° or 270 ° or separating brake can to make the magnetizing inrush current of this phase be zero, and the magnetizing inrush current of two-phase is peaked 0.866 times in addition, this not only shoves three phase excitation and has done effective inhibition, and the appearance that makes magnetizing inrush current no longer is unknowable at random numerical value, and then can take the eluding game determined.
As shown in Figure 2, the restraining device of transformer excitation flow comprises following a few part: 1, three-phase voltage phase measuring circuit and computing circuit, the phase place α of real-time online measuring three-phase mains voltage, 0.1 ° of certainty of measurement.Promptly can obtain the half period T/2 of sinusoidal voltage by the time interval of measuring adjacent two zero crossings, and then can calculate 1 ° of required time t of the every variation in phase angle
α=T/360 °, after powering on a power frequency period T, the inhibition circuit that shoves to obtain real-time t
αAfter this value is refreshable t last time every the T time
αValue.Begin cumulative time t at each supply voltage zero crossing backward
v, up at next zero crossing the time to former t
αValue is refreshed and again by zero timing again, be its objective is that seizure is at random by closing/the pairing time mark of separating brake order that send the outside.2, control assembly receive to measure and computing circuit according to the closing of known controlled circuit breaker, opening time t
cAnd t
o, and the t that calculates
α, the t before this phase supply voltage phase place is (2n-1) 90 ° of arrivals
cOr t
oThat constantly sends closes/the separating brake order, and then branch, the closing operation of circuit breaker when being implemented in the supply voltage phase place for (2n-1) 90 °, and n is 1,2,3 ... positive integer.Though measuring circuit is only measured and computing a phase voltage, but the phase place that keeps between the three characteristics of the middle term voltage determining respectively differs 120 relations of spending, therefore, arithmetic unit can provide closing/separating brake calculated value constantly of other two-phases simultaneously, thereby guarantee after closing of receiving that the outside sends/separating brake order, can make that arrive 90 ° or 270 ° at first realize mutually closing earlier/sub-switching operation.3, the setting operation circuit breaker that is connected with computing circuit with measurement parts are set, parts are set in order to import following parameter: (1), breaker operator mode classification: three-phase phase-splitting operation/three-phase is operated simultaneously; (2), circuit breaker three-phase closing time t
CA, t
CB, t
Cc(3), circuit breaker three-phase opening time t
OA, t
OB, t
OC(4), outlet MOSFET t relay actuation time
MOS(5), circuit breaker three-phase auxiliary contact displacement time and main contact close/time difference Δ t of separating brake operate time
CA, Δ t
CB, Δ t
CC, Δ t
OA, Δ t
OB, Δ t
OC, these values are used to proofread and correct measure with the circuit breaker auxiliary contact and respectively are harmonious/error of opening time; (6), the low pressure definite value U of sub-switching operation time starting magnetizing inrush current inhibit feature
L, busbar voltage was lower than U when short circuit appearred in the transformer outlet
LShi Zidong starting magnetizing inrush current inhibit feature.4, circuit breaker is an object of accepting the control of magnetizing inrush current restraining device, and each side of transformer all is equipped with circuit breaker.
As shown in Figure 3, be example with A phase making process: after circuit powered on, each power frequency period T for example will carry out the measurement of a half period T/2 in the OA section.Begin to do following calculating in the AB section subsequently:
OA section: survey the half period T/2 of supply voltage, calculate period T.
AB section:, calculate the every increase of supply voltage 1 ° of required time t in phase angle 1. according to period T
α=T/360.2. according to t
αCalculate closing time t with circuit breaker
cCorresponding angle value α
c=t
c/ t
α, α
cTerminal point should drop on (2n-1) 90 ° of points.3. calculate at closing time t
cThe interior phase place that is experienced is the number M of 90 ° or 270 ° points, i.e. M=(α
c/ 180 °+1) integer value, and P=(α
c/ 180 °+1) fractional value, P * 180 ° a angle for nearest first 90 ° or the 270 ° some G of supply voltage of execution combined floodgate point H distance.
BC section: the half period T/2 that 1. surveys supply voltage once more.So do not have the outside order of closing a floodgate in the section, be the T/2 that refreshable last time OA section is measured then, and calculate new t in the CD section to zero crossing C
α, α
c, parameters such as M, P.2. when surveying T/2, begin to carry out timing, constantly accumulate clocking value t from the B point
v, and calculate t
YValue, t
Y=BC-BQ-HC=180t
α-t
v-(the t of P * 180-90)
α=90t
α(1-2P)-t
vMillisecond.By the time during the C point with t
vAnd t
YZero clearing, and then change the CD section over to, repeat the work of BC section, so constantly repeat, until welcoming a combined floodgate order from the outside.3. as at the Q of BC section point, be t apart from the B point
vTime receives the outside order of closing a floodgate, and then reads t
vThe time-delay t that measured value and Q point are correspondingly ordered to the H that carries out the order of closing a floodgate
Y, so that at Q point back t
YSend to circuit breaker constantly and carry out the order of closing a floodgate, through time t
cCircuit breaker is finished closing operation at 90 ° of points of K point (2n-1).
The closing operation data of two-phase produce calculating first phase time in addition, and first is 120 ° of phase phasic differences with second, third main difference mutually.The sub-switching operation of three-phase is identical with the computational methods of closing operation.
Consider three of phase-splitting operation three-phase breaker be harmonious/opening time is not necessarily identical, its closing time is respectively t
CA, t
CB, t
CC, opening time is t
OA, t
OB, t
OC, and B compares A and lags behind 120 ° mutually, and C compares B and lags behind 120 ° mutually, and therefore the closing of every phase circuit breaker/sub-switching operation order is sent a little and will be taken into account these differences.But each all is identical mutually for the measured value of half period T/2, so needn't independent measurement.
The execution link of branch/combined floodgate control assembly divides three-phase combined floodgate execution link and three-phase separating brake to carry out link, carries out link for being with the high-power MOSFET switch of photoelectricity isolation and codan, and operate time is less than 1ms.Close in order to make/the sub-switching operation phase angle is accurately dropped on (2n-1) 90 ° and is located, t operate time of MOSFET
MOSIn calculating, should consider, it can be counted t
CA, t
CB, t
CC, t
OA, t
OB, t
OC, in.Time for the single-chip microcomputer executive program also should count.
The circuit breaker of operating simultaneously for three-phase, according to calculating proof optimal closing/separating brake is to carry out three-phase mutually at that occurs (2n-1) 90 ° at first to close simultaneously/sub-switching operation constantly, this moment transformer the magnetizing inrush current value to close when 90 ° or 270 °/minute that be zero mutually, in addition two-phase is √ 3/2 (Im), Im closes for being 0 ° in phase place/and the magnetizing inrush current maximum of separating brake.Although magnetizing inrush current is non-vanishing, a given value, easier strick precaution.
For guaranteeing to close/separating brake accuracy constantly, designed closing/measuring automatically during separating brake and three be harmonious/function of opening time, promptly sending a phase circuit breaker and closing/picking up counting during the separating brake order, when the auxiliary contact displacement of this phase circuit breaker, stop timing, be closing/opening time of this phase circuit breaker this writing time.Be accurate meter, can be under power down mode, the operate time of measuring circuit breaker main contact and auxiliary contact in advance is poor, revises the error of measurement with this value.Can realize by software closing/the separating brake angle is in the continuous corrections of 90 degree or 270 degree both sides, to take into account the influence of transformer frequency response lateral coil resistive component and other factors, and can realize finding optimum to close/the separating brake angle by the actual tests of transformer, magnetizing inrush current is suppressed to floor level.
As shown in Figure 4, the inhibition method flow of transformer excitation flow is as follows: 1, measurement, computing circuit Connect Power and carry out self check behind the source, if mistake occurring will report to the police, as if normally then closing the interruption flow process; 2, obtain and close/separating brake set point parameter, detect the numerical value of Transformer Winding resistance, distributed capacitance; 3, detect the signal of the arbitrary phase voltage zero crossing of supply voltage, then do not continue to detect if detect; 4, pick up counting; 5, detect the signal of the next zero crossing of supply voltage, then do not continue to detect if detect; 6, stop timing, calculate this phase supply voltage half period T/2; 7, calculate the time of 1 ° of this every increase in phase supply voltage phase angle; 8, calculate the angle of 90 ° of the number of 90 ° and 270 ° points closing/comprised in the lead when separating brake point is 90 ° integral multiple at the phase angle and less thaies, determine to begin to carry out and close/the separating brake command point, numerical value according to detected Transformer Winding resistance, distributed capacitance, calculating closes/and sub-switching operation finishes the correction value at drop point phase angle, after taking into account factor affecting such as Transformer Winding resistance, distributed capacitance can ± the precision correction of 0.1 degree closes/sub-switching operation finishes the phase angle of drop point, in the hope of realizing the maximum of magnetizing inrush current is suppressed. 9, the open flow process of interrupting is not closed/the separating brake order as if receiving at supply voltage next again zero point, then turns back to the signal that detects the arbitrary phase voltage zero crossing of supply voltage and begins to remeasure and calculate, and the data of previous measurements and calculations are refreshed.
Measurement and computing circuit are after obtaining the half period real time data, per half period is all carried out the work that picks up counting from last zero crossing, and prepare to meet to close/the separating brake order, arrive as next zero crossing also do not close/when the separating brake order is assigned, measure, computing circuit will replace previous measured value with the half period of current measurement and with the result calculated zero clearing, detect time half period of the arbitrary phase voltage of supply voltage more in real time, and calculate the time at the every increase unit of phase of supply voltage angle.In case certain is measured and has received outside closing/the sub-switching operation order of sending in the half period process in this phase voltage, circuit of measurement and control is read from zero crossing immediately to closing/time value the separating brake order, closes/sub-switching operation basis constantly as calculating to carry out with it.The closing of three-phase mains voltage/separating brake can adopt single-phase detection, phase-splitting control, or the mode controlled simultaneously of single-phase detection, three-phase.Single phase poaer supply then is single-phase detection, single-phase control.
As shown in Figure 5, the interruption flow process of closing a floodgate is: at first check the breaker switching-on operation mode, if the phase-splitting operation, then calculate the time-delay of three-phase combined floodgate, send successively and close a floodgate order mutually and measure the three-phase closing time, after breaker switching-on operation is finished, return and continue to measure T/2; If three-phase is operated simultaneously, then calculate the time-delay of closing a floodgate, send the order of three-phase combined floodgate and measure closing time, after breaker switching-on operation is finished, return and continue to measure T/2.
As shown in Figure 6, separating brake interrupts flow process and is: at first check the separating brake mode of circuit breaker, if the phase-splitting operation, then calculate the time-delay of three-phase separating brake, send the order of three-phase separating brake successively and measure the three-phase opening time, after the breaker open operation operation is finished, return and continue to measure T/2; If three-phase is operated simultaneously, then calculate the separating brake time-delay, send the order of three-phase separating brake and measure opening time, after the breaker open operation operation is finished, return and continue to measure T/2.
Circuit breaker is closed/occasion of separating brake for the three-phase phase-splitting, control circuit is that the principles of 120 degree are sent three successively and are harmonious/the separating brake fill order by the three-phase mains voltage phase angle difference, finish no-flashy-flow and close/sub-switching operation, close/minute control opportunity the execution principle be from occur at first 90 the degree or 270 the degree that mutually.To circuit breaker is that three-phase closes/occasion of separating brake simultaneously, realizing occurring the earliest voltage phase angle is that 90 degree or 270 those phase no-flashy-flows of spending close/sub-switching operation, all the other two-phases are shoved and are 3/2 times of peaked √, and this is for discerning magnetizing inrush current and then avoiding its influence and created advantage.
Because exciting surge suppressor is round-the-clock charged work in 24 hours, therefore, single-chip microcomputer is provided with anti-flight distance preface and deadlock circuit such as house dog.
As shown in Figure 7 with shown in Figure 9, comprise that the exciting surge suppressor that measuring circuit, computing circuit and control assembly constitute is core with the single-chip microcomputer, input signal has two classes, one is a phase voltage of each side of transformer high, medium and low voltage, whether its effect has two: one, differentiates the current operating mode of transformer, have magnetizing inrush current to occur to determine closing backward/sub-switching operation.The 2nd, parameters such as measuring voltage, frequency, phase place are as the initial data of calculating and controlling.The another kind of defeated signal of inhibitor is that external device (ED) or operations staff issue closing/the separating brake control signal of circuit breaker, inhibitor according to receive close/the separating brake control signal after, three-phase phase-splitting operating breaker carried out closing/the separating brake movement decomposition is three times close/the separating brake order in succession, so that three-phase breaker is all realized closing/sub-switching operation for the moment of (2n-1) 90 ° in phase place.To three-phase simultaneously operating breaker then will close/sub-switching operation is arranged in that phase voltage phase place that arrives at first and realizes closing/sub-switching operation for the moment of (2n-1) 90 °.
Single-chip microcomputer adopts the U.S. high speed SOC C8051F of Cygnal company series monolithic, this single-chip microcomputer provides Industry Control required whole simulations, numeral and communication interface, and the memory under program in the sheet and the capacity of data memory are enough to support the demand of every measurement and control.The bus of more valuable is this single-chip microcomputer does not go out chip, for the control appliance of working under abominable electromagnetic environment provides very strong antijamming capability.Because the integrated level of single-chip microcomputer is high so incoming current suppression device is very compact, is convenient to install.The input signal of single-chip microcomputer is as follows: 1, three of transformer high, medium and low voltage side voltages with the famous prime minister, and 100V or 100/ √ 3V are used for as basis; 2, the auxiliary contact of each phase of high, medium and low voltage side circuit breaker closes/opening time in order to determine circuit-breaker status and measurement; 3, three sides sent of outside are closed circuit breaker and are divided the switching value signal of circuit breaker, and this is to trigger the inhibitor starting of shoving and close/signal of branch; 4, combined floodgate and the separating brake type selecting switching value signal operated simultaneously of two groups three high and low, medium voltage side circuit breaker phase-splitting operations or three-phase judged breaker closing and separating brake classification, still is operation simultaneously in order to determine three-phase phase-splitting operation; 5, the switching value signal of locking circuit breaker branch/combined floodgate; 6, distant place reset switch amount signal.The output signal of single-chip microcomputer is as follows: 1, transformer high, medium and low voltage side circuit breaker phase-splitting energization control signal totally 9 groups of photoelectricity isolation MOSFET relays output; 2, transformer high, medium and low voltage side circuit breaker phase-splitting separating brake control signal totally 9 groups of photoelectricity isolation MOSFET relays output; 3, device alarm switch amount output; 4, with the communication interface of host computer.Photoelectricity isolate the MOSFET relay look controlled circuit breaker and close/operating voltage of sub-gate control circuit and the high-power photoelectricity of the AQZ164B02 that electric current can adopt the PANASONIC electrician isolates the MOS relay, or adopts PANASONIC electrician APV1122 photoelectricity to isolate the combination of the MOSFET high power relay of mosfet driver and Japanese IR company.
The transformer excitation flow restraining device can constitute control device separately, also can dissolve in other control system that this demand is arranged.In every environment or system that has a transformer, bad even ill effect can be caused, all this device can be used as magnetizing inrush current.More demand results from power plant, transformer station and the power consumer of electric power system, the place of having used power transformer in other words.
As shown in Figure 8, describe two kinds of situations that produce transformer excitation flow and suppressed, a kind of is to suppress the unloaded magnetizing inrush current that drops into transformer, and T is a power transformer, and B1 to B6 is a circuit breaker.Transformer is connecting the power supply from four aspects, will produce magnetizing inrush current when powering on to transformer again as long as the equal non-transformer in transformer both sides occurs.As B
1, B
2Disconnect B
3, B
4, B
5, B
6Close, no matter close B this moment
1Or close B
2Magnetizing inrush current appears in the capital.Therefore, at B
1, B
2Should increase the inhibition circuit that shoves in the breaker closing loop, whether according to transformer both sides have voltage determine whether will use inhibit feature, then start inhibit feature as the both sides no-voltage if suppressing circuit, promptly catches power phase and be the opportunity of 90 ° or 270 ° and close a floodgate.Then directly implement the control of three-phase combined floodgate as the existing voltage of either side.
Another kind is to suppress transformer the magnetizing inrush current that short circuit excision back voltage raises and causes suddenly, B to occur
1To B
6Circuit breaker is all at closing position, and transformer T normally moves.This moment as generation outlet short trouble, for example short circuit on the circuit of power supply 3, voltage U at this moment
2To sharply descend, treat that protective relaying device is with B
5Voltage U after the tripping
2Suddenly raise again, this also can produce magnetizing inrush current, and may cause the differential protection malfunction tripping B of transformer
1And B
2, large-area power-cuts appears.Therefore, this situation also needs to introduce magnetizing inrush current and suppresses circuit, and introducing method is to increase the inhibition circuit that shoves in the separating brake control loop of circuit breaker, separating brake when guaranteeing that protective relaying device is 90 ° or 270 ° at the supply voltage phase angle.The degree that voltage descends when suppressing circuit according to fault determines whether needs start inhibit feature.
As shown in figure 10, be example with the phase voltage in the transformer frequency response closing operation process, in two kinds of situation: 1, the combined floodgate order is sent at the Q point, has recorded T/2=9.8ms before the Q point, i.e. T=19.6ms, and t
vValue, and calculated the time-delay ty of ordering from the Q point to H, the combined floodgate writ of execution sends at the H point, experience t
c, be made as the 47ms circuit breaker and connect at the K point just.2, the order of closing a floodgate is sent at Q ', and this is the M=5 that Q point calculates with send dissimilarity at Q point, P=0.94, and it is to carry out 90 ° or 270 ° nearest some G calculating of a H to closing a floodgate.And the M=6 of Q ' calculating, P=0.24, then for 90 ° or 270 ° of some L, so the time are L points to close a floodgate carrying out some H nearest 90 ° or 270 ° of points.
Owing to begin to have opened interruption from B point, promptly can receive closing/the separating brake order of outside at any time in that B point is later, the as above point of the Q among the figure or Q ' point, close certainly/the separating brake order also may occur in negative half period CD section.No matter certain that occurs in positive half cycle or negative half period a bit, can in this half cycle, calculate to carry out and close/the H point of separating brake order, make valley point that the main contact of circuit breaker just in time drops on the summit of positive half cycle or negative half period promptly on (2n-1) 90 ° of points, realize closing/separating brake of no magnetizing inrush current.
Claims (3)
1. the restraining device of a transformer excitation flow, the transformer frequency response side is connected with circuit breaker, it is characterized in that: the combined floodgate of described circuit breaker, separating brake control end connect the output of the inhibitor of shoving, the inhibitor of shoving comprises measuring circuit and computing circuit, and the input of measuring circuit receives the arbitrary phase voltage input signal in the three-phase mains voltage; Described measuring circuit and computing circuit adopt single-chip microcomputer, the input of single-chip microcomputer is connected with the transformer height to three-winding transformer, in, three voltage signal inputs of low-pressure side with the famous prime minister, the transformer height, in, the auxiliary contact of low-pressure side circuit breaker three-phase, three sides that send the outside are closed circuit breaker and are divided the switching value signal input part of circuit breaker, three high, in, low-pressure side breaker closing classification selector switch amount signal input part, three locking height, in, the downside breaker open operation, the switching value signal input part that closes a floodgate, a distant place reset switch amount signal input part; The output of single-chip microcomputer is connected with the transformer high, medium and low voltage side circuit breaker phase-splitting energization control signal output that 9 photoelectricity are isolated the output of MOSFET relay, 9 photoelectricity are isolated the transformer high, medium and low voltage side circuit breaker phase-splitting separating brake control signal output ends of MOSFET relay output, device alarm switch amount signal output part is with the communication interface of host computer.
2. the restraining device of transformer excitation flow according to claim 1 is characterized in that: described measuring circuit be connected with control circuit breaker three-phase phase-splitting operating mechanism and three-phase simultaneously operating mechanism parts and execution unit be set.
3. the restraining device of transformer excitation flow according to claim 2, it is characterized in that: described single-chip microcomputer adopts SOC C8051F series monolithic, photoelectricity is isolated the MOSFET relay and is adopted the high-power photoelectricity of AQZ164 B02 type to isolate the MOS relay, or APV1122 type photoelectricity is isolated the combination of mosfet driver and high-power MOSFET relay.
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| CNB2004100152087A CN100367595C (en) | 2004-01-15 | 2004-01-15 | Static exciter inrush current inhibition method and apparatus |
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| CNB2004100152087A CN100367595C (en) | 2004-01-15 | 2004-01-15 | Static exciter inrush current inhibition method and apparatus |
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| CN100367595C true CN100367595C (en) | 2008-02-06 |
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| CN100403615C (en) * | 2005-04-27 | 2008-07-16 | 叶念国 | Method for suppressing power transformer excitation surge current and suppressor |
| CN100421327C (en) * | 2006-03-17 | 2008-09-24 | 中国电力科学研究院 | Transformer bias protector of large power power electronic appliance |
| CN100452601C (en) * | 2006-08-17 | 2009-01-14 | 江苏省电力试验研究院有限公司 | New magneting inrush current recognition method adapted for large-scale power transformer additional with phase discrimination |
| JP5208593B2 (en) * | 2008-06-20 | 2013-06-12 | 株式会社東芝 | Inrush current suppressing device for transformer and control method thereof |
| JP5547013B2 (en) * | 2010-09-22 | 2014-07-09 | 株式会社東芝 | Inrush current suppression device |
| CN102055173B (en) * | 2010-12-08 | 2013-02-06 | 河南省电力公司许昌供电公司 | Method for preventing differential protection false operation caused by exciting inrush current of no-load transformer |
| JP5651508B2 (en) * | 2011-03-17 | 2015-01-14 | 株式会社東芝 | Inrush current suppression device |
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| CN113937731A (en) * | 2021-09-29 | 2022-01-14 | 南京钢铁股份有限公司 | Method for restraining magnetizing inrush current of transformer |
| CN113991606B (en) * | 2021-10-18 | 2024-01-02 | 国电南瑞科技股份有限公司 | Excitation surge current misoperation prevention method and device for transformer |
| CN114284999A (en) * | 2021-12-31 | 2022-04-05 | 杭州电力设备制造有限公司 | Transformer grouping switching-on device based on real-time magnetic flux error estimation |
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