CN108767826B - Do not demagnetize converter power transformer air-drop excitation surge current suppressing method after straight resistance test - Google Patents
Do not demagnetize converter power transformer air-drop excitation surge current suppressing method after straight resistance test Download PDFInfo
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- CN108767826B CN108767826B CN201810615879.9A CN201810615879A CN108767826B CN 108767826 B CN108767826 B CN 108767826B CN 201810615879 A CN201810615879 A CN 201810615879A CN 108767826 B CN108767826 B CN 108767826B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/001—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off
- H02H9/002—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection limiting speed of change of electric quantities, e.g. soft switching on or off limiting inrush current on switching on of inductive loads subjected to remanence, e.g. transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/04—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/02—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Protection Of Transformers (AREA)
Abstract
The invention discloses the converter power transformer air-drop excitation surge current suppressing methods that do not demagnetize after a kind of straight resistance test, this method is adjusted to the straight resistance test connection of converter power transformer tradition, on the basis of becoming the reversed straight resistance test of the separate progress in part to star, converter power transformer switching order and each phase combined floodgate voltage phase angle are determined according to directly resistance test direction and sequence；This method is not when Overhaul site has iron core demagnetization condition, it only needs to adjust straight resistance test direction and carries out phase selection position combined floodgate accordingly, the converter power transformer air-drop excitation surge current that do not demagnetize after straight resistance is tested can be effectively suppressed, relevant parameter easily obtains, it may be convenient in Practical Project.
Description
Technical field
The invention belongs to power system main equipment technical field of relay protection, and in particular to a kind of based on the straight of phase selection
The converter power transformer that do not demagnetize after resistance test encourages air-drop magnetic surge suppression method.
Background technique
Converter power transformer is one of the core equipment in DC transmission engineering, is broken down after damaging since maintenance is difficult
Degree is big, the time between overhauls(TBO) is long, not only will affect the normal operation of electric system, or even will cause immeasurable economic loss and society
It will affect.Converter power transformer iron core magnetic flux in zero load investment cannot be mutated, and the transient state magnetic flux generated due to voltage jump can
Iron core can be caused to be saturated, it will to generate the very big electric current of numerical value in the side of transformer voltage mutation, which is referred to as
Excitation surge current.Since iron core flux density is higher, saturation point is lower while winding resistance is smaller, and converter power transformer excitation surge current shows
The highly attenuating slow feature of amplitude influences to be much larger than conventional electric power transformer caused by operating normally system, it is therefore necessary to adopt
Measure is taken to inhibit it.
The major influence factors of excitation surge current are iron core magnetization characteristic, iron core remanent magnetism and switching voltage phase angle.Change of current transformation
Device often carries out straight resistance experimental test during maintenance, and there are very and magnetizing each phase iron core to saturation for the test
Big remanent magnetism directly carries out its iron core magnetic flux when zero load puts into operation and is likely to be breached three times if handling later without iron core demagnetization
Rated flux causes the great excitation surge current of amplitude, the serious safe and stable operation for destroying high voltage ac/dc system.If therefore existing
When field does not have iron core demagnetization condition, using the generation of transient state magnetic flux during phase selection position combined floodgate means control idle-loaded switching-on, mitigate
To inhibit excitation surge current, the normal operation of the successful air-drop and system of exchanging rheology has important the degree of saturation of iron core magnetic flux
Meaning.
Phase selection switch technology exists applied to the key that the converter power transformer that do not demagnetize after the straight resistance test of inhibition drops excitation surge current
It in selecting optimal switching-on phase angle, that is, include the analysis and alternate conjunction to converter power transformer iron core remanent magnetism information after straight resistance test
The cooperation of lock sequence.Unlike conventional transformer, 12 pulse conversion transformer of monopole is by organizing Circuit Breaker Switching together
It is coupled two groups of converter power transformer group paired runnings that pattern is respectively YNyn0 and YNd11 to constitute.To each single-phase change of current become successively into
After the straight resistance test of row, iron core remanent magnetism difference causes two best closing phase angles of changes of current change of same phase different, mutual when inphase angle closes
It is affected.Therefore the present invention has fully considered after straight resistance test between remanent magnetism polarity and change of current change group and inter-phase electromagnetic couples shadow
It rings, gives one kind for converter power transformer phase selection method of not demagnetizing after straight resistance test, this method can be very good to inhibit
The excitation surge current that transformer during no-load closing generates.
Summary of the invention
In order to solve the above-mentioned problems of the prior art, the present invention provides change of current transformation of not demagnetizing after the straight resistance of one kind is tested
Device drops excitation surge current suppressing method, and this method is not when Overhaul site has iron core demagnetization condition, it is only necessary to become part phase to star
On the basis of reversed directly Jin Hang not hindering test, according to straight resistance test direction and sequentially determining converter power transformer switching order and each phase
Switching voltage phase angle, that is, can be effectively suppressed the converter power transformer air-drop excitation surge current that do not demagnetize after straight resistance is tested, and relevant parameter easily obtains
It takes, it may be convenient in Practical Project.
In order to achieve the above object, the present invention adopts the following technical scheme:
1, do not demagnetize converter power transformer air-drop excitation surge current suppressing method after straight resistance test, includes the following steps:
Step 1: each single-phase transformer being become to the angle in 12 pulse conversion transformer of monopole and successively carries out forward direction in net side
Straight resistance test, the separate M that record is finally tested；Direct resistance metering instrument positive terminal is connect net by the positive straight resistance test
Side winding end of incoming cables, negative terminal connect source side winding ground terminal；
Step 2: each single-phase transformer being become to the star in 12 pulse conversion transformer of monopole and is successively directly hindered in net side
Test, wherein M phase carries out positive straight resistance test, remaining two-phase carries out reversed straight resistance test；The reversed straight resistance test will be straight
It hinders the positive and negative end of tester and exchanges wiring, the DC current for enabling net winding inflow direction opposite；
Step 3: closing a floodgate first to M phase after receiving switching signal, switching voltage angle is α1=180 °；Be delayed 2~3 cycles
It closes a floodgate simultaneously to remaining two-phase afterwards, switching voltage angle is α2=0 ° or α2=180 °, the combined floodgate angle with M phase voltage just
It is reference point to zero crossing.
The 12 pulse conversion transformer of monopole of the step 1 is by same group of Circuit Breaker Switching, and the mode of connection is respectively
The converter power transformer group that two groups of parallel operation of transformers of YNyn0 and YNd11 are constituted, primary side is connect with AC system, for step
Rapid 1 net side, secondary side are connect with converter valve, referred to as valve side.
Step 1 angle becomes the transformer group that the mode of connection in 12 pulse conversion transformer of monopole is YNd11.
Step 2 star becomes the transformer group that the mode of connection in 12 pulse conversion transformer of monopole is YNyn0.
Compared to the prior art compared with the present invention has following advantage:
1, relevant parameter easily obtains.I.e. all parameters of excitation surge current suppressing method can be by directly measuring acquisition.
2. this method fully considers and has adjusted straight resistance test compared to traditional converter power transformer excitation surge current Restrain measurement
Iron core remanent magnetism size and polarity afterwards, when not having iron core demagnetization condition at the scene, directly progress phase selection position idle-loaded switching-on, operation is simple
Single excitation surge current inhibitory effect simultaneously is more preferable.
Detailed description of the invention
Fig. 1 is that transformer directly hinders test equivalent circuit diagram.
Fig. 2 is 12 pulse conversion transformer connection figure of monopole.
Iron core magnetic flux variation diagram during Fig. 3 is phase selection.
Fig. 4 is overall plan figure.
Fig. 5 is simulation model figure.
Fig. 6 is the switching current waveform diagram that emulation obtains.
Fig. 7 is the switching voltage waveform diagram that emulation obtains.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and detailed description:
Single-phase transformer as shown in Figure 1 directly hinders test equivalent circuit, and L and R are respectively transformer winding equivalent inductance and electricity
Resistance, i is loop current, and E is DC voltage source, can column loop-voltage equation have:
It solves
In formula: t=L/R indicates down slope time constant.
It can be seen that k combined floodgate primary iron core is unsaturated, winding equivalent inductance is larger to cause its partial pressure larger, and test loop is equivalent to
Winding charge circuit, iron core magnetic flux constantly rise, and electric current is gradually increased.Until iron core magnetic flux is saturated, winding equivalent inductance is almost
0 is sported, loop current increases to i=E/R suddenly, has di/dt=0 according to formula (1) at this time, therefore loop current reaches stable state not
Increase again, D.C. resistance R can be sought using DC voltage E and steady-state current i.As the above analysis, straight resistance, which is tested, is
Magnetize iron core to the process of saturation, thus after testing remanent magnetism close to saturation flux Φs, generally estimate directly to hinder according to field experience
Remanent magnetism is 0.85p.u. after test.
12 pulse conversion transformer device structure of monopole and the method for operation are as shown in Fig. 2, comprising by organizing together Circuit Breaker Switching
It is coupled two groups of changes of current that pattern is respectively YNyn0 (hereinafter referred to as star change) and YNd11 (hereinafter referred to as angle change) and becomes paired running, often
The group change of current becomes tri-phase iron core independence, carries out independent operation to every phase iron core during straight resistance test.For angle becomes, due to valve
Side (secondary side and converter valve connecting side) Δ winding can not be unlocked, hair when remaining two-phase iron core magnetic is colluded when certain mutually carries out directly hindering test
Changing can obtain tri-phase iron core magnetic flux by voltage integrating meter and be constantly equal to 0 in view of Δ winding is by three-phase windings voltage and to clamp down on be 0,
That is iron core balance of flux.Assuming that A phase iron core finally carries out directly hindering test, then angle becomes remanent magnetism as [0.85-0.425-0.425]
p.u..And for star change, tri-phase iron core magnetic flux is independent of each other, if carrying out positive straight resistance test, three-phase remanent magnetism is equal
And polarity is identical, and zero sequence fluxes in hereafter making process is caused greatly to influence transient state flux decay.Become three-phase to reduce star
The unbalanced influence of remanent magnetism is taken and carries out positive straight resistance test to above-mentioned A phase (i.e. angle becomes most end test phase), B with C phase carries out instead
To the test method of straight resistance test (reversal connection of direct resistance metering instrument positive and negative electrode), then remanent magnetism is [0.85-0.85-0.85] after testing
p.u.。
Two changes of current of same phase in view of paired running when putting into operation become by same breaker control combined floodgate, then above-mentioned straight resistance examination
It selects star to become the identical A phase with angle change remanent magnetism after testing first to close a floodgate.If A phase supply voltage is uA(t)=Umsin(ωt+
α), UmIt is primary side winding voltage peak, ω is voltage angular frequency, and α is supply voltage initial phase angle, to A phase transformer source side winding
Column loop-voltage equation are as follows:
Wherein: R is transformer primary circuit equivalent resistance, and i is transformer primary circuit electric current, N1It is net umber of turn,
φAIt is A phase iron core magnetic flux；It is often negligible due to transformer primary circuit equivalent resistance R very little, then have
Enabling A phase closing moment is that t=0 then has since iron core magnetic flux can not be mutated
φA(0)=ΦrA (5)
Iron core magnetic flux is after convolution (4) closes a floodgate with A phase known to formula (5)
In formula,For stable state magnetic flux peak value, L is equivalent magnetizing inductance.
Enable ΦrA+φmα=0 cos, in conjunction with Analysis ofremanence after straight resistance test as a result, the best closing phase angle of A phase known to then is optional
It is selected as
α=arccos (- ΦrA/Φm)=arccos (- 0.85)=150 ° (7)
Then A phase iron core magnetic flux after phase angle combined floodgate is directly entered steady-state operation without being saturated, and excitation surge current obtains
To eliminate.A phase close a floodgate after due to delta windings effect, angle become B, C phase valve side winding generate induced voltage, iron core magnetic flux
It is no longer held at that remanent magnetism is constant, but with the dynamic magnetic flux of A phase flux change, such as t in Fig. 31~t2It is shown.Since angle becomes three-phase
Magnetic flux balances always, thus have B, C phase magnetic flux be A phase 1/2,180 ° of delayed phase.
In addition, angle become B, C phase iron core flux change cause its net winding equally to have induced voltage generation, respectively with corresponding phase
Other star becomes net winding and constitutes current loop (shown in Fig. 2 dotted line), so that star becomes B, C phase net winding and has exciting current circulation, iron
The variation of core flux synchronous.Since two single-phase converter power transformers of every phase paired running are by same Circuit Breaker Switching, net winding
It is connected directly and neutral ground, therefore the source side winding pressure drop of two transformers is identical, that is, has
uyv=udv (8)
Wherein, v=A, B, C；
Both sides integral can obtain iron core flux change and be
Δφyv=Δ φdv (9)
Become stable state iron core magnetic flux with two changes of current of phase to be consistent, it follows that star becomes B, C phase iron core after A phase is closed a floodgate
Flux synchronous variation, such as t in Fig. 31~t2It is shown.At this time since star becomes three-phase initial magnetic flux and not into 0, B, C phase iron core magnetic flux
Consistently greater than angle becomes, and can not determine that exact time makes star change and angle become iron core magnetic flux (Fig. 3 identical as pre- inducting flux at this time
Shown in middle dotted line), therefore for practical implementation, using approximately equal moment-A phase magnetic flux peak value, that is, voltage over zero to B, C
It mutually closes a floodgate, that is, determines that the best closing phase angle of B, C phase is α '=0 ° or α '=180 °, t in magnetic flux such as Fig. 3 after combined floodgate2Institute after moment
Show.
Fig. 4 is the overall plan figure of the method for the present invention, in figure: XLIndicate line impedance, TV indicates voltage transformer, TA table
Show that current transformer, QK indicate three-phase breaker.
Embodiment
Fig. 5 is the simulation model built, and two groups of transformers are three-phase two-simulation transformer group in this simulation model, specified
Voltage is 345/289kV, and rated capacity 1209MVA, rated no-load current is about 2A.Transformer primary is acquired by I, V in Fig. 5
Side winding current and voltage waveform, control switch close at the not inphase angle of voltage waveform, observe primary side winding current waveform.
To simulate remanent magnetism distribution situation after straight resistance is tested, emulation setting angle becomes and star change remanent magnetism is respectively [0.85-0.425-0.425]
And [0.85-0.85-0.85] p.u. p.u..
It closes a floodgate at α=150 ° to A phase first after straight resistance test as the above analysis, later in α '=0 ° to B, C phase
It closes a floodgate simultaneously, the voltage current waveform difference emulated is as shown in Figure 6 and Figure 7, it is seen that it is straight that combined floodgate relief angle becomes three-phase current
It taps into and is generated into stable state without excitation surge current, and star becomes due to closing moment approximation, has lesser bias to generate, iron core goes out after combined floodgate
There is the lesser excitation surge current of amplitude in existing a degree of saturation, B, C phase.
Above-described specific embodiment has carried out further the purpose of the present invention, technical scheme and beneficial effects
It is described in detail, it should be understood that being not intended to limit the present invention the foregoing is merely a specific embodiment of the invention
Protection scope, all within the spirits and principles of the present invention, any modification, equivalent substitution, improvement and etc. done should all include
Within protection scope of the present invention.
Claims (2)
1. do not demagnetize converter power transformer air-drop excitation surge current suppressing method after straight resistance test, which comprises the steps of:
Step 1: each single-phase transformer being become to the angle in 12 pulse conversion transformer of monopole and successively carries out positive straight resistance in net side
Test, the separate M that record is finally tested；The positive straight resistance test i.e. by direct resistance metering instrument positive terminal connect net side around
Group end of incoming cables, negative terminal connect source side winding ground terminal；
Step 2: each single-phase transformer is become to the star in 12 pulse conversion transformer of monopole and successively carries out directly hindering test in net side,
Wherein M phase carries out positive straight resistance test, remaining two-phase carries out reversed straight resistance test；The reversed straight resistance test is i.e. by direct resistance metering
The positive and negative end of instrument exchanges wiring, the DC current for enabling net winding inflow direction opposite；
Step 3: closing a floodgate first to M phase after receiving switching signal, switching voltage angle is α1=150 °；It is right after 2~3 cycles of delay
Remaining two-phase is closed a floodgate simultaneously, and switching voltage angle is α2=0 ° or α2=180 °, the switching voltage angle with M phase voltage just
It is reference point to zero crossing；
Angle described in step 1 becomes the transformer group that the mode of connection in 12 pulse conversion transformer of monopole is YNd11；
Star described in step 2 becomes the transformer group that the mode of connection in 12 pulse conversion transformer of monopole is YNyn0.
2. do not demagnetize converter power transformer air-drop excitation surge current suppressing method after straight resistance test according to claim 1, special
Sign is that 12 pulse conversion transformer of monopole described in step 1 is by same group of Circuit Breaker Switching, and the mode of connection is respectively
The converter power transformer group that two groups of parallel operation of transformers of YNyn0 and YNd11 are constituted, primary side is connect with AC system, for step
Rapid 1 net side, secondary side are connect with converter valve, referred to as valve side.
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| CN111398881B (en) * | 2020-03-21 | 2023-07-18 | 重庆大学 | One-time solving method for excitation characteristics of reversible pi model of transformer based on excitation surge |
| CN115347533B (en) * | 2022-10-18 | 2023-01-31 | 保定市英电电力科技有限公司 | Method for reducing excitation inrush current of large transformer |
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| CN107482600A (en) * | 2017-07-18 | 2017-12-15 | 西安交通大学 | Yyn0 type three-phase group formulas transformer drops excitation surge current suppressing method |
| CN108107384A (en) * | 2017-12-18 | 2018-06-01 | 国网新疆电力公司检修公司 | 750kV auto-transformers directly hinder remanent magnetism amount computational methods after experiment |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5172067A (en) * | 1991-05-20 | 1992-12-15 | Commonwealth Edison Company | Apparatus for determining DC resistance in high voltage winding with nonlinear resistance energy dissipation circuit |
| CN101951221A (en) * | 2010-09-25 | 2011-01-19 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Twelve pulsating commutation transformer and method and circuit for removing residual magnetism thereof |
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