CN104280662B - A kind of power transformer balances winding anti-short circuit capability analysis method - Google Patents

Abstract

A kind of power transformer balances winding anti-short circuit capability analysis method, and the analysis method is directed to balance winding and this winding is close to interior winding construction unshakable in one's determination.According to balance winding operation characteristic, calculate the Nonsymmetric Short Circuit dash current flowed through in balance winding, and then calculate average Leakage flux distribution and stress of conductor distribution, balance winding anti-short circuit capability is compared by the relation pair of circumference stress and unstability stress to be judged, theoretical foundation reports that CIGRE209 papers " short-circuit of power transformer characteristic " put forward concept and the technical specifications of GR1094.5 2008 by international conference on large HV electric systems.The present invention can be analyzed the anti-short circuit capability that each voltage class power transformer balances winding, both the complexity that axial unstability is calculated had been avoided, the precision of calculating has been in turn ensure that, check result is intuitively accurate, more suit produce reality, make check result more directiveness and specific aim.

Description

A kind of power transformer balances winding anti-short circuit capability analysis method

Technical field

The present invention relates to the field that power transformer balances winding, more particularly to a kind of power transformer balance winding resists short Road capability analysis method.

Background technology

The selection of power transformer balance coil volume mainly considers that it must be able to bear by the serious uneven institute of system The largest loop electric current of generation, this largest loop current value occurs in transformer Nonsymmetric Short Circuit, therefore balance winding is anti-short Road is analyzed must go out largest loop current value according to all kinds of Nonsymmetric Short Circuit condition calculatings first with research.Transformer is normally run Electric current is very small in Shi Pingheng windings, the characteristics of eddy-current loss and the temperature rise of copper conductor can be neglected, and this also determines balance winding Resistance to shorting design with resistance to shorting analysis method there is particularity.

As it was previously stated, electric current is very small when balance winding is normally run, eddy-current loss and the temperature rise of copper conductor can be neglected, it is single The ring size (during self-adhering transposed conductor by total width after self-adhesion to consider) of root wire exceeds well over high pressure coil solid conductor width To size, according to analysis, its axial stability ability preferably, during analysis anti-short circuit capability, can be carried out just for its width to unstability Judge.

At present, the method that GB1094.5-2008 technical specifications are checked to transformer anti-short circuit capability is with three-phase symmetrical short circuit Based on calculating, sudden short circuit experiment is also to take three-phase symmetrical short circuit current flow, and the single-phase completion of substep, it is difficult to the zero sequence electricity that only circulates The balance winding of stream is examined.

The content of the invention

The particularity that the present invention is analyzed for above-mentioned balance winding itself design feature with its anti-short circuit capability, the present invention is public A kind of power transformer balance winding anti-short circuit capability analysis method is opened, it is characterised in that comprise the following steps：

S100：The short-circuit impact electric current I in winding is balanced under each side Nonsymmetric Short Circuit operating mode of calculating transformer, is taken maximum short Road dash current value I_max；

S200：Utilize maximum short-circuit impact electric current I_maxThe average axial leakage field B of calculated equilibrium winding_pj；

S300：Utilize maximum short-circuit impact electric current I_max, average axial leakage field B_pjAnd balance winding is electrically joined with mechanical performance The circumference stress of number calculated equilibrium winding

S400：Circumference stress to balancing windingJudged, judgment formula is as follows：

In formula：Et- balances the tangent modulus of elasticity of winding conducting wire, and k- balances the manufacture coefficient of winding conducting wire equivalent thickness, B- balances winding conducting wire ring thickness, and D- balance winding average diameters, N- balances the Equivalent strut number of winding ring；

When the balance winding, which carries out circumference stress, can not meet the determination requirement of this step, illustrate " pressure warpage " side Face anti-short circuit capability is unqualified, need to strengthen the transformer balance winding resistance to shorting design, " the pressure warpage " is adjacent two The failure mode of the inside overbending of the wire in span between support member；Step is gone to after meeting judgment formula requirement S500；

S500：Circumference stress judgement is carried out to balance winding according to GB1094.5-2008 appendix As technical specification；

Ring on Continuous winding, Helical winding and the multi-layer winding of conventional wires and non-tack continuous transposed conductor Shape stress judges to be shown below：

In formula：R_p0.2For the yield value of stress of wire；

The circumference stress of tack continuous transposed conductor judges to be shown below：

When the result of calculation of this step can not meet the determination requirement of the circumference stress, illustrate in terms of " free warpage " Anti-short circuit capability is unqualified, it is necessary to strengthen the transformer balance winding resistance to shorting design；" the free warpage " be due to around Group width causes the wire width at one around winding or a few places to the failure mode of gross distortion to loss of stability；Strengthening anti- After short circuit design, carry out step S300 to step S500 in order again and calculate, when result of calculation meets step S400 and S500 Judgment formula requirement when, illustrate that transformer balance winding resistance to shorting design is qualified, terminates calculating.

The beneficial effects of the invention are as follows：Transformer balance winding anti-short circuit capability is checked using circumference stress check method, Concept and GB1094.5-2008 skills are carried with international conference on large HV electric systems report CIGRE209 papers " short-circuit of power transformer characteristic " Art specification is foundation, had both avoided the complexity that axial unstability is calculated, and in turn ensure that the precision of calculating, check result is intuitively accurate Really, more suit produce reality, make check result more directiveness and specific aim.

Brief description of the drawings

Fig. 1 is typical Nonsymmetric Short Circuit-low-pressure side single-line to ground fault elementary diagram；Wherein：HV, LV are high pressure, low Voltage source system；ABC (abc) is high pressure ABC (low pressure abc) phase winding；Wa (wb, wc) is balance winding a (b, c) phase winding；

Fig. 2 is the flow chart of analysis method in the present invention.

Embodiment

For the ease of skilled artisan understands that the present invention, special the present invention is further illustrated.

A kind of power transformer balance winding anti-short circuit capability analysis method disclosed in this invention, is comprised the following steps that：

Step (1)：According to transformer impedance value and the network system method of operation, each side Nonsymmetric Short Circuit of transformer is calculated The short-circuit impact electric current I in winding is balanced under operating mode, maximum short-circuit impact electric current I is taken_maxCarry out subsequent analysis；As 101 in Fig. 2 It is shown.

For the short-circuit impact current calculation method under Nonsymmetric Short Circuit operating mode, such as shown in Figure 1 is typical asymmetric Short circuit-low-pressure side single-line to ground fault；The theoretical calculation of power system symmetrical component method can be used, GB13499-2002 is referred to Power transformer stress directive/guide, it is also possible by means simulation analysis software is analyzed, and I will not elaborate.

Step (2)：, can be flat according to ampere-turn equilibrium law and Ampere circuit theorem because balance winding is interior winding The average axial leakage field intensity B of weighing apparatus winding_pj, as shown in Fig. 2 102.In view of being balanced under transformer accidental conditions in winding The characteristics of electric current is very small, typically using single thicker wire coiling, solid conductor thickness is winding thickness in conventional products More than 2 times, according to GB1094.5-2008 axial limits lodge power algorithm, may be summarized as follows functional relation：

In formula：- axial limit lodging power, beq- wire equivalent thickness, K₁、K₂- respectively other influences factor is Number.

As can be seen that axial resistance to shorting can improve 2 times to 8 times from above formula, so the axial unstability intensity of balance winding Due to its particularity, far above its width to intensity, the complexity problem that axial unstability is calculated can be avoided during engineering calculation, with school Core width is judged the security for balancing winding to the method for intensity.

Step (3)：According to short-circuit impact electric current I_max, average axial leakage field B_pjAnd winding electrically with mechanical performance parameter such as Reactance height, conductor size and winding width calculate wire circumference stress to size etc.As shown in Fig. 2 103；

Average axial direction leakage field B in step (2)_pjAnd with circumference stress in this stepCalculating refers to what Yin Kening write 《Design of transformer principle》Theory meter of (China Electric Power Publishing House published, issued in October, the 2003) chapter 7 on circumference stress Calculation method, it is also possible by means simulation analysis means are completed.

Step (4)：Consider copper conductor tangent modulus of elasticity and the inner support effect of balance winding, should to balance winding ring PowerJudged：

In formula：Et- balances the tangent modulus of elasticity of winding copper conductor, and k- balances the manufacture system of winding copper conductor equivalent thickness Number, b- balance winding copper conductor ring thickness, D- balance winding average diameters, the Equivalent strut number of N- winding rings is above-mentioned to sentence Disconnected scheme proposes for the report CIGRE209 papers " short-circuit of power transformer characteristic " of international conference on large HV electric systems；

When result of calculation can not meet the judgment formula requirement of this step, illustrate that anti-short circuit capability does not conform in terms of " pressure warpage " Lattice, are unsatisfactory for the paper requirement of international bulk power grid, and product need to strengthen resistance to shorting design, meet carried out after judgment formula requirement it is next Step is adjusted.As shown in Fig. 2 104." the pressure warpage " is that the wire in the span between adjacent two support member is inwardly excessive The failure mode of bending.

Step (5)：Circumference stress judgement is carried out to balance winding according to GB1094.5-2008 appendix As technical specification, continuously Average angular compression stress on formula winding, Helical winding and multiple field winding is to conventional wires and non-tack continuous shifting Wire judgment formula is：

R_p0.2- wire yield value of stress,

It is to tack continuous transposed conductor judgment formula：

As shown in 105 in flow chart 2：When result of calculation can not meet the judgment formula requirement of this step, illustrate " freely to stick up Song " aspect anti-short circuit capability is unqualified, is unsatisfactory for estimation technique requirement, and product need to strengthen resistance to shorting design, enter in order again The step of row 103 to 105 steps are analyzed, and are met each step judgment formula requirement and be can determine whether that product is qualified." the free warpage " be due to Loss of stability and cause the wire width at one around winding or a few places to the failure mode of gross distortion.

A kind of power transformer balance winding anti-short circuit capability analysis method provided by the present invention has been carried out in detail above It is thin to introduce, for those skilled in the art, according to the thought of the present invention, had when in embodiment or application Change part, in summary, this specification content should not be construed as limiting the invention.

Claims (4)

1. a kind of power transformer balances the analysis method of winding anti-short circuit capability, it is characterised in that comprise the following steps：

S100：The short-circuit impact electric current I in winding is balanced under each side Nonsymmetric Short Circuit operating mode of calculating transformer, maximum short circuit punching is taken Hit current value Imax；

S200：Utilize the average axial leakage field B of maximum short-circuit impact electric current Imax calculated equilibrium windings_pj；

S300：Utilize maximum short-circuit impact electric current Imax, average axial leakage field B_pjAnd balance winding is electrically and mechanical performance parameter The circumference stress of calculated equilibrium winding

S400：Circumference stress to balancing windingJudged, judgment formula is as follows：

${\mathrm{\σ}}_{t.act}^{*}\≤Et\·{\left(kb\right)}^2{N}^2/\left(12D^2\right)$

In formula：Et- balances the tangent modulus of elasticity of winding conducting wire, and k- balances the manufacture coefficient of winding conducting wire equivalent thickness, and b- is put down Weigh winding conducting wire ring thickness, and D- balance winding average diameters, N- balances the Equivalent strut number of winding ring；

When the balance winding, which carries out circumference stress, can not meet the determination requirement of this step, illustrate anti-in terms of " pressure warpage " Short-circuit capacity is unqualified, need to strengthen the transformer balance winding resistance to shorting design, and " the pressure warpage " is adjacent two supports The failure mode of the inside overbending of the wire in span between part；Meet and step S500 is gone to after judgment formula requirement；

S500：Circumference stress judgement is carried out to balance winding according to GB1094.5-2008 appendix As technical specification；

Annular on Continuous winding, Helical winding and the multi-layer winding of conventional wires and non-tack continuous transposed conductor should Power judges to be shown below：

${\mathrm{\σ}}_{t.act}^{*}\≤0.35\·R_{p0.2};$

In formula：Rp0.2 is the yield value of stress of wire；

The circumference stress of tack continuous transposed conductor judges to be shown below：

${\mathrm{\σ}}_{t.act}^{*}\≤0.6\·R_{p0.2};$

When the result of calculation of this step can not meet the determination requirement of the circumference stress, illustrate anti-short in terms of " free warpage " Road ability is unqualified, it is necessary to strengthen the transformer balance winding resistance to shorting design；" the free warpage " is due to winding width Cause the wire width at one around winding or a few places to the failure mode of gross distortion to loss of stability；Strengthening resistance to shorting After design, carry out step S300 to step S500 in order again and calculate, when result of calculation meets sentencing for step S400 and S500 During disconnected formula requirement, illustrate that the transformer balance winding resistance to shorting design is qualified, terminate to calculate；

Wherein, described balance winding is close to interior winding unshakable in one's determination, according to transformer impedance value and the network system method of operation Calculate described short-circuit impact electric current I.

2. analysis method as claimed in claim 1, it is characterised in that：Stream is calculated according to transformer impedance and system impedance parameter Through the maximum short-circuit impact current value Imax for balancing winding.

3. analysis method as claimed in claim 1, it is characterised in that：The winding electrically includes reactance with mechanical performance parameter Highly, conductor size and winding width are to size.

4. analysis method as claimed in claim 1, it is characterised in that：According to ampere-turn equilibrium law and Ampère circuital theorem Balance the average axial leakage field intensity B of winding_pj。