CN106295216A - A kind of high-power transformer Damage by Short Circuit risk probability appraisal procedure - Google Patents

Abstract

The invention discloses a kind of high-power transformer Damage by Short Circuit risk probability appraisal procedure, the method is by gathering transformer device structure parameter, checking transformer short-circuit tolerance, this check result is classified with factors such as transformator running environment, low-pressure side configuring conditions, score is set, gives weight, in conjunction with situations such as the transformer short circuit fault information having occurred and that, quantify transformer short-circuit and damage risk probability, and carry out classification.Staff it will be seen that the damage risk of current transformer, provides technical support to taking control measures the most targetedly.The present invention is applied widely, can be suitably used for multiple different electric pressure, the Damage by Short Circuit probability assessment of different capabilities transformator.Reliability of the present invention is high, low cost, can calculate in real time by common computer, decrease the participation of staff, reduce operating error, improve work efficiency.

Description

A kind of high-power transformer Damage by Short Circuit risk probability appraisal procedure

Technical field

The present invention relates to a kind of high-power transformer Damage by Short Circuit risk probability appraisal procedure, it is short to be that one is applicable to transformator The novel method of path loss bad state analysis, belongs to transformator and runs detection and maintenance field.

Background technology

Transformator is the core of electric power system, and its reliability of operation is on power system security impact greatly.But, along with The increase day by day of current electric grid capacity, system short circuit capacity increases the most therewith, and meanwhile, transformer station's access lines running environment is not allowed Optimism, various overvoltage happen occasionally.In recent years, for various reasons, external short circuit causes the accident that high-power transformer damages Occur repeatedly, the feelings of the level that many transformators are promised to undertake far away from national standard requirement and producer at short circuit current, short circuit duration Winding deformation and damage i.e. occur under condition, and the transformator external short circuit first and second newly put into operation having i.e. is damaged.Therefore, Understand whether transformator anti-short circuit capability meets on-the-spot service requirement by calculating, be the feelings of current run unit urgent need grasp Condition.

The short-circuit force F that can bear with transformator self_BThe maximum on winding can be produced during with transformator external short circuit Short-circuit force F_CRatio characterize the anti-short circuit capability of transformator, referred to as transformer short-circuit tolerance Z.This value shows the most greatly Transformator winding after suffering external short circuit deform damage probability the least, otherwise, this value get over small transformers short circuit damage Bad probability is the biggest.The method of Japan transformator committee proposed algorithm calculating transformer short circuit tolerance Z is as follows.

Short circuit tolerance Z is obtained by formula (1):

$Z=\frac{F_B}{F_C}---\left(1\right)$

F in formula (1)_CObtained by formula (2),

$F_c=\frac{F_r}{{\mathrm{Ml}}_m},(g/mm)---\left(2\right)$

In formula (2): l_mFor the average perimeter of coil, mm；M is line cake number；F_rThe electric power born for interior loop during short circuit, g；

F in formula (2)_rObtained by formula (3)；

$F_r=6.4A_m^2{\mathrm{hI}}_m=\frac{6.4l_m}{h}{\left(\frac{I_n\×N\×k}{70u_k}\right)}^2,\left(g\right)---\left(3\right)$

In formula (3): N is the number of turn of coil；H is the height of coil, mm；K is coefficient, depend in short-circuit impedance reactance with The ratio of resistance, can look into GB1094.5-2008 and obtain；I_nFor rated current, A；u_kFor system impedance, %；l_mAverage for coil Girth, mm.

F in formula (1)_BObtained by formula (4),

$F_B=\frac{EI}{R^3}(m^2-1),(g/mm)---\left(4\right)$

In formula (4): E is the elastic modelling quantity of copper conductor, common soft copper wire generally takes E=12.25 × 10⁴MPa；R is line The mean radius of circle, mm, by formulaObtain；

In formula (4): m be internal coil diameter stay effectively support number, for the half of actual stay number, by formula? Arrive, wherein Z_kFor actual stay number；

1. for plain conductor, wire the moment of inertia I in formula (4) is obtained by formula (5):

$I=\frac{n_b^y{b}^3\×n_l\×t}{12},\left({\mathrm{mm}}^4\right)---\left(5\right)$

In formula (5): nb is wire radical radial in line cake；B is the radial width of solid conductor, mm；n_lFor in line cake Axial wire radical；T is the axial height of solid conductor, mm；Y is the empirical coefficient of bond state between strands, usual 1≤y ≤ 3, for plain conductor y=1；

2. for transposed conductor, wire the moment of inertia I in formula (4) is obtained by formula (6):

$I=\frac{1}{6}{\left(\frac{x}{2}\right)}^y{n}^{1.5}\×b^3\×t,\left({\mathrm{mm}}^4\right)---\left(6\right)$

In formula (6): x is the number of share of stock of a transposed conductor inside conductor；B is the radial width of per share wire, mm；T is per share The axial height of wire, mm；N is the radical of transposed conductor in line cake；Y is the empirical coefficient of bond state between strands, usual l≤ Y≤3, for autohension transposed conductor y=2.3～2.5, the outer layer such as conductor turns insulation is coated with thermosetting cement, y=1.4.

Each company of net province is calculated at fortune transformer short-circuit tolerance at present, some employing Japan transformator The algorithm that committee is recommended, some employing Finite Element Method calculating etc., by these algorithms, run unit can be grasped intuitively The short-circuit tolerance of transformator, have also to run step down side equipment quality and failure condition carried out statistical Analysis, thus understand the probability of transformer low voltage side outlet tripping operation, and then analyze what transformer low voltage short circuit in winding damaged intuitively Probability, but not yet find the operating mode phase short-circuit tolerance of transformator and transformator running environment and history suffered at present In conjunction with, and then evaluate the method for transformator probability of damage when transformator suffers short circuit.

Summary of the invention

For the problems referred to above, the present invention provide a kind of applied widely, reliability is high, low cost, and under operation The appraisal procedure of Damage by Short Circuit risk probability can be suffered by visual assessment transformator.

For have been put into run transformator, its Damage by Short Circuit potential risk is acted on jointly by many factors, not only with Its short circuit tolerance is relevant, also relevant with its ruuning situation, low-pressure side configuring condition etc..Affect transformer short-circuit and damage potential The principal element of risk is as follows.

(1) transformer short-circuit tolerance: transformer short-circuit tolerance is that to affect Transformer Winding Damage by Short Circuit potential The most important factor of risk, is determined by the structural parameters of transformator, transformator committee of Japan proposed algorithm can be used to calculate and become Depressor short circuit tolerance Z, carries out stepping according to following rule；

First grade: Z≤1.2, short circuit tolerance is less than 2.0, and from the point of view of anti-short circuit capability, its anti-short circuit capability is serious not Foot；Second gear: 1.2 ＜ Z≤1.7, its anti-short circuit capability is the most not enough；Third gear: 1.7 ＜ Z≤2.1, its anti-short circuit capability is in Meet the edge of anti-short circuit capability；Fourth speed: between 2.1 ＜ Z≤10, its anti-short circuit capability meets anti-short from the point of view of check result Road Capability Requirement；Fifth speed: Z ＞ 10, its anti-short circuit capability is greatly improved.

(2) Transformer Operation Status: affected by accumulative effect, once suffered the transformator of short-circuit current rush more It is susceptible to sudden short circuit and damages fault, so being considered as transformator to suffer size and the number of times of short-circuit current rush, Yi Jibian The factors such as deformation of transformer winding result of the test.

(3) step down side configuring condition: low-voltage side outlet quantity is the most, transformator is exported or near region short circuit Probability the highest, so be considered as its low-voltage side outlet quantity, whether install current-limiting reactor and low-pressure side bus insulation Change and improve the anti-implementation status factors of arranging such as situation.

The present invention provides a kind of high-power transformer Damage by Short Circuit risk probability appraisal procedure, and its particular content is: according to table 1 Transformer short-circuit tolerance check result, Transformer Operation Status and step down side configuring condition are arranged score, Give weight, quantify transformer short-circuit and damage risk probability F, and carry out classification.Formula (7) is that transformer short-circuit damages risk probability The computing formula of F:

F=A1 × 0.6+ (B1+B2+B3+B4+B5) × 0.2+ (C1+C2+C3) × 0.2 (7)

According to the result of calculation of formula (7), transformer short-circuit probability of damage F is divided into 5 ranks: first level, F >=80, It is low that transformer short-circuit damages risk；Second level, 70≤F ＜ 80, it is relatively low that transformer short-circuit damages risk；Third level, 55≤F ＜ 70, transformator faces certain Damage by Short Circuit risk, should take the precautionary measures；Fourth level, 35≤F ＜ 55, transformator is short Path loss bad risk is higher, should take comprehensive control measures；Fifth level, F ＜ 35 points, it is high that transformer short-circuit damages risk.

Table 1 transformer short-circuit damages risk factor score and weight

Beneficial effects of the present invention: transformer short-circuit tolerance, ruuning situation and low-pressure side are configured feelings by (1) present invention Condition is combined, and system have rated the Damage by Short Circuit risk probability of the transformator of operation all sidedly, solves current transformer and resists Short-circuit capacity is evaluated not comprehensive, a not difficult problem for system；

(2) parameters such as running environment, short circuit number of times and outlet short circuit are considered by the present invention, can Real-time and Dynamic Transformer short-circuit is damaged risk be estimated；

(3) present invention is applied widely, can enter the Damage by Short Circuit risk probability of the high-power transformer of various multi-forms Row is evaluated, and the probability factor affecting transformer short-circuit damage is the most all taken into account, so it can be suitably used for many by the method Plant the Damage by Short Circuit probability assessment of different electric pressure transformators；

(4) reliability of the present invention height, low cost, can calculate in real time by common computer, reduces hardware and puts into Cost；Decreasing the participation of staff, improve the operating error that work efficiency and minimizing personnel participate in bringing, improve can By property.

Detailed description of the invention

As a example by a main transformer Damage by Short Circuit in a certain case is evaluated below, the present invention is made further details of Explanation.

No. 2 main transformer calendar year 2001s of Hengshui produce, and transformer capacity is 180MVA, and rated voltage is 220/110/ 38.5kV。

Transformer short-circuit tolerance Z is checked, according to the method for the present invention according to transformator committee of Japan proposed algorithm Obtain the score of each factor quantity of state.

Factor A: obtain transformer short-circuit tolerance Z=1.13 according to transformator committee of Japan algorithm, be first grade, A1 score 20.

Factor B: had been subjected to once more than 70% short-circuit current rush, B1 score 30 through adding up it；Short-circuit impedance, around Group capacitance and frequency response test all show and are unsatisfactory for requirement, and B2, B3, B4 score is 0；Oil chromatogram analysis is defective, B5 score 0。

Factor C: one outlet of step down side, C1 score 10；Current-limiting reactor, C2 score 0 are not installed；Insulate Change, but still there is weak spot, C3 score 20.

Then, by formula (7) calculating transformer Damage by Short Circuit risk probability F:

F=A1 × 0.6+ (B1+B2+B3+B4+B5) × 0.2+ (C1+C2+C3) × 0.2

=20 × 0.6+30 × 0.2+ (10+20) × 0.2

=12+6+6

=24

From the point of view of judgment principle, by transformer short-circuit probability of damage F less than 35, belong to fifth level, i.e. transformer short-circuit Damage risk is high.Final result shows: i.e. there occurs damage after transformator short circuit.

Claims (3)

1. a high-power transformer Damage by Short Circuit risk probability appraisal procedure, it is characterised in that: by transformer short-circuit tolerance Check result, Transformer Operation Status and step down side configuring condition arrange score, give weight, quantify transformator short Path loss bad risk probability F, and carry out classification.

Appraisal procedure the most according to claim 1, it is characterised in that: comprise the steps of,

(I) quantify transformer short-circuit and damage risk probability F

According to table 1, transformer short-circuit tolerance check result, Transformer Operation Status and step down side are configured feelings Condition arranges score, gives weight, sets up transformer short-circuit and damages risk probability F calculating formula (7)；

F=A1 × 0.6+ (B1+B2+B3+B4+B5) × 0.2+ (C1+C2+C3) × 0.2 (7)

Check transformer short-circuit tolerance Z according to transformator committee of Japan proposed algorithm, determine A1's according to the value stepping of Z Score；

Table 1 transformer short-circuit damages risk factor score and weight

(II) transformer short-circuit obtained damage risk probability F is carried out classification

First level, F >=80；Second level, 70≤F ＜ 80；Third level, 55≤F ＜ 70；Fourth level, 35≤F ＜ 55； Fifth level, F ＜ 35.

Appraisal procedure the most according to claim 2, it is characterised in that according to following rule by resistance to for the transformer short-circuit obtained Stepping is carried out by ability Z:

First grade: Z≤1.2；Second gear: 1.2 ＜ Z≤1.7；Third gear: 1.7 ＜ Z≤2.1；Fourth speed: 2.1 ＜ Z≤10 it Between；Fifth speed: Z ＞ 10.