CN102135585A - Method for precisely positioning turn-to-turn short circuit fault point of rotor of large turbo-generator - Google Patents

Abstract

The invention relates to a method for precisely positioning a turn-to-turn short circuit fault point of a rotor of a large turbo-generator, which comprises the following steps: 1) performing a voltage distribution test on a rotor winding, and determining that a turn-to-turn short circuit fault is happened between which two turns of which coil; 2) finding two turns of the coils, which are symmetrical to the two turns with turn-to-turn short circuit in the other pole according to symmetry of two poles of windings; 3) finding two public potential points on two magnetic poles respectively, wherein the two potential points have the symmetrical relationship, that is the voltage absolute values are equivalent, and the directions are opposite; 4) imposing a direct current test on the rotor winding; 5) finding a certain section of region on the two turns with the fault from the public potential points along the current flow direction, wherein the voltage values in the region are equivalent; 6) measuring the voltage value in the symmetrical position of the other magnetic pole; 7) calculating the voltage difference between the two magnetic poles in the symmetrical positions; and 8) calculating the voltage drop of the rotor winding on unit length, and converting the voltage different value to the corresponding length, that is positioning the turn-to-turn short circuit fault point.

Description

The rotor of large turbo-type generator shorted-turn fault is put pinpoint method

Technical field

The present invention relates to a kind of rotor of large turbo-type generator shorted-turn fault and put pinpoint method.

Background technology

For the short Fault Diagnosis of rotor of large turbo-type generator circle, often just only limited to judge qualitatively whether rotor exists the short fault of circle to get final product, and is exactly then to return to handle after factory disintegrates in the past.But because the short fault of circle occurs in the different parts of rotor, its processing scheme and processing cost just may have very big difference, if the concrete position of the localization of faults in advance, the cost that just might cost a lot of money is handled, waste great amount of manpower and material resources and financial resources cause enormous economic loss.In addition, if the position of the localization of faults in advance just makes power plant be difficult to formulate scientifically and rationally, targetedly follow-up programme of work.

But there is not the rotor of large turbo-type generator shorted-turn fault to put pinpoint method so far.

Goal of the invention

Purpose of the present invention just provides and a kind ofly can carry out pinpoint method to rotor of large turbo-type generator shorted-turn fault point, carries out according to the following steps successively:

(9) carry out rotor winding voltage distribution test, determine that shorted-turn fault occurs in (this is prior art) between which two circle of which coil;

(10), find the two circle coils symmetrical in extremely with two circles of turn-to-turn short circuit at another according to the symmetry of the two poles of the earth winding;

(11) respectively look for a common electrical site on two magnetic poles, should there be the relation of symmetry in these two common electrical sites, and promptly absolute value of voltage equates, direction is opposite;

(12) the rotor winding is applied the DC current test;

(13) on fault two circles, from the common electrical site, the direction along electric current flows finds a certain section zone, and the magnitude of voltage in this zone equates that the variation with position in this zone changes hardly;

(14) measure the magnitude of voltage of another magnetic pole symmetric position;

(15) calculate the voltage difference of two magnetic poles in above-mentioned symmetric position;

(16) calculate voltage drop on this rotor winding unit length, and above-mentioned voltage difference is converted to corresponding length, can navigate to the shorted-turn fault point.

Beneficial effect: for the rotor of large turbo-type generator shorted-turn fault, the concrete position of the energy localization of faults in advance, just might handle the short fault of circle well, thereby save great amount of manpower and material resources and financial resources, retrieve enormous economic loss with very little cost.In addition, the short fault of circle occurs in the different parts of rotor, and its processing scheme and processing cost just may have very big difference.If the position of the localization of faults in advance just can make power plant can formulate follow-up programme of work scientifically and rationally, targetedly.For example, the 2# generator amature of ZH power plant, because the singularity of its rotor structure, if the short point of circle is positioned at rotor and encourages end, dealing with so is exactly one " minor operation ", if be in rotor vapour end, dealing with so will be one " major operation ", its disintegration operation, required spare part etc. all can quite bother, and entire process duration almost twice is positioned at the situation of encouraging end in the short point of circle.At this moment, grasp the short particular location of putting of its circle in advance and just seem particularly important.

Description of drawings

The present invention is described in further detail below in conjunction with the drawings and specific embodiments.

Fig. 1 is the accurate positioning analysis synoptic diagram of shorted-turn fault point;

Fig. 2 is the form in rotor ventilation hole;

Fig. 3 is the utmost point 1 winding 3# coil of application example and the voltage distribution situation synoptic diagram of each circle line rod of 3# coil below air vent of the utmost point 2 windings;

Embodiment

The present invention can carry out pinpoint method to rotor of large turbo-type generator shorted-turn fault point, and concrete implementation step is undertaken by following successively:

(1) at first carries out rotor winding voltage distribution test, determine shorted-turn fault occurs between which two circle of which coil;

(2), find the two circle coils symmetrical in extremely with two circles of turn-to-turn short circuit at another according to the symmetry of the two poles of the earth winding;

(3) respectively look for a common electrical site on two magnetic poles, these two potential points should have the relation of symmetry, and promptly absolute value of voltage equates, direction is opposite;

(4) the rotor winding is applied the DC current test;

(5) on fault two circles, from the common electrical site, the direction along electric current flows finds a certain section zone, and the magnitude of voltage in this zone equates, changes with moving of position in this zone hardly;

(6) measure the magnitude of voltage of another magnetic pole symmetric position;

(7) calculate the voltage difference of two magnetic poles in above-mentioned symmetric position;

(8) calculate voltage drop on this rotor winding unit length, and above-mentioned voltage difference is converted to corresponding length, can navigate to the shorted-turn fault point.

Illustrate with Fig. 1.Fig. 1 is the coil of two symmetries, the 3# coil of the utmost point 1 winding that the left side is, the right be the 3# coil of the utmost point 2 windings.

Suppose in advance and to determine on the 3# coil of turn-to-turn short circuit point in the utmost point 1 winding by the winding voltage distribution test, and between the 5# on 3# coil right side and 6# circle turn-to-turn short circuit has taken place, short dot is at A ₁C ₁The place, and the 3# coil of the utmost point 2 does not have shorted-turn fault.Then, two slip rings by rotor inject constant DC stream, because DC current when winding circulates, can not produce the magnetic flux of alternation, therefore, the voltage of whole rotor winding distributes only relevant with its direct current resistance (length in other words).

On the utmost point 1 and the utmost point 2, respectively look for a common electrical site, as the some O on the 3# coil of the utmost point among the figure 1 ₁Some O with the 3# coil of the utmost point 2 ₂, and O ₁And O ₂Be the symmetric points on the two poles of the earth.For the 3# coil of the utmost point 1, electric current is from O ₁Flow into and arrive A ₁C ₁During short dot, direction is flow through in change, no longer forward, continue in the 5# line rod to flow forward but be transferred in advance along 6# line rod.Therefore, A ₁B ₁C ₁The line rod of section is fallen by short circuit, and it is constant that the magnitude of voltage of this part line rod keeps substantially, and equal A ₁C ₁The voltage of short-circuit point.And for the 3# coil of the utmost point 2, the A of the same area ₂B ₂C ₂Voltage then distribute by normal rule.

Owing to the A that is fallen by short circuit ₁B ₁C ₁Therefore the zone is generally all long, is easy to just can find a bit of in this zone.In this is a bit of, appoint and get 1 P ₁, measure P ₁The voltage of point is made as U ₁, in the 3# of the utmost point 2 coil, find P again ₁Symmetric points P ₂, measure P ₂The voltage of point is made as U ₂, then voltage difference between the two is

ΔU＝U ₂-U ₁ (6-1)

The voltage drop of the 6# circle of 3# coil of measuring the utmost point 2 again after around a circle, i.e. B ₂, O ₂Voltage between 2 is made as U, measures the girth of rotor 6# circle again, is made as L, and then serving as reasons apart from l between P1 and the A1 simply calculated by following formula:

$l=\frac{\mathrm{\ΔU}}{U}\×L=\frac{U_2-U_1}{U}\×L---(6-2)$

Can navigate to the shorted-turn fault point thus.

Application example

In the positioning analysis of the 2# of ZH power plant generator amature shorted-turn fault point, but adopt a kind of so very simple cleverly method exactly, located the shorted-turn fault point soon.Be described in detail below.

The 2# generator amature adopts semiaxis to the aeration structure form, and all there are 12 air vents the left and right sides of each coil, and these 12 logical sees that the hole is positioned at the rotor body middle part.

The air vent in left side be from vapour blow side into the hydrogen air outlet opening, the air vent on right side is from encouraging the hydrogen air outlet opening that side-blown is gone into.Therefore the ventilation of certain circle line rod separately that each air vent is all corresponding, can arrive the magnitude of voltage of corresponding circle line rod with probe measurement at these air vent places.For example, the the 1st, the 2nd air vent on the 3rd row right side the is corresponding respectively from top to bottom utmost point 1 winding 3# coil is by the 6# that encourages side, the ventilation of 5# circle line rod, the the 1st, 2 air vent in left side is the then corresponding utmost point 1 winding 3# coil is so analogized by the 6# that encourages side, the ventilation of 5# circle line rod.The inner structure of this ventilation form as shown in Figure 2.

By these air vents, probe can be inserted into the bottom, measure the voltage of each circle line rod of 3# coil of the utmost point 1 winding or the utmost point 2 windings, its voltage distributes as shown in Figure 3.

In left figure, check along clockwise direction from the beginning of O1 point, then check along counter clockwise direction that from the beginning of O2 point relatively the voltage insulation value of both each points begins to occur evident difference wherein among the right figure.Obviously, left figure is when first air vent of 5# coil that walks to the left side and right figure when walking to first air vent of 5# coil on right side, and both voltage occurs significantly different.The former voltage is 25.3V, and the latter's voltage is 32.1V, and both voltage is 6.8V.From right figure as seen, walk to first air vent of 5# coil from first air vent of the 6# coil on right side, the voltage of a promptly whole circle is reduced to (32.1-5.9) V=26.2V, and the length of whole winding is 15m, therefore, the pairing length of 6.8V can be calculated as follows into

$\frac{6.8}{26.2}\×15m=3.89m$

That is to say, from left figure the left side the 5# coil first air vent back (counterclockwise) walk 3.89 meters, be exactly the trouble spot of rotor inter-turn short circuit, the S point among the promptly left figure.

According to above-mentioned analysis, the 2# generator amature return factory pull out encourage the side retaining ring after (this fashion do not disintegrate rotor bar), just directly check the corner between 5#～6# circle with the inspection mirror, really find to have one to melt the copper ashes of formation because of overheat short circuit burns herein, its trouble location and above-mentioned positioning analysis fit like a glove.After this copper ashes removing, phenomenon of the failure is eliminated immediately.

Claims (1)

1. the rotor of large turbo-type generator shorted-turn fault is put pinpoint method, carries out according to the following steps successively:

(1) carries out rotor winding voltage distribution test, determine shorted-turn fault occurs between which two circle of which coil;

(2), find the two circle coils symmetrical in extremely with two circles of turn-to-turn short circuit at another according to the symmetry of the two poles of the earth winding;

(3) respectively look for a common electrical site on two magnetic poles, should there be the relation of symmetry in these two common electrical sites: promptly absolute value of voltage equates, direction is opposite;

(4) the rotor winding is applied the DC current test;

(5) on fault two circles, from the common electrical site, the direction along electric current flows finds a certain section zone, and the magnitude of voltage in this zone equates, changes with moving of position in this zone hardly;

(6) measure the magnitude of voltage of another magnetic pole symmetric position;

(7) calculate the voltage difference of two magnetic poles in above-mentioned symmetric position;

(8) calculate voltage drop on this rotor winding unit length, and above-mentioned voltage difference is converted to corresponding length, can navigate to the shorted-turn fault point.

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