CN106199349A - Partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio - Google Patents

Abstract

Invention relates to a kind of partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio, and its technical characteristics is: from transformer high-voltage, middle pressure and low pressure by bottom shielding of bushing or coupling capacitor extraction partial discharge test signal；Side each to transformator carries out square wave calibration, calculates and record the transmission ratio between the signal of each side；When partial discharge quantity exceedes calibration limit value in partial discharge test reaches test voltage or process of the test, record high pressure, middle pressure, the local discharge signal measured value of low pressure；Obtain the actual shelf depreciation value of each side of transformator；Exclude the interference signal according to each side shelf depreciation value.Disturb signal and local discharge characteristics and the arbitration functions quick, effective, convenient, reliable of position during present invention achieves transformer field partial discharge test, during solving transformer field partial discharge test, disturb signal and local discharge characteristics and the decision problem of position.

Description

Partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio

Technical field

Invention belongs to existing partial discharge of transformer technical field, a kind of change based on calibration square-wave signal transmission ratio Depressor shelf depreciation region decision method.

Background technology

Transformer field partial discharge test is can to reflect the insulation status of transformator in advance, in finding transformator in time The insulation defect in portion, is dispatched from the factory at equipment, joins, is both needed to be examined transformer insulating system by this test after overhaul.But It is that, during on-the-spot test, the transformator each side shelf depreciation value shown by Partial discharge detector often cannot effectively be divided Precipitation is the interference of low pressure test (LPT) system, high pressure, middle pressure, low-pressure side electric discharge, or real local discharge signal, say, that The region measuring the local discharge signal obtained cannot be determined.This directly affects the judgement of testing crew, even causes local to put The erroneous judgement of electricity.

Summary of the invention

It is an object of the invention to overcome the deficiencies in the prior art, it is provided that a kind of change based on calibration square-wave signal transmission ratio Depressor shelf depreciation region decision method, disturbs signal and shelf depreciation during solving transformer field partial discharge test Character and the decision problem of position.

The present invention solves it and technical problem is that and take techniques below scheme to realize:

A kind of partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio, comprises the following steps:

Step 1, when carrying out transformer field shelf depreciation wiring, pass through from transformer high-voltage, middle pressure and low pressure respectively Bottom shielding of bushing or coupling capacitor extraction partial discharge test signal；

Step 2, side each to transformator carry out square wave calibration, calculate and record the transmission ratio between the signal of each side；

Step 3: when partial discharge quantity exceedes calibration limit value in partial discharge test reaches test voltage or process of the test, Record high pressure, middle pressure, the local discharge signal measured value P of low pressure₁、P₂、P₃；

Step 4, by solving ternary linear function, the actual shelf depreciation value of each side of transformator can be obtained；

Step 5, according to each side shelf depreciation value, local region of discharge is judged, excludes the interference signal.

The implementation method of described step 2 is: after square-wave signal is injected in high-pressure side, pressure and the square wave of low pressure in reading simultaneously Signal level, records the ratio P of high pressure and middle pressure square-wave signal_1-2Ratio P with high pressure with low pressure square-wave signal_1-3；In middle pressure and low Pressure is injected separately into square-wave signal, it is thus achieved that the ratio P of middle pressure and high-voltage square wave signal_2-1, the ratio P of middle pressure and low pressure square-wave signal_2-3, low Press the ratio P with high-voltage square wave signal_3-1, the ratio P of low pressure and middle pressure square-wave signal_3-2。

The computational methods of described step 4 are:

$\left\{\begin{array}{c}{P}_1=P_X+P_Y/P_{2-1}+P_Z/P_{3-1}\\ P_2=P_X/P_{1-2}+P_Y+P_Z/P_{3-2}\\ P_3=P_X/P_{1-3}+P_Y/P_{2-3}+P_Z\end{array}\right.$

Wherein, P_X、P_Y、P_ZIt is respectively the actual shelf depreciation value of each side of transformator.

Invention advantage and good effect be:

Signal and local discharge characteristics and position is disturbed during present invention achieves transformer field partial discharge test Arbitration functions quick, effective, convenient, reliable, solve disturb during transformer field partial discharge test signal and Shelf depreciation character and the decision problem of position, can effectively assist on-the-spot testing crew to improve the accurate of partial discharge test analysis Property.

Accompanying drawing explanation

Fig. 1 is the process chart of invention.

Detailed description of the invention

Below in conjunction with accompanying drawing, inventive embodiments is further described:

A kind of partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio, as it is shown in figure 1, include Following steps:

Step 1, when carrying out transformer field shelf depreciation wiring, pass through from transformer high-voltage, middle pressure and low pressure respectively Bottom shielding of bushing or coupling capacitor extraction partial discharge test signal.

Process require that each side of transformator possesses by end shield and the condition of coupling capacitor extraction signal.This step, needs Will be from transformer high-voltage, middle pressure and low pressure by bottom shielding of bushing or coupling capacitor extraction partial discharge test signal.

Step 2, carry out square wave timing in side each to transformator, after square-wave signal is injected in high-pressure side, in reading simultaneously Pressure and the square-wave signal level of low pressure, record the ratio P of high pressure and middle pressure square-wave signal_1-2Ratio with high pressure with low pressure square-wave signal P_1-3, same, it is injected separately into square-wave signal in middle pressure and low pressure, it is thus achieved that the ratio P of middle pressure and high-voltage square wave signal_2-1, middle pressure with The ratio P of low pressure square-wave signal_2-3, the ratio P of low pressure and high-voltage square wave signal_3-1, the ratio P of low pressure and middle pressure square-wave signal_3-2。

Step 3: when partial discharge quantity exceedes calibration limit value in partial discharge test reaches test voltage or process of the test, Record high pressure, middle pressure, the local discharge signal measured value P of low pressure₁、P₂、P₃。

Step 4, by solving ternary linear function, the actual shelf depreciation value P of each side of transformator can be obtained_X、P_Y、 P_Z, computing formula is as follows:

$\left\{\begin{array}{c}{P}_1=P_X+P_Y/P_{2-1}+P_Z/P_{3-1}\\ P_2=P_X/P_{1-2}+P_Y+P_Z/P_{3-2}\\ P_3=P_X/P_{1-3}+P_Y/P_{2-3}+P_Z\end{array}\right.$

Step 5, according to each side shelf depreciation value, local region of discharge is judged, excludes the interference signal.

Actual shelf depreciation value according to each side of transformator just can tentatively judge the fundamental region that shelf depreciation occurs, Such as when local discharge signal is derived only from the interference of step down side pilot system, the transformator obtained by calculating is high The actual partial discharge quantity of pressure and middle pressure will be close to background value, and low-pressure side partial discharge quantity will be close to signal measurements.

If it should be noted that the excessive shelf depreciation value that will flood reality of partial discharge test background and then impact The effectiveness of this method, therefore, should control level of background signal well during on-the-spot test.Additionally, the signal used by this method calculating Transmit than relation by winding line end inject square wave calibration signal obtain, therefore, once shelf depreciation do not occur around In group, the deviation that actual signal transmission in transformator each side is more certain than having, but be not sufficient to impact and local region of discharge is sentenced Disconnected.

It is emphasized that the embodiment described in invention is illustrative rather than determinate, therefore invention includes also It is not limited to the embodiment described in detailed description of the invention, every is drawn according to the technical scheme of invention by those skilled in the art Other embodiments, also belong to the scope of invention protection.

Claims (3)

1. one kind based on calibration square-wave signal transmission ratio partial discharge of transformer region decision method, it is characterised in that include with Lower step:

Step 1, when carrying out transformer field shelf depreciation wiring, pass through sleeve pipe from transformer high-voltage, middle pressure and low pressure respectively End shield or coupling capacitor extraction partial discharge test signal；

Step 2, side each to transformator carry out square wave calibration, calculate and record the transmission ratio between the signal of each side；

Step 3: when partial discharge quantity exceedes calibration limit value in partial discharge test reaches test voltage or process of the test, record High pressure, middle pressure, the local discharge signal measured value P of low pressure₁、P₂、P₃；

Step 4, by solving ternary linear function, the actual shelf depreciation value of each side of transformator can be obtained；

Step 5, according to each side shelf depreciation value, local region of discharge is judged, excludes the interference signal.

Partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio the most according to claim 1, It is characterized in that: the implementation method of described step 2 is: after square-wave signal is injected in high-pressure side, pressure and low pressure in reading simultaneously Square-wave signal level, records the ratio P of high pressure and middle pressure square-wave signal_1-2Ratio P with high pressure with low pressure square-wave signal_1-3；In middle pressure It is injected separately into square-wave signal, it is thus achieved that the ratio P of middle pressure and high-voltage square wave signal with low pressure_2-1, the ratio of middle pressure and low pressure square-wave signal P_2-3, the ratio P of low pressure and high-voltage square wave signal_3-1, the ratio P of low pressure and middle pressure square-wave signal_3-2。

Partial discharge of transformer region decision method based on calibration square-wave signal transmission ratio the most according to claim 2, It is characterized in that: the computational methods of described step 4 are:

$\left\{\begin{array}{c}{P}_1=P_X+P_Y/P_{2-1}+P_Z/P_{3-1}\\ P_2=P_X/P_{1-2}+P_Y+P_Z/P_{3-2}\\ P_3=P_X/P_{1-3}+P_Y/P_{2-3}+P_Z\end{array}\right.$

Wherein, P_X、P_Y、P_ZIt is respectively the actual shelf depreciation value of each side of transformator.