CN202267732U

CN202267732U - Device for online detection of transformer bushing

Info

Publication number: CN202267732U
Application number: CN2011203545204U
Authority: CN
Inventors: 周长莒; 张国栋; 刘家�; 王启敏; 赵玉晓
Original assignee: SHANDONG WUYUE ELECTRICAL APPLIANCES CO Ltd
Current assignee: SHANDONG WUYUE ELECTRICAL APPLIANCES CO Ltd
Priority date: 2011-09-21
Filing date: 2011-09-21
Publication date: 2012-06-06
Anticipated expiration: 2021-09-21

Abstract

This utility model discloses a device for the online detection of a transformer bushing, which comprises a current sensor (1), an output terminal (2) of PT (Potential Transformer) secondary voltage, a measuring circuit (3), a control device (4) and a display (5), wherein the current sensor (1) is arranged on a bushing; the current sensor (1) and the output terminal (2) of PT secondary voltage are connected with the input end of the measuring circuit (3) respectively; the output end of the measuring circuit (3) is connected with the input end of the control device (4); the output end of the control device (4) is connected with the display (5); and the control device (4) is provided with a printing interface, a keyboard interface and a communication interface, thus the safety performance of transformer is improved.

Description

The device of online detection bushing shell for transformer

One, technical field

The utility model relates to a kind of device of online detection bushing shell for transformer, and especially a kind of adaptation is used for the device of the online detection bushing shell for transformer of big-and-middle-sized transformer.

Two, background technology

Insulating property for the HV Terminal that guarantees transformer; Usually need be on HV Terminal mounting sleeve; Therefore sleeve pipe is the vitals that guarantees transformer performance; The high-pressure side sleeve pipe of transformer is subject to high dielectric influence simultaneously, and high-pressure side sleeve pipe fault is one of principal element that causes compelled stoppage in transit and transformer fault, and some researchs show that the sleeve pipe fault accounts for 40% of transformer fault.Data show that also 52% sleeve pipe fault is very serious, can cause that promptly getting angry calamity causes indirect hazard; The modal two kinds of faults of bushing shell for transformer are that moisture immerses and inner shelf depreciation causes; Moisture can be through the gasket materials of corrosion, and crack and loosening terminal get into sleeve pipe; Moisture can cause that therefore the increase of decreasing that is situated between causes power factor to increase; Cover pipe insulation situation continued worsens, and can cause the capacitor layers fault, develops into the fault of whole sleeve pipe then, and it is an important link that guarantees the transformer security performance that bushing shell for transformer is carried out online detection.The method of surveying the sleeve pipe degradation of insulation is traditional off-line test that we know, and the 10kV off-line test that carries out under the normal temperature needs long test interval and needs suspension to have a power failure; Conventional On-line Measuring Method is through after the bottom shielding of bushing electric current is drawn; Cable is passed current transformer; Through measuring secondary side current; Calculating convert into once survey analyze behind the electric current, associative operation such as calculating owing to directly the data of gathering are analyzed, not high to the accuracy of detection of sleeve pipe.

Three, summary of the invention

In order to overcome above-mentioned technical disadvantages, the purpose of the utility model provides a kind of device of online detection bushing shell for transformer, has therefore improved the security performance of transformer.

For achieving the above object; The technical scheme that the utility model is taked is: the lead-out terminal, metering circuit, control device and the display that include current sensor, PT secondary voltage; Current sensor is arranged on the sleeve pipe; The lead-out terminal of current sensor and PT secondary voltage is set to respectively be connected with the input end of metering circuit; The output terminal of metering circuit is set to be connected with the input end of control device, and the output terminal of control device is set to be connected with display, and control device is provided with printing interface, keyboard interface and communication interface.

The technique effect of the utility model is: because the current signal that passes through sleeve pipe that has designed gathering carries out Treatment Analysis; The variation of difference DELTA I through monitoring electric capacity I and the difference DELTA tan δ of angular difference tan δ; Judge the insulating property of sleeve pipe; Variation size according to the difference DELTA tan δ of the angular difference tan δ of angular difference tan δ k then and 1 year has improved the precision of monitoring, has therefore improved the security performance of transformer.

Four, description of drawings

Fig. 1 is the structural representation of the utility model:

Fig. 2 is an equivalent circuit diagram.

Five, embodiment

Accompanying drawing is an embodiment of the utility model; Specify present embodiment in conjunction with accompanying drawing; The lead-out terminal 2, metering circuit 3, control device 4 and the display 5 that include current sensor 1, PT secondary voltage; Current sensor 1 is arranged on the sleeve pipe, and the lead-out terminal 2 of current sensor 1 and PT secondary voltage is set to respectively be connected with the input end of metering circuit 3, and the output terminal of metering circuit 3 is set to be connected with the input end of control device 4; The output terminal of control device 4 is set to be connected with display 5, and control device 4 is provided with printing interface, keyboard interface and communication interface.

Current sensor 1 is transferred to the current signal through sleeve pipe in the metering circuit 3, and bus voltage signal is transferred in the metering circuit 3 through the lead-out terminal 2 of PT secondary voltage, in metering circuit 3; Filter interference through Fourier transform; Isolate the signal first-harmonic, voltage detection signal and current detection signal carried out vector calculus, to the amplitude of the electric current through sleeve pipe calculate electric capacity I, angular difference calculate tan δ; Through vector and the end screen current value that calculates the three-phase sleeve pipe, calculate Δ I; Store the current signal that passes through sleeve pipe more than 3 years; Calculate the tan δ of every day respectively, Japan-China together to the same month, calculate the Δ tan δ 2 in 1 year; The difference of the tan δ 2 in promptly 1 year and the tan δ 1 in 1 year is exactly Δ tan δ 2; Calculate the Δ tan δ 3 in the 3rd year, promptly the difference of the tan δ 1 of the tan δ 3 in the 3rd year and 1 year is exactly Δ tan δ 3, can calculate the Δ tan δ 4 in the 4th year equally, calculate the Δ tan δ k of k; When the 0.1mA≤Δ I, send the alerting signal that breaks down through control device 4.To the same month on the same day, the deviate between Δ tan δ and the Δ tan δ several years ago relatively, when deviate greater than 0.3 the time, send the alerting signal that breaks down.

The method of application of present embodiment the steps include:

A, current acquisition device 1 is installed on the position of bottom shielding of bushing cover; Be connected the lead-out terminal 2 of current acquisition device 1 and PT secondary voltage with metering circuit 3; The voltage of lead-out terminal 2 outputs of PT secondary voltage is identical with the phase place of bus high pressure; Three current acquisition devices 1 are measured A last mutually screen electric current of end screen electric current, B and the last mutually screen electric current of C mutually respectively, and the lead-out terminal 2 of PT secondary voltage is set to export A phase PT voltage, B phase PT voltage and C PT voltage mutually;

B, metering circuit 3 gathers A end screen electric current, B end screen electric current and the C end screen electric current mutually mutually mutually through the bottom shielding of bushing cover, utilizes vector calculation method, promptly A mutually end screen electric current, B mutually end screen electric current and C mutually end screen electric current carry out vector and calculate and electric current Δ I;

C, to the A of bottom shielding of bushing cover end screen electric current mutually, be reference voltage with A phase PT voltage, metering circuit 3 filters interference through Fourier transform; Isolate the signal first-harmonic, voltage detection signal and current detection signal are carried out vector calculus, the A of sleeve end screen cover end screen electric current I a mutually resolves into horizontal component Ira and vertical component Ica; Promptly according to C=2 π fUa, electric capacity C is the capacitance of sleeve pipe, f is set to=50HZ; Voltage U a is set to A phase PT magnitude of voltage, confirms the Ica value, again according to funtcional relationship; Shield electric current I a in the end mutually through A; Calculate Ira, according to dielectric dissipation factor tan δ A=(Ica) * 100%, thereby calculate dielectric dissipation factor tan δ A;

To the B of bottom shielding of bushing cover end screen electric current mutually, be reference voltage with B phase PT voltage, metering circuit 3 filters interference through Fourier transform; Isolate the signal first-harmonic, voltage detection signal and current detection signal are carried out vector calculus, the B of sleeve end screen cover end screen current Ib mutually resolves into horizontal component Irb and vertical component Icb; Promptly according to C=2 π fUb, electric capacity C is the capacitance of sleeve pipe, f is set to=50HZ; Voltage U b is set to B phase PT magnitude of voltage, confirms the Icb value, again according to funtcional relationship; Shield current Ib in the end mutually through B; Calculate Irb, according to dielectric dissipation factor tan δ B=(Icb) * 100%, thereby calculate dielectric dissipation factor tan δ B;

To the C of bottom shielding of bushing cover end screen electric current mutually, be reference voltage with C phase PT voltage, metering circuit 3 filters interference through Fourier transform; Isolate the signal first-harmonic, voltage detection signal and current detection signal are carried out vector calculus, the C of sleeve end screen cover end screen electric current I c mutually resolves into horizontal component Irc and vertical component Icc; Promptly according to C=2 π fUc, electric capacity C is the capacitance of sleeve pipe, f is set to=50HZ; Voltage U c is set to C phase PT magnitude of voltage, confirms the Icc value, again according to funtcional relationship; Shield electric current I c in the end mutually through C; Calculate Irc, according to dielectric dissipation factor tan δ C=(Icc) * 100%, thereby calculate dielectric dissipation factor tan δ C;

D, the current signal that pass through sleeve pipe of storage more than 3 years; Calculate tan δ A, tan δ B and the tan δ C of every day respectively; To tan δ A, tan δ B and the tan δ C of each, Japan-China together to the same month respectively, calculate the Δ tan δ 2 in 1 year; The difference of the tan δ 2 in promptly 1 year and the tan δ 1 in 1 year is exactly Δ tan δ 2; Calculate the Δ tan δ 3 in the 3rd year, promptly the difference of the tan δ 1 of the tan δ 3 in the 3rd year and 1 year is exactly Δ tan δ 3, can calculate the Δ tan δ 4 in the 4th year equally, calculate the Δ tan δ k of k;

E, through control device 4, as Δ I during, send the alerting signal that breaks down more than or equal to 0.1mA; To the same month on the same day, relatively the deviate between Δ tan δ and the Δ tan δ several years ago when deviate is worth greater than 0.3, is sent the alerting signal that breaks down.

In every day, can repeatedly gather current signal and bus high-voltage signal through sleeve pipe, repeatedly calculate through step B.

In the Casing Detection of existing transformer, all be directly to detect the parameter of transformer, through the big or small variation of the value of parameter itself through sleeve pipe; Carry out the judgement of sleeve pipe insulating property, do not consider the influence of the running environment factor of transformer, in the actual motion of transformer; Particularly the insulating property of sleeve pipe and environmental factor have very big relation, and my company is the intelligent artifact of professional production transformer, when the transformer security performance is investigated; Find how to be associated the parameter of the insulating property that detect sleeve pipe with transformer running environment factor; Thereby improve the precision to the insulating property detection of sleeve pipe, guarantee the security of transformer better, this scientific research project we and Wuhan Water Conservancy and Electric Power Univ unite tackles key problems; The design of the technical scheme through the utility model; Difference monitoring through angular difference tan δ over the years combines the environmental factor of transformer with the insulating property of sleeve pipe, solved the technical matters of the utility model.

The characteristics of the utlity model has down:

1, because the current signal that passes through sleeve pipe that has designed gathering carries out Treatment Analysis; The variation of difference DELTA I through monitoring electric capacity I and the difference DELTA tan δ of angular difference tan δ; Judge the insulating property of sleeve pipe; Variation size according to the difference DELTA tan δ k of the angular difference tan δ of angular difference tan δ k then and 1 year has improved the precision of monitoring, has therefore improved the security performance of transformer.

2, owing to designed difference DELTA tan δ k, take into full account the running environment of transformer, realized the transformer unicity ground monitoring under the varying environment, more guaranteed the security performance of the transformer under the varying environment.

3, owing to designed lead-out terminal 2, metering circuit 3, control device 4 and the display 5 of current sensor 1, PT secondary voltage, various module performances are stable, and reliability is high.

4, the sleeve pipe insulation line monitoring device can not only real time on-line monitoring bushing shell for transformer insulation status; And can when cover pipe insulation outlet problem, can in time report to the police; Avoid the generation of sleeve pipe fault and transformer fault; Be the guarantee that provides of transformer, avoided because of the sleeve pipe accident cause directly and the indirect loss that causes of interruption maintenance.

But 5, sleeve pipe insulation line monitoring device real time on-line monitoring sleeve pipe Jie damage, electric capacity and end screen current value.Test data under all weather, load and the voltage conditions can be provided, and have the sensitivity same with off-line measurement; Acquired signal is carried out the calculating and the comparison of several different methods, ensure the reliability of output result and warning.

The foregoing description is a kind of way of realization of the device of the online detection bushing shell for transformer that provides of the utility model; Other distortion according to the scheme that the utility model provided; Increase or reduce step wherein; The technical field approaching with the utility model that perhaps the utility model is used for other all belongs to the protection domain of the utility model.

Claims

1. the device of an online detection bushing shell for transformer; It is characterized in that: the lead-out terminal (2), metering circuit (3), control device (4) and the display (5) that include current sensor (1), PT secondary voltage; Current sensor (1) is arranged on the sleeve pipe; The lead-out terminal (2) of current sensor (1) and PT secondary voltage is set to respectively be connected with the input end of metering circuit (3); The output terminal of metering circuit (3) is set to be connected with the input end of control device (4); The output terminal of control device (4) is set to be connected with display (5), and control device (4) is provided with printing interface, keyboard interface and communication interface.