CN103454480A - Method for measuring and calculating transformer invading lightning voltage waveforms with transformer bushing - Google Patents

Abstract

The invention provides a method for measuring and calculating transformer invading lightning voltage waveforms with a transformer bushing. The method comprises the following steps: S1, according to the impulse withstand voltage test national standard, exerting lightning impact voltage waves on the transformer bushing same as a measured transformer in type in a testing room, and measuring waveforms i(t) of the current flowing through an end screen ground connection wire of the transformer bushing and lightning impact waveforms u(t) of the voltage exerted on the transformer bushing, S2, obtaining the transfer impedance of the transformer bushing, S3, recording the waveforms il(t) of the current measured by a current sensor and flowing through the end screen ground connection wire of the transformer bushing, and S4, calculating to obtain U1(jomega) according to the formula U1(jomega)=Z(jomega)*I1(jomega), and obtaining the invading lightning voltage waveforms u1(t) of the measured transformer according to the obtained U1(jomega). According to the method for measuring and calculating the transformer invading lightning voltage waveforms with the transformer bushing, the method that a self high-voltage bushing of the transformer is inversely pushed into the invading lightning voltage is used, the operation is simple, the method is easy to implement, the real amplitude and the real waveforms of the invading lightning voltage can be obtained, the accurate lightning prevention parameters are provided for the transformer, and the lightning prevention level of the transformer is improved.

Description

A kind of method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform

Technical field

The present invention relates to Transformer Substation Lightning Protection protection field, be specifically related to a kind of method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform.

Background technology

After lightning surge invasion transformer station, the lightning impulse voltage ripple that the waveform rising edge is very precipitous or section ripple caused because of lightning arrestor movement can produce huge electric potential gradient, the minor insulation of serious threat transformer on Transformer Winding.

Invade at present the prevention of lightning wave for the transformation station; mostly resting on over-voltage simulation calculates; device there are no invasion lightning voltage waveform on direct measuring transformer; thereby whether over-voltage simulation calculating is accurately unknown, the accuracy of transformer lightning protection and Insulation Coordination also just is difficult to ensure.

Summary of the invention

The present invention is directed to existing transformation station and invade in the prevention method of lightning wave the present situation of the means that there is no direct measuring transformer invasion thunder and lightning waveform, proposed a kind of method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform.The method is by comprising:

Step S1: on the bushing shell for transformer of laboratory and tested transformer same model, according to the impulse voltage withstand test national standard, described bushing shell for transformer is applied to the lightning impulse voltage ripple, measure and flow through the current waveform i (t) on described Transformer Bushing Tap ground wire and be applied to the thunderbolt High Voltage Impulse Waveform u (t) on sleeve pipe;

Step S2: the transfer impedance of asking for described bushing shell for transformer

Wherein U (j ω) and I (j ω) are respectively the Fourier transforms of u (t) and i (t);

Step S3: on the bottom shielding of bushing ground wire of tested transformer, current sensor is installed at the scene, when described tested transformer suffers lightning impulse voltage ripple when invasion, is recorded the current waveform i flow through on the bottom shielding of bushing ground wire that described current sensor measurement obtains ₁(t);

Step S4: according to formula U ₁(j ω)=Z (j ω) * I ₁(j ω) calculates U ₁(j ω), according to the U tried to achieve ₁(j ω) tries to achieve the invasion lightning voltage waveform u of described tested transformer ₁(t), U wherein ₁(j ω) and I ₁(j ω) is respectively u ₁and i (t) ₁(t) Fourier transform.

In the embodiment mono-of a kind of method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform provided by the invention: the device that described step S1 flows through the current waveform i (t) on described Transformer Bushing Tap ground wire and is applied to the thunderbolt High Voltage Impulse Waveform u (t) on described bushing shell for transformer in laboratory measurement comprises: impulse voltage generator, bushing shell for transformer and current sensor;

Described impulse voltage generator is connected with the guide rod top of described bushing shell for transformer, and described current sensor is nested on the end shield ground wire of described bushing shell for transformer.

A kind of beneficial effect of the method for bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform that utilizes provided by the invention comprises:

The anti-method of invading lightning voltage that pushes of bushing shell for transformer of utilizing provided by the invention, simple to operate, easy to implement, amplitude and the waveform of real reaction invasion lightning voltage, for transformer station provides lightning protection parameter more accurately, improve the lightning protection level of transformer station.

The accompanying drawing explanation

Be illustrated in figure 1 the structural drawing of embodiment of the device of a kind of measuring transformer sleeve pipe transfer impedance provided by the invention.

Embodiment

Below with reference to the accompanying drawings the specific embodiment of the present invention is described in further detail.

The invention provides a kind of method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform, comprising:

Step S1: on the bushing shell for transformer of laboratory and tested transformer same model, according to the impulse voltage withstand test national standard, it is applied to the lightning impulse voltage ripple, measure and flow through the current waveform i (t) on the Transformer Bushing Tap ground wire and be applied to the thunderbolt High Voltage Impulse Waveform u (t) on this bushing shell for transformer simultaneously.

Step S2: according to formula (1), utilize above-mentioned current waveform and voltage waveform to ask for the transfer impedance Z of this model sleeve pipe (j ω):

$Z\left(\mathrm{j\ω}\right)=\frac{U\left(\mathrm{j\ω}\right)}{I\left(\mathrm{j\ω}\right)}---\left(1\right)$

Wherein U (j ω) and I (j ω) are respectively the Fourier transforms of u (t) and i (t).

Step S3: on the bottom shielding of bushing ground wire of tested transformer, current sensor is installed at the scene.When this tested transformer suffers lightning impulse voltage ripple when invasion, record the current waveform i flow through on the bottom shielding of bushing ground wire that this current sensor measurement obtains ₁(t).

Step S4: according to formula (2), utilize the current waveform i monitored ₁(t) the lightning impulse voltage waveform u that the inverse transformer suffers ₁(t) u ₁(t).

U ₁(jω)＝Z(jω)*I ₁(jω) （2）

U wherein ₁(j ω) and I ₁(j ω) is respectively u ₁and i (t) ₁(t) Fourier transform, according to the U tried to achieve ₁(j ω) can be in the hope of the invasion lightning voltage waveform of tested transformer.

Further, be illustrated in figure 1 the structural drawing of the device embodiment of a kind of measuring transformer sleeve pipe transfer impedance provided by the invention.As shown in Figure 1, the embodiment of the device of this measuring transformer transfer impedance comprises impulse voltage generator (1), bushing shell for transformer (2) and current sensor (3).Impulse voltage generator (1) is connected with the guide rod top of bushing shell for transformer (3), and current sensor (3) is nested on the end shield ground wire of bushing shell for transformer (2).

In measuring process: impulse voltage generator (1) applies lightning impulse voltage to the guide rod top of bushing shell for transformer (2), with the electric current on current sensor (3) measuring transformer sleeve pipe (2) end shield ground connection, pass through again Fourier transform, can obtain the transfer impedance of this model bushing shell for transformer.

Under substation, utilize the electric current on current sensor (3) measuring transformer sleeve pipe (2) end shield ground connection, can instead push amplitude and the waveform of invading lightning voltage according to transfer impedance obtained above.

Finally should be noted that: above embodiment is only in order to illustrate that technical scheme of the present invention is not intended to limit, although with reference to above-described embodiment, the present invention is had been described in detail, those of ordinary skill in the field are to be understood that: still can modify or be equal to replacement the specific embodiment of the present invention, and do not break away from any modification of spirit and scope of the invention or be equal to replacement, it all should be encompassed in the middle of claim scope of the present invention.

Claims (2)

1. a method of utilizing bushing shell for transformer measuring and calculating transformer invasion lightning voltage waveform, is characterized in that, described method comprises:

Step S1: on the bushing shell for transformer of laboratory and tested transformer same model, according to the impulse voltage withstand test national standard, described bushing shell for transformer is applied to the lightning impulse voltage ripple, measure and flow through the current waveform i (t) on described Transformer Bushing Tap ground wire and be applied to the thunderbolt High Voltage Impulse Waveform u (t) on sleeve pipe;

Step S2: the transfer impedance of asking for described bushing shell for transformer

Wherein U (j ω) and I (j ω) are respectively the Fourier transforms of u (t) and i (t);

Step S3: on the bottom shielding of bushing ground wire of tested transformer, current sensor is installed at the scene, when described tested transformer suffers lightning impulse voltage ripple when invasion, is recorded the current waveform i flow through on the bottom shielding of bushing ground wire that described current sensor measurement obtains ₁(t);

Step S4: according to formula U ₁(j ω)=Z (j ω) * I ₁(j ω) calculates U ₁(j ω), according to the U tried to achieve ₁(j ω) tries to achieve the invasion lightning voltage waveform u of described tested transformer ₁(t), U wherein ₁(j ω) and I ₁(j ω) is respectively u ₁and i (t) ₁(t) Fourier transform.

2. the method for claim 1, it is characterized in that, the device that described step S1 flows through the current waveform i (t) on described Transformer Bushing Tap ground wire and is applied to the thunderbolt High Voltage Impulse Waveform u (t) on described bushing shell for transformer in laboratory measurement comprises: impulse voltage generator, bushing shell for transformer and current sensor;

Described impulse voltage generator is connected with the guide rod top of described bushing shell for transformer, and described current sensor is nested on the end shield ground wire of described bushing shell for transformer.

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