JPH0820484B2 - Partial discharge detection device for electrical equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a partial discharge detection device for an electric device, and more particularly, to an internal partial discharge of an electric device in which an electric device main body is housed in a tank to detect a discharge occurrence position. The present invention relates to a partial discharge detection device for locating.

[Prior Art] FIG. 4 is a block diagram showing a conventional partial discharge detection device. In FIG. 4, (1) shows a tank for housing a main body of an electric device such as a transformer or a reactor, for example, an oil tank.
(2) is a bushing provided on the upper part of the tank (1), (3) is connected to the bushing (2), an electric pulse detector for detecting an electric pulse generated due to partial discharge inside the tank, (4a) to (4c) are attached to different positions on the outer wall surface of the tank (1), and an acoustic pulse detector for detecting an acoustic pulse generated by the partial discharge, for example, an ultrasonic pulse, (5) is an electric pulse Triggered by the output of the detector (3), the acoustic pulse detectors (4a)-(4
A delay time detector that detects the acoustic pulse delay time from the output of c), (6) calculates the position of partial discharge generation using the delay time detected by this delay time detector (5), and outputs the result. It is a computing device that does.

The conventional partial discharge detection device is configured as described above, and the electric pulse detector (3) detects an electric pulse, for example, a discharge current generated due to the occurrence of the partial discharge generated inside the tank (1). The output of the pulse detector (3) triggers the delay time detector (5), which causes the delay time detector (5) to start time counting. Next, the acoustic pulse generated by the occurrence of the partial discharge is detected by the acoustic pulse detectors (4a) to (4c), and the output signal is input to the delay time detector (5), and the electric pulse is generated by the electric pulse. Stop the time counts that have been started. FIG. 5 is a time chart showing an electric pulse and an acoustic pulse. In the figure, (7) is an electric pulse,
(T ₀ ) represents the time when the electric pulse (7) was generated. (8a)
~ (8c) are acoustic pulses, (Ta) ~ (Tc), (ta)
~ (Tc) are the generation points and delay times of the acoustic pulses (8a) to (8c), respectively. These delay times (ta) ~ (tc) are
Counting starts from T ₀ . Delay time detector (5)
Output, that is, a signal representing the delay times (ta) to (tc) is input to the arithmetic unit (6). Here, the coordinates of the discharge occurrence position are obtained by the conditional expression.

However, (x ₀ , y ₀ , z ₀ ) is the coordinate of the position where the partial discharge occurs,
(Xa, ya, za), (xb, yb, zb), (xc, yc, zc) are the coordinates of the acoustic pulse detectors (4a) to (4c), and V is the insulation inside the tank (1). It is the propagation velocity of the acoustic pulse in the medium. The delay time calculated as described above is output from the arithmetic unit (6) and simultaneously displayed in the arithmetic unit (6).

[Problems to be Solved by the Invention] In the conventional partial discharge detection device as described above, the insulating medium in the tank accommodating the actual electric device main body is not necessarily composed of a single substance, and propagates it. Since the sound velocity is also not uniform, the value of the sound propagation velocity V in the conditional expression is not constant depending on the discharge occurrence position, an error occurs in the discharge position as the calculation result, the discharge position is calculated outside the tank, and Has a problem that the discharge position cannot be obtained.

The present invention has been made in order to solve such a problem, and an object thereof is to obtain a partial discharge detection device capable of always detecting the occurrence position of partial discharge with high accuracy.

[Means for Solving the Problems] A partial discharge detection device for an electric device according to the present invention detects a delay time theoretical value when an arbitrary point in a tank is assumed to be a partial discharge generation position and an acoustic pulse detector. An arithmetic unit is provided for calculating an error from each of the generated delay times and setting the one having the smallest error as the partial discharge occurrence position.

[Operation] In the present invention, the error between the theoretical delay time and the measured delay time when an arbitrary point in the tank is assumed to be the partial discharge occurrence position is calculated, and the error with the smallest error is determined. Set to the position where the partial discharge occurs.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of the present invention, in which (1) to (5) are exactly the same as those of the conventional device. (6A) is an arithmetic unit for calculating and locating a partial discharge occurrence position by the output of the delay time detector (5) and an internal memory program, and outputting and displaying the result.

Next, the operation of the above embodiment will be described with reference to FIGS. 2, 3 (a) and 3 (b). FIG. 2 is a flow chart for explaining the operation of FIG. 1, and FIGS. 3 (a) and 3 (b) are divided block diagrams of a partial discharge occurrence area for assuming a partial discharge position in the tank.

First, similar to the operation described in the conventional apparatus, when partial discharge occurs in the tank (1) in step (S1), the electric pulse and the acoustic pulse generated with the partial discharge are the electric pulse detector (3) and the acoustic pulse, respectively. Detector (4a) ~ (4c)
And their outputs are input to the delay time detector (5), and the delay time of the acoustic pulse from the point of partial discharge occurrence to each of the acoustic pulse detectors (4a) to (4c) is detected in step (S2). To be done. Each detected acoustic pulse delay transfer is input to the arithmetic unit (6A) in the next stage. In the arithmetic unit (6A), an arbitrary point in the tank (1) is assumed to be a partial discharge occurrence position in step (S3).
As a method of assuming this partial discharge occurrence position, for example, the third method
As shown in FIG. 3A, the tank (1) is three-dimensionally divided into an arbitrary number of blocks, for example 24 blocks, and the center point of the divided blocks (9) is assumed to be a partial discharge occurrence position. Next, in step (S4), the theoretical value S of the acoustic pulse delay time obtained by dividing the distance from this hypothetical point to each acoustic pulse detector (4a) to (4c) by the sound velocity V propagating through the insulating medium.
Calculate a, Sb, Sc by the conditional expression.

Where (xa, ya, za), (xb, yb, zb), (xc, yc, zc)
Is the coordinates of the position where the acoustic pulse detectors (4a) to (4c) are attached to the tank (1), and (xi, yi, zi) is the assumed i-th partial discharge occurrence in the tank (1). The coordinates of the position. Next, in step (S5), by substituting the acoustic pulse delay time theoretical values Sa, Sb, Sc into the conditional expression, the total error Gi with the acoustic pulse delay time detection value detected by the delay time detector (5) is given. Is calculated.

Gi = | (Sa-ta) | + | (Sb-tb) | + | Sc-tc | As described above, the total error Gi is calculated for the i-th divided block, and similarly, the total errors for all divided blocks are calculated. G1, G2, G3, ... Gn are required (S3 to S5 are repeated). Next, in step (S6), the above total error
The minimum one is selected from G1, G2, G3, ... Gn, and the partial discharge occurrence assumed position corresponding thereto is determined as the actual partial discharge occurrence position. These results are output in step (S7). In addition, after the discharge position is determined in step (S6), the divided block corresponding to the position is divided into third blocks.
As shown in Figure (b), it is further divided into arbitrary blocks,
It is possible to obtain a highly accurate discharge generation position by calculating the total error by the same method, selecting the minimum value from the total error, and calculating the discharge generation position.

In the above embodiment, the acoustic pulse detector (4a)-
Although the example in which three units (4c) are provided is shown, any number may be used as long as it is three or more, and the accuracy is further improved as compared with the above-mentioned embodiment.

Furthermore, in the above-described embodiment, the error comparison between the theoretical value and the actually measured value is performed by the delay time in the arithmetic processing, but the object can be achieved by comparing the delay time with the distance.

[Effect of the Invention] As described above, according to the present invention, the error between the delay time theoretical value when an arbitrary point in the tank is assumed to be the partial discharge occurrence position and each delay time detected by the acoustic pulse detector. Since a calculation device for calculating the partial discharge occurrence position having the smallest error as the partial discharge occurrence position is provided, a reliable and highly accurate partial discharge occurrence position can be obtained by a simple calculation, which in turn results in reliability. This has the effect of realizing high partial discharge monitoring.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation of FIG. 1, and FIGS. 3 (a) and 3 (b) are partial discharge occurrence assumed positions in a tank. FIG. 4 is a block diagram of division in a tank for determining, FIG. 4 is a block diagram showing a conventional partial discharge detection device, and FIG. 5 is a time chart diagram of electric pulses and acoustic pulses generated when partial discharge occurs. In the figure, (1) is a tank that stores the main body of the electric device,
(3) is an electric pulse detector, (4a) to (4c) are acoustic pulse detectors, (5) is a delay time detector, and (6A) is an arithmetic unit. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An electric pulse detector connected to a tank accommodating a main body of an electric device to detect an electric pulse generated by a partial discharge generated in the main body of the electric device; A plurality of acoustic pulse detectors for detecting the acoustic pulse generated by, a delay time detector for detecting the delay time of the acoustic pulse from the time difference between the electric pulse and the acoustic pulse,
An error between the theoretical value of the delay time connected to the output side of the delay time detector and assuming the arbitrary point in the tank as the partial discharge occurrence position, and each delay time detected by the acoustic pulse detector And a calculation device that performs calculation with the error of which is the smallest as the partial discharge generation position, and a partial discharge detection device for electric equipment.