JPS638433B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that can very easily identify short-circuit accidents caused by rare shorts or case ground faults inside a transformer.

Conventionally, when investigating whether there is a rare short or case ground fault inside a transformer, a mega ring or an internal inspection of the transformer with the naked eye has been relied upon. With such inspection methods, it is difficult to accurately identify short circuit accidents caused by rare shorts or case ground faults inside the transformer.
This problem was often overlooked, resulting in an accident when the power was turned on again.

SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned problems and provide a simple transformer short-circuit detection device that can easily determine the presence or absence of a short-circuit accident due to a rare short or case ground fault inside a transformer. That is.

The drawings showing the embodiments of the present application will be described below. In FIG. 1, 1 indicates a short circuit detection device,
In the figure, the dashed line indicates the existence of that case. 2
Reference characters a and 2b indicate connection terminals for the transformer to be measured, which are attached to the case. Next, in each member provided in the case, 3 is a voltage applying capacitor, which is connected to connection terminals 2a and 2b via a switch circuit 4.
It is connected to the. 5 is an integrating circuit, connecting terminal 2
It is configured to integrate the waveforms appearing at a and 2b. A display section 6 is configured to display the magnitude of the integral value of the integrating circuit 5. Next, 10 is a transformer to be measured, which is generally installed on a utility pole. In this transformer 10, 11 is a case, 12 and 12 are high voltage side terminals, and 13 and 14 are low voltage side terminals, respectively.

Next, the usage and operation of the above configuration will be explained.

(1) When inspecting the presence or absence of a rare short in the transformer under test In this case, connect the connecting terminals 2a and 2b of the detection device 1 to the transformer 10 using the connecting wires 16, respectively.
Connect to the low voltage side terminals 13 and 14 at. Further, the high voltage side terminals 12, 12 of the transformer 10 are left open. In this state, switch circuit 4
Close the circuit. Then, the charge stored in capacitor 3 is transferred to switch circuit 4 and connection terminal 2.
It is momentarily applied to the low voltage side terminal of the transformer 10 via a and 2b. In this way, the transformer 10
When voltage is applied to the low voltage side terminals 13 and 14 of the
3 and 14, voltages with various waveforms as shown in FIG. 2 appear. This voltage is applied to the connection terminals 2a, 2b of the detection device 1 via the connection line 16. Then, in the detection device 1, the above-mentioned waveform is integrated by the integrating circuit 5, and the display section 6 performs a display operation depending on the magnitude of the integrated value. In this case, if the transformer 10 under test is healthy, the waveform shown by A in FIG.
If there is a rarity in the transformer 10, a waveform as shown by (b) will appear at the connection terminals 2a, 2b, and if there is a gap accident in the transformer 10, a waveform as shown by (c) will appear at the connection terminals 2a, 2b, respectively.
Therefore, when these waveforms are integrated by the integrating circuit 5, if the transformer 10 is healthy, the integrated value exceeds the voltage indicated by V in FIG. In response, it displays an indication that the transformer is healthy. In addition, if the rare shot hits or there is a gap accident, the integral value will not reach the above-mentioned value of V, so the display section 6 will display a message indicating that it is defective.

Next, once such one measurement is completed, the same measurement is performed by reversing the connection relationship between the connection terminals 2a, 2b of the detection device 1 and the low voltage side terminals 13, 14 of the transformer 10.

(2) When inspecting the presence or absence of a ground fault in the case of a high-voltage winding In this case, as shown in FIG.
The connection relationship between the low voltage side terminals 13 and 14 in the transformer 10 is the same as above, and the high voltage side terminal 1 in the transformer 10
2 and 12 is connected to the case 11. In this state, perform the same operations as above. Then, if there is a case ground fault in the high-voltage winding of the transformer 10, a waveform similar to that in the case of the rare short shown in FIG. Therefore, in this case as well, the display section 6 displays a message that the transformer 10 is defective, as described above.

After completing one measurement like this, next, connect the high voltage side terminal 1 as shown by the broken line in Figure 3.
Similar measurements are made by connecting the other terminal of 2 and 12 to case 11.

(3) When inspecting the presence or absence of a case ground fault in the low voltage winding In this case, as shown in FIG. , 14 to the case 11 and perform the same operation as described in (2) above. By performing such an operation, if there is a case ground fault in the low voltage winding in the transformer 10, the display unit 6 will display a message indicating that the transformer is defective.

Next, connect the connecting terminals 2a and 2b to the terminals 13' and 14' of the other low voltage winding of the transformer 10, respectively, as shown by broken lines, and
Connect one of them to case 11 and perform the same operation as described in (2) above.

Next, FIG. 5 shows an example of a specific circuit of the detection device. In the figure, 21 is a power supply circuit, which includes a power switch 24 and a rechargeable battery 25.
and a charging circuit 26 for the battery. Reference numeral 22 indicates a capacitor charging circuit, in which reference numeral 27 is an inverter configured to convert low voltage DC input to itself into high voltage DC output and send it out. In this example, the DC output voltage is configured such that an output of 350 V appears at the terminal a, and an output of 175 V appears at the terminal b. 2
8 is a charge switch, 29 is a voltage changeover switch, and when the transformer to be measured is a 210V tap, it is used by switching to side a, and 105V is used.
In the case of a tap, it is used by switching to the b side.

Next, reference numeral 23 denotes a detection section, which is constructed using a transistor Q ₁ and a thyristor CR ₁ in addition to the integration circuit 5. Note that 30 is a clipper used to limit excessive input.
Reference numeral 31 designates a polarity changeover switch, which is provided to eliminate the need to change the connection between the connection terminals 2a and 2b as described in (1) above. As an example of the voltage application capacitor 3,
A 1000μF470V one is used. Further, in the switch circuit 4, NE ₁ indicates a charge confirmation lamp, which indicates that the capacitor 3 has been charged to an appropriate value. Also
NE ₂ indicates an excessive charge indicator lamp, which indicates that the capacitor 3 has been excessively charged. Also, K is a discharge switch,
This switch is provided in order to discharge the electric charge stored in the capacitor 3 by closing this switch, so that the amount of charge becomes appropriate. In addition, in the display section 6, P ₁ and P ₂ indicate indicator lamps, respectively. Indicator lamp P ₁ indicates that the transformer is healthy, and P ₂ indicates that the transformer is defective. It is a lamp that Note that this lamp _P2 also serves as a power indicator lamp. Furthermore, L,
M and N indicate relays, respectively, and in the figure Na ₁ ,
Mb ₁ , La _{1 ,} etc. each indicate a number of contacts of the above-mentioned relay. Also, Sa ₂ , Sb _{1 ,} etc. are start switches, and Ra ₁ , Rb ₁ , etc. are reset switches.

Next, a method of operating the above-mentioned device will be explained. First, the power switch 24 is switched to the ON position indicated by b. Then, the lamp _P2 lights up, confirming that there is power in the battery 25. Next, operate the reset switch. Then, relay M operates and the associated contacts switch, causing the lamp to turn on.
_P2 goes out. Next, charge switch 28 is closed. Then, the inverter 27 is activated and the voltage applying capacitor 3 is sequentially charged with electric charge. When the charge confirmation lamp NE ₁ lights up and it is confirmed that the voltage application capacitor 3 has been charged to an appropriate value, the start switch is activated. Then, relay N is activated and all of the associated contacts are switched. Then, a contact is made from voltage application capacitor 3.
A signal is applied to the gate of thyristor CR ₂ in switch circuit 4 through Na ₁ . Thyristor _CR2 is therefore conducting. Then connection terminal 2
The electric charge stored in the voltage applying capacitor 3 appears at a and 2b, and is applied to the low voltage winding of the transformer.

By applying such a voltage to the low voltage winding, the above-mentioned waveform is applied from the low voltage winding of the transformer to the connecting terminals 2a, 2b. This waveform is applied to the detection section 23. In this detection section 23, the waveform is integrated in an integrating circuit 5. In this case, if the transformer is healthy, the integral value will be large enough, so the thyristor CR ₁ becomes conductive via the transistor Q ₁ . When thyristor CR ₁ becomes conductive, relay L is activated. The operation of this relay L switches the corresponding contacts, and the indicator lamp _P1 lights up to indicate that the transformer is healthy. If the transformer is defective, the output of the integrating circuit, that is, the integrated value, will not be a sufficient value, so the thyristor _CR1 will not conduct through the transistor _Q1 , and therefore the relay L will not operate. Therefore, the defect indicator lamp _P2 lights up, indicating that the transformer is defective. Next, if you want to inspect the transformer again, operate the reset switch. Then, the relay M is activated, the contacts associated therewith are switched, and the indicator lamp _P1 or indicator lamp _P2 is turned off. Thereafter, the same operations as described above may be performed.

If the indicator lamp _P2 does not light up when the power switch 24 is switched to position b, it is because the battery 25 has been exhausted, so switch the power switch 24 to position a. The battery 25 is charged by the charging circuit 26.

As described above, in the present invention, when measuring the presence or absence of a rare short or gap-like accident inside the transformer under test 10, the connecting terminals 2a and 2b of the device are simply connected to the terminals. , applies an instantaneous voltage to the transformer by closing switch circuit 4, thereby causing terminal 2 to
The waveforms appearing at a and 2b are integrated by an integrating circuit 5, and the magnitude of the amount thereof is displayed on a display section 6, so that the internal condition of the transformer under test 10 can be judged from the display. , has an excellent feature that it is possible to easily judge whether or not the transformer 10 is good or bad by observing the display section 6.

Moreover, even though it is configured so that it can be easily determined, the power required for measurement is extremely small as is clear from the above explanation, and the incidental circuits include a capacitor 3 and an integrating circuit 5. , the display unit 6, etc., can be made extremely small and lightweight, so it has the advantage that it is extremely easy to pack these items together so that they can be easily carried around. This makes the design extremely versatile due to its miniaturization, for example allowing transformers on poles to be grouped together so that they can be used for inspection while in situ. It has period features.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and Fig. 1 shows the configuration of the detection device as a block and shows the connection relationship between this and the transformer, and Fig. 2 shows the input waveform to the connection terminal of the transformer under test. Figures 3 and 4 are diagrams showing connection relationships for performing different measurements, respectively.
FIG. 5 is a circuit diagram showing an example of a specific circuit of the detection device. 2a, 2b...Transformer under test connection terminal, 3...
...Voltage application capacitor, 4...Switch circuit, 5...Integrator circuit, 6...Display section.

Claims (1)

[Claims] 1. A capacitor for voltage application, a connecting terminal for a transformer under test connected to the output terminal of the capacitor via a switch circuit, and a waveform appearing at the connecting terminal for the transformer under test; The input terminal is connected to an integrating circuit connected to the connecting terminal of the transformer under test, and a display unit connected to the integrating circuit and displaying the magnitude of the integral value in the integrating circuit. A transformer short circuit detection device.