JPH0418633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention particularly relates to a protection diagnosis device for a transformer by analyzing gas dissolved in oil.

[Technical background of the invention and its problems] In recent years, new protection and diagnostic devices have been installed on equipment installed in power transmission systems, such as transformers, due to their importance in power transmission. Examples include methods for detecting partial discharges occurring inside oil-immersed transformers, and devices for extracting and analyzing gas dissolved in the oil of oil-immersed transformers. Such a diagnostic device is attached to a transformer in an attempt to prevent accidents and prevent them from spreading.

Conventional oil-immersed transformer oil analysis diagnostic equipment is
The system extracted the dissolved gas in the transformer, compared the amount of extracted gas with a reference gas amount, and issued an alarm if an abnormal amount of gas was detected. In such a diagnostic device, the amount of extracted gas is compared with the amount of gas extracted in a certain step before extraction for diagnosis, and from the increase or decrease in both, the transformer The aim is to find abnormalities in

Conventional methods such as this, which perform gas analysis and diagnose abnormalities based on changes in the amount of gas, assume that the amount remains constant over time, even if there is no abnormality in the transformer. The amount of gas in the insulating oil of a transformer is constantly changing. For example, in the early stages of operation, the amount of gas that oozes out from the insulating oil also increases.
For example, as shown in the relationship between the number of months of operation of a transformer and the amount of hydrogen gas shown in Figure 2, the amount may increase or decrease by around 30 PPM in one month. The increase or decrease in this gas amount is
It varies depending on the load conditions during operation and processing conditions for insulators and insulating oil.

Therefore, it is difficult to predict the rate of increase or decrease in advance. However, the conventional method
Since the judgment is simply made by comparing the gas amount based on the previous analysis value and the gas amount at the time of diagnosis, there is a high risk of misjudgment.

[Object of the Invention] An object of the present invention is to provide a transformer protection diagnosis device using gas analysis that does not cause erroneous judgments.

[Summary of the Invention] The transformer protection diagnosis device according to the present invention extracts gas dissolved in oil from two transformers of a plurality of transformers that have been subjected to the same treatment at the same time, and calculates the amount of gas. The present invention is characterized in that it is configured to detect abnormalities in the transformer by comparing the values.

[Embodiments of the Invention] The present invention will be described below with reference to an embodiment shown in FIG. In FIG. 1, a plurality of transformers 1A and 1B according to the present invention are unit transformers in which one phase of the transformer is divided into two. Inside each of the transformers 1A and 1B, the transformer contents of the winding and iron core and insulating oil are sealed. The lead wires from the windings are drawn out from the bushings 2 and 3 in common. Then, semipermeable membrane type gas extraction devices 4A, 4B are attached to the side walls of the tanks of the unit transformers 1A, 1B to extract, for example, hydrogen gas from the insulating oil. The amounts of gas extracted by the gas extractors 4A and 4B are compared by a comparator 5, and if there is a particular difference between the two gas amounts, an alarm is issued from the alarm device 6 to take protective measures. I will have to give a lecture.

In the transformer protection/diagnosis device according to the present invention configured as described above, the transformers 1A and 1B have the same load and are operated at the same location and under the same environmental conditions. Moreover, since the assembly, on-site installation, period, and insulation treatment of the transformer are performed at exactly the same time, changes in the amount of gas that naturally increases
A and 1B are the same. Therefore, in the present invention, since the gas amount is extracted from both transformers 1A and 1B and compared, even a slight change in the gas amount can be detected with high sensitivity, and abnormalities in the transformer can be detected at an early stage. can be found in. 2 unit transformers 1
Since the amount of dissolved gas is extracted from A and 1B at the same time, when an abnormality occurs, it is not only possible to determine which transformer is abnormal, but also eliminates erroneous judgments. In addition, since the gas amount is compared between two unit transformers operated under the same operating conditions, only one comparison device or alarm device is required, and an inexpensive diagnostic device can be obtained. Even if one gas extraction device fails, the other transformer can be diagnosed. In addition, it uses a semi-permeable membrane gas extraction method, so it is easy to handle.
An inexpensive monitoring device can be obtained.

In addition, although the drawing shows an example of a transformer in which one phase is divided into two as unit transformers 1A and 1B,
The transformer may be divided into three or more transformers that are operated with the same load and perform the same processing, or may be applied to a plurality of transformers that are operated in parallel.

[Effects of the Invention] As described above, according to the present invention, dissolved gas in the oil of a plurality of transformers is extracted, the gas is analyzed, and abnormalities are detected by comparing the mutual gas amounts. Accordingly, an inexpensive and highly reliable transformer protection/diagnosis device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a transformer protection diagnosis device according to the present invention, and FIG. 2 is a characteristic diagram showing changes over time in hydrogen gas dissolved in oil. 1A, 1B... Unit transformer, 2, 3... Bushing, 4A, 4B... Gas extraction device, 5... Comparison device, 6... Alarm device.

Claims (1)

[Scope of Claims] 1. A plurality of unit transformers manufactured at the same time and operated under the same load and the same environmental conditions, and a gas extractor for extracting dissolved gas in oil in each of the unit transformers. , a transformer comprising: a comparison device that compares the amounts of gas detected by each of the gas extractors; and an alarm device that issues an alarm when the results compared by the comparison device are abnormal. protection diagnostic equipment. 2. The transformer protection and diagnosis device according to claim 1, wherein the plurality of unit transformers are unit transformers in which one phase of the transformer is divided into a plurality of units. 3. The transformer protection and diagnosis device according to claim 1, wherein the plurality of unit transformers are plural transformers operated in parallel. 4. The transformer protection and diagnosis device according to claim 1, wherein the gas extractor is of a semi-transparent type.