JPH0498162A - Abnormality monitoring device for transformer - Google Patents

Abstract

PURPOSE:To ensure an abnormality decision which is done by means of the density of combustible gas, by detecting the density of combustible gas generated by a transformer, and deciding the existence of the abnormality of the transformer on the basis of the extent of a gas density increase rate at a predetermined period unit. CONSTITUTION:Gas-in-oil analyzers 11-1n are respectively fitted to (n) transformers TF1-TFn which are decision objects, and the automatic measurement of the combustible gas-in-oil density of each transformer is conducted by giving them periodically an analysis command. Sequence units 21-2n respectively collect combustible gas density data analyzed by means of analyzers 11-1n, and at the same time conduct data transmission to a central computer 4 via a transmission passage 3. At the computer 4, the gas-in-oil density data of respective transformers TF1-TFn are collected at a day unit, and the existence of abnormality is decided from the increase rate of gas density which is made by the computer 4. As a result, a decision from the degree of density increase is realized and an exact decision can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an abnormality monitoring device for a transformer, and more particularly to an abnormality monitoring device based on flammable force concentration.

B1 Summary of the Invention The present invention monitors abnormalities in a transformer based on the concentration of flammable gas generated by the transformer, by determining the presence or absence of an abnormality from the rate of increase in gas concentration in units of a predetermined period of time. It is for obtaining a judgment.

C8 Conventional Technology Oil-immersed transformers generate gas as a result of the deterioration reaction of the insulator, and this gas is dissolved in the insulating oil or becomes foam and released into the space above the oil level. Therefore, there is a method of determining whether there is an abnormality in a transformer by analyzing dissolved gas in oil or gas in a sealed conservator, and determining the presence or absence of an abnormality based on the concentration of flammable gas (hydrogen, methane, ethane, etc.).

For this determination, for example, oil is manually collected from the transformer body by a maintenance worker, the collected oil is analyzed by gas chromatography, etc., and an abnormality is determined based on the magnitude of the gas concentration.

D0 Problems to be solved by the invention In the conventional determination method, the determination is made only by the magnitude of the gas concentration, and the gas concentration fluctuates greatly depending on the oil temperature at the time of oil extraction, the state of corona discharge in the transformer, etc. Therefore, there was a problem that accurate judgment could not be made.

An object of the present invention is to provide a monitoring device that ensures abnormality determination based on combustible gas concentration.

In order to achieve the above object, the present invention provides a concentration measuring means for detecting the concentration of combustible gas generated by a transformer, and a method for collecting the concentration as daily concentration data. comprising a data collection means, a calculation means for calculating a concentration increase rate in units of a predetermined period by comparing each of the concentration data, and a means for determining an abnormality of the transformer based on whether the concentration increase rate exceeds a predetermined value, The presence or absence of an abnormality in the transformer is determined based on the magnitude of the gas concentration increase rate in units of a predetermined period.

Further, in the present invention, the concentration increase rate is determined by comparing the average value obtained by removing the maximum value and the minimum value from the concentration data of a plurality of dates, thereby preventing erroneous determination due to fluctuations in the concentration data.

F. Embodiment FIG. 1 is a system configuration diagram showing an embodiment of the present invention. Gas-in-oil analyzers 11-1n are installed in each of the n transformers TF, ~TF, to be determined, and detect combustible gas in the oil of each transformer periodically or when an analysis command is given. Automatically measure concentration. Sequencer unit 2□~2
fi is a gas-in-oil analyzer 1. ~14 collects the combustible gas concentration data analyzed and transmits the transmission line 3 of the LAN configuration.
Data is transmitted to the central computer 4 through the central computer 4. The computer 4 has sequencers 21-2. , and data collection for each transformer type, and the collected data is used to determine the abnormality of each transformer. The output device 5 is composed of a CRT, a printer, etc., and displays and prints out data and abnormality determinations from the computer 4.

With the above-described configuration, the data on the gas concentration in oil of each transformer TF, -TF is collected by the computer 4 on a daily basis or other periodic basis, and the presence or absence of an abnormality is determined from the rate of increase in the gas concentration by the computer 4.

FIG. 2 shows a processing flowchart for abnormality determination.

Gas analyzer 1□~1. The measurement data is collected together with the transformer number and measurement date as daily density data for at least one year (step S1), and the density (white density) on that day is determined (step S2). In order to eliminate errors due to differences in gas generation conditions depending on the day of measurement, this white concentration is determined as the average value for three days excluding the maximum and minimum values from the white concentration for the past five days including the current day. For example, for the white density change shown in FIG. 3, the average value of the current day's data excluding the maximum value DMAX and the minimum value DIJ1N, the data from two days before, and the data from four days ago is set as the white density.

Returning to FIG. 1, monthly concentrations (monthly concentrations) are determined while periodically storing daily concentration data (step S3).

Similar to the daily concentration, this monthly concentration is determined as the average value for the past 7 days, including the current day one month ago, excluding the maximum and minimum values for the past 5 days.

Similarly, as the annual concentration (yearly concentration), remove the maximum value, minimum value, and the next largest and smallest values from the daily concentration for the past 14 days, including the day one year ago. It is obtained as an average value of the minutes (step S4). For example, the fourth
The figure shows the concentration data from that day one year ago to the day before to 13 days ago, and from this data, the maximum value D1 and the next largest value D2 were removed, and the minimum value D3 and the next smallest value D4 were removed. The average value of the remaining 10 days' worth of data is determined as the annual concentration one year ago.

Through the processing described above, on the day when the daily concentration is determined, the monthly concentration one month ago and the annual concentration one year ago are determined. An annual concentration increase rate and a monthly concentration increase rate are determined from these concentration data, and a transformer abnormality is determined based on whether the increase rate is greater than a predetermined value. Step S5 determines the annual concentration increase rate, and if the difference between the daily concentration and the annual concentration one year ago exceeds a predetermined value α, it is determined that a transformer abnormality requires attention. For this determination, a caution warning is generated by the output device 5 or a buzzer (step S6).
. Step S7 determines the monthly concentration increase rate, and if the difference between the daily concentration and the monthly fishing index one month ago exceeds a predetermined value β, it is determined that the transformer is abnormal, and an abnormality alarm is issued in step S8.

Note that step S5. The determination formula in S7 shows the case where a difference is calculated, but the same applies when calculating from a ratio.

Further, the concentration of combustible gas generated by the transformer may be determined from the detection of the gas concentration in the sealed conservator.

In addition, although the concentration increase rate is determined on a monthly or yearly basis, it is determined on a half-monthly, half-yearly, or other period basis as appropriate based on the operational status of the transformer.

Effects of the G1 Invention As described above, according to the present invention, the rate of increase in the concentration of combustible gas generated by the transformer is determined in units of predetermined values, and abnormalities in the transformer are determined based on the magnitude of the increase rate, so that Compared to the conventional determination method based only on the magnitude of the concentration, it is possible to obtain a more accurate determination based on the degree of increase in concentration.

In addition, since the present invention calculates the concentration increase rate as an average value excluding the maximum and minimum values from data for multiple dates, accurate concentration determination is possible even when the degree of gas generation fluctuates depending on the operating status of the transformer, etc. Accurate abnormality determination can be obtained.

Furthermore, by determining the rate of increase in concentration, it is possible to predict the increase in concentration after that day, and it is possible to predict when to replace insulating oil and the lifespan of a transformer, and to use this information for operational management of a substation, etc.

[Brief explanation of drawings]

Fig. 1 is a system configuration diagram showing one embodiment of the present invention;
The figure is a processing flowchart of the embodiment, FIG. 3 is a mode diagram of daily concentration determination, and FIG. 4 is a mode diagram of annual concentration determination. 1. 1. ... Gas in oil analyzer, 2+, 2. ...Sequencer unit, 4.Computer, 5.Output device. 1 other person

Claims (2)

[Claims] (1) Concentration measurement means for detecting the concentration of combustible gas generated by the transformer, data collection means for collecting the concentration as daily concentration data, and concentration increase for a predetermined period by comparing each of the concentration data. 1. An abnormality monitoring device for a transformer, comprising: arithmetic means for determining the concentration increase rate; and means for determining abnormality in the transformer based on whether the concentration increase rate exceeds a predetermined value. (2) The abnormality monitoring device for a transformer, wherein the concentration increase rate is determined by comparing an average value obtained by removing a maximum value and a minimum value from concentration data for a plurality of days.