JPS6324267B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention mainly aims to simply and quantitatively measure and record the drop in flashfault voltage due to salt contamination of insulators in indoor substations, and constantly monitor it, and when the flashfault voltage value reaches a certain limit value or less, the decrease in flashfault voltage due to insulator contamination is detected. This invention relates to an insulator stain measurement method for estimating flash flash. Many methods have been proposed to measure and record salt contamination on the surface of insulators, some of which have been put into practice, but the following are some of the main ones: A method of manually or automatically cleaning the surface of a pilot insulator and quantifying the amount of contamination from the conductivity of the cleaning solution. A method of measuring and recording the intensity of ultrasonic waves emitted from the contaminated surface of an energized insulator. A method of measuring the amount of salt in the air and weather conditions (wind direction, wind speed) and estimating the amount of salt deposited on the insulator surface. A method of calculating a multiple correlation regression equation between various topographical factors, weather conditions, and the amount of salt pollution, and then using this equation to estimate the amount of pollution at unobserved points. A method for constantly measuring and monitoring the commercial frequency leakage current of some of the power insulators in an actual system. Regarding the model insulator, for example, during measurement, the leakage current is measured by cooling it to below the dew point with an electronic cooling element and humidifying it, or similarly, by placing the model insulator in a steam ball during measurement and humidifying the surface to measure the leakage current. Method. Although each of these methods has its own advantages, they also have the following drawbacks. That is, according to the method, the cost per observation point or per observation is high in any case, and it is not suitable for the purpose of continuous measurement recording at multiple points. This method uses the correlation between the contamination leakage surge current and the ultrasonic radiation intensity, but since the magnitude of the leakage surge current is greatly affected by weather conditions such as temperature and humidity, accurate measurement is difficult. Have difficulty. This method requires high costs for analyzing observation records of atmospheric salinity and meteorological conditions per observation point, and is not a good idea as it is only an indirect estimation. According to the above method, it is necessary that actual measurement values of contamination have already been accumulated for a large number of wide-ranging points. Furthermore, since it estimates the maximum pollution and average pollution for one year, it is not possible to constantly monitor the current pollution value, and furthermore, it is not possible to accurately estimate local pollution. In this method, the situation in which surge leakage current occurs differs significantly depending on surrounding weather conditions such as temperature, humidity, and rainfall, and the flash-fault danger judgment value and flash-fault occurrence are close to each other, so it cannot be used for danger prediction. Hateful. In both methods, it is difficult to provide constant humidity conditions, the correlation between leakage current and salt deposition amount is not very good, and the cost per observation point is not low. The present invention solves these drawbacks by discovering that there is a correlation between the leakage current from the insulator surface and the insulator flash voltage under constant humidity.
Using this, the output of the hygrometer can be set to a constant value (for example, 75
%, 80%, etc.), the leakage current is automatically converted to a flash voltage value and recorded, and an alarm is also output. It provides: An embodiment of the present invention will be explained with reference to the drawings. Data detected by the temperature detection section 1 and the humidity detection section 2 are constantly sent to the calculation section 3 and the control section 4. When the humidity and the moisture adsorbed on the soiled surface of the insulator are maintained for more than 30 minutes, for example, the power supply section 5 is immediately operated through the control section 4 to detect the leakage current on the surface of the insulator using the detection section 6. It is measured and recorded in the recording section 7 along with the temperature and humidity at that time. At this time, the flash voltage is calculated by the multiple regression equation estimated in advance in the calculating section 3, and this value is also recorded. When the calculated value of the flashover voltage falls below a predetermined limit value, the alarm section 8 issues an alarm and records this fact. Further, the time when the power supply section 5 was activated is recorded in the recording section 7 using a clock signal from the clock section 9. Regarding the calculation of the flash fault voltage using the multiple regression equation, we will first obtain the multiple regression equation from the test results using a 33kV LP insulator as shown in Figure 2, and then we will explain how to assemble the calculation circuit from this equation. show. The leakage resistance between the electrodes for leakage current measurement installed between each shade (y) of the LP insulator 10 consisting of 9 shades is x ₁ MΩ (however, leakage resistance = 500V ÷ leakage current. 500V is measured. ), the temperature was x ₂ ℃, the humidity was x ₃ %, and the insulator flash voltage was vkV. As a result of testing 44 cases, the obtained data is as shown in the table below. Become.

【table】

[Table] From this table, a multiple regression equation of the form v=a+b ₁ x ₁ +b ₂ x ₂ +b ₃ x ₃ is determined by the method of least squares. As a result, an equation for estimating the flash fault voltage v is obtained: v=103.14+2.448x ₁ -1.950x ₂ -0.105x ₃ . Comparing the estimated value of v using this estimation formula with the actual measured value of v, the result is shown in Figure 3, and the multiple correlation coefficient R between the two is R = 0.871 (87.1%), which is practically It has sufficient accuracy. Since the detection section outputs voltages proportional to leakage current, temperature, and humidity, the calculation section divides, amplifies, reverses polarity, and adds as appropriate, as shown in Figure 4. Therefore, the target estimated flash fault voltage v can be output. In this way, the present invention constantly measures the leakage current between electrodes installed on a part of an insulator used in an indoor substation, etc., as well as the temperature and humidity, and uses these measured values to determine the leakage resistance of the insulator through experiments in advance. An estimated flash fault voltage is calculated using a correlation formula obtained from the temperature, humidity, and temperature, and when the flash fault voltage value falls below a predetermined limit value, a flash fault due to contamination of the insulator is estimated. Since it is related to the insulator stain measurement method,
This has great effects as listed below. In Japan, even during the low humidity season from January to March, humidity usually reaches 70% once a day, such as before dawn, so daily measurements (constant monitoring) are possible all year round. Also, April is when the danger of flashbacks is actually high.
During the high temperature and high humidity season of October, the humidity drops to 80 degrees several times a day.
% or more, it is possible to constantly estimate and monitor the flash fault voltage with extremely high accuracy. Since the present invention essentially utilizes natural temperature and humidity, there is no need to artificially control or maintain the temperature or humidity as in conventional methods, and therefore no extra cost is required. Changes in temperature and humidity will not have a negative effect. There are three sensors to measure: leakage current, temperature, and humidity, and the power supply and control parts can be shared, so by adding more sensors, the cost per observation point can be reduced, making it possible to constantly monitor multiple points. Are suitable. The method of the present invention is suitable for control using electronic circuits, and enables low-cost control.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and Fig. 1 is a block diagram of its configuration, Fig. 2 is a front view of the insulator, Fig. 3 is a correlation diagram between measured values and estimated values of flash voltage, and Fig. FIG. 4 is a block diagram showing the configuration of the calculation section. 1...Temperature detection section, 2...Humidity detection section, 3...
Arithmetic unit, 4...control unit, 6...detection unit, 7...recording unit, 8...alarm unit.

Claims (1)

[Claims] 1. Constantly measure the leakage current between electrodes installed on a part of an insulator used in an indoor substation, etc., as well as the temperature and humidity, and calculate the leakage resistance of the insulator, temperature, and humidity through experiments in advance from these measured values. An insulator contamination measurement method comprising: calculating an estimated flash fault voltage using a correlation equation, and estimating flash fault due to contamination of the insulator when the flash fault voltage value falls below a predetermined limit value. .