JP2875944B2 - Apparatus for calculating the amount of snow accumulation on transmission lines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for calculating an estimated amount of snow accumulation on a transmission line in order to perform a snow damage alarm on the transmission line, and more particularly to an apparatus for calculating an estimated amount of snow accumulation corresponding to weather data. The present invention relates to an apparatus for calculating an estimated amount of snow accumulation on a transmission line.

[0002]

2. Description of the Related Art Transmission lines are exposed to harsh natural environments, and are subject to various natural disasters. In particular, during snowfall in winter, the load on the transmission line may become excessive due to snow on the transmission line, which may cause a disconnection accident or a tower collapse accident. Therefore, it is extremely important to quantitatively estimate the amount of snow on the transmission line during snowfall from the viewpoint of preventing accidents.

[0003] In order to estimate the amount of snow accumulation based on weather data such as temperature, wind speed, and precipitation, the following various snow accumulation estimation equations have been proposed.

1) Admirat's equation P. Admirat et al., "Measurement of snow accumulation model based on examples in Japan and France; 4th International Conference on Atmospheric Icing of Structures, September 1988" 2) Erbic Equations M. Ervik et al., "A Wide Range Measurement Model for Transmission Line Icing Applied to Laboratory and Field Observations; 4th International Conference on Atmospheric Icing of Structures, September 1988" 3) McConnen Equation by Makkonen "Estimation of wet snow growth on structures; science and technology in cold regions" 4) Sakamoto's equation According to Sakamoto, Central Research Institute of Electric Power Industry.

On the other hand, a neural network for predicting snow damage has been proposed. That is, using the weather data in the past snow damage case, the neural network is trained to output an event of "accident" or "no accident" when the weather data is input. By inputting weather forecast data into this neural network, it is possible to classify and predict any of the events of "accident" or "no accident".

Further, a system has been invented in which the neural network determines that "accident exists" and issues an alarm when the estimated snowfall calculated by the above snowfall estimation formula exceeds a predetermined value. I have.

[0007]

By the way, it is generally known that the amount of snow on a power transmission line becomes maximum when the temperature is 0 to 2 ° C. However, even at other temperatures, considerable snowfall can occur. Each of the above-mentioned snowfall amount estimation formulas presupposes 0 to 2 ° C. as an applicable range for temperature, and if these formulas are used as they are for temperature conditions other than 0 to 2 ° C., the prediction result is reliable. Disappears.

[0008] The judgment of "accident" or "no accident" by the neural network is based on learning from past cases. For this reason, when weather forecast data having few past cases is input, there is a high possibility that the judgment is erroneous. For example, when the estimated amount of snowfall calculated by the snowfall amount estimation formula is extremely large as never before, an alarm should be clearly issued, but the neural network has few such cases in the past. It is conceivable that the judgment is made. In this case, an alarm is required but an alarm is not issued, which is inconvenient.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide an apparatus for calculating an estimated amount of snowfall on a transmission line, which calculates an estimated amount of snowfall in response to weather data.

[0010]

In order to achieve the above object, an apparatus for calculating an estimated amount of snow accretion according to the present invention is characterized in that the temperature of the weather data is 0 to 2 ° C, 2 ° C or more and 0 ° C or less. A temperature determining circuit for determining, a first snow amount calculating circuit for calculating a snow amount when the temperature is 0 to 2 ° C., a water content calculating circuit for calculating a water content when the temperature is 2 ° C. or more, and snow accretion A second snowfall amount calculation circuit for calculating the amount of snowfall, a snowfall determination circuit for determining snowfall from the snowfall amount and the water content, a dry snow adhesion determination circuit for determining snowfall when the temperature is 0 ° C. or lower, and And a third snowfall amount calculation circuit for calculating the snowfall amount.

[0011]

[0012]

The gist of the present invention is that if the temperature is 0 to 2 ° C., the snow amount is obtained by the snow amount estimation formula as it is. Is determined first, and then the amount of snow accumulation is estimated. That is, according to the above configuration, the temperature of the weather data is 0 to 2 ° C.,
Aside from the case where the temperature is higher than 0 ° C. and lower than 0 ° C., the amount of snow accumulation is estimated in accordance with the temperature condition. When the temperature is 2 ° C or higher, the water content in the snow is calculated to determine whether or not snowfall has occurred. If snowfall has occurred, it is determined that the amount of snowfall is small. If snowfall has not occurred, snowfall has occurred. The amount of snow accretion is determined by the amount estimation formula. When the temperature is 0 ° C. or less, it is determined whether or not snow has occurred. If snow has not occurred, it is determined that the amount of snow is small. If the snow has occurred, the amount of snow is determined by the snow amount estimation formula. Ask.

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

The snow damage warning system shown in FIG. 1 is configured to issue a snow damage warning using the apparatus for calculating the estimated amount of snow accretion on a transmission line according to the present invention. That is, the snow damage warning system includes a data receiving device 1 that receives weather data including external weather conditions and weather forecasts, and a temperature of the weather data of 0 to 2 ° C., 2 ° C. or more, and 0 ° C. or less. A first snow accumulation calculating circuit 4a which is driven by an output of 0 to 2 ° C. of the temperature judgment circuit 2 and calculates a snow accumulation at that time; Driven by an output of 2 ° C. or more, the water content calculation circuit 5 for calculating the water content at that time, the second snow content calculation circuit 4b for calculating the snow content, and the snowfall from the snow content and the water content are used to determine the snowfall. A dry snow adhesion determination circuit 3 that is driven by an output of 0 ° C. or less from the snow fall determination circuit 6 and the temperature determination circuit 2 that determines snow adhesion at that time, and a third snow accumulation amount that calculates the snow accumulation amount According to the calculation circuit 4c and the amount of snow accumulation under the temperature condition And a determining alarm determination unit 7 whether issue broadcast.

In this embodiment, the first, second, and third snow amount calculation circuits 4a, 4b, and 4c are all circuits that use Sakamoto's equation as a snow amount estimation equation. )

[0017]

(Equation 1)

## EQU1 ##

Where: w; snowfall (g / cm) T; temperature (° C.) V; wind speed (m / s) Pnt; effective precipitation intensity during t hours.

In the first snow amount calculation circuit 4a, when the air temperature is 0 to 2 ° C., the snow amount is calculated by the equation (1).

Next, the equation for calculating the water content is obtained by experiments, and the equation (2) is

[0022]

(Equation 2)

Here, LWC; water content D; snow outside diameter (cm) D ₀ ; electric wire outside diameter (cm) H; humidity (%) I; load current (A) R; electric resistance (Ω) α ₀ Initial water content θ; angle ω between electric wire and wind direction; falling speed of snowflakes (cm) γ; 0.04T ² .

In the water content calculating circuit 5, the second snow amount calculating circuit 4b, and the snow falling determining circuit 6, when the temperature is 2 ° C. or more, the water content is obtained by the equation (2), and the water content is 50%. If this is the case, it is assumed that snow has fallen, the snowfall amount is set to zero, and if the water content is less than 50%, the temperature is set to 2 ° C., and the snowfall amount is calculated according to equation (1).

In the dry snow adhesion determination circuit 3 and the third snow accumulation amount calculation circuit 4c, when the air temperature is 0 ° C. or lower, whether the electric wire has already snowed or the wind speed is 3 m / s or higher. And if any of the above, the temperature is set to 0 ° C. and the equation (1)
Calculates the amount of snowfall, and otherwise sets the amount of snowfall to zero.

The alarm judging device 7 generates an alarm when the result of calculation of the amount of snow from the circuit selected by the temperature judging circuit 2 exceeds a predetermined value.

Next, the operation of the embodiment will be described.

The temperature determination circuit 2 selects a circuit according to the temperature of the weather data.

When the temperature is between 0 and 2 ° C., the first snowfall amount calculation circuit 4a calculates the snowfall amount. The result is immediately output to the alarm determination device 7.

When the temperature is 2 ° C. or more, the water content calculating circuit 5
Determines the moisture content. Further, the second snow amount calculation circuit 4b calculates the snow amount by setting the temperature to 2 ° C. Snow fall judgment circuit 6
If the water content is 50% or more, it is assumed that snow has fallen, and the amount of snowfall is set to zero. The alarm determination device 7 outputs the calculated snowfall amount or zero.

When the air temperature is 0 ° C. or less, the dry snow adhesion determining circuit 3 determines whether or not snow has adhered. Further, the third snowfall amount calculation circuit 4c calculates the snowfall amount by setting the temperature to 0 ° C. If it is determined that no snow is attached, the amount of snow is set to zero. The alarm determination device 7 outputs the calculated snowfall amount or zero.

Each of the alarm determining devices 7 includes a snow amount calculating circuit 4
The snowfall amount or zero snowfall amount calculated in is input. If the snowfall exceeds a predetermined value, an alarm is transmitted to a transmission line management facility or the like through a communication line (not shown).

In the present embodiment, Sakamoto's equation is used as the snowfall estimation equation, but Admira's equation, Elbic's equation, McConnen's equation, etc. may be used.

Next, a second embodiment of the present invention will be described.

The snow damage warning system shown in FIG. 3 is connected to a device (not shown) for receiving weather data including the weather status and weather forecast from the outside. The snowfall amount calculation circuit 31 that calculates the snowfall amount from the weather data uses Sakamoto's formula as the snowfall amount estimation formula. The snow amount determination circuit 32 to which the snow amount is input from the snow amount calculation circuit 31 has two kinds of set values set in advance. One of them is a set value for determining whether or not to give an alarm immediately, and the value is 15.9. When the amount of snowfall is 15.9 or more, "alarm present" =
"1" is output. Another set value is a value for determining whether “accident exists” = “1” or “no accident” = “0”. Neural network evaluation circuit 3
No. 3 evaluates the presence / absence of snow damage by a neural network based on the above weather data, and determines whether “accident” = “1” or “no accident” = “0”. Arithmetic circuit 34
Is a logical AND of the evaluation result of the neural network evaluation circuit 33 and the judgment result of the presence / absence of an accident of the snow accumulation amount calculation circuit 31. If "1", "alarm is present"
= "1". If the logical product is “0”, “no alarm” = “0” is output. Alarm generator 3
5, the output of the arithmetic circuit 34 and the output of the snow amount determination circuit 32 are input. If either one of the inputs is “alarm present” = “1”, an alarm is generated. .

According to the above configuration, if the snow amount by the snow amount estimation formula is 15.9 (g / cm) or more, a warning is issued regardless of the evaluation of the neural network. 15.9 (g / c
If less than m), a warning is issued by ANDing the evaluation of the neural network and the determination based on the amount of snowfall, as in the prior art.

The reason why the amount of snow arrival of 15.9 (g / cm) is used as the value for judging "the presence of an alarm" is based on the graph of FIG. That is, FIG. 2 categorizes snow damage accidents into accidents that occurred when the snowfall amount was W or more and accidents that occurred when the snowfall amount was W or less.
The ratio of the number of accidents below the snowfall amount W to the total number of accidents was calculated, and the snowfall amount W was plotted on the horizontal axis.
The vertical axis plots the ratio of the number of accidents with the snowfall amount W or less to the total number of accidents. Specifically, the amount of snowfall at a point where snow damage occurred in the past was calculated using Sakamoto's formula for the day when the snow damage occurred in the past and the day where the pressure distribution was similar on that day. From this graph, W = 15.9
(G / cm), 99% of accidents occurred when the amount of snow reached 15.9 or less, and only 1% occurred when the amount of snow reached 15.9 or more. That is, it is considered that an alarm may be issued unconditionally if the snowfall is 15.9%.

Even in this configuration, instead of Sakamoto's equation, an Admira's equation, an Elvic's equation,
McConnen's formula or the like may be used.

[0039]

The present invention exhibits the following excellent effects.

(1) Even if the temperature is other than 0 to 2 ° C., the estimated amount of snow accumulation can be calculated, and the result corresponding to the weather data can be obtained, so that the practicality is high.

(2) A highly reliable snow damage prediction can be made.

[Brief description of the drawings]

FIG. 1 is a block diagram of a snow damage warning system according to a first embodiment of the present invention.

FIG. 2 is a graph showing a ratio of the number of accidents under the snowfall amount W to the whole.

FIG. 3 is a block diagram of a snow damage warning system according to a second embodiment of the present invention.

[Explanation of symbols]

 2 Temperature judgment circuit 3 Dry snow adhesion judgment circuit 4 Snow accumulation amount calculation circuit 5 Moisture content calculation circuit 6 Snow fall judgment circuit

Continuation of the front page (56) References JP-A-5-197708 (JP, A) Teruhiko Tanaka et al., “Development of a snow forecasting system for power transmission lines”, Snow and Ice, 1992, Vol. 54, No. 3, p. 245-257 (58) Field surveyed (Int. Cl. ⁶ , DB name) G01W 1/10 G01W 1/14

Claims (1)

(57) [Claims] An apparatus for calculating the amount of snowfall on a transmission line based on weather data such as temperature, wind speed, and precipitation, wherein the temperature of the weather data is 0 to 2 ° C, 2 ° C or more and 0 ° C or less. And a temperature determination circuit for determining whether the temperature is 0 to 2 ° C.
A first snow accumulation calculation circuit for calculating the snow accumulation at the time of; a water content calculation circuit for calculating the water content when the temperature is 2 ° C. or more; a second snow accumulation calculation circuit for calculating the snow accumulation; A snowfall determination circuit that determines snowfall from the snowfall amount and the water content, a dry snow adhesion determination circuit that determines snowfall when the temperature is 0 ° C. or less, and a third snowfall amount calculation that calculates the snowfall amount An apparatus for calculating an estimated amount of snow accumulation on a transmission line, comprising: a circuit;