JPH04281314A - Snow and ice accretion prevention equipment for power transmission line - Google Patents

Abstract

PURPOSE:To make it possible to melt and remove snow and ice accretion on a power transmission line by eliminating waste in the quantity of heat by arranging heating elements separately at certain intervals instead of placing the heating elements throughout the whole length of power line. CONSTITUTION:A cross section of a spiral rod 5 at the position of a heating portion 5A comprises conductors 4a and 4b placed in parallel through an aluminum pipe 6 and a heating body 7 is filled around the conductors. A cross section at the position of non-heating portion 5B comprises conductors 4a and 4b inserted through an aluminum pipe 6 and the remaining space filled with insulating body 8, thereby creating an unheated portion. That is, heating portions 5a or non-heating portions 5B are arranged at random or at certain intervals in the spiral rod 5. Also, the total length of the built-in heating body is made almost a half of the total length of the spiral rod 5; a built-in portion of the heating body 7 is so wound that the heating body is always located on the upper half portion of a conductor 1. Thus, heating portion 5A is located at the upper half portion of conductor 1 and the non-heating portion 5B at the lower half portion in order to prevent snow and ice accretion on the conductor 1 with the highest efficiency.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an ice-and-snow prevention device in which a heating element is attached to an electric wire and the generated heat is used to melt and fall ice and snow on the electric wire.

0002

2. Description of the Related Art The appearance of ice and snow on overhead power transmission lines does not always appear uniform depending on the quality of the snow and wind speed.

That is, for example, when dry snow falls under light wind conditions as shown in FIG. 7, the snow 20 grows above the electric wire 1. However, when the wind speed is strong and the snow is wet, the frozen snow 20 grows in the shape of wings in the horizontal direction of the electric wire 1, as shown in FIG. 8, and when the outside temperature is particularly low, the wings freeze. This can lead to overhanging, causing sleet jumps and galloping vibrations, which can lead to serious accidents such as phase-to-phase short circuits.

Furthermore, even when snow falls upward as shown in Figure 7, depending on the quality of the snow, the snow may rotate and grow around the outer periphery of the electric wire and fall as a snow mass, causing damage to structures and crops beneath the wire. If the above-mentioned rotational growth becomes even larger, there is a risk that the excessive tension may cause a wire breakage accident, or in the worst case, even cause the tower to collapse.

[0005] For this reason, many proposals and attempts have been made to prevent ice and snow from accreting on power transmission lines.

For example, as shown in FIG. 6, a measure to prevent snow accretion is to attach rings 10, 10 at predetermined intervals around the outer circumference of a power transmission line 1, to prevent snowflakes from growing while sliding along the twisted grooves of the power line. The idea is to use the ring 10 to prevent this from falling quickly, and among the various proposals mentioned above, this one has been considered to be relatively reliable, and has been implemented in several actual sections. However, it is rare for snowflakes to slide as described above, and in reality, it is not expected to be very effective in preventing snow from accreting on ice.

[0007] In addition, a spiral rod is wound around the electric wire and expected to have the same effect as the above ring, or a damper is installed to prevent twisting, considering that twisting of the electric wire promotes the growth of ice and snow. Attempts are being made to put some methods into practical use.

However, the reality is that a countermeasure that is effective for all types of snow has not yet been found.

As shown in FIG. 4, a current transformer (preferably a split type) 2 is attached to the power transmission line 1, and a heating spiral rod 5' is connected to the secondary coil 3 as shown in the figure. Attach the rod 5' by winding it in the longitudinal direction of the wire,
The method of melting snow by causing the heating spiral rod 5' to generate heat using a current generated according to the number of turns of the secondary coil 3 wound around the current transformer 2 as a power source can be used regardless of the snow quality as long as the necessary amount of heat can be supplied. It is possible to reliably melt and fall frozen snow.

Specifically, conductors 4a, 4 are connected to the secondary coil 3.
As shown in FIG. 5, which is a sectional view taken along line C-C in FIG. , a heating element (preferably a self-regulating heating element made by dispersing conductive pieces such as carbon black in a heat-resistant resin) 7 is filled between the conductors 4 and 4.
energize a and 4b using the current transformer 2 as a power source,
This is to cause the heat generating spiral rod 5' to generate heat.

[0011]

However, in the device shown in FIG. 4, if the current generated by the current transformer 2 is supplied to the heat-generating spiral rod 5' throughout the year, it has no relation with, for example, icing and snow. Even in the summer when there is no electricity, heat is generated, resulting in an unnecessarily high temperature rise in the electric wire or an increase in power loss.

[0012] Therefore, the applicants first developed the conductors 4a and 4b.
A temperature switch 9 that can sense the outside temperature is installed between the
When the outside temperature is higher than a predetermined temperature, the switch is configured to operate and power to the heating element is stopped, or a switch is connected in parallel to appropriate positions of the conductors 4a and 4b near the current transformer 2 when the temperature is high. When the outside temperature is high, a resistor whose resistance value is low and whose resistance value increases as the temperature decreases is connected so as to function as a temperature switch, and when the outside temperature is high, the current flows only to the resistor side with the low resistance value. On the other hand, when the outside temperature becomes very low, the resistance value of the resistor installed in parallel increases rapidly, so the current does not flow through the resistor and flows to the heating element side. We proposed an anti-icing device that allows ice to flow and initiates the desired heat generation phenomenon.

However, although wasteful heat generation can be prevented by the above method, the amount of heat required for snow melting is proportional to the length of the spiral rod 5' with a built-in heating element, so as shown in FIG. If the current transformer 2 is wound, the required current becomes large and it becomes difficult to supply a sufficient current from the main line current through the current transformer 2. In order to secure the necessary amount of heat, the capacity and shape of the current transformer 2 must be increased. However, it is impossible to attach many heavy objects due to the mechanical strength of the power transmission line, and there is a limit to increasing the size.

In view of the above-mentioned circumstances, it is an object of the present invention to install a current transformer on a power transmission line, install a heating element wound around the outer periphery of the transmission line in the longitudinal direction, and use the current transformer as a power source to generate the heat. In a device configured to generate electricity and generate heat to melt and remove ice and snow on electric wires, the capacity and shape of the current transformer can be made as small as possible, and the snow melting effect is sufficiently demonstrated. The present invention aims to provide a novel device for preventing ice and snow from accumulating on power transmission lines.

[0015]

[Means for Solving the Problems] The present invention provides a method for attaching a current transformer to a power transmission line, and winding a spiral rod having a heating element around the longitudinal outer circumference of the transmission line, and using the current transformer as a power source to generate the heating element. A device configured to melt and remove ice and snow on electric wires by applying electricity to generate heat, in which heating elements and non-heating elements are arranged alternately at regular intervals or at random within the spiral rod. The total length of the built-in heating element is approximately half the total length of the spiral rod, and the wire is wound so that the heating element built-in portion is located approximately in the upper half of the wire.

[0016]

[Effect] By arranging the heating element in segments instead of arranging it along its entire length, and heating the necessary position intensively, there is no waste of heat, and the required amount of heat is reduced accordingly, making the current transformer more compact. It is possible to exert a sufficient snow melting effect even if the snow melts.

[0017]

[Examples] The present invention will be explained below with reference to Examples.

FIG. 1 is an explanatory view showing an embodiment of the ice and snow prevention device according to the present invention, and the same reference numerals as those in FIGS. 4 and 5 described above indicate the same configurations.

In the present invention, a split type current transformer 2 is attached to the electric wire 1, the current obtained by the secondary coil 3 is passed through the conductors 4a and 4b, and a temperature switch 9 (mechanically operated (It may be a resistor such as a thermistor or a resistor whose resistance value changes rapidly depending on the temperature), and when the outside temperature reaches a point where it is snowing, the spiral rod 5 side There is no difference from the already proposed example described above in that the current supply is configured so that energization is started at .

However, in the present invention, the aluminum pipe constituting the spiral rod 5 (although not limited to aluminum, considering that the electric wire 1 is composed of stranded aluminum wires, the aluminum pipe is an electrochemically similar metal). The aluminum pipe is characterized by the fact that heating elements and non-heating elements (insulators) are arranged at regular intervals or randomly within the aluminum pipe, without filling the entire length of the aluminum pipe with heating elements.

That is, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and shows the sectional structure of the spiral rod 5 at the position of the heat generating portion 5A. Its structure is the same as that shown in FIG. 5, in which conductors 4a and 4b are inserted in parallel into an aluminum pipe 6, and a heating element 7 is filled around the conductors 4a and 4b.

However, in the present invention, instead of having the configuration shown in FIG. 2 over the entire length of the spiral rod 5,
FIG. 1B at the non-heat generating part 5B position of the spiral rod 5
As shown in FIG. 3, which is a cross-sectional view of -B, conductors 4a and 4b are inserted into the aluminum pipe 6, but their surroundings are filled with an insulator 8, and there are parts that do not generate heat. .

As described above, the spiral rod 5 according to the present invention has a configuration in which the heat generating portions 5A and the non-heat generating portions 5B are arranged at regular intervals or randomly, and the heating portions 5A can intensively heat the ice and snow. Therefore, Figure 4
Compared to the case where the entire length generates heat as in the proposed example shown in , the required current is correspondingly smaller, and even if the current transformer 2 is small, it can provide the necessary capacity of current. be able to.

[0024]Accordingly, as explained above with reference to FIGS. 7 and 8, ice and snow accretion on the electric wire 1 first occurs at approximately the upper half position of the electric wire, and ice and snow accretion starts from the lower half position. Such a thing is highly unlikely.

Therefore, the most preferred embodiment of the present invention, as typically shown in FIG. The internal part of the wire is wound so that it is located approximately in the upper half of the wire, and the heat generating portion 5 is placed approximately in the upper half of the wire.
It is preferable to configure it so that A exists and the non-heat generating part 5B exists approximately in the lower half. Thereby, it is possible to prevent ice and snow from accumulating on the electric wire 1 with maximum efficiency.

[0026] In the above, a self-regulating heating element is illustrated as a heating element, but this does not have a limiting meaning. There is no harm in using it.

[0027] In areas where the weather is subject to particularly rapid fluctuations, such as in mountain valley areas where light wind conditions and strong wind conditions mix, or in areas where both wet snow and dry snow air masses tend to merge, it is difficult to prevent snow from coming from any direction. The heat generating part 5A is also effective.
It is preferable that the non-heat generating portions 5B and 5B are randomly arranged.

[0028]

[Effects of the Invention] As described above, according to the icing and snow prevention device according to the present invention, the current transformer can be made smaller if the length of the spiral rod is the same, and if the same current transformer is used, the current transformer can be made smaller. The longer the countermeasure length is, the more the length of the countermeasure can be lengthened, and the significance of improving efficiency and reducing waste is significant.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of the icing and snow prevention device according to the present invention.

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

FIG. 3 is a sectional view taken along line BB.

FIG. 4 is an explanatory diagram showing an already proposed example.

FIG. 5 is a sectional view taken along line CC in FIG. 4;

FIG. 6 is a sketch of a conventional example in which a ring is attached to an electric wire.

FIG. 7 is an explanatory diagram showing the state of icing and snow on electric wires.

FIG. 8 is an explanatory diagram showing the state of icing and snow on electric wires.

[Explanation of symbols]

1 Electric wire 2 Split type current transformer 3 Secondary coil 4a, 4b Conductor 5 Spiral rod 5A Heat generating part 5B Non-heat generating part 6 Aluminum pipe 7 Heating element 8 Insulator 9 Temperature switch

Claims (2)

[Claims] Claim 1: A current transformer is attached to a power transmission line, and a spiral rod having a heating element is wound around the outer periphery of the transmission line in the longitudinal direction, and the current transformer is used as a power source to energize the heating element and heat the electric wire. A power transmission line ice and snow prevention device configured to melt and remove ice and snow, wherein heating elements and non-heating elements are alternately arranged at regular intervals or randomly within the spiral rod. Claim 2: The electric wire is wound so that the total length of the built-in heating element is approximately half the total length of the spiral rod, and the built-in portion of the heating element is located approximately at the upper half of the wire. 2. The ice and snow prevention device according to claim 1.