JPS60180010A - Low corona noise wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hanging electric wire that significantly reduces noise caused by corona discharge generated in overhead power transmission lines, that is, corona noise.

Corona discharge generated in direct current or alternating current overhead power transmission lines causes corona noise pollution, and may also cause radio wave interference to communication equipment and a decrease in power transmission efficiency due to corona loss.

In particular, when corona noise occurs on DC power lines,
Corona discharge called streamer corona makes a major contribution. In this case, corona noise becomes a major problem in positive polarity conductors where streamer corona is more likely to occur than in negative polarity conductors. On the other hand, in order to realize large power transmission, it is necessary to increase the transmission voltage in order to reduce resistance loss in the transmission line conductor, but this also increases the occurrence of streamer corona. thus preventing the occurrence of corona discharges in power transmission lines;
Alternatively, reduction is extremely important from the standpoint of noise pollution prevention.

Various countermeasures have been taken in the past, including reducing the potential gradient on the wire surface and suppressing the occurrence of corona discharge by making the wire conductive. However, since these methods inevitably increase the weight of the conductor, strong support structures such as transmission towers and insulators are required. For this reason, along with the increase in the size of transmission towers due to the increase in the height of transmission lines above the ground due to boosting the voltage, there is also the problem of a significant increase in the cost of constructing transmission lines due to their strength.

Therefore, for DC high voltage power transmission and IQOOKV ultra-supervoltage transmission lines, which have been actively researched recently,
There is a strong demand for prevention or reduction of corona discharge by methods other than those described above.

However, nothing that satisfies this requirement has been found so far.

The present invention has been made for the purpose of providing a low-corona noise electric wire that meets the above-mentioned requirements, and will now be described in detail with reference to the drawings.

The present invention is based on the discovery that by attaching fine carbon powder to the surface of a conductor, the generation of streamer corona, which is a predisposition to the generation of corona noise, can be significantly reduced. Thereby, it is possible to reduce the corona of the conductor weight electric line as in I) the above-mentioned potential gradient reduction method.

Δ FIG. 1 is an example of the experimental results of the low corona noise electric wire according to the present invention. An aqueous solution of carbon powder type 1.2 specified by the Japan Powder Industry Association standards was uniformly applied and dried on the 240-copper core aluminum stranded wire (1) as shown in Figure 2.
A carbon layer (2) was formed on the surface of the electric wire. Then, this electric wire is connected at a height of 3 m above the ground and a DC voltage is applied to it. ) is determined using the polarity of the applied voltage and the voltage value as parameters.

As is clear from this result, when applying a negative polarity voltage, which generally generates less corona noise than the positive polarity, of course, the applied voltage can be changed to the positive polarity of 250 KV or even more.
Even at a high 300 KV, the corona noise level decreases with increasing carbon content. That is, the amount of carbon is 20
In the case of g/l, when the negative polarity is 250 KV, it becomes zero (undetectable) compared to level 3 (dBA) when no carbon is applied, and when the positive polarity is 250 KV, it becomes zero (undetectable) compared to the level 3 (dBA) when no carbon is applied. Level 6 (dBA)
1/6 (dBA). Also positive polarity 30
Even at 0 KV, the level is 3 (dBA), which is about 1/6 of the level 19 (dBA) when no carbon is applied. Furthermore, when the amount of carbon is increased to 20 g// or more, corona noise is suppressed to the extent that it is almost undetectable even at an applied voltage of +300 KV.

On the other hand, since the weight of the carbon powder required to reduce the corona noise level to an insignificant level is completely negligible compared to the weight of the wire, there is no need to increase the strength of the support structure. Therefore, it is very clear that the present invention provides an electric wire that can significantly reduce corona noise by a method other than the potential gradient reduction method that increases the weight of the electric wire.

By the way, regarding the mechanism of the above-mentioned remarkable reduction effect on corona noise, it is clear up to now that the electric wire of the present invention is a low corona noise electric wire. However, there is a concern in practical terms that the effect will decline due to carbon flaking off over time, but according to experiments to date, it is possible to apply an aqueous solution of carbon powder and dry it to form a carbon layer on the surface of the wire. It has been confirmed that due to the adsorption properties of the carbon powder itself, the surface of the wire does not peel off even after two years have passed since application. Therefore, it is expected that it will be fully practical even in the case of power transmission lines that are exposed to severe weather conditions.

As is clear from the above description, the present invention improves the corona noise characteristics of the electric wire itself by attaching carbon powder to the surface of the electric wire. Therefore, unlike the conventional method of reducing corona noise by lowering the potential gradient, this method does not increase the weight of the wires, so it does not increase the cost of constructing power transmission lines, and it is possible to prevent noise disturbances caused by corona discharge. In particular, the present invention is aimed at reducing corona noise on DC overhead power transmission lines, where the corona noise level is higher on clear and cloudy days, rather than on AC overhead power transmission lines, where the behavior of water droplets adhering to the wire surface has a large effect on corona noise during rainy days. You can expect great effects when using it.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between carbon content and corona noise level showing an embodiment of the present invention, and FIG. 2 is a sectional view of the electric wire of the present invention. (1)...Electric wire, (2)...Carbon powder layer. Patent applicant: Patent attorney representing the Central Research Institute of Electric Power Industry
Manabu Otsuka

Claims (1)

[Claims] A low-corona noise electric wire characterized by having carbon on the surface to significantly reduce corona noise.