GB2175458A

GB2175458A - Electrical transmission systems

Info

Publication number: GB2175458A
Application number: GB08611183A
Authority: GB
Inventors: Irving Reedy
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-05-09
Filing date: 1986-05-08
Publication date: 1986-11-26
Also published as: GB8611183D0; CA1277703C; GB2175458B

Abstract

An electrical power transmission system is described comprising at least one high potential power conductor positioned vertically above two neutral conductors and to which a broken conductor guard is connected. The broken conductor guard comprises a conductive rod electrically connected transverse to the neutral conductors. The rod extends a predetermined distance on each side of the two neutral conductors in a substantially horizontal plane such that a broken high-potential conductor will fall on the rod and be short-circuited to the neutral conductors. <IMAGE>

Description

SPECIFICATION Electrical transmission systems This invention relates to overhead electrical transmission systems comprising a device, herein called a broken conductor guard, which prevents high voltage electrical wires that have been broken by accident or by metal fatigue from falling to the ground and remaining there for long periods of time, thus endangering human lives and property.

During the history of overhead high voltage electric power line operation, thousands of people and domestic animals have been killed and thousands more have been seriously injured by electric shock from conductors which have mechanically failed, fallen on high resistance sand or rock and which have remained energized for long periods of time. The conductors remain energized because the resistance to electric current flow of the return path to the electrical neutral is so high that insufficient current flows in the faulted conductor wire to cause protective fuses to blow, or in the case of main feeder circuits, to signal the power circuit breaker to open and deenergize the line.

According to this invention a device is provided which when attached to the neutral wires in the span between supporting poles of an overhead electric distribution line or transmission line, will establish and provide a low resistance path to neutral for the electric current to follow. When an energized phase conductor wire inadvertently breaks and falls across the device an abnormally high electrical current flow will cause upstream protective overload fuses to blow, or will signal power circuit breakers to open, thus de-energizing the faulted conductor and protecting from injury or death anyone who might come into physical contact with the fallen conductor.

More particularly, the present invention provides an electrical power transmission system including at least one high-potential power conductor positioned vertically above two neutral conductors attached adjacent to a power pole, and a broken conductor guard comprising a conductive rod electrically connected to and oriented transversely with respect to the neutral conductors and extending a predetermined substantially horizontal distance on each side thereof such that a broken high-potential power conductor will fall on said rod and be short-circuited to the neutral conductors.

The invention will be further described with reference to the accompanying drawings in which: Figure 1 illustrates a broken conductor guard in accordance with the present invention; Figure 2 illustrates a top plan view of typical power lines in conjunction with broken conductor guards; and Figure 3 illustrates an elevation view of power lines having a broken line contacting broken conductor guards.

As shown in Fig. 1, the device generally comprises an elongated rod with hooked ends and which may be fabricated from drawn copper or aluminium alloy metal. The rod is of large enough diameter to support the weight of the conductor. The ends of the rod are turned upwards and back towards the center to prevent the fallen conductor from sliding off. (See Fig. 1.) The length is sufficient to extend approximately six inches (15 cms) farther out from the neutral than the alignment of the outside energized conductors. For this reason the length of the rod will vary from approximately two feet (0.6 m) for a single phase (one single energized conductor) to approximately twelve feet (3.6 m) for a three phase line employing wooden crossarms for conductor support. In other words, the length of the rod will vary depending upon the specific type of line design.The longer rods also would be larger in diameter (see Fig. 1). In use, the device will be placed two or more to a span and at a distance from the poles which would afford optimum opportunity for the falling conductor to make contact with the rod.

Fig. 2 shows a typical positioning of the device on a power line in plan view, and Fig.

3 illustrates the performance of the device in elevation or side view.

1. An electrical power transmission system including at least one high-potential power conductor positioned vertically above two neutral conductors attached adjacent to a power pole, and a broken conductor guard comprising a conductive rod electrically connected to and oriented transversely with respect to the neutral conductors and extending a predetermined substantially horizontal distance on each side thereof such that a broken high-potential power conductor will fall on said rod and be short-circuited to the neutral conductors.

2. An electrical power transmission system according to claim 1, comprising at least two high-potential power lines supported above the ground by spaced power poles and a third, neural line spanning said poles and positioned vertically below said power lines, wherein there is provided: (a) a second neutral line spanning said poles, said second neutral line being parallel to and displaced horizontally from the first neutral line for establishing a neutral plane below the high-potential power lines, the horizontal distance between the first and second neutral lines being less than the distance between the high-potential power lines; ; (b) at least one electrically conductive rod connected transversely to and supported by the first and second neutral lines between said poles, said rod extending horizontally beyond each neutral line, whereby a broken high-po

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Electrical transmission systems This invention relates to overhead electrical transmission systems comprising a device, herein called a broken conductor guard, which prevents high voltage electrical wires that have been broken by accident or by metal fatigue from falling to the ground and remaining there for long periods of time, thus endangering human lives and property. During the history of overhead high voltage electric power line operation, thousands of people and domestic animals have been killed and thousands more have been seriously injured by electric shock from conductors which have mechanically failed, fallen on high resistance sand or rock and which have remained energized for long periods of time. The conductors remain energized because the resistance to electric current flow of the return path to the electrical neutral is so high that insufficient current flows in the faulted conductor wire to cause protective fuses to blow, or in the case of main feeder circuits, to signal the power circuit breaker to open and deenergize the line. According to this invention a device is provided which when attached to the neutral wires in the span between supporting poles of an overhead electric distribution line or transmission line, will establish and provide a low resistance path to neutral for the electric current to follow. When an energized phase conductor wire inadvertently breaks and falls across the device an abnormally high electrical current flow will cause upstream protective overload fuses to blow, or will signal power circuit breakers to open, thus de-energizing the faulted conductor and protecting from injury or death anyone who might come into physical contact with the fallen conductor. More particularly, the present invention provides an electrical power transmission system including at least one high-potential power conductor positioned vertically above two neutral conductors attached adjacent to a power pole, and a broken conductor guard comprising a conductive rod electrically connected to and oriented transversely with respect to the neutral conductors and extending a predetermined substantially horizontal distance on each side thereof such that a broken high-potential power conductor will fall on said rod and be short-circuited to the neutral conductors. The invention will be further described with reference to the accompanying drawings in which: Figure 1 illustrates a broken conductor guard in accordance with the present invention; Figure 2 illustrates a top plan view of typical power lines in conjunction with broken conductor guards; and Figure 3 illustrates an elevation view of power lines having a broken line contacting broken conductor guards. As shown in Fig. 1, the device generally comprises an elongated rod with hooked ends and which may be fabricated from drawn copper or aluminium alloy metal. The rod is of large enough diameter to support the weight of the conductor. The ends of the rod are turned upwards and back towards the center to prevent the fallen conductor from sliding off. (See Fig. 1.) The length is sufficient to extend approximately six inches (15 cms) farther out from the neutral than the alignment of the outside energized conductors. For this reason the length of the rod will vary from approximately two feet (0.6 m) for a single phase (one single energized conductor) to approximately twelve feet (3.6 m) for a three phase line employing wooden crossarms for conductor support. In other words, the length of the rod will vary depending upon the specific type of line design.The longer rods also would be larger in diameter (see Fig. 1). In use, the device will be placed two or more to a span and at a distance from the poles which would afford optimum opportunity for the falling conductor to make contact with the rod. Fig. 2 shows a typical positioning of the device on a power line in plan view, and Fig. 3 illustrates the performance of the device in elevation or side view. CLAIMS

2. An electrical power transmission system according to claim 1, comprising at least two high-potential power lines supported above the ground by spaced power poles and a third, neural line spanning said poles and positioned vertically below said power lines, wherein there is provided: (a) a second neutral line spanning said poles, said second neutral line being parallel to and displaced horizontally from the first neutral line for establishing a neutral plane below the high-potential power lines, the horizontal distance between the first and second neutral lines being less than the distance between the high-potential power lines; ; (b) at least one electrically conductive rod connected transversely to and supported by the first and second neutral lines between said poles, said rod extending horizontally beyond each neutral line, whereby a broken high-po tential power line above said rod will contact said rod when falling vertically; (c) clamping means attaching each rod to said first and second neutral lines; and (d) means for at least temporarily capturing a falling line on said rod.

3. A system according to claim 1 or 2, wherein said rod or rods have upwardly curved ends to capture, at least temporarily, a falling power line.

4. A system according to claim 1, 2 or 3, wherein a plurality of said rods are positioned on said neutral lines and spaced therealong between adjacent poles.