Live conductor stringing, maintenance and repair method

The present invention relates to replacing conductors in a high-voltage power transfer system. The method provides, for example, a method for maintaining sections of electrically conductive phases in a three-phase power conductor line, wherein the three phases are parallel and spaced apart in an ordered sequence. The phases are strung between support structures and supported above the ground. Maintenance work, which include replacement or repair, is performed on sections of the three phases without interrupting a power load in any one of the three phases and without transposing the relative positions of the phases out of their ordered sequence.

FIELD OF THE INVENTION

The present invention relates generally to high voltage power transfer systems. In particular, the present invention relates to replacing conductors in a high voltage power transfer system.

BACKGROUND OF THE INVENTION

Users of large amounts of electrical power such as cities, manufacturing facilities, and other high-power users are often located quite a distance away from sources of electrical power such as hydroelectric dams and power plants. In order to deliver large amounts of power from the source of generation to the power consumers, large, high-capacity, high-voltage power lines are used.

Typically, alternating current (“AC”) is generated in a three-phase configuration. For the purposes of this document, the three phases will be referred to as A, B and C phase. A phase, B phase and C phase are all transported over separate conductors. In some instances direct current (DC power) is used in which case two conductors are used and are referred to as A and C phase. Typically, the conductors are comprised of long wires supported on large support structures such as towers or power poles. The separate A, B and C phase conductors are typically attached to the same support structures on insulators.

From time to time, the power lines transporting the power may require maintenance. For example, a section of the conductor may need to be replaced, an insulator insulating the power line from the support structure may need to be replaced, or, the support structure itself may need repair or replacement. In some cases, conductors may be functioning properly, but need to be replaced by higher-capacity conductors in order to transport more power.

Typical maintenance on power lines requires that the power be shut off before the line can be worked on. High induction currents may be induced into a conductor located in the proximity of other high voltage conductors, thus creating a hazard in order to work on a particular conductor.

Shutting off the power creates a disruption of power delivery to customers. A power user may be forced to do without power during the time the power line is maintained, which is undesirable for a variety of reasons. To provide consumers power while a particular line is being worked on, the load may be shifted to other power lines to deliver the power to the end user. Unfortunately, shifting power to other transmission lines is not always possible because redundant systems may not exist, or transmission lines may already be operating at or near capacity level and not able to deliver the required power.

Previously, the applicant developed methods for conducting maintenance work on energized high voltage conductors in electrical transmission systems, such as the methods described in the U.S. Pat. No. 7,535,132 issued on May 19, 2009 to Quanta Associates, L.P. One of the methods taught in U.S. Pat. No. 7,535,132 involves moving each of the conductors needing replacement to a temporary position, stringing new conductors in or near the originating positions of the old conductors, transferring the power load from each of the old conductors to each of the new conductors using transfer buses, and removing the old conductors.

However, one problem that often occurs during the execution of the methods described in U.S. Pat. No. 7,535,132 is that the movement of each of the old conductors requiring replacement to temporary positions at the same time will often result in the transposition of the conductors carrying phases A, B and C, whereby, for example, if the phases were originally arranged in the relative horizontal positions of A-B-C prior to moving the phases to their temporary positions, the relative horizontal positions may often end up in the positions B-A-C after the movement has occurred. Furthermore, in order to achieve moving all three phases to temporary positions at the same time using the methods described in U.S. Pat. No. 7,535,132, it is often necessary to utilize long jumper cables to connect the temporarily relocated section of conductor to the remaining sections, which jumper cables for one phase must necessarily cross over the conductors of another phase while carrying a power load, as illustrated in FIG. 35 of U.S. Pat. No. 7,535,132. These are examples of what the Applicant refers to as illegal transpositions of the phase conductors. The disclosure of U.S. Pat. No. 7,535,132 is incorporated herein in its entirety, and is hereinafter referred to as the '132 patent.

Both scenarios described above results in the transposition of the phase conductors, leading to an imbalance in the impedances of the phase conductors and therefore, fluctuations in the voltage and current carried on the phase conductors. Such fluctuations, if large enough, will cause the protective relays to trip the breakers, causing a disruption in the delivery of power on the transmission lines being worked upon. To avoid this result, the owner of the power transmission line may choose to disable the safety relays while a live reconductoring project is underway. However, disabling the safety relays results in a risk that a sudden fluctuation in the voltage and current during the live reconductoring project may damage the transmission network.

Accordingly, it is desirable to provide an improved method to allow high voltage power transmission lines to be worked on, replaced or maintained without requiring power to stop being delivered or diverted over to other remote transmission lines, and without resulting in the illegal transposition of the phase conductors that could lead to faults in the transmission line.

SUMMARY

One example embodiment of the present invention provides a method for maintaining a section of an electrified, three-phase power conductor line, wherein the three phases are in a common plane, in an ordered sequence and strung between a set of support structures, wherein at least two equal potential zones are employed in communication with at least one of said three phases, the method comprising steps of:a) positioning at least one auxiliary support substantially adjacent the set of support structures so as to support an electrified section of a first phase-needing-maintenance,b) moving said section of said first phase-needing-maintenance so as to be strung upon said at least one auxiliary support and said at least two auxiliary dead end supports, wherein said first and second dead end junctures are supported by said at least two auxiliary dead end supports,c) stringing a first new phase conductor between the set of support structures where the section was moved from,d) electrically connecting a first transfer bus and a second transfer bus to said first new phase conductor,e) electrically connecting said second conductor of said first transfer bus and said second conductor of said second transfer bus to a second phase section of a second phase-needing-maintenance that is proximate to said first phase-needing-maintenance, wherein said second phase section comprises a third dead end juncture and a fourth dead end juncture,f) electrically connecting said first transfer bus so as to bring said first new phase conductor to an electrical potential that is equal to said second phase-needing maintenance,g) completing a first electrically parallel connection between said first new phase conductor and said second phase-needing-maintenance,h) electrically connecting said new phase conductor to a first segment of said second phase-needing-maintenance on opposite sides of said third dead end juncture, and electrically connecting said first new phase conductor to a second segment of said second phase-needing-maintenance on opposite sides of said fourth dead end juncture, so as to complete a second electrically parallel connection between said first new phase conductor and said second phase-needing-maintenance,i) electrically disconnecting said section of said second phase-needing-maintenance so as to isolate said second phase section of said second phase-needing-maintenance from said first and second segments of said second phase-needing-maintenance and said first new phase conductor, andj) maintaining said second phase section of said second phase-needing-maintenance.

Another example embodiment of the present invention provides a method for maintaining sections of electrically conductive phases in a three phase power conductor line, the three phases denoted as the A, B and C phases, wherein the three phases are parallel and spaced apart in an ordered sequence wherein the A phase is proximate to the B phase and the B phase is proximate to the C phase, but the A phase is not proximate to the C phase, and wherein the A, B and C phases are strung between support structures supporting the three phases suspended above a ground, and wherein maintenance work is performed on sections of the three phases without interruption of a power load in any one of the three phases and without transposing the relative positions of the A, B and C phases out of their ordered sequence, wherein at least two equal potential zones are employed in communication with at least one of said A, B and C phases.

Another example embodiment of the present invention provides a method of maintaining sections of electrically energized phases in a three phase power conductor line, the three phases being an A phase, a B phase and a C phase, the method comprising:a) providing, between two support structures above a ground surface, the A phase is proximate to the B phase, the B phase is proximate to the C phase and the B phase is located between the A phase and the C phase with the phases all in a common plane;b) without interrupting an alternating current power of the A phase, the B phase and the C phase, performing maintenance work on sections of the A phase, the B phase and the C phase;c) without interrupting an alternating current power of the A phase, the B phase and the C phase, non-transposing the relative positions of the A phase, the B phase and the C phase; and,d) employing at least two equal potential zones in conjunction with at least one of said A phase, B phase and C phase.

As described in the '132 patent entitled Live Conductor Stringing and Splicing Method and Apparatus, the disclosure of which is incorporated herein by reference in its entirety, a person ordinarily skilled in the art will readily understand how to employ the aforementioned stringing method described above, including the construction of equal potential zones, the use of hot line tools and live line work methods that are described in the '132 patent specification. In particular, see FIGS. 57 through 98 and column 22, line 48 through column 33, line 60 of patent '132.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention will now be described with reference to the Figures, in which like reference numerals refer to like parts throughout. An embodiment in accordance with one aspect of the present invention provides an improved method for replacing high-voltage power transmission conductors without affecting power users or power suppliers. The method avoids a requirement of having the power transmitted by the conductors shut off or diverted to other remote power transmissions systems. The method also avoids an illegal transposition of the phase conductors when transferring the power loads from a phase conductor to a proximate phase conductor during the maintenance or repair work, which illegal transposition may otherwise lead to faults in the transmission line.

As stated above, power delivery systems such as high voltage power lines often transport Alternating Current (“AC”) power in a three phase configuration. Direct Current (“DC”) power systems transfer power over two phases. Each phase is transferred over a separate conductor. For the purposes of this specification, each of the letters A, B, and C will represent one of three phases of a three-phase AC system. The methods and apparatus described herein can be adapted for use in a DC system by applying the methods and apparatus described herein for the A and B phases for the two phases of a DC system and where reference is made, for example in the claims, to the A, B and C phases, such references are intended to include merely the A and B phases for a DC implementation. Systems carrying voltages of 44 kV or higher are contemplated in the embodiments of the present invention.

In addition, throughout this specification there is often reference to a fourth phase conductor, referred to as the “D phase” conductor. The D phase conductor, as that term is used in this specification, denotes a section of a phase conductor that is not electrically connected to any of the phase conductors that are carrying the A, B or C phases. In other words, the D phase is not carrying the current of any of the A, B, or C phases. Throughout the Figures illustrating examples of embodiments of the present invention, a phase conductor labelled as the “D phase” conductor in one figure may be labelled as an A, B or C phase conductor in the next Figure, where the “D phase” conductor becomes electrically connected to another phase conductor carrying the A, B or C phase current. For example, seeFIGS. 12 and 13, wherein the “D phase” conductor114inFIG. 12becomes a “B phase” conductor114inFIG. 13, upon establishing an electrical connection between the conductor114and the original B phase conductor102(B) when the breaker142connected to the second transfer bus118″ is closed. In each Figure of this specification, a phase conductor is either labelled “D phase”, when it is electrically isolated from any other phase conductors in the power transfer system100, or it is labelled “A phase”, “B phase” or “C phase” when the phase conductor is carrying the A, B or C phase current, or is otherwise electrically connected to a phase conductor that carries either the A, B or C phase current.

In an embodiment of the invention, a section of a first conductor located between two dead end junctures is moved to a temporary position on temporary support structures. The dead end junctures of the section of the first conductor are also transferred to the temporary positions on the temporary support structures. A new conductor is then strung in or near the old conductor's originating position, and the power load from a first proximate phase-needing-maintenance is transferred to the new conductor. Once the power load from the first proximate phase-needing-maintenance is transferred to the new conductor, a section of the old conductor of the first proximate phase-needing-maintenance is removed and replaced with a second new conductor. Once the second new conductor is in place, the power load of a second proximate phase-needing-maintenance is transferred to the second new conductor, enabling work to be conducted on a section of the second proximate phase-needing-maintenance conductor. This procedure is repeated until all of the proximate phase conductors requiring maintenance work have had their power loads transferred to other phase conductors. Once all of the maintenance work is complete, the power loads of each phase are consecutively transferred to the phase conductors strung into the positions where each phase was originally carried. This procedure provides for maintenance work to be conducted on high voltage transmission lines, without having to interrupt the supply of power to users and avoiding the illegal transposition of the respective phase conductors during the transfer of the power load from one phase conductor to an adjacent phase conductor.

FIGS. 1 through 43generally show, in schematic diagrams, a power transfer system100undergoing consecutive stages of a method in accordance with an embodiment of the invention, so that a section of a phase conductor to be worked on may be electrically isolated from the system power. As used herein, the term “maintenance work” includes the replacement of the phase conductor, and may also include maintenance of the conductor, replacement of insulators, resagging of the conductor, all without disrupting the transmission of power to downstream power customers.

In many instances there may be miles between dead end junctures. If the distance between the dead end junctures for a particular section of phase conductor to be worked upon is too great for pulling new conductors through the system100, then new or temporary dead end junctures may be constructed as described later herein.

The temporary relocation of a phase conductor, the stringing of new phase conductor in a position at or near the originating position of the phase conductor, and the process of successively transferring the power load from an adjacent phase to the new conductor such that the next phase may be isolated and worked upon, will now be described with reference toFIGS. 1-43.

FIG. 1is a schematic diagram for power transfer system100. The power transfer system100includes three conductors102, labeled A phase, B phase and C phase, indicating that each of the conductors102carries one of the A, B, or C phase load. The system100transfers power in the form of AC, although this is not intended to be limiting as the method described herein may be used for DC power systems. The conductors102are supported by support structures104. Each support structure104may include or be in the form of a power pole or a tower. One example of a support structure104, not intended to be limiting, is seen inFIG. 2. Other support structures are seen in FIGS. 53, 55 and 56 of the '132 patent. A conductor102is attached to dead end support structures103via insulators in tension106(hereinafter insulators106). As seen inFIG. 1, dead end junctures110′,110″ are formed by a pair of insulators106when in-line with conductors102and under tension with conductors102. Jumper cables108, as shown inFIG. 1, electrically connect conductors102around insulators106and dead end support structures103to an oppositely disposed section of conductors102.

Another way conductor102may be supported by support structure104is shown for example inFIG. 2. The conductor102hangs from tangent insulator116. Tangent insulator116is supporting both the conductor tension and the weight of conductor102. When the weight of conductor102is being supported by tangent insulator116, jumper cables108are not required.

In some embodiments of the present invention, a temporary support structure (otherwise referred to as an auxiliary support)112is constructed near the location of an existing support structure104, as shown inFIGS. 2 and 3. The temporary support structure112is preferably located near or adjacent the location of an existing support structure104, whereby the distance L between the original location95and the temporary location96of the A phase conductor102is substantially equivalent to the phase spacing J between phases A and B and between phases B and C, when those phase conductors,102(A),102(B) and102(C) respectively, are suspended on the existing support structure104. The temporary support structure112may be located adjacent the existing support structure104, or in the alternative the temporary support structure112may be connected to the support structure104as shown in FIG. 54 in the '132 patent, for example.

Once the temporary support structures112are in place, a section87of the A phase conductor102(A) located between dead end junctures110′ and110″ is removed from the original location95on the existing support structures104and transferred to the temporary position96on the temporary support structure112.FIG. 4shows the transfer of the A phase conductor102(A) from its original location95on support structure104to the temporary location96on temporary support structure112, using a robotic mechanical arm device101, such as the Remote Manipulator for Manipulating Multiple Sub-conductors in a Single Phase Bundle described in the Applicant's U.S. Pat. No. 8,573,562, or similar robotic mechanical arm device adapted to manipulate heavy energized conductors such as the A phase conductor102(A).

As seen inFIG. 5, although there are only two temporary support structures112, it will be appreciated by a person ordinarily skilled in the art that a section of phase conductor102to be replaced may be supported by numerous support structures104and that more than two temporary support structures112may be required to support the section of the phase conductor102that needs to be transferred to a temporary location96. Furthermore, it will be appreciated by a person skilled in the art that a section of a different phase conductor, such as a section of the C phase conductor102(C) illustrated inFIG. 3, may alternatively be moved to a temporary position96adjacent the originating position95of conductor102(C) in accordance with the procedure described above with respect to conductor102(A) and that such procedure would be within the scope of the present invention described herein.

As illustrated inFIGS. 6 and 7, once the section87of phase conductor102(A) that is the subject of maintenance work has been moved to temporary support structures112, each of the dead end junctures110′,110″ at either end of the section87of phase conductor102(A) are transferred to temporary dead end poles (otherwise referred to as auxiliary dead end supports)113′,113″. It will be readily understood by a person ordinarily skilled in the art, having read this specification, that although two temporary support structures112,112are illustrated inFIG. 7, that it is possible to carry out the procedure described herein utilizing a single temporary support structure112, or otherwise to utilize more than two temporary support structures112, to support a section87of phase conductor102(A).

The section87of conductor102(A) is mounted to the temporary dead end pole113′,113″ while the jumper cable108remains attached to the phase conductor102(A), such that the power load on the phase conductor102(A) continues to be transferred around the dead end juncture110′,110″ by the jumper cables108while the section87of phase conductor102(A) is being relocated.FIG. 8shows a first new phase conductor114(also referred to as the D phase) strung into the original location95of the A phase conductor102(A). The first new phase conductor114becomes the D phase conductor, as the new phase conductor114, with the exception of any induced current caused by the surrounding current-carrying phases, initially does not carry any power load after being strung into place.

In many of the schematic diagrams of this patent specification, beginning withFIG. 8, an ellipses or a circle is sometimes used to highlight a feature illustrated in the schematic diagram that has been added or which has changed from the immediately preceding Figure. For example,FIG. 8shows an ellipses around the new phase conductor114strung into the original location95of the A phase conductor102(A), which is a new feature not illustrated in the immediately precedingFIG. 7. It is understood that such ellipses and circles are merely included to clearly illustrate the changes that occur in the sequential steps of a preferred embodiment of the present method invention described herein, and are not themselves representing features of the power transfer system100.

Once the new phase conductor114is in place, the power load is transferred from an adjacent phase conductor102to the new D phase conductor114. In the example illustrated inFIGS. 9-20, the B phase load in conductor102(B) will be transferred to the D phase conductor114. One way to accomplish the power transfer is with a temporary transfer bus118′,118″.

FIG. 43shows a preferred embodiment of a temporary transfer bus118constructed of substantially rigid conductors120,120, an insulator94located between the two conductors120,120, arranged in a substantially co-linear relationship with respect to the conductors120,120, bus clamps123,123and a plurality of connectors121for temporarily attaching a jumper cable108or other conductor to one of the conductors120of the transfer bus118. Each of the conductors120of the transfer bus118are attached to a tangent insulator116by means of a bus clamp123. Each tangent insulator116is suspended from either an existing phase conductor102or a new phase conductor114. Once the temporary transfer bus118is in place, there is no electrical connection between the rigid conductors120of the transfer bus118due to the intervening transfer bus insulator94. An electrical connection may be established across the insulator94of the transfer bus118by means of a jumper cable108attached to one or more of a plurality of connectors121located on each of the rigid conductors120. Optionally, and as further discussed below and illustrated inFIG. 43, the electrical connection across the insulator94of the transfer bus118may also be established by means of a switch140(illustrated inFIGS. 44 and 45) or preferably, a breaker142, whereby jumper cables148,150are used to connect each of the first and second bushings,144,146of the breaker142to the first and second rigid conductors120,120respectively of the transfer bus118.

As mentioned above, care must be taken when connecting or disconnecting an energized conductor from another conductor in high voltage applications such as the voltages associated with high voltage power lines, because when the conductors are near each other, either before connection or after the disconnection, a large potential will exist between the energized conductor and the non-energized conductor. Due to the large electrical potential between the conductors, large arcs can form between the conductors if the difference in potential is high enough.

Thus, there are three options for establishing and breaking an electrical connection between the rigid conductors120of the transfer bus118across the insulator94. First, live line equipment such as hot sticks may be used to physically connect each end of a jumper cable108to a conductor120of the transfer bus118, as illustrated inFIG. 48. Second, a conductor including a switch140may be connected to each conductor120of the transfer bus118. The switch140will initially be set in the open position before the connection of the switch to each conductor120of the transfer bus118is made, and each conductor120of the transfer bus118may then be connected to a phase conductor102or new phase conductor114using jumper cables134(seeFIGS. 9 and 9a) and hot sticks. Once each of the two conductors120,120of the transfer bus118are electrically connected to either the phase conductor102or phase conductor114, the switch140may be closed to establish the electrical connection between the two conductors102,114. Similarly, the third option of establishing an electrical connection between two conductors120,120across the insulator94of a transfer bus118is similar to the second option described above, except that a breaker142is used in place of the switch, as shown inFIG. 43, and will not be repeated here.

Which method to use, the hot sticks and jumper cable, the switch or the breaker depends on several factors. Two factors to consider are the electrical potential between the conductors to be connected and the mass of the non-energized conductor that is to be connected to the energized conductor across the transfer bus118. If the mass of the conductor to be connected and/or the voltage potential is relatively minor, the two conductors may be connected across the transfer bus by a jumper cable108using hot sticks. As the mass of the conductor to be connected to the energized conductor increases and/or the voltage difference between the two conductors increases, a switch may be used to establish the electrical connection across the insulator94of the transfer bus118; finally, with conductors having a large mass and/or a large voltage potential between the conductors, a breaker142is used to establish the connection across the insulator94of the transfer bus118. In the preferred embodiment of the method described below, which is not intended to be limiting in any way, the electrical connection is established across the insulator106of the transfer bus118by means of a breaker142; however, it will be well understood by a person ordinarily skilled in the art that the electrical connection may also be established across the insulator94of the transfer bus118by means of a switch140or by means of a length of a conductor, such as for example a jumper cable108, depending on factors which include the electrical potential and the mass of the non-energized conductor that is to be connected to an energized conductor, as described above.

Once the D phase conductor114is in place, the power load is transferred from the conductor102(B) of the B phase line onto the D phase conductor114over the course of several steps.FIG. 9shows that one rigid conductor120of a first transfer bus118′ is electrically connected to the D phase conductor114by means of a jumper cable134.FIG. 10shows one rigid conductor120of a second transfer bus118″ is electrically connected to the D phase conductor114by means of a second jumper cable134. InFIGS. 9 and 10, although it appears that the rigid conductors120of each of the transfer buses118′,118″ that are opposite of the rigid conductors120connected to the D phase conductor114by means of the jumper cables134,134are in close proximity to the B phase conductor102(B), there is no physical or electrical connection between those rigid conductors120of the transfer buses118′,118″ and the B phase conductor102(B), as the transfer buses118,118are positioned either above, or preferably, below the B phase conductor102(B).

As illustrated inFIGS. 11 and 12, once the breaker142of each transfer bus118′,118″ is confirmed to be set in the open position, a jumper cable134is used to electrically connect a rigid conductor120of each transfer bus118′,118″ to a section90of the B phase conductor102(B) located between two dead end junctures110′,110″. As illustrated inFIG. 12, once the first rigid conductors120of each transfer bus118′,118″ are each connected to the D phase conductor114and the second rigid conductors120of each transfer bus118′.118″ are connected to the B phase conductor102(B), the breaker142on each transfer bus118′,118″ remains in the open position and therefore the D phase conductor114remains de-energized.

InFIG. 13, the breaker142of transfer bus118″ is closed, thereby establishing an electrical connection between the energized B phase conductor102(B) and the new phase conductor114, whereby the new phase conductor114is brought to the same voltage potential difference as the B phase conductor102(B). Because the new phase conductor114shown inFIG. 13is connected to the B phase conductor102(B) at only one location, current is flowing only over the B phase conductor102(B) and not over the new phase conductor114. The new phase conductor114has the same electrical potential as the B phase conductor102(B), but the new phase conductor114does not yet transport a power load.

In order for current to flow through the new phase conductor114, the breaker142of the transfer bus118′ must be closed, as shown inFIG. 14. Once the breakers142,142on each of the transfer buses118′,118″ are closed, a parallel path is created for the B phase current to run through both the new phase conductor114and the original B phase conductor102(B).

As illustrated inFIG. 15, at one of the dead end juncture110′ on opposite ends of section90of the original B phase conductor102(B), one end of a long jumper cable111is connected to a section91of the original B phase conductor102(B) that is oppositely disposed on dead end juncture110′, and the other end of the long jumper cable111is connected to the new phase conductor114, creating a parallel connection for the B phase current to flow around the dead end juncture110′. As shown inFIG. 16, jumper cables108,108are removed from around one dead end juncture110′ on the B phase conductor102(B). The removal of the jumper cables108,108can, if the voltage and/or the mass of the conductor102(B) is low enough, be removed by using hot sticks. If the voltage and/or mass of the conductor102(B) are too high, other means of breaking the connection around the dead end juncture110′ may be used which may include a switch or breaker described in greater detail above.

As shown inFIG. 17, at the second dead end juncture110″ on the opposite end of the section90of the original B phase conductor102(B), one end of a long jumper cable111is connected to a section (or otherwise referred to as a “segment”)92of the B phase conductor102(B) that is oppositely disposed of dead end juncture110″, and the other end of the long jumper cable111is connected to the new phase conductor114, creating a parallel connection for the B phase current to flow around the second dead end juncture110″. As shown inFIG. 18, jumper cables108,108are removed from around the second dead end juncture110″ of the original B phase conductor102(B).

InFIG. 19, the breaker142of one transfer bus118′ is opened. The effect of opening one breaker142is that the current no longer flows through the section90of the original B phase conductor located between the dead end junctures110′,110″. All of the B phase current now flows through the new conductor114rather than the original B phase conductor102(B). However, because the breaker142of the other transfer bus118″ remains closed, an electrical connection still exists between the original B phase conductor102(B) and the new conductor114at one point; therefore, the electrical potential between the original B phase conductor102(B) and the new phase conductor114remains the same.

To electrically isolate the section90of the original B phase conductor102, the breaker142of the second transfer bus118″ is opened, as shown inFIG. 20. In other embodiments of the present invention, if the voltage and/or the mass of the original B phase conductor102is low enough, either a switch or a jumper cable may be substituted for the breaker142to establish and break the electrical connection between the rigid conductors120,120of the transfer bus118″. Upon opening the second transfer bus118″, section90of the original B phase conductor becomes electrically isolated from the system (except for currents which may be induced in section90of phase conductor102due to the electromagnetic effects of the surrounding current-carrying phase conductors), and the original B phase conductor therefore becomes the D phase conductor, as it no longer carries the B phase current or any phase current of the power transfer system100.

One of the jumper cables134connecting a first end of the transfer bus118″ to the new B phase conductor114is removed, de-energizing the open breaker142. The second jumper cable134connecting a second end of the transfer bus118″ to the original B phase conductor102(which is now de-energized and therefore has become the D phase conductor102) is also removed, and the temporary transfer bus118″ is then removed from the power transfer system100, as illustrated inFIG. 21. Similarly, the two jumper cables134,134connecting the transfer bus118′ at the first end to the new B phase conductor114and at the second end to the D phase conductor102are removed, and then the transfer bus118′ is removed from the power transfer system100, as shown inFIG. 22.

The section90of the D phase conductor102between the dead end junctures110′,110″ is now isolated from all B phase potential by both dead end junctures110′,110″. All current formerly carried by the D phase conductor102now travels through the new B phase conductor114. It is important to note that section90of the D phase conductor102, now isolated from the system100power load, is not void of potential. The isolated section90of the D phase conductor102is, and should be treated as, a live conductor, because the isolated section90of the D phase conductor102is subject to induced currents caused by the surrounding current-carrying phase conductors102,114and may still have a large potential with respect to ground.

At this stage in the procedure, the isolated section90of the original B phase conductor may be broken down, worked on, or replaced without disrupting downstream power delivery. For example, as illustrated inFIG. 23, the section90of the original B phase conductor102is removed and a second new phase conductor115is strung, sagged, dead ended and clipped into the position of the original B phase conductor102. In some embodiments of the invention, the original B phase line102is not removed but is rather worked on in other ways, such as replacing an insulator106. One skilled in the art can appreciate that other types of work may be done on the isolated section90of the B phase conductor102in accordance with the invention.

The above describes the procedure, illustrated inFIGS. 1-23, for moving the A phase conductor102(A) to a temporary location96, stringing a first new phase conductor114in or near the original location95of the A phase conductor102(A), transferring the power load from the B phase conductor102(B) to the D phase conductor114, electrically isolating the section90of the B phase conductor102(B) located between two dead end junctures110′,110″ from the power transfer system100, and replacing the electrically isolated section90of the B phase conductor102with a second new phase conductor115. The procedure for transferring the power load from the C phase conductor102(C) to the new D phase conductor115in accordance with the invention, described below and illustrated inFIGS. 24-28, is similar to the procedure for transferring the power load from the B phase conductor102(B) to the new phase conductor114described above.

As shown inFIG. 24, a section97of the C phase conductor102(C), located between two dead end junctures110′,110″ requires replacement or other maintenance or repair work. A first transfer bus118′, with a breaker142connected to each of the two rigid conductors120of the transfer bus118, is connected at one end to the D phase conductor115with a jumper cable134, and the opposite end of the first transfer bus118′ is connected to the section97of the C phase conductor102(C) with a second jumper cable134. A second transfer bus118″ with a breaker142connected to each of the two rigid conductors120of the transfer bus118″, is connected at one end to the D phase conductor115with a third jumper cable134, and the opposite end of the second transfer bus118″ is connected to the section97of the C phase conductor102(C) with a fourth jumper cable134. The electrical connections described above between the transfer buses118′,118″ and the phase conductors115,102(C) are established after first checking to confirm that the breaker142attached to each transfer bus118′,118″ is open.

The breaker142attached to the first transfer bus118′ is closed, thereby energizing the new phase conductor115at the same electrical potential as the C phase conductor102(C). However, because an electrical connection between the new D phase conductor115and the C phase conductor102(C) has only been established through the first transfer bus118′, although the new phase conductor115is energized it does not carry any current. The breaker142attached to the second transfer bus118″ is then closed, bringing the new phase conductor115in parallel with the C phase conductor102(C). Upon closing the breakers142,142on each of the transfer buses118′,118″, the C phase current runs in parallel on both the new phase conductor115and the C phase conductor102(C), as illustrated inFIG. 25.

Once the C phase current is carried in parallel over the new phase conductor115and the original C phase conductor102(C), the section97of the original C phase conductor102(C) located between two dead end junctures110′,110″ is electrically isolated from the power transfer system100. As shown inFIG. 26, at the first dead end juncture110′ a first long jumper cable111is connected at a first end to a first section98of the original C phase conductor102(C) extending from the first dead end juncture110′ oppositely to section97, and a second end of the first long jumper cable111is connected to the new phase conductor115, establishing a parallel path around the first dead end juncture110′ for the C phase current to flow. Similarly, at the second dead end juncture110″ a second long jumper cable111is connected at a first end to a second section99of the original C phase conductor102(C) extending from the second dead end juncture110″ oppositely to section97, and a second end of the second long jumper cable111is connected to the new phase conductor115, establishing a parallel path around the second dead end juncture110″ for the C phase current.

The breaker142connected to the first transfer bus118′ is opened, breaking the parallel circuit between the original C phase conductor102and the new phase conductor115. However, the section97of the original C phase conductor102remains at the same electrical potential as the new phase conductor115until the breaker142connected to the second transfer bus118″ is opened, as illustrated inFIG. 27. When each of the breakers142,142connected to the transfer buses118′,118″ are open, the section97of the original C phase conductor102is electrically isolated from the new C phase conductor115and becomes the D phase conductor. Although the D phase conductor102is de-energized at this stage of the reconductoring or maintenance procedure, it is again important to note that section97of the original C phase conductor102, while isolated from the system100power load, is not void of potential. The isolated section97of the original C phase conductor102is, and should be treated as, a live conductor, because the isolated section97of the original C phase conductor102is subject to induced currents caused by the surrounding current-carrying phase conductors102(C),115,114and may still have a large potential with respect to ground.

The isolated section97of the original C phase conductor102may be broken down, worked on, or replaced without disrupting downstream power delivery. For example, as illustrated inFIG. 28, the two transfer buses118′,118″ are removed, section97of the original C phase conductor102is removed, and a third new phase conductor117is strung, sagged, dead ended and clipped into the position of the original C phase conductor102. In some embodiments of the invention, the original C phase line102is not removed but is rather worked on in other ways, such as replacing an insulator106. One skilled in the art will appreciate that other types of work may be done on the isolated section97of the phase conductor102within the scope of the invention.

Once the reconductoring, maintenance and/or repair work is completed on the sections of the A, B and C phase conductors located between the dead end junctures110′,110″, the power load may be transferred to conductors located in the originating positions of the A, B and C phase conductors, as described below and illustrated inFIGS. 29-42.

As illustrated inFIG. 29, a first transfer bus118′ attached to an open breaker142is connected at a first end of the transfer bus118′ to the new D phase conductor117using a jumper cable134, and a second end of the transfer bus118′ is connected to the new phase conductor115using a second jumper cable134. A second transfer bus118″ attached to an open breaker142is connected at a first end of the transfer bus118″ to the new D phase conductor117using a third jumper cable134, and a second end of the second transfer bus118″ is connected to the C phase conductor115using a fourth jumper cable134.

As illustrated inFIG. 30, the breaker142attached to the first transfer bus118′ is then closed, thereby energizing the new D phase conductor117and bringing the new D phase conductor117to the same electrical potential as the C phase conductor115. The breaker142attached to the second transfer bus118″ is closed, thereby bringing the new D phase conductor117into parallel with the C phase conductor115, whereby the C phase current flows through both the C phase conductor115and the D phase conductor117, as shown inFIG. 30.

Next, as illustrated inFIG. 31, two jumper cables108,108are used to connect the section98of the original C phase conductor102(C) opposite the new phase conductor117across the first dead end juncture110′ to the new phase conductor117. Two additional jumper cables108,108are used to connect the section99of the original C phase conductor102(C) opposite the new phase conductor117across the second dead end juncture110″ to the new C phase conductor117across the second dead end juncture110″. Once the permanent jumper cables108are in place, the temporary long jumper cables111,111connecting each of the sections98,99of the original C phase conductor102to the C phase conductor115are removed. The connection of the jumper cables108and the disconnection of the temporary long jumper cables111is accomplished using live line equipment, such as hot sticks. Once this jumpering procedure is complete, whereby the new permanent jumper cables108are installed and the temporary long jumper cables111are removed, the C phase current continues to flow in parallel through both the new C phase conductor117and the phase conductor115, through the circuit path provided by the closed breakers142on the two temporary transfer buses118′,118″ as shown inFIG. 31.

The breaker142connected to the first transfer buses118′ is then opened, thereby breaking the parallel circuit between the new C phase conductor117and the phase conductor115. However, the phase conductor115remains energized and at the same electrical potential as the new C phase conductor117. The breaker142connected to the second transfer bus118″ is then opened, thereby de-energizing the phase conductor115, which becomes the D phase conductor because the phase conductor115no longer carries the C phase current, or any phase current, as illustrated inFIG. 32. At this stage, the two temporary transfer buses118′,118″ may be removed from the power transfer system100. Although the phase conductor115is de-energized and is not carrying current at this point in the reconductoring procedure, it must still be treated as a live conductor because the isolated D phase conductor115is subject to induced currents caused by the surrounding current-carrying phase conductors114,117and may still have a large potential with respect to ground.

As illustrated inFIG. 33, two temporary transfer buses118′,118″ connected to breakers142,142set in the open position are temporarily installed between the D phase conductor115and the B phase conductor114, by utilizing jumper cables134to firstly connect a first end of each transfer bus118′,118″ to the D phase conductor115near each of the dead end junctures110′,110″, and then secondly using jumper cables134to connect a second end of each transfer bus118′,118″ to the B phase conductor114near each of the dead end junctures110′,110″. Once the temporary transfer buses118′,118″ are installed with the breakers142,142remaining open, the B phase current continues to flow through the sections91,92of the original B phase conductor102(B) opposite of the D phase conductor115on opposing sides of the dead end junctures110′,110″ and through the B phase conductor114. As such, the B phase current continues to bypass the D phase conductor115while the breakers142,142remain open.

The breaker142connected to the first temporary transfer bus118′ is closed, energizing the D phase conductor115and bringing the phase conductor115to the same electrical potential difference as the B phase conductor114. The breaker142connected to the second temporary transfer bus118″ is closed, thereby providing a parallel path for the B phase current to flow through both the phase conductors114and115, as illustrated inFIG. 34. Once each of the two breakers142,142connected to the two transfer buses118′,118″ are closed, the B phase current flows through the section91of the original B phase conductor102(B) opposite the new phase conductor115across the first dead end juncture110′, through the long jumper cable111to the B phase conductor114, through the temporary transfer buses118′,118″ and the closed breakers142,142to the new B phase conductor115, and through the second long jumper cable111to the section92of the original B phase conductor102(B) located opposite the new phase conductor115across the second dead end juncture110″.

As illustrated inFIG. 35, two jumper cables108,108are used to connect the section91of the original B phase conductor102(B) opposite the new phase conductor115across the first dead end juncture110′ to the new B phase conductor115. Two additional jumper cables108,108are used to connect the section92of the original B phase conductor102(B) opposite the new phase conductor115across the second dead end juncture110″ to the new phase conductor115. Once the permanent jumper cables108are in place, the temporary long jumper cables111,111connecting each of the sections91,92of the original B phase conductor102(B) to the new B phase conductor115are removed. The connection of the jumper cables108and the disconnection of the temporary long jumper cables111is accomplished using live line equipment, such as hot sticks. Once this jumpering procedure is complete, whereby the new permanent jumper cables108are installed and the temporary long jumper cables111,111are removed, the B phase current continues to flow in parallel through both the new B phase conductor115and the B phase conductor114, through the path provided by the closed breakers142,142connected to each of the two temporary transfer buses118′,118″, shown inFIG. 35.

The breaker142connected to the first transfer bus118′ is then opened, thereby breaking the parallel circuit between the new B phase conductor115and the phase conductor114. However, the phase conductor114remains energized and at the same electrical potential as the new B phase conductor115once only one of the breakers142connected to the transfer buses1181,118″ has been opened. The breaker142connected to the second transfer bus118″ is then opened, thereby de-energizing the phase conductor114, which becomes the D phase conductor because the phase conductor114no longer carries the B phase current, as shown inFIG. 36. At this stage, the two temporary transfer buses118′,118″ may be removed from the power transfer system100. Although the phase conductor114is de-energized and is not carrying current at this point in the reconductoring procedure, it must still be treated as a live conductor because the electrically isolated phase conductor114is subject to induced currents caused by the surrounding current-carrying phase conductors115,102(A) and may still have a large potential with respect to ground.

As illustrated inFIG. 37, a first transfer bus118′ connected to an open breaker142is connected at one end of the transfer bus118′ to the D phase conductor114using a jumper cable134, and a second end of the first transfer bus118′ is connected to the original A phase conductor102(A) using a second jumper cable134. A second transfer bus118″ connected to an open breaker142is connected at a first end of the transfer bus118″ to the D phase conductor114using a third jumper cable134, and a second end of the second transfer bus118″ is connected to the original A phase conductor102(A) using a fourth jumper cable134.

The breaker142connected to the first transfer bus118′ is then closed, thereby energizing the D phase conductor114and bringing the D phase conductor114to the same electrical potential as the original A phase conductor102(A). The breaker142connected to the second transfer bus118″ is closed, thereby bringing the new phase conductor114into parallel with the original A phase conductor102(A), whereby the A phase current flows through both the original A phase conductor102(A) and the new A phase conductor114, as shown inFIG. 38.

As illustrated inFIG. 39, two jumper cables108,108are used to connect the section88of the original A phase conductor102(A) located opposite the new A phase conductor114across the first dead end juncture110′ to the new A phase conductor114. Two additional jumper cables108,108are used to connect the section89of the original A phase conductor102(A) located opposite the new A phase conductor114across the second dead end juncture110″ to the new A phase conductor114. Once the permanent jumper cables108are in place, the temporary long jumper cables111,111connecting each of the sections88,89of the original A phase conductor102(A) to the new A phase conductor114are removed. The connection of the jumper cables108and the disconnection of the temporary long jumper cables111is accomplished using live line equipment, such as hot sticks.

Once this jumpering procedure is complete, whereby the new permanent jumper cables108are installed and the temporary long jumper cables111are removed, the A phase current continues to flow in parallel through both the new A phase conductor114and the original A phase conductor102(A), through the path provided by the closed breakers142connected to each of the two temporary transfer buses118′,118″ as shown inFIG. 39.

The breaker142connected to the first transfer bus118′ is then opened, thereby breaking the parallel circuit between the new A phase conductor114and the original A phase conductor102(A). However, the original A phase conductor102remains energized and at the same electrical potential as the new A phase conductor114. The breaker142connected to the second transfer bus118″ is then opened, thereby de-energizing the original A phase conductor102(A), which becomes the D phase conductor because the original A phase conductor102(A) no longer carries the A phase current or any other current, as illustrated inFIG. 40.

At this stage, the two temporary transfer buses118′,118″ and the breakers142,142connected to the transfer buses118′,118″ may be removed from the power transfer system100, as illustrated inFIG. 41. Although the original A phase conductor102(A), which is de-energized and is not carrying current at this point in the reconductoring procedure and has therefore become the D phase, it must still be treated as a live conductor because the electrically isolated phase conductor102is subject to induced currents caused by the surrounding current-carrying phase conductor114and may still have a large potential with respect to ground. As shown inFIG. 42, the original A phase conductor102(A) may be removed from the temporary support structures112,112; optionally, the temporary support structures112may also be removed from the power transfer system100.

As a person ordinarily skilled in the art will appreciate, the improved method for conducting repairs and maintenance on live conductors described herein provides the ability to replace, maintain or repair one or more phase conductors without interrupting the supply of power to downstream customers by relocating a section of a phase conductor located between two dead end junctures to a temporary location, transferring the power load from a section of an adjacent conductor located between two dead end junctures to the temporarily relocated conductor, performing maintenance or repair work on the adjacent conductor, or in the alternative, replacing the adjacent conductor with a new conductor, and then repeating the steps of transferring power loads and conducting repair, maintenance or replacement on each adjacent conductor until all of the desired repair, maintenance or replacement work is complete.

Importantly, this improved method described herein enables repair, maintenance or replacement work to be conducted on live conductors while avoiding the illegal transposition of the phase conductors throughout the entire procedure. Because of the effect of induced currents and impedance on a phase conductor caused by the close proximity of additional live phase conductors, it is possible that transposing one phase conductor with respect to the other phase conductors may result in an electrical surge in one or more of the phase conductors, which in turn may trip a protective relay and result in the disruption of power delivery to downstream customers.

By way of illustrating an example of illegal transposition, consider three phase conductors carrying phases A, B and C that are arranged horizontally with respect to each other in the following order: A-B-C. In the method described herein, as illustrated inFIGS. 1-42, the relative position of each of the phase conductors, “A-B-C”, remains the same at each step of the re-conductoring procedure. In other words, at no point during the procedure described herein does the relative positions of the A, B and C phase conductors change from the original A-B-C relative arrangement; that is, at no point in the example illustrated and described herein does the method result in transposition of the phase conductors to, for example, an A-C-B arrangement or a C-A-B arrangement or any other transposed arrangement.

Furthermore, in the example of the procedure described herein and illustrated inFIGS. 1-42(see in particular,FIGS. 4 and 5), the A phase conductor102is relocated to temporary position96at a distance L from the originating position95of the A phase conductor102, wherein the distance L is substantially equal to the phase spacing distance J between C phase conductor102and B phase conductor102, and L is also substantially equal to the phase spacing distance J between B phase conductor102and the originating position95of the A phase conductor102. Temporarily relocating A phase conductor102to a temporary position96at a distance L from the originating position95that is substantially equal to the existing phase spacing J between the A, B and C phase conductors minimizes the induced current and resulting impact on the impedance on the phase conductors A, B and C that may otherwise occur if distance L was substantially shorter or longer than phase spacing J, and/or if the positions of any of the phase conductors A, B and C were to be transposed from their original A-B-C relative positioning at any point during the maintenance and repair work described herein.

An example of a procedure for stringing a de-energized, new phase conductor into a transmission system, such as for example the D phase conductor114illustrated inFIG. 8, involves connecting a traveler to a support structure, stringing a pull line (or pulling line) with at least one non-conductive end through the traveler, connecting the pull line via a swivel and a flexible isolator to the conductor, pulling the pull line through the traveler and thereby causing the conductor to be strung through the traveler, attaching the conductor to the support structure, removing the traveler from the support structure, and disconnecting the pull line from the conductor. It is known by a person ordinarily skilled in the art to use a di-electric tested section of rope installed between the pulling line and the new conductor being strung onto the support structure to provide the non-conductive end of the pull line. The Applicant recently filed United States application Ser. No. 14/664,724 filed on Mar. 20, 2015, entitled Flexible Electrical Isolation Device, the disclosure of which is incorporated herein in its entirety, which describes a flexible elongated insulator having couplings mounted at either end of the insulator. This isolation device, otherwise referred to as a flexible isolator or flexible insulator, consists of a flexible, bendable or otherwise deformable (herein collectively referred to as flexible) member to accommodate the bending radius of a traveler and is composed of a high tensile strength, dielectric material with attachment points, or couplings, on each end. The attachment points or couplings are constructed so as to control both rotation imparted by the cables and bi-directional shear induced when the couplings or attachment points pass through the conductive travelers.

A switch140may be used in place of the breaker for lighter applications. Operation using the switch in place of a breaker is basically the same and will not be repeated. The switch140is a typical air break disconnect switch. It has a disconnect blade141that can be operated to a closed position (seeFIG. 44) and an open position (seeFIG. 45). The switch140has connectors145on each end that permits conductors120,120of the transfer bus118to be electrically connected to the switch140. When the disconnect blade141is in the closed position, it provides an electrical connection between the two conductors120,120via the switch140. When the disconnect blade141is in the open position, there is no electric connection between the two conductors120,120.

The switch140has an actuator143that operates the disconnect blade141. The opening and closing of the switch is controlled by the actuator143. The switch140is supported on a frame147that provides mechanical support for the switch140. The frame147is insulated from the conductors by insulators149. According to some embodiments of the invention, the switch140may be mounted on temporary support structure or a lift apparatus, such as a boom of a vehicle or, for example, preferably a robotic mechanical arm device101adapted to manipulate heavy energized conductors such as the phase conductors102described in the Applicant's U.S. Pat. No. 8,573,562, for ease and convenience in practicing some embodiments of the invention.

The breaker142shown schematically inFIGS. 9-40 and 43will now be further illustrated and described with reference toFIG. 46. In some embodiments of the invention, the breaker142is a single pole (phase) of a 345 kV breaker that has been modified to be portable. A typical breaker of this magnitude consists of three single pole breakers mechanically connected together to be a three phase breaker and break all three circuits at once. The three phase breaker includes three breakers connected together and configured to act in unison. Because only a single phase needs to be disconnected or energized at once in many embodiments of the invention, only one pole (or phase) of a breaker is needed. To make the breaker more portable, one pole is separated from the three phase unit and modified to be portable as described in more detail below.

A breaker142in accordance with the invention may be, as an example not intending to be limiting, a 2,000 amp SF6breaker wherein SF6is an insulating gas that is used in the breaker142. In other embodiments of the invention, the breaker142could be a minimum oil breaker, or any other breaker suited to the applied voltage. The breaker142has two insulated bushings144,146projecting from a housing156. Jumpers148,150are attached to an end of the bushings144,146for connecting the breaker142to conductors.

The breaker142has a closed position that permits an electrical connection from a conductor connected to one bushing144via jumper148through the breaker142to a conductor connected to the other bushing146via jumper150. When it is desired to break the electrical connection between the two conductors120,120of the transfer bus118, the breaker142is operated to achieve an open position. In the open position, the two jumpers148,150connected to the two bushings144,146are isolated from each other.

Normally, a breaker142having the capacity for high voltage power is located in fixed locations, such as for example power generating faculties, terminals, switching stations or substations, and consists of three poles or phases. In accordance with the invention, a standard breaker142, such as a 345 kilovolt, 2,000 amp SF6breaker, is used. Because these types of breakers have three poles or phases, a single pole or phase is separated out from the other two phases and is modified so as to be portable. As shown inFIG. 46, the breaker142is mounted onto a trailer158. A support structure160mounts the breaker142to the trailer158. Optionally, the breaker142could be mounted on a truck bed or some other suitable type of vehicle.

The breaker142has a housing156from which two insulated bushings144,146project. One of the bushings144is located on what is referred to as the line side162, meaning that that bushing144connects to the conductor, for example phase conductor102, that is connected to a power source. The other side164of the breaker142is referred to as the load side164and includes the other bushing146. Within the housing156a non-conductive gas, SF6for example, is used for electrical insulation. Other breakers in accordance with the invention may be oil-filled breakers or other types of breakers suitable for the applied voltage.

A control panel166for operating the breaker142is located on the trailer158and operatively connected to the breaker142. Optionally, the control panel166may be the same one that would normally operate a standard non-portable breaker. A portable power generator168is located on the trailer158and is operatively connected to the breaker142and/or control panel166to provide power to operate the breaker142. The generator168may be gasoline powered and is of sufficient capacity to permit operation of the breaker142, including charging of the springs in the breaker142. Preferably, the generator168can produce 120 volts.

Additional containers170of SF6gas are kept on the trailer158in order to permit recharging of the breaker142with gas if necessary. The manufacturer's recommendations for gas pressure in the breaker142should be observed.

The exact modifications necessary to make the breaker142portable will vary depending on the type of breaker is being modified. A person ordinarily skilled in the art after reviewing this disclosure will be able to appropriately fashion a portable breaker142.

Before use of the breaker142, the tow vehicle is detached and the trailer158is held in place by jacks172and a wheel chocks174. The trailer158and the breaker142is bonded to ground with grounding cables176. A temporary protective fence178is constructed around the trailer158.

FIGS. 49 to 56depict a method of replacing energized high-voltage power transmission conductors while they remain energized.

FIG. 49is a front, elevation view of a schematic of a support structure104that is supporting three phases of conductors102A,102B and102C by insulators116. Each of the conductors102A,102B and102C carry an electrical load. The A phase conductor102A is positioned on the support structure104in a first conductor position400. The B phase conductor102B is positioned on the support structure104in a second conductor position402. The C phase conductor102C is positioned on the support structure104in a third conductor position404. The configuration of the support structure104depicted inFIGS. 49 to 56and, in particular the first, second and third conductor positions400,402,404may be in different positions upon the support structure104and the positions depicted are not intended to be limiting. While the first, second and third conductor positions400,402,404are depicted as being in one single, horizontal plane, these positions can be in a single plane that is not horizontal, for example it may be substantially vertical or between a horizontal plane and a vertical plane or may not be in a single plane at all. The ordered sequence of the three phases of conductors102A,102B and102C is maintained with the conductor102A adjacent conductor102B but not adjacent conductor102C. Conductor102B is adjacent, or in between, both of conductor102A and conductor102C.

FIG. 50depicts a step of installing, providing, or using an existing temporary structure112along side the support structure104. In this example, the temporary structure112provides a fourth conductor position406. The C phase conductor102C is transferred in step200from the support structure104to the fourth conductor position406on the temporary structure112. A first replacement conductor300is strung in to the position on the support structure104where the C phase conductor102-C was located, in other words at the third conductor position404.

FIG. 51depicts a transferring step202wherein the electrical load of the B phase conductor102B is transferred to the first replacement conductor300in the third conductor position404. The B phase conductor102B is replaced by a second replacement conductor302. At this step in this method, the electrical load of the C phase conductor102C is carried through the C phase conductor102C, which is supported on the fourth conductor position406by the temporary structure112. The electrical load of the B phase conductor102B is carried through the first replacement conductor300in the third conductor position404.

FIG. 52depicts transferring step204wherein the electrical load of the A phase conductor102A is transferred to the second replacement conductor302in the second conductor position402. The A phase conductor102A is the replaced by a third replacement conductor304.

FIG. 53depicts transferring step206wherein the electrical load on the second replacement conductor302is transferred to the third replacement conductor304.

FIG. 54depicts transferring step208wherein the electrical load on the first replacement conductor300is transferred to the second replacement conductor302.

FIG. 55depicts transferring step210wherein the electrical load from the C phase conductor102C is transferred to the first replacement conductor404.

During this method, the electrical load of the C phase is transferred from the third conductor position404to the fourth conductor position. The electrical load of the B phase is transferred from the second conductor position402to the third conductor position404. The electrical load of the A phase is transferred from the first conductor position400to the second conductor position402. Between each of these transfer steps, an old conductor is replaced with a new, replacement conductor wire. Then the steps are reversed with the electrical load of the A phase being transferred back to the first conductor position400from the second conductor position402, the electrical load of the B phase being transferred back to the second conductor position402from the third conductor position404, the electrical load of the C phase being transferred back to the third conductor position404from the fourth conductor position406. In this fashion illegal transpositions of the A, B and C phases are avoided while the electrical loads of the A, B and C phases are returned to their original conductor positions, now carried through new conductor lines300,302,304, as depicted inFIG. 56.

The various embodiments of the method of the invention described herein, temporarily relocating a phase conductor102, stringing a D phase conductor into place and using the D phase conductor to successively and in sequence transfer the electrical loads from proximate conductors, permits sections of new conductors, located between dead end junctures, to be strung one at a time. If it is desired to string new conductors along the entire length of a system100, or a length longer than practical for stringing conductors, then the re-conductoring methods are used for lengths that are practical and repeated along the length of the system until a desired length of new conductor is installed along the system.

It is appreciated by one skilled in the art, that in some power transfer systems100, more than one conductor102carries the power load for a particular phase. This may be done in instances when a power load is greater than a single-phase conductor can accommodate. In such cases, multiple (bundled) phase conductors102are often located next to each other and may hang from the same insulator116as shown inFIG. 47. The conductors may be separated by spacers198. Such bundle conductor systems100may be re-conductored in accordance with the invention by application of the procedures described herein to each conductor102.

While the above disclosure describes certain examples of the present invention, various changes, adaptations and modifications of the described examples will also be apparent to those skilled in the art. The scope of the claims should not be limited by the examples provided above; rather, the scope of the claims should be given the broadest interpretation that is consistent with the disclosure as a whole.