Motion control device for overhead transmission lines

A motion control device for an overhead utility transmission line includes a phase spacer and first and second spacer dampers connected to the phase spacer. The first spacer damper separates conductors of a first phase and the second spacer damper separates conductors of a second phase. The phase spacer separates the conductors of the first and second phases.

FIELD

Various exemplary embodiments relate to motion control devices for power transmission lines.

BACKGROUND

Utility lines are used to transmit power from a generating facility to a distribution point. Typically, high voltage conductor lines are bundled over long distances to efficiently and economically transfer power and must be spaced from one another to avoid damage.

Damage to individual conductors in bundled electrical transmission lines may be caused by unwanted movement of the conductors. Typical types of conductor movement include short-wave or Aeolian vibrations, subspan or wake-induced oscillations, and long-wave vibrations or galloping. Motion in the conductors can lead to strain and stress on the conductors or the conductor support structures and damage can result from medium and high intensity short period events or low intensity continuous Aeolian vibrations. Flashover can also occur where two conductors of different phases come near each other or touch, leading to a power surge that triggers a circuit breaker. Such undesired motions may be induced by the wind, and may have longitudinal, transverse and vertical components. Suppressing and damping of these vibrations and oscillations requires a resilient connection between the conductors (both phase to phase and within a bundle) being spaced from one another while allowing a limited amount of flexing to occur.

The motion of the conductors in a bundle may also be caused by electrical power surges, which cause the conductors in a bundle to be attracted toward the center thereof. For example, in a bundle of three conductors defining, in cross section, a triangle, a surge causes the conductors to be attracted to a point at the center of the triangle. Similarly, in a bundle of four conductors defining, in cross section, a quadrilateral, a surge causes the conductors to be attracted to a point at the center of the quadrilateral.

SUMMARY

An exemplary method of controlling motion of utility lines includes providing a utility line motion control device having, a phase spacer having a first end, a second end, and an insulating member positioned between the first end and the second end, a first spacer damper having a first body connected to the first end of the phase spacer, a first clamp connected to the first body, and a second clamp connected to the first body, the first clamp at least partially defining a first opening and the second clamp at least partially defining a second opening, and a second spacer damper having a second body connected to the second end of the phase spacer, a third clamp connected to the second body, and a fourth clamp connected to the second body, the third clamp at least partially defining a third opening and the fourth clamp at least partially defining a fourth opening. A first conductor of a first phase is connected to the first clamp and a second conductor of the first phase is connected to the second clamp. A third conductor of a second phase is connected to the third clamp and a fourth conductor of the second phase is connected to the fourth clamp. The first spacer damper is electrically isolated from the second spacer damper by the phase spacer.

According to an exemplary embodiment, a utility line motion control device includes a phase spacer having a first end, a second end, and an insulating member positioned between the first end and the second end. A first spacer damper has a first body connected to the first end of the phase spacer. A first clamp is pivotally connected to the first body. A second clamp is pivotally connected to the first body. The first clamp at least partially defines a first opening for receiving a first overhead utility line conductor of a first phase and the second clamp at least partially defines a second opening for receiving a second overhead utility line conductor of the first phase. A second spacer damper has a second body connected to the second end of the phase spacer. A third clamp is pivotally connected to the second body. A fourth clamp is pivotally connected to the second body. The third clamp at least partially defines a third opening for receiving a third overhead utility line conductor of a second phase and the fourth clamp at least partially defines a fourth opening for receiving a fourth overhead utility line conductor of the second phase.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

It is important to prevent or avoid damage to power transmission lines caused from galloping, subspan, and/or Aeolian vibrations.

FIG. 1depicts an exemplary embodiment of a motion control device10that includes a first spacer12, a second spacer14, and a phase spacer16connected to the first and second spacers12,14. The connection between the phase spacer16and the first and second spacers12,14can be fixed or rotatable. The first and second spacers12,14can be rigid spacers or spacer dampers. According to various exemplary embodiments, the phase spacer16keeps apart two groups of conductors of different phases in a span of conductors and prevents the conductors from coming close enough to each other and causing a short circuit. The first and second spacers12,14connect to conductors in each group or bundle, for example 2, 3, 4, or more conductors, to provide separation in the groups and can provide vibration dampening and/or subspan oscillation. Using the spacers12,14and the phase spacer16can reduce strain on the conductors by suppressing and damping unwanted motion.

The first and second spacer dampers12,14include a body18, a first clamp20, and a second clamp22. The first clamp20is pivotally connected to a first end of the body18and the second clamp22is pivotally connected to a second end of the body18. Each clamp20,22includes an opening for receiving a conductor. The clamps20,22can be connected to the body in a variety of manners as would be understood by one of ordinary skill in the art. The position, size, and spacing of the clamps20,22and the body18may vary dependent on the application. Although two clamps20,22are shown, the spacers can include more clamps to provide spacing for any number of conductors.

The clamps20,22include a first jaw24and a second jaw26pivotally connected to the first jaw24. The second jaw26is moveable with respect to the first jaw24from an open position to a closed position. The first and second jaws24,26may be held in the closed position by a mechanical fastener28having a first portion and a second portion. In the exemplary embodiment shown, the first portion is a bolt and the second portion is a nut, although any suitable mechanical fastener may be used. The nut can be held captive in the first jaw24so that a user does not need to worry about the nut becoming dislodged. When the first and second jaws24,26are in the closed position, the mechanical fastener28may be tightened to prevent movement of the jaws24,26with respect to one another.

The first and second jaws24,26include a clamping surface30. The exemplary embodiment shows a curvilinear clamping surface30for clamping a cylindrical conductor. Various alternative embodiments may utilize a non-round configuration, for example an elliptical or polygonal configuration, to clamp different shaped conductors.

According to an exemplary embodiment, the first and second spacers12,14can include an additional vibration damper feature. This damper feature helps to reduce vibrations in or between conductors. The damper feature includes resilient elements or materials used in the spacer damper. For example, an elastomeric material can be used on the clamping surfaces to help reduce vibrations. A vibration damper feature can alternatively, or additionally, be present at the connection between the clamp20,22and the body18. For example an elastomeric element can be positioned around or between each clamp20,22and the body18. The pivotal nature of the clamps20,22with respect to the body18and the rigidity of the body18can also act as a damper feature.

According to an exemplary embodiment, the phase spacer16includes a first section32and a second section34. The first and second sections32,34can be adjustably connected to one another, such as a pivoting and/or linearly moveable connection. For example, an adjustable fastener can be used to connect the first and second sections32,34and the fastener can be tightened to retain the first section32relative to the second section34once a desired position has been achieved. The first and second sections32,34can also be integrally formed or fixedly attached. The first section32is connected to the first spacer12and the second section34is connected to the second spacer14. In an exemplary embodiment, the connection between the phase spacer16and the first and second spacers12,14can be a moveable connection, for example a pivoting or sliding connection either freely moveable or selectively moveable by a user. The connection can include a mechanical fastener or other suitable device or an integral connection.

In an exemplary embodiment, the first and second sections32,34include portions having insulating material and may also include insulation members, for example a plurality of insulation fins36. The inner portions of the phase spacer16and the insulation fins36can be made from materials including silicone, polymers, ceramics, elastomers, for example EDPM, fiberglass, or other non or low conductive insulating materials. The connection points of the phase spacer16near the first and second spacers12,14can be made from a material that includes metal. In an exemplary embodiment, the phase spacer16can include a first and second ring38. The rings38can be positioned at the transition points between the metal material and the insulating material where an electric field may be concentrated to prevent corona discharge.

The foregoing detailed description of the certain exemplary embodiments has been provided for the purpose of explaining the general principles and practical application, thereby enabling others skilled in the art to understand the disclosure for various embodiments and with various modifications as are suited to the particular use contemplated. This description is not necessarily intended to be exhaustive or to limit the disclosure to the exemplary embodiments disclosed. Any of the embodiments and/or elements disclosed herein may be combined with one another to form various additional embodiments not specifically disclosed. Accordingly, additional embodiments are possible and are intended to be encompassed within this specification and the scope of the appended claims. The specification describes specific examples to accomplish a more general goal that may be accomplished in another way.

As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the exemplary embodiments of the present application, and are not intended to limit the structure of the exemplary embodiments of the present application to any particular position or orientation. Terms of degree, such as “substantially” or “approximately” are understood by those of ordinary skill to refer to reasonable ranges outside of the given value, for example, general tolerances associated with manufacturing, assembly, and use of the described embodiments.