physics

Optical attached cable

Optical attached cable is a physics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Optical attached cable rather than just read about it. In short: Optical attached cable (OPAC) is a type of fibre-optic cable that is installed by being attached to a host conductor along overhead power lines. The attachment system varies and can include wrapping, lashing or clipping the fibre-optic cable to the host.

Key takeaways

Optical attached cable belongs to physics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Optical attached cable to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Optical attached cable from memory before moving on to harder problems.

Reference excerpt

Optical attached cable (OPAC) is a type of fibre-optic cable that is installed by being attached to a host conductor along overhead power lines. The attachment system varies and can include wrapping, lashing or clipping the fibre-optic cable to the host. Installation is typically performed using a specialised piece of equipment that travels along the host conductor from pole to pole or tower to tower, wrapping, clipping or lashing the fibre-optic cable in place. Different manufacturers have different systems and the installation equipment, cable designs and hardware are not interchangeable. Although lashed cable systems and clipped cable systems have been investigated as a means of attaching optical fibre cables to overhead power lines, wrapped cables were the first type to be developed and are the only type in common use today. Wrapped cable systems were developed independently in the UK (SkyWrap) and Japan (GWWOP) during the 1980s and have been widely used, with installations in every continent except Antarctica. Through licensing and through independent development, wrapped cable systems have also been supplied by French, Italian, German and Russian companies. The installation process for wrapped cables involves passing a drum of cable around and around the host conductor as the carrying device moves across the span. For installation on hosts within 10 m of the ground (medium or low voltage overhead lines), it is possible to pull the wrapping machine by hand from the ground below the line. However, a radio-controlled power unit using batteries or a petrol engine is normally required when the host conductor is on a high voltage transmission line. Wrapped cables can be applied to earth wires (ground wires, shield wires) on power transmission lines and to phase conductors on transmission, sub-transmission or distribution lines. SkyWrap is the most successful example of OPAC and is used together with more familiar optical fibre cables such as optical ground wire (OPGW) and all-dielectric self-supporting cable (ADSS) to build communications networks for power utilities.

Etymology The generic International Electrotechnical Commission (IEC) and IEEE designation for attached cable is OPAC. OPAC can be used in the same sense as the nomenclature OPGW and ADSS. OPAC refers specifically to fibre-optic cables and specifically to installations where the host conductor is part of the electricity supply system. Installations using metallic cables (coax or copper telephone cables) or messenger wires as the host are not covered by the term OPAC. The term ground-wire wound optical cable (GWWOP) is sometimes used to describe wrapped fibre-optic cables for installation on power lines. and may be a brand name owned by Furukawa Electric of Japan. The Russian language description for wrapped cable technology is "ОКНН" (оптоволоконного кабеля неметаллического навивной) (in English: OCNN = Optical Cable, Non-metallic, coiling or wrapping (Navivnoj)). The French language term is "Câble Optique Enroulé" (COE) The name SkyWrap is one of three related brand names introduced by FOCAS in 1990 to describe its fibre-optic cable products used in the construction of power utility communications networks, the others being SkyLite OPGW and SkySpan ADSS. When AFL acquired FOCAS in 2000, the SkyLite and SkySpan brand names were dropped but SkyWrap has continued to be used. Prior to 1992 the brand name was Rayfos. The Rayfos name is owned by Raychem Corporation, who developed the technology before selling it to FOCAS. Rayfos is a portmanteau name constructed from "Raychem" and "fibre optic system".

History

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Optical attached cable

Start with the simplest possible case. Write down what Optical attached cable claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Optical attached cable before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Optical attached cable ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Optical attached cable

In research: Optical attached cable appears in physics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Optical attached cable in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Optical attached cable is common in secondary-school and first-year university syllabi. It links to neighbouring topics Optical fiber, so understanding it makes those chapters shorter.
In everyday life: Look for Optical attached cable outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Optical attached cable in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Optical attached cable means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Optical attached cable out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Optical attached cable in simple terms?

Why does Optical attached cable matter?

Because it connects several physics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Optical attached cable?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Optical attached cable.