Optical Power Ground Wire（OPGW）

1. OPGW Application

OPGW name is" Optical fiber composite overhead Groud Wire", in power system communication, OPGW cable is a composite line with common overhead ground line and optical communication capability，it is mainly used for 35kV and above communication lines of overhead high voltage transmission system. It can also be used to replace the ground wire of the old overhead high voltage transmission system, increase the optical communication line, transmit the short-circuit current and provide protection against lightning strike, integrating the ground wire and optical communication functions as a whole. OPGW common voltage are 66kV, 132kV, 230kV, 500kV, 750kV.

OPGW Not only can protect against lightning strikes, but also can be used to communicate without the additional fibre-optic cables. The optical cable is in the middle of OPGW, and the outer layer is protected by aluminum clad steel or aluminum alloy wire ，which has high reliability. The OPGW is built along with the electricity, so it can save construction costs, because the OPGW is built at the same time as the transmission line; OPGW is set up on the transmission line tower, relatively safe and reliable, not easy to steal.

OPGW cable has small outer diameter, low load on the tower, good design of stainless steel tube and cable core stranded, stainless steel tube to protect the optical fiber, high tensile strength, stainless steel tube light unit in the middle layer of the cable, distortion resistance, excellent pressure performance. Good safety performance, not easy to be stolen, strong resistance, different armored combination or different electrical and mechanical performance combination.

2. OPGW structure

OPGW material fiber paste is used in the fiber unit tube to protect the fiber from moisture, impact and other functions,it has water resistance. Fiber paste for optical unit requires good temperature characteristics, no dripping at high temperature (70 degrees), no hardening and cracking at low temperature (-40), no thickening phenomenon of optical fiber transmission, no oil separation, corrosion resistance and oxidation resistance.

Main technical indexes of fiber paste; Flash point, drop point, coning degree, viscosity, oxidation induction period, hydrogen absorption (hydrogen absorption more than 0.25 mL /g). The stainless steel belt is used as the main material to protect the optical fiber in the OPGW optical cable. The commonly used steel belt is type 304 and can also be used as 304L. The main characteristics require the strength, flatness, thickness uniformity, chemical composition requirements and trace elements of the steel belt.

AS line is aluminum clad steel，it is mainly used to bear the tension of the optical cable, the design also need consider the electrical properties，aluminum clad steel is the same round steel core with a layer of uniform continuous aluminum layer structure round line. Aluminum clad steel according to its specifications and geometric, physical mechanical, electrical three kinds of performance has different indicators: geometric parameters: outer diameter, aluminum layer minimum thickness, aluminum layer minimum thickness physical properties,tensile strength, 1% elongation，stress,torsion, density，electrical properties.

3. OPGW main production process.

Central tube type: stainless steel tube to anticorrosive oil filling, aluminum clad steel or aluminum alloy wire twisted back all around the ground - meter 3 - traction - and take-up gysts: aluminum clad steel strengthening core pay-off to anticorrosive oil filling, aluminum clad steel or aluminum alloy wire and stainless steel tube around the ground to anticorrosive oil filling, aluminium alloy wire or aluminum clad steel wire around the ground - meter - traction and wiring.

4. OPGW work environment

1)Aluminum-clad steel OPGW: heavily polluted areas and coastal areas;
2)Lightning-resistant OPGW compression type: small cable diameter, lightning resistant OPGW optical cable;
3)Logging cable: it is mainly used for transmission and connection during underground temperature measurement and analysis tests such as oil mining;
4)OPPC optical fiber composite overhead phase line: the two functions of transmission and optical fiber communication are integrated at 220KV and below.