Optical Ground Wire (OPGW) is a kind of electric wire used in aerial power lines. In fact, it has an electrical power system that serves two purposes: a protective mechanism against lightning strikes and other electrical faults, resulting in ground conductivity for interacting with the other conductors.
OPGW acts as the second line of defense in power lines since its function is to act as the grounding line in cases of lightning strikes and major fault currents. Also, it provides the path to ground, which is the last defense for the electric potion of the power lines.
This cable has optical fibers that are data-transport fibers with a high-speed rate and they are used to support data communication between these power companies. This yields a double use of the infrastructure: for the power transmission and for the communication purposes.
Generally, OPGW cables consist of a combination of aluminum and steel layers, which can provide them with the necessary mechanical strength and conductivity. In a protective structure in the middle of the cable are housed optical fibers. The building can be different according to the particulars of the wiring installation.
Similar to ordinary transmission lines, OPGW is placed on top of the towers. The process could be maintained and include the line maintenance or upgrading, scheduled outside normal working hours.
Applications of OPGW
Transmit lines of electrical power among the iron-mental grid, which enables quick communication caused by the integration of communication networks in many places. Additionally, this is essential for monitoring, controlling, and managing power distribution systems in power companies.
Some of the key functions where OPGW is widely utilized include the commuter communication infrastructure in remote locations where the underground cabling might be more difficult to be laid. The fiber optic content in the OPGW allows the fast data transfer that mandates the associated telecommunication service infrastructure.
Functioning as an important part in any smart grid is OPGW in the area of real-time data exchange, which is in turn necessary for automation, monitoring, and efficient control of the grid.
OPGW networks supply the backup communication path where some downed communication facilities might occur. This redundancy ensures there is a power backup in cases where the communication facilities fail.
Planning and Preparation:
Site Survey:
Prior to OPGW placement, an extent site survey has to be made in order to determine the existing infrastructure, terrain, and environmental conditions. The level of OPGW required and means to install it will be determined through the survey.
Design Considerations:
Based on the tower’s height, span length, tension requirements, and its frictional force, the Engineers specify which cable to use. The cable size, which correlates with these mechanical-physical properties, is determined to withstand the load stresses.
Permitting and Safety:
Nothing is as important as acquiring permits and following safety requirements, particularly in proximity to live power systems. Safety procedures must also be set up and the recommended measures taken into account to ensure the safety of the workforce and prevent additional damage.
Installation Methods:
Stringing the OPGW:
The trolling of the OPGW along the tops of the transmission towers is the most common approach. The OPGW is adequately tightened and managed by the means of particular accessories like tensioners or pullers in order to ensure that it does not sag or endure stress that far outweighs its required level of strain.
Dead-End Towers:
Located along the transmission lines at exact points, the "dead-end" towers serve as the main anchor point for the cable. The principal function of this specification is to maintain the stringing tension, thus avoiding the cable from mechanical stresses.
Jointing and Splicing:
For some long distance OPGW lines, there is a need to connect different parts of the OPGW thus making it more than one piece of cable in what is commonly referred to as splicing. The first step is the optical fiber straightening which is used to align all the different fibers in exactly the same line. Then a specialized tool is used to fuse them. Finally, the fiber joints are protected by a weather-resistant sealing method.
Sagging and Tension Adjustment:
Adjustment of the sag as any of the cables go to be energized with the aim that this will conform with the actual design. Ideally speaking, this stage can either be a make or break for the project since excessive sag can thus cause mechanical stress leading to a cable failure.
Integration with the Grid:
The power line system is made stronger as OPGW links to the electrical grid and is blended into the communication network. The fibers are taken to the ground equipment located at the substation or communication hubs that is part of the OPGW network.
Considerations for Live-Line Installation:
Here are several specific cases of using OPGW across the world power and communication infrastructure that exemplify its criticality:
United States:
Western Area Power Administration (WAPA):
WAPA, a government power plant, has been an improved member in the OPGW network as to strengthen and upgrade the grid system and communication within their power plant system. The optical fiber network of this region, that facilitates the flow of monitoring, control, and system maintenance data for the thousands of miles of high voltage transmission lines, is one of a kind.
Southern California Edison (SCE):
The OPGW has been placed at the SCE transmission network to assist in the ease of power transfer and expand the telecommunications infrastructure. The utilization of this system was undoubtedly key in their efforts in managing the wildfires, which was used to monitor the situation and take effective control, hence manage the power properly.
Europe:
National Grid (UK):
In the UK, National Grid installed an OPGW RWCCS above the high voltage electricity transportation lines to maximize the area's supply and demand for electricity. Smart grid used to upgrade the overall performance of the UK's electricity system.
Réseau de Transport d'Électricité (RTE) in France:
RTE, a major French transmission system operator, has installed OPGW across the different lines and cables that are in use for the grid. OPGW conductors are responsible for both electrical grounding and transmission of vital communications for controlling and balancing the French power system.
Asia:
State Grid Corporation of China (SGCC):
recently, State Grid Corporation of China (SGCC), which is one of the greatest power utilities in the world, have succeeded in applying OPGW wire stringing systems in a wide range of areas, which include remote and rural districts. The integration of OPGW has played a major role in China's plans to upgrade their grid infrastructure, thanks to the smart grid strategies that include the use of the new technology.
Power Grid Corporation of India Limited (PGCIL):
India, through implementing OPGW, has sought to beef up its old conventional power lines. The deployment of OPGW has been taken up within the comprehensive network improvement strategy being initiated, which is expected to support both the power transmission and communication.
Africa:
Eskom (South Africa):
In the complex arrangement of Eskom, another option that had proven to enforce OPGW system is the operation of OPGW in the transmission system network where it facilitated data communication as well as the actual transmission of electricity. This has been essential in aiding in navigation and monitoring of the grid in the remote locations.
Conclusion
The concern for Optical Ground Wire (OPGW) deployment should be considered a vital one to upgrading transmission systems and sustainable communication infrastructure. By taking fiber optic communication and grounding and uniting them in a single cable application, a utility company can save much money, have dependable connections, and give way to emerging smart grid technologies. The implementation process, whether it is in the cities of the developed countries or the rural areas of the developing countries, demonstrates the importance of OPGW in building resilient and efficient grids.
