Transmission tower designs have changed greatly over time in order to reduce the need for right-of-way (RoW), assure quick project completion, and resist various environmental conditions. As opposed to traditional lattice towers, utilities are increasingly embracing monopoles and multicircuit transmission towers because of their lower RoW requirements. To ensure swift execution and dependable infrastructure, improvements have been made to tower foundation designs, survey methodologies, and installation techniques. Additionally, in order to boost productivity and guarantee accuracy during the construction designing process, utilities are implementing model-based software tools. Some of the innovations that are transforming the towers and poles market segment include:
The lattice type of transmission tower is one of the most popular styles and is typically utilized for voltage levels over 100 kV. These towers are self-supporting constructions that are simple to erect in inaccessible sites due to the minimal weight of the tower members. It is simple and less expensive to erect the lattice guyed-V gearbox towers that are frequently employed by gearbox firms. Instead of using concrete to build the guyed gearbox tower, steel piles were used to create the angle towers. As a result, these towers can be prefabricated and put up at the required location. The prefabricated buildings are transported to the location, where quick installation is completed. Before being moved to the installation location, the tower's entire construction needs to be tightly fastened.
Extreme weather zones, particularly those with snow-covered hills and forests, are ideally suited for these towers. The high RoW required for lattice towers is one of their drawbacks. In crowded metropolitan locations or along small corridors, lattice towers—especially guyed towers—are not recommended because they need a lot of space.
Monopole usage is quickly gaining popularity. These towers are made of tubular polygonal sections with tubular crossarms attached to them for tension and suspension clamp installation. A single tubular form or an H-form are both possible for the tubular construction. Lattice-type towers require one-sixteenth the space that monopoles do, which results in lower RoW requirements. In comparison to lattice towers, they also have the advantages of quicker installation (due to less components needed) and more design flexibility. Furthermore, monopoles can survive severe weather and have a considerable wind loading capability.
For instance, the state transmission company Madhya Pradesh Power Transmission Company Limited has installed 220 kV multicircuit monopoles along the existing 132 kV North Zone-Jaitpura line corridor. Monopoles are being utilised for multivoltage gearbox systems for the first time in India. A 220 kV (double-circuit [D/C]) line was installed on the multicircuit monopole's upper panel, while a 132 kV D/C line was installed on the lower panel. The action assisted in meeting Indore City's increased load requirement. For the Kerala State Electricity Board, Sterlite Power employed monopoles to upgrade the Mallapuram-Manjeri line from 66 kV single-circuit (S/C) to 110 kV D/C. The community built around a 30-year-old network that the state utility was battling to maintain, leaving no room for any new line construction. It was necessary to find a way to accommodate the growth in load and enhance the quality of the power, therefore this 66 kV S/C old line was constructed to meet the needs of the populace. With the help of its AL59 conductor solution technology, Sterlite made it possible to accommodate peak load demand with greater ampacity and lower line losses under typical loading situations. Additionally, it installed the line using monopoles to minimize its environmental impact.
Multicircuit towers can transmit more power over a given distance. They have higher factored operating systems built into them. The towers drastically lower the total RoW needed for transmission lines. These have proved effective in places like densely populated cities, forested areas, and substation access and departure lanes.
Insulated crossarms that help minimize the height and width of the towers, delta or vertical configuration towers, and tower designs with fewer parts and bends to shorten lead times and inventories are more new tower ideas. Furthermore, fewer towers are needed per kilometre when adopting tower designs that require less steel for easier shipment and assembly. Delta configuration towers and chainette towers are two other sophisticated tower kinds. The former are more compact than traditional lattice towers and hold electrical cables in an equilateral triangle. Chainette towers are compact buildings made of two tiny masses held together by guy wires and suspended insulators. These take less time to install, inexpensive, and are lightweight.
The tower foundation, which aids in withstanding powerful winds, storms, and other severe weather conditions, is another essential part of a tower. Micropiling is a new tower foundation design. Tower foundations built on micropiles have piles with a diameter of less than 200 mm. Micropiles are a great option for gearbox projects in desert, mountain and coastal locations since they may be used in a variety of geotechnical circumstances. Precast foundations (used during constrained building times), grillage foundations (used in places with firm soil), and reinforced cement concrete spreads (used in a range of soil conditions) are a few other tower foundation ideas.
In order to reduce outages, emergency restoration systems (ERS) have gained popularity. These are made to swiftly avoid all types of permanent gearbox towers, regardless of voltage or terrain. ERS is appropriate for hand, crane, and helicopter installation methods and may be set up in a matter of hours. Utility companies maintain ERS towers in continuous service for more than ten years even though they were only intended for temporary usage. ERS provides a quick, practical, and above all safe way to restore power any place. The Indian Electrical and Electronics Manufacturers' Association and the state power utilities of Odisha, for instance, were able to swiftly restore power in the state's cyclone-affected areas in May 2019. Cyclone Fani completely destroyed the electrical infrastructure in and around the Puri district, including 75 220 kV and 25 132 kV voltage level towers. Between Lilo and Puri-Samkuha, a steel-based ERS tower that was locally constructed was used to replace the destroyed 132 kV towers. It made it possible to charge a 70 MW bulk load between the Samkuha and Puri grids. Using the ERS structure, the tower was reconstructed in five hours. The use of ERS is not restricted to disasters that destroy gearbox line segments. It can also be used to temporarily redirect an existing line to make room for a construction project or to maintain power flow while a line is being updated.
Model-based software products are utilized to provide digital architecture in addition to design advances. The most up-to-date solutions for enhancing efficiency and accuracy throughout the construction layout process as well as reducing rework and lost time are made available to users of advanced 3D software. Users can design layout points for important field operations. The building information model can then import the layout data again for quality assurance (QA) and quality control (QC) verification. The user can import layout points, such as "as-built" or "staked" locations, to help with QA/QC workflows. Before inputting data for comparison using AutoCAD or Revit, the user can check the point properties. With the help of these tools, the user can quickly and easily generate the field points needed for layout on a range of model entities.
On the whole, technological developments in foundations, and transmission tower designs would greatly reinforce and expand the transmission network. By preserving an uncongested transmission network and guaranteeing grid stability, this would assist in assuring a 24 hour, high-quality electricity supply.