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The US has an established network of producers of electrical energy utilizing various processes to generate electrical power. This ensures uninterrupted and reliable availability of electrical energy.
Electrical energy is such that once generated, it has to be transmitted immediately. The voltages produced by the generating source/station are around 15 to 25 kV. These voltages need to be enhanced for transmission in order to reduce transmission losses. Hence, transformers are used to enhance voltage. This generated high voltage energy then feeds into the transmission network. The transmission network is a complex infrastructure and uses a variety of voltages generally between 230 kV and 500 kV. Specially designed ACSR’s (Aluminum conductor steel reinforced) conductors are used, strung across huge steel towers. These overhead transmission lines transmit power over long distances of varying terrains to their destination, which is a sub-station.
In the US, the majority of power transmission is with AC (Alternating Current).
HVDC (High Voltage Direct Current) is a system that interconnects two alternating-current (AC) networks, converting AC voltage to DC voltage and vice versa. Ultra-HVDC (UHVDC) lines can operate at voltages of up to 800 kV, enabling bulk transport of power over longer distances. One much-emphasized benefit is that HVDC systems have lower losses than AC systems, which makes them more economical. Though there are significant benefits of utilizing HVDC transmission of power over longer distances, the US has been slow in deployment of HVDC transmission. The first US HVDC line is planned and is a 600 kV HVDC 720-mile project that could deliver 4 GW of renewable power from the Oklahoma Panhandle region to states in the Southeast. This is being called the “Super Grid”. This is one area which offers opportunities.
Once the transmitted energy reaches the substation(s), generally located outside an urban area, the voltages are “Stepped down”. The voltage is reduced at the 500 kV/220 kV EHV (Extra high voltage) substation to the high voltage level and high voltage lines transmit the energy to high voltage substations located within cities. This is called “Distribution”. Distribution is done using underground cables, which require special construction to dissipate the generated heat and provide adequate protection, by insulation.
The distribution of power in urban and industrial areas utilizes high voltage and extra high voltage underground cables, which traditionally have been 69 kV to 230 kV underground cables-LPFF (low pressure fluid filled), HPFF (high pressure fluid filled), gas filled and a few XLPE ( Solid di-electric, Cross-linked polyethylene)
Due to environmental concerns, reliability issues and frequent maintenance requirements, Europe and the rest of the world has moved away from “fluid/oil” and “gas filled” cables, towards “solid dielectric” or “XLPE- Cross linked polyethylene” constructions.
XLPE cables in particular have numerous advantages: XLPE high voltage (69 kV to 115 kV) and extra high voltage (230 kV to 500 kV) are more reliable with established tests, installation records and a long history of reliable performance. Their continuous demand has resulted in improvements in manufacturing processes resulting in products of better quality and higher reliability.
US utilities, contractors have been slow to install cables with “XLPE” constructions. Constraints slowing down this migration are the delays in release of funds for the upgrading of the electrical grid and the slow process of approvals required for the use of new products/systems by utility companies.
The market drivers for HV, EHV cable systems are undergrounding of overhead lines in urban areas, grid expansion, deployment of distributed renewable energy generators, and more recently the need to underground overhead lines in potential fire hazard regions. This presents a great opportunity for manufacturers and sales divisions dealing in XLPE HV, EHV cables and accessories.
The US electrical grid, utility companies are in a midst of a paradigm shift due to the generation and flow of renewable energy into the grid from multiple generation sources. This has created a unique scenario for utility companies. States have mandated utility companies with targets on utilizing renewable energy in their grid(s). This shift means a major change, migration from centralized generation to distributed generation and will require major changes in the utility business models. This presents a huge opportunity for business involved is assisting utility companies for this transition.
