HTLS Conductors: A Way to Optimize RES Generation and to Improve the Competitiveness of the Electrical Market—A Case Study in Sicily

Abstract

Stringent environmental constraints make more difficult to identify new energy corridors and build new power lines. The increase in the generation of electricity from renewable energy sources (RESs) makes the operation of electrical systems increasingly difficult in some areas. The transmission system operators (TSOs), in Italy Terna, are forced to exploit the existing overhead transmission lines, increasing the possibility of dispatching energy, in particular RES, optimizing the transmission capacity. Therefore, after a brief presentation of the Sicilian electricity system and a brief description of high-temperature low-sag (HTLS) conductors, a case study is presented. It is shown how it is possible to optimize the dispatching from renewable sources and, finally, it is demonstrated how the use of HTLS conductor can contribute, together with other actions taken by the TSO, to the decrease of the zonal price of electricity, to the creation of a market with fewer constraints and to new operating conditions that increase the resilience of the electricity system in case of disturbances.

Issues and Challenges in Voltage Uprating for Sustainable Power Operation: A Case Study of a 132 kV Transmission Line System in Malaysia

“…Hence, the increased utilisation of existing transmission line systems has been identified as a possible alternative to accommodate the extraordinary demand for electricity. Several studies have been carried out on different methods of uprating, including increased conductor rating, increased conductor temperature, increased thermal rating by active line rating system, probabilistic rating, high surge impedance, and increased electrical clearances [35][36][37][38][39][40][41][42][43][44]. The studies cover different techniques such as conductor replacement, conductor tension, line thermal, conductors bundling, and increased conductor attachment height [18,[45][46][47][48][49][50][51].…”

Uprating of transmission lines by means of HTLS conductors for a sustainable growth: Challenges, opportunities, and research needs

“…Today, it becomes particularly difficult to construct new lines [18], mainly due to public, social [19], legislative, economic and environmental constraints, specifically those related to land requirements due to the required right of way [14]- [16], since there is scarcity of corridors, particularly in dense populated urban areas [23] and in regions of ecological interest. In addition, fulfilling the regulatory aspects and environmental regulations [24], and obtaining the required licenses [18], [25] is increasingly difficult [26]. The period required between there is the need to install a new line and its coming into service often exceeds the time tolerable by the utility [27].…”

“…However, transmission system operation can be enhanced by increasing the thermal ratings of the limiting transmission paths [29], and thus, line reconductoring with HTLS conductors is a feasible possibility. TSOs often must dispatch the energy produced by renewable energy sources through the existing overhead power lines in order to optimize transmission capacity [24]. The use of HTLS conductors allows increasing flexibility in power operation [103], and along with other strategies applied by the TSO, it may contribute to reduce the electricity's zonal price, reduce the number of constraints of the electricity market, while increasing power system resilience in front of disturbances.…”

“…Economic and environmental limitations are key factors for applying uprating methods when planning new transmission lines [1]. The European energy and climate strategy includes a set of measures for the reducing greenhouse gas emissions and thus fighting the climate change, as well as minimizing energy imports dependence, so renewable sources of energy are fundamental to achieve these objectives [24]. However, the literature assessing the environmental impact of HTLS conductors is extremely scarce.…”

“…This is an important benefit of HTLS technology, since most of the countries have approved GHG reduction initiatives, whereas governors, regulators and policy makers consider these benefits as high-value topics. HTLS conductor technology also allows a smoother power system operation, especially in terms of capacity adaption due to the extra ampacity margin that this technology offers, thus providing increased flexibility in power system operation [24]. Capacity adaptation is nowadays an important issue, mainly due to the gradual increase of renewable energy resources in the electricity generation mix [111] as illustrated in Table 6.…”