Optimal costing of overhead power transmission lines using genetic algorithms

In the era of ever increasing power demand and deregulation of the power industry globally, it becomes extremely essential for transmission utilities to strengthen their infrastructure for accommodating the changes posed by deregulation and transfer reliable power to consumers. Construction of transmission lines involves heavy investment and hence, a careful analysis needs to be carried out at the planning stage in order to take investment decisions. There is a need for assessing the cost of these lines based on scientific principles as compared to those adopted conventionally based on availability of standard designs and line designer's experience. In the present study, an attempt has been made to analyse the cost components of overhead transmission lines and to develop correlations for estimating the overall transmission line cost. An error analysis has also been performed based on the comparison of parameters determined from developed correlations with the data collected on existing transmission lines.

This article well proposed a novel miniature unequal Wilkinson power divider using dual transmission line (DTL) design scheme with synthetic quasi‐TEM transmission line whose name is called complementary conducting strip (CCS). Our study technically and theoretically compared the miniaturized unequal Wilkinson power divider (UWPD) consisting of high‐impedance CCS and low‐impedance DTL with traditional microstrips. Under same conditions of process, simulation skill, and electrical performance, the analyses at operating frequency of 2.4 GHz result in that the area needed for CCS DTL UWPD with a power dividing ratio of 5 to 1 is merely 53% of traditional microstrips, input return loss is above 22 dB, isolation figure is over 21 dB, insertion loss of two output ports are 1.5 dB and 8.51 dB, respectively, and a fairly high output power ratio of 5 to 1 is exhibited. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012

This paper introduces a new concept that we call smart transmission expansion planning (TEP) based on unconventional high surge impedance Loading (HSIL) line designs that will revolutionize power delivery. To date, these two areas (TEP and transmission line design) have been conducted separately. For TEP, planners use the electrical parameters of a few standard conventional line designs to study planning scenarios, and then, the final candidate line is constructed. In such a sequence, cost-effective scenarios often do not meet the technical criteria of load flow. This paper will demonstrate that this sequence can be overturned; namely, a transmission expansion planner can get optimal line parameter values that will lead to the most cost-effective scenario, and then a transmission line for those parameters is designed. Although this cannot currently be realized through conventional designs, we demonstrate in this paper that this becomes a possibility by using the breakthrough designs for transmission lines by shifting phase configurations and sub-conductors into unconventional HSIL arrangements, leading to the optimal line parameters determined by TEP. Several case studies are simulated, and it is shown that using unconventional HSIL lines can lead to an overall least expensive scenario, considering both capital cost for new transmission lines and the cost related to network power loss.

This paper presents an innovative approach to optimize the process of the transmission line towers spotting using genetic algorithms. The mathematical model as well as the process of setting and decoding the variables of the genetic algorithm in the Matlab program package is explained. Possible settings of the fitness function and other parameters of the genetic algorithm in Matlab are outlined and described in order to find optimal arrangement of the transmission towers with minimizing the cost of construction and future maintenance of the transmission line on a particular section. Restrictions imposed due to environmental and geological conditions, legal regulations, standardization and typification of structures as well as other factors imposed by public utility companies and investors have been Taken into account.

An algorithm is proposed for precise extraction and comprehensive analysis of various complicated meteorological parameters along transmission lines. By means of GIS-based spatial reasoning, spatial relations between transmission lines and meteorological parameters were analyzed and handled properly, providing a solid foundation for the design of transmission lines. Experiments proved that the algorithm could effectively extract and analyze meteorological parameters along transmission lines, and the results were highly reliable and accurate. 2013. The authors.

The tower grounding device plays an indispensable role in the lightning protection and grounding of transmission lines. Reducing the grounding resistance of the tower grounding device is an important means to improve the lightning resistance of the line. However, the difficulty of reducing resistance in permafrost areas is a major challenge in engineering. Currently, there is still a lack of intensive grounding solutions in permafrost areas. Based on this, this article proposes two grounding devices using a conductive concrete foundation, establishes simulation calculation models using the boundary element method (BEM), studies the grounding characteristics under different structural parameters, and obtains an intensive grounding design plan for transmission lines in permafrost regions, providing practical design references for the intensive grounding design of transmission lines in permafrost regions.

In the paper an optimal procedure is proposed in order to face with power upgrading of transmission line of a double circuit line. The methodology is quite general, allowing to take properly into account all the technical constraints which have to be satisfied for a line acceptable behaviour. This procedure is based upon an optimal power flow which maximizes the power line capability, ensuring that the original line structure is not altered. The results of the optimal power flow could be of great interest being a powerful mean for the designers aligned with the recent tendency towards the exploitation of the existing structures, avoiding the construction of new transmission lines. In the last part of the paper relevant numerical applications are reported in order to demonstrate the feasibility of the proposed approach.

Chapter 7 - UHV AC Transmission Lines

This paper presents a model for computing power frequency electromagnetic field of overhead high voltage transmission line based on simulation charge method. Based on this model, the electric field intensity under power line is calculated and the distribution is analyzed in different condition such as different distant between phase line, different phase order for double circuit, and different arrangement of line in single circuit or double circuit. According to the simulation results, the electric fields under overhead transmission line can be forecast. This is no doubt important in environment protection and available in the design of transmission line.

In the design of electric and electronic devices, it is required to pursue a solution which satisfies simultaneously multi-objective performances sometimes including conflicting requirements. This paper newly attempt to propose a concurrent design method for a multi-objective satisfactory design method, Preference Set-Based Design (PSD), to a transmission line (TL) with impedance resonators for realizing negative group delay and slope characteristics. The TL is consisted of four different resonators with different resonant frequency. The design parameters of the TL are obtained in ranges by PSD. The validity of the design parameters is demonstrated by numerical modeling.

Along with the rapid economic development in recent years, people's demands for electricity have also been increasing very rapidly, which makes the power industry grow very fast, however, there have also been new challenges for the safety of the grid. Due to the complexity of China's topography, many power transmission lines under construction and planning are inevitable to pass through the high-altitude areas. Due to the high altitude and low air pressure, a number of external environmental factors are quite different from these of the low-altitude areas, and all these factors have a great impact on the power transmission lines, which will bring a lot of special problems to the design and operation of the power transmission lines. This paper describes the finite element method analysis which is used to calculate the relevant parameters of power transmission lines in high-altitude areas, as well as the status quo of the research on high-voltage AC power transmission lines in high-altitude areas. By analyzing the status quo of these studies and combined with the actual terrain situations of high-altitude areas, we can provide the construction of high-voltage AC power transmission line in high-altitude areas with some valuable references, thus to ensure the safe operation of such power transmission lines.

New methodology for design and failure analysis of underground transmission lines

Direct current volt-ampere characteristics of long arc on ice surface

According to the actual requirements, it is necessary to design a line connecting the 150MW hydropower station and the 230KV hydropower station. The first is to plan the overall process of the project, by consulting the data, objectively evaluating the transmission line parameters, combining Matlab and Excel to calculate the transmission line parameters, including barrier current calculation and safety analysis, and finally combining power system simulation and cost calculation, the only one is selected from hundreds of scenarios. Rationale, power flow analysis, and power loss analysis are used to evaluate transmission lines, including series reactors and new transmission lines in parallel. The process reflects the continuous refinement of the initial design to create a transmission line that is both economical and safe.

Lightning is the main cause of transmission system outages, affecting reliability of power supply and resulting in economic losses. Shielding failure is an important issue in addressing the lightning performance of overhead transmission lines. In this paper an improved method based on the electro-geometric model is proposed to evaluate the shielding failure flashover rate (SFFOR) of transmission lines, considering the influences of landform, lightning polarity and stroke angle. In the improved method, the striking distances to phase conductors, shield wires and ground are properly differentiated by using recent equations developed to take into account other factors not only magnitude of lightning strokes. These factors include height of wires as well as lightning polarity. To reflect the effects of changes in terrain and height of wires on SFFOR, a method for identifying the topography and the relative position among the wires and ground is proposed. A 400-kV double-circuit transmission line section in complex terrain area was taken as example, and the results show that this method can reflect changes of the SFFOR along the span and can be useful to figure out which towers are easy to be struck by lightning along the entire transmission line. This research is helpful for the design and operation of overhead transmission lines.