Technical Brochure Research Articles

Quality system in central mixers and construction works at construction sites

Quality control in the construction industry is very important to ensure that what is being done conforms to established standards or good practices as per contract documents and technical specifications brochure. A central mixer for mixing concrete in the Al-Fataeh locality to verify whether the quality control and measures that are being implemented in the sites are in accordance with the specifications by extracting a set of questions in the form of a questionnaire to verify the extent to which the work is completed at the site, whether it is distortions of materials, insulation works, buildings or formwork and through them Judging the degree of quality used in each item. Samples of materials were taken and laboratory tested, then recommendations were obtained through the results to determine measures and to enhance quality control at construction sites. Keywords: concrete, quality management, construction works, building materials, technical specifications.

Dynamic line rating for grid transfer capability optimization in Malaysia

<div align="center"><span>This paper details a case study on the implementation of dynamic line rating (DLR) to enhance the ampacity rating of Malaysia’s grid. Utilizing heat balance equations endorsed by the Institute of Electrical and Electronics Engineering (IEEE 738) and the International Council on Large Electric Systems (CIGRE technical brochure 601), the ampacity rating of a Zebra-type aluminum cable steel reinforced (ACSR) conductor on a 275 kV transmission line has been assessed. Real-time weather conditions and conductor temperatures, measured hourly by the DLR sensor over the course of a year, were incorporated into the ampacity calculation to determine the available margin. The weather parameters were analyzed based on the monsoon seasons. A comparative analysis between various methods outlined in the standards and the estimated ampacity rating derived from both standards is presented. According to both standards, the findings indicate that DLR surpasses static line rating (SLR), highlighting the presence of untapped ampacity for grid optimization. Remarkably, CIGRE TB 601 exhibits a higher ampacity rating margin than the IEEE 738 standard, with a percentage difference of 16.20%. The study concludes that the conductor is underutilized and proposes optimization through the integration of real-time weather conditions data into the heat balance equations.</span></div>

Voltage Dip Immunity of Equipment and Installations Messages to stakeholders

This paper presents the messages to the stakeholders on voltage-dip immunity as extracted by UIE WG2 from CIGRE TB412 [1]. The paper summarizes the main recommendations from this technical brochure in the form of messages towards regulators, standard-setting-organizations, network operators, industrial customers, equipment manufacturers, and power quality monitor manufacturers, researchers.

Objective Interpretation of SFRA, in the Light of CIGRE TB 812

The SFRA (Sweep Frequency Response Analysis) technique has become quite popular as a condition monitoring technique for transformers. The SFRA technique holds a vast repertoire of data in terms of the electromagnetic behaviour of the transformer. Much research has happened in comprehending this data but no effort has succeeded in determining a universal objective criterion for the interpretation of SFRA data. CIGRE study committee A2.53 has recently released Technical Brochure 812 which has been the result of nearly half a decade of international efforts in arriving at an objective criterion for the interpretation of SFRA. This paper discusses the state of the art in objective interpretation of SFRA data with special reference to TB 812. The paper also presents a case study in HPL where SFRA was compared to a conventional method.

Bulletin Board: Activities of the DEIS Technical Committee on “HVDC Cable Systems (Cables, Joints and Terminations)” for the development of IEEE Std. 2862TM-2020

High voltage direct current (HVDC) cable systems with extruded insulation are becoming increasingly attractive versus the traditional mass impregnated non-draining (MIND) HVDC cable systems [1]. Voltage and power ratings of HVDC extruded cable systems commercially available-after being qualified according to CIGRE Technical Brochure (TB) 496 [2]-are exceeding 500 to 600 kV and 1 GW, respectively [3]-[6]. Of course, HVDC extruded cable systems still have issues.

Dynamic Rating Management of Overhead Transmission Lines Operating under Multiple Weather Conditions

Integration of a large number of renewable systems produces line congestions, resulting in a problem for distribution companies, since the lines are not capable of transporting all the energy that is generated. Both environmental and economic constraints do not allow the building new lines to manage the energy from renewable sources, so the efforts have to focus on the existing facilities. Dynamic Rating Management (DRM) of power lines is one of the best options to achieve an increase in the capacity of the lines. The practical application of DRM, based on standards IEEE (Std.738, 2012) and CIGRE TB601 (Technical Brochure 601, 2014) , allows to find several deficiencies related to errors in estimations. These errors encourage the design of a procedure to obtain high accuracy ampacity values. In the case of this paper, two methodologies have been tested to reduce estimation errors. Both methodologies use the variation of the weather inputs. It is demonstrated that a reduction of the conductor temperature calculation error has been achieved and, consequently, a reduction of ampacity error.

The Effect of Insulation Characteristics on Thermal Instability in HVDC Extruded Cables

This paper aims at studying the effect of cable characteristics on the thermal instability of 320 kV and 500 kV Cross-Linked Polyethylene XLPE-insulated high voltage direct-current (HVDC) cables buried in soil for different values of the applied voltages, by the means of sensitivity analysis of the insulation losses to the electrical conductivity coefficients of temperature and electric field, a and b. It also finds the value of dielectric loss coefficient βd for DC cables, which allows an analytical calculation of the temperature rise as a function of insulation losses and thermal resistances. A Matlab code is used to iteratively solve Maxwell’s equations and find the electric field distribution, the insulation losses and the temperature rise inside the insulation due to insulation losses of the cable subjected to load cycles according to CIGRÉ Technical Brochure 496. Thermal stability diagrams are found to study the thermal instability and its relationship with the cable ampacity. The results show high dependency of the thermal stability on the electrical conductivity of cable insulating material, as expressed via the conductivity coefficients of temperature and electric field. The effect of insulation thickness on both the insulation losses and the thermal stability is also investigated.

The Effects of Transient Overvoltages on the Reliability of HVDC Extruded Cables. Part 2: Superimposed Switching Impulses

In a previous paper (Part 1) the authors have performed the simulative evaluation of the life lost by HVDC extruded cables subjected to long TOVs occurring in VSC HVDC cable systems. The conclusions were that it cannot be completely ruled out that the field levels and the duration of such TOVs are a potential threat to certain cable designs, and tests other than Load Cycling Type Tests after CIGRÉ Technical Brochure 496 could assess quantitatively the potential threat associated with long TOVs. For these reasons, in this Part 2 superimposed switching impulses applied during Type Tests after TB 496 are analyzed in order to check if such impulses might be equivalent to long TOVs as for their electro-thermal stress effects on extruded insulation. The analysis is similar to that carried out for long TOVs in Part 1, i.e., it consists of: calculating the electric field during superimposed switching impulses; comparing it with the field during long TOVs; calculating with Miner's law of cumulated damage the life lost during superimposed switching impulses and comparing it with the loss of life during TOVs. A brief literature survey of potential high field effects during long TOVs is also reported.

Calculation of the overhead transmission line conductor temperature in real operating conditions

The integration of fluctuating renewable sources, load growth and aging of the current power system is the major reasons for the development of the electric power engineering. Transmission lines are recently facing new technical and economic challenges. The immediate utilization of advanced technologies and modern methods could solve these issues. This study deals with the transmission and distribution of electrical energy with orientation on the calculation of operating temperature on the conductor of transmission line, which is under actual current load. The load of the transmission line is limited with allowable operating temperature. The operating temperature should not exceed the allowable operating temperature because the conductors of the transmission line have mechanical limit from the standpoint of deflection of conductors. The operating temperature as well as operating conditions of the conductor is determined by the type and material of the ACSR conductor. This article aims to propose the suitable calculation methods of the operating temperature of the overhead transmission line conductor in real operating conditions (external weather influences, current loading and corona effect). The originality of this proposed method (by differential equation) lies in considering corona effect. This improves the accuracy of the calculation of the operating temperature of the conductor under real conditions. In this article, the calculations are compared according to methodology of differential equation and methodology described in CIGRE Technical Brochure 601—guide for thermal rating calculations of overhead lines. The methodology of differential equation counts with or without losses by corona. The article also compares these methods of operating temperature during days in various different weather conditions like environment temperature, solar irradiance, wind speed and direction. It was found that under the action of the corona, the temperature of the conductor increases to a small extent.

The effect of temperature and stress coefficients of electrical conductivity on the life of HVDC extruded cable insulation subjected to type test conditions

This paper investigates the effect of temperature and stress coefficients of electrical conductivity of the insulation material on the life and reliability of HVDC extruded cables subjected to type test load cycles according to CIGRE Technical Brochure 496. The investigation is done by refining a procedure for the estimation of cable insulation life and reliability in the presence of load cycles, developed and implemented in a previous stage of this research, but applied so far to prequalification test load cycles only. Electric field is calculated using both the rigorous approach based on Maxwell's equations for transient electric field computation (exact method) and the closed-form steady-state Eoll's formula often employed in the preliminary design of DC cable insulation (approximated method). This enables also to assess the accuracy of the overall approximation involved by Eoll's formula in the case of type test conditions.

Calculation and analysis of the steady-state line ampacity weather sensitivity coefficients

The continuous increase in electrical power demand entails the need for larger ratings of overhead lines. For spatial, economic and ecological reasons, contemporary solutions are focused on incrementing the ratings of existing lines. One of these solutions is the real-time determination of line ampacity according to the measured or predicted weather and/or line parameters. The paper is focused on a novel calculation procedure and analysis of the steady-state line ampacity (SSLA) weather sensitivity coefficients (WSCs). The calculation of WSCs is based on the sensitivity analysis of the methodology for the SSLA given in Cigre N° 601 Technical Brochure. On the one hand these WSCs allow a fast estimate of the potential in the introduction of real-time ampacity calculation concept. On the other hand they give a good basis on the requirements for the measurement equipment installed in contemporary dynamical line rating systems (DLRSs). The interrelations between the WSCs and the SSLA are investigated using correlation and regression analysis. Finally, according to the typical design parameters of overhead lines the WSCs and their interrelations with the SSLA are calculated and analysed for typical aluminium steel-reinforced conductors (ACSRs) present in the Croatian transmission system.

Enhanced Method for Pressure Rise Calculation in SF6 GIS Due to Fault Arcs

Modeling of pressure rise in SF6 GIS (Gas Insulated Switchgear) due to internal arc faults is a complex and challenging task, due to a large number of highly variable factors, which influence the whole process. This is especially the case in GIS with high rated short circuit currents, where the effects, such as material evaporation and erratic arc behavior, and consequently the pressure build-up rate, are much more pronounced. These severe conditions ultimately determine the design limits and must therefore be carefully investigated. The enhanced internal arc simulation model, presented in this paper, considers the impact of evaporation of different materials on gas properties and the pressure rise, as well as the dependence of released arc energy, thermal transfer and evaporation intensity on the state of gas. The experimental set-up and the test configuration, used to validate the calculation results, are evaluated and discussed. An evident finding, which is supported by measurements, is that the implemented improvements of the basic simulation model (introduced in the Technical Brochure 602 by the CIGRE working group A3.24) increase the prediction accuracy of GIS withstand performance during internal arc faults.

Temperature calculation of overhead power line conductors based on CIGRE Technical Brochure 601 in Slovakia

An overhead power line is a structure used in the electric power system to transmit electrical energy. The performance of overhead power lines depends on their parameters. An important parameter of the power line in the power system is its thermal limit. This article deals with the temperature calculation of overhead power line ACSR conductors according to the methodology stated in CIGRE Technical Brochure 601: Guide for thermal rating calculations of overhead lines. The calculated temperature is also compared with the measurement under laboratory conditions and also on a real power line in the Slovakia power system. At the end of the article, the dynamic thermal rating of ACSR conductors depending on climatic conditions is also calculated. Obtained results are compared with ampacity limits for summer and winter season used by Slovak transmission system operators. The article also compares the CIGRE Technical Brochure 601 with its older version CIGRE Technical Brochure 207: Thermal behavior of overhead conductors.

Facilitated Direct Dimethyl Ether Fuel Cells through High Temperature Membrane Electrode Assemblies

In searching for an exemplary carbon neutral fuel, dimethyl ether (DME) may be the most appealing. This simplest of the ethers can be readily produced from renewably sourced hydrogen and CO2, making it essentially a hydrogen carrier (1). Both nontoxic and easy to liquefy under moderate pressure, DME closely matches diesel and has been run in trucks (2). The ubiquitous propane grill tanks can store DME without modification. Recently, Los Alamos National Laboratory (LANL) demonstrated the potential for direct oxidation of DME in a fuel cell.The breakthrough of our work is LANL’s highly active catalyst for direct oxidation of DME that in the early phase of development shows similar performance to direct methanol when using typical low-temperature membranes. However, the output is not sufficient to approach commercial acceptance targets for higher power applications or precious metal cost. High-temperature membrane electrode assemblies (HT-MEAs), based on phosphoric-acid-imbibed membranes, operate at 160 °C to 180 °C without additional water and are highly tolerant to carbon monoxide – an intermediate of DME oxidation. This work exploits a novel ternary LANL anode catalyst with the features of high-temperature operation to produce high-power, low-cost direct DME MEAs.In support of direct DME oxidation, scientists at LANL have recently shown a direct liquid fuel cell operating with DME as part of a program to develop technology for direct methanol (MeOH), ethanol (EtOH), and DME fuel cells (3). In this work, it has been shown that DME can be directly oxidized via a PtRuPd ternary catalyst that not only activates the ether bonds but facilitates the removal of CO as a reaction by product (Figure 1). Even at this early stage, the team led by LANL has shown results that approach a highly developed DMFC system with regards to performance and precious metal loading (3). One highly relevant aspect of this work is the sharp temperature dependency of the current-voltage behavior, with an increase in the cell temperature from 80 °C to 90 °C leading to an increase in the current density at 0.5 V by ca. 50%, from 140 mA cm-2 to 220 mA cm- 2 High-temperature PEM MEAs developed by BASF for the polybenzylimide (PBI) system or pyridine polymer based TPS®system of Advent Technologies, Inc. have demonstrated utility and robustness when operating with highly impure reformates of around 1-3% CO (4). Similarly, cathode sensitivity to air contaminants is also ameliorated. The electrolyte in both systems is phosphoric acid imbibed into a stable and inert polymer matrix. Phosphoric acid is notable in that it does not need water to conduct protons, and can do so over a wide temperature range from ~120 °C to more than 200 °C. Advent is a licensee of BASF’s MEA and gas-diffusion-electrode technology.This presentation will summarize our on-going efforts at facilitating direct oxidation of DME by using high temperature PEM MEAs with both PBI and TPS combined with the LANL catalyst operating at 160 oC to 180 oC. Olah, G.A., Goeppert, A. and Prakash, G.K. Surya in J. Org. Chem., 2009, 74, 487-498. Hutchinson, H., 2013 in ASME web article www.asme.org/engineering-topics/articles/transportation/diesel-alternative-hits-the-road. Advanced Materials and Concepts for Portable Power Fuel Cells, 2014 Hydrogen and Fuel Cells Program AMR presentation. Technical Brochure, 2014 Advent Technologies, Inc. at www.Advent-Energy.com. Figure 1

UHF partial discharge detection system for GIS: Application guide for sensitivity verification: CIGRE WG D1.25

The paper, prepared by CIGRE WG D1.25, presents the experience in practical application of sensitivity verification of the UHF partial discharge detection system for GIS after its introduction by ELECTRA Report in 1999. A detailed description of the two-step procedure, Step 1 in laboratory and Step 2 on-site, is given and supported by examples. Guidelines will help manufacturers and users in the effective application of the UHF method for PD detection on GIS and will permit to avoid technical misinterpretations. The procedure is described in details in CIGRE Technical Brochure.

Comparison between IEEE and CIGRE Thermal Behaviour Standards and Measured Temperature on a 132-kV Overhead Power Line

This paper presents the steady and dynamic thermal balances of an overhead power line proposed by CIGRE (Technical Brochure 601, 2014) and IEEE (Std.738, 2012) standards. The estimated temperatures calculated by the standards are compared with the averaged conductor temperature obtained every 8 min during a year. The conductor is a LA 280 Hawk type, used in a 132-kV overhead line. The steady and dynamic state comparison shows that the number of cases with deviations to conductor temperatures higher than 5 ∘ C decreases from around 20% to 15% when the dynamic analysis is used. As some of the most critical variables are magnitude and direction of the wind speed, ambient temperature and solar radiation, their influence on the conductor temperature is studied. Both standards give similar results with slight differences due to the different way to calculate the solar radiation and convection. Considering the wind, both standards provide better results for the estimated conductor temperature as the wind speed increases and the angle with the line is closer to 90 ∘ . In addition, if the theoretical radiation is replaced by that measured with the pyranometer, the number of samples with deviations higher than 5 ∘ C is reduced from around 15% to 5%.

Life Estimation of HVDC Cables Under the Time-Varying Electrothermal Stress Associated With Load Cycles

In this paper, a new procedure is presented for life estimation of HVDC cables subjected to the time-varying electrothermal stress associated with load cycles and voltage. The electric-field inversion phenomenon in the insulation of dc cables is accounted for by updating the field profile as the temperature profile changes with the load. The thermal transients due to load cycles are modeled via the CIGRÉ transient thermal network adapted to dc cables. The life fractions lost during each cycle because of the cyclic variation of the electrothermal stress are computed via an adequate electrothermal life model for the insulation of HVDC cables. The Weibull hypothesis is made for relating cable life to failure probability. The procedure is applied to the load cycles of the prequalification test for HVDC extruded cables after CIGRÉ Technical Brochure 496 that does not consider the effect of thermal and synergistic electrothermal aging. It is thus shown that this test might be less severe than it should be.

Risk assessment on defects in GIS based on PD diagnostics

The paper, prepared by CIGRE WG D1.03 (TF 09), presents the guidelines for risk assessment procedure on defects in GIS based on PD diagnostics. The procedure, described in detail in CIGRE Technical Brochure 525, starts with sensitive PD measurement to detect the critical defects and follows with identification of the type of the defect and its location inside the GIS. This information taken together with other essential data from laboratory measurements, manufacturer's experience, design aspects and trend analysis of the PD activity, are the base for the estimation of the criticality of the defects. Finally, the risk assessment is performed based on the estimated dielectric failure probability and failure consequences that can be different in case of on-site testing or in service activity.

Technical Brochure “Construction with Cross‐Laminated Timber in Multi‐Storey Buildings: Focus on Building Physics” available

Technical Brochure “Construction with Cross‐Laminated Timber in Multi‐Storey Buildings: Focus on Building Physics” available

無効電力補償装置用交流フィルタの新設計手法と実系統試験結果との比較検討

AC filter design method for SVC and HVDC is commonly known in the relevant CIGRE technical brochure and IEC technical report. However the conventional method requires many iterative calculations of the harmonic voltages and currents until the calculation results become within the regulation levels by changing filter parameters based on the experience. In this respect, a new improved design method is proposed, which enables efficient evaluation on the complex impedance plane to confirm as to whether the proposed filter impedance is in the permissible range. In an actual project of Okuura SVC of Kyusyu Electric Power Co., Inc., the new method was applied to the AC filter design. This paper describes on the actual procedure of the AC filter design with the new method, the actual references of the harmonic performance calculation, and the field test measurement results on Okuura SVC. The calculation results and the filed measurement results are consistent with each other, thus the validity of the new design method is verified on its accuracy and effectiveness.