High Voltage Power Transmission Lines Research Articles

Childhood leukaemia and distance from power lines in California: a population-based case-control study.

Background:Studies have reported an increased risk of childhood leukaemia associated with living near high-voltage electric power transmission lines that extend to distances at which magnetic fields from lines are negligible. We conducted a large records-based case-control study of childhood leukaemia risk in the population living near power lines in California.Methods:The study included 5788 childhood leukaemia and 3308 central nervous system (CNS) cancer cases (for comparison) born in and diagnosed in California (1986–2008), and matched to population-based controls by age and sex. We geocoded birth address and estimated the distance from residence to transmission lines using geographic information systems, aerial imagery, and, for some residences, site visits.Results:For leukaemia, there was a slight excess of cases within 50 m of a transmission line over 200 kV (odds ratio 1.4, 95% confidence interval 0.7–2.7). There was no evidence of increased risk for distances beyond 50 m, for lower-voltage lines, or for CNS cancers.Conclusions:Our findings did not clearly support an increased childhood leukaemia risk associated with close proximity (<50 m) to higher voltage lines, but could be consistent with a small increased risk. Reports of increased risk for distances beyond 50 m were not replicated.

FUZZY SHORTEST ROUTE ALGORITHM FOR TELEPHONE LINE CONNECTION USING THE LC-MST ALGORITHM

In computer science, there are many algorithms that finds a minimum spanning tree for a connected weighted undirected fuzzy graph. The minimum length (or cost) spanning tree problem is one of the nicest and simplest problems in network optimization, and it has a wide variety of applications. The problem is tofind a minimum cost (or length) spanning tree in G. Applications include the design of various types of distribution networks in which the nodes represent cities, centers etc.; and edges represent communication links (fiber glass phone lines, data transmission lines, cable TV lines, etc.), high voltage power transmissionlines, natural gas or crude oil pipelines, water pipelines, highways, etc. The objective is to design a network that connects all the nodes using the minimum length of cable or pipe or other resource in this paper we find the solution to the problem is to minimize the amount of new telephone line connection using matrixalgorithm with fuzzy graph.

Review on Operation Fault of High-voltage Power Transmission Lines and Effective Prevention Countermeasures

In the power system, transmission line as a guarantee for effective power supply, takes charge of the transmission from output power of substation to the consumers. The present study mainly focuses on the fault of transmission line resulted from external uncertainties, such as lightning, wind age yaw, ice coating and bird damage, as well as internal factors of high-voltage transmission line, including the grounding and short circuit. Accordingly, fault diagnosis and protecting measures on the high-voltage transmission line are proposed with advices on the improvement of operation and maintenance management of the line to reduce the fault frequency of the transmission line in the process of operation at a greater extent and to ensure the power supply stability of the whole power grid system to the user.

A STUDY ON FUZZY SHORTEST ROUTE ALGORITHM FOR TELEPHONE LINE CONNECTION

In computer science, there are many algorithms that finds a minimum spanning tree for a connected weighted undirected fuzzy graph. The minimum length (or cost) spanning tree problem is one of the nicest and simplest problems in network optimization, and it has a wide variety of applications.The problem is tofind a minimum cost (or length) spanning tree in G. Applications include the design of various types of distribution networks in which the nodes represent cities, centers etc.; and edges represent communication links (fiber glass phone lines, data transmission lines, cable TV lines, etc.), high voltage power transmissionlines, natural gas or crude oil pipelines, water pipelines, highways, etc. The objective is to design a network that connects all the nodes using the minimum length of cable or pipe or other resource.In this paper we find the solution to the problem is to minimize the amount of new telephone line connection using matrix algorithm with fuzzy graph.

Pilot Electromagnetic Field Measurements in Certain Areas in Greece

This paper reports preliminary electromagnetic field measurements conducted indoors in selected locations in Greece. The paper focuses on the electromagnetic radiation (EMR) of the extremely low-frequency (ELF) and radiofrequency (RF) frequency bands because these bands are considered as possible human carcinogens according to the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). ELF electric and magnetic fields and RF electric fields were measured indoors in several locations in urban, suburban and rural areas of the Zakynthos and Lesvos islands, suburban houses of Ileia Prefecture (Peloponnisos) and urban dwellings of Attica. A total number of 4816 measurements were taken in Zakynthos (276), Lesvos (964), Ileia (29) and Attica (3547) in the frequency range 50 Hz–2500 MHz. Measurements were conducted with NARDA EMR-300 RF survey meter (3935), Aaronia HF and NF spectrum analyzers (795), HI 3604 Holaday ELF survey meter (48) and ANTENNESSA EME SPY (38). The maximum electric field strengths were in most cases below 5 V/m. Strength of electric fields up to 3000 V/m were addressed near high voltage power transmission lines. Stronger average electric fields were measured in urban areas. The strengths of the magnetic field were in most cases lower than 1000 nTesla (1 μTesla), but values up to 6000 nTesla (6 μTesla) were observed near high voltage power transmission lines. The results indicated that the EMR strength values varied but were all below domestic and international established limits.

Protection relay of phase-shifting device with thyristor switch for high voltage power transmission lines

Problems of functioning of differential current protection systems of phase shifting devices (PSD) with mechanically changed coefficient of transformation of shunt transformer are analyzed. Requirements for devices of protection of PSD with thyristor switch are formulated. Based on use of nonlinear models of series-wound and shunt transformers of PSD modes of operation of major protection during PSD, switching to zero load operation and to operation under load and during short circuit operation were studied for testing PSD with failures. Use of the principle of duplicating by devices of differential current protection (with realization of functions of breaking) of failures of separate pares of PSD with thyristor switch was substantiated. To ensure protection sensitivity to the shunt transformer winding short circuit, in particular, to a short circuit that is not implemented in the current differential protection for PSD with mechanical switch, the differential current protection reacting to the amount of primary ampere-turns of high-voltage and low-voltage winding of this transformer was designed. Studies have shown that the use of differential current cutoff instead of overcurrent protection for the shunt transformer wndings allows one to provide the sensitivity during thyristor failure with the formation of a short circuit. The results of simulation mode for the PSD with switch thyristor designed to be installed as switching point of Voskhod-Tatarskaya-Barabinsk 220 kV transmission line point out the efficiency of the developed solutions that ensure reliable functioning of the PSD.

Soil corrosion of the AISI1020 steel buried near electrical power transmission line towers

Soil corrosion of carbon steel samples buried up to hundred days close to a high voltage power transmission line tower was examined by weight loss vs. time. A higher weight loss was observed if the samples were electrically connected to the tower than if they were not. This was attributed to the influence of alternating current (AC) signals induced in the soil by the transmission line. This field study showed for the first time the influence of the AC power line on the buried structure of the tower, while other studies so far were focused only on AC corrosion of cathodically protected coated pipelines, running parallel to the transmission line. An improved method was used to measure weight loss by descaling in Clark solution. The new method substitutes discontinuous measurements, proposed in the ASTM-G1-90 standard, by in situ measurements of the weight loss during descaling, using a computer controlled microbalance.

Prediction of Flashover and Pollution Severity of High Voltage Transmission Line Insulators Using Wavelet Transform and Fuzzy C-Means Approach

Major problem in the high voltage power transmission line is the flashover due to polluted ceramic insulators which leads to failure of equipments, catastrophic fires and power outages. This paper deals with the development of a better diagnostic tool to predict the flashover and pollution severity of power transmission line insulators based on the wavelet transform and fuzzy c-means clustering approach. In this work, laboratory experiments were carried out on power transmission line porcelain insulators under AC voltages at different pollution conditions and corresponding leakage current patterns were measured. Discrete wavelet transform technique is employed to extract important features of leakage current signals. Variation of leakage current magnitude and distortion ratio at different pollution levels were analyzed. Fuzzy c-means algorithm is used to cluster the extracted features of the leakage current data. Test results clearly show that the flashover and pollution severity of power transmission line insulators can be effectively realized through fuzzy clustering technique and it will be useful to carry out preventive maintenance work.

Health responses to a new high-voltage power line route: design of a quasi-experimental prospective field study in the Netherlands

BackgroundNew high-voltage power transmission lines will be introduced due to increasing demand for reliable and renewable energy supplies. Some residents associate non-specific health complaints with exposure to electromagnetic fields from nearby power lines. This study protocol describes the design and rationale of a prospective study investigating whether the introduction of a new power line triggers health responses in residents living nearby.Methods/DesignThe study is designed as a quasi-experimental field study with two pretests during the construction of a new power line route, and two posttests after it has been put into operation. Key outcomes are self-reported non-specific somatic and cognitive health complaints, and attribution of these health complaints to a power line. The main determinant is proximity to the new power line route. One member of every household (n = 2379) residing in close proximity (0-500 meters) to the overhead parts of a new power line route in the Netherlands is invited to participate, as well as a sample of household members (n = 2382) residing farther away (500-2000 meters). Multilevel analysis will be employed to test whether an increase in key outcome measures is related to proximity to the line. Longitudinal structural equation models will be applied to test to what extent health responses are mediated by psychosocial health mechanisms and moderated by negative oriented personality traits.DiscussionThis is the first study to investigate health responses to a new power line route in a prospective manner. The results will provide theoretical insight into psychosocial mechanisms operating during the introduction of an environmental health risk, and may offer suggestions to policymakers and other stakeholders for minimizing adverse health responses when introducing new high-voltage power lines.

Use of active sources of reactive power for power-flow control in electrical networks

Methods for regulating current in a high-voltage power-transmission line using active and hybrid reactive-power sources are considered. A circuit of a series hybrid source of reactive power based on a dc/ac-voltage thyristor converter with inductive energy storage is proposed. The device provides line power regulation with high indices of current quality. The main parameters of the parallel circuit of a passive filter are determined.

Fault Diagnosis of a High Voltage Transmission Line Using Waveform Matching Approach

This paper is based on the problem of accurate fault diagnosis by incorporating a waveform matching technique. Fault isolation and detection of a double circuit high voltage power transmission line is of immense importance from point of view of Energy Management services. Power System Fault types namely single line to ground faults, line to line faults, double line to ground faults etc. are responsible for transients in current and voltage waveforms in Power Systems. Waveform matching deals with the approximate superimposition of such waveforms in discretized versions obtained from recording devices and Software respectively. The analogy derived from these waveforms is obtained as an error function of voltage and current, from the considered metering devices. This assists in modelling the fault identification as an optimization problem of minimizing the error between these sets of waveforms. In other words, it utilizes the benefit of software discrepancies between these two waveforms. Analysis has been done using the Bare Bones Particle Swarm Optimizer on an IEEE 2 bus, 6 bus and 14 bus system. The performance of the algorithm has been compared with an analogous meta-heuristic algorithm called BAT optimization on a 2 bus level. The primary focus of this paper is to demonstrate the efficiency of such methods and state the common peculiarities in measurements, and the possible remedies for such distortions.

Atmospheric Corrosion Study on High-Voltage Overhead Power Transmission Line

Influence of atmosphere corrosion on conductor in the high-voltage overhead power transmission line has been paid more and more attention. This paper carries out experimental test research on atmosphere corrosion forms of aged conductor wires through metallographic analysis, electron microscope scanning etc. technologies, analyzing the influence of corrosion on its mechanical performance, which has provided theoretical reference for operation and maintenance of the overhead power transmission line.

Support Vector Machines for classification and locating faults on transmission lines

This paper presents a new approach to classify fault types and predict the fault location in the high-voltage power transmission lines, by using Support Vector Machines (SVM) and Wavelet Transform (WT) of the measured one-terminal voltage and current transient signals. Wavelet entropy criterion is applied to wavelet detail coefficients to reduce the size of feature vector before classification and prediction stages. The experiments performed for different kinds of faults occurred on the transmission line have proved very good accuracy of the proposed fault location algorithm. The fault classification error is below 1% for all tested fault conditions. The average error of fault location in a 380kV–360-km transmission line is below 0.26% and the maximum error did not exceed 0.95km.

Estimation of Battery State of Charge With $H_{\infty}$ Observer: Applied to a Robot for Inspecting Power Transmission Lines

Battery state-of-charge (SOC) estimation is essential for a mobile robot, such as inspection of power transmission lines. It is often estimated using a Kalman filter (KF) under the assumption that the statistical properties of the system and measurement errors are known. Otherwise, the SOC estimation error may be large or even divergent. In this paper, without the requirement of the known statistical properties, a SOC estimation method is proposed using an H∞ observer, which can still guarantee the SOC estimation accuracy in the worst statistical error case. Under the conditions of different currents and temperatures, the effectiveness of the proposed method is verified in the laboratory and field environments. With the comparison of the proposed method and the KF-based one, the experimental results show that the proposed method can still provide accurate SOC estimation when there exist inexact or unknown statistical properties of the errors. The proposed method has been applied successfully to the robot for inspecting the running 500-kV extra high voltage power transmission lines.

A Novel Transient Directional Unit Based on Adaptive Median Filtering

A new transient directional unit for extra high voltage(EHV) power transmission lines is proposed, which identifies fault direction by means of comparing the time-domain transient energy of the forward traveling-wave with that of the backward one in the very short period of time after fault occurs. The unit algorithm is designed with the technology of adaptive median filtering, which is first employed to process the forward and backward traveling-waves, and then calculates the time-domain transient energy ratio of the forward traveling-wave to the back one, by which the fault direction is discriminated. Numerous ATP-EMTP simulation tests show that this proposed directional unit not only operates reliably, sensitively and ultra-high-speed, but also endure the influences of various factors, including different fault types, fault locations, transition resistances or fault inception angles. It will be worthy of application greatly.

Risk factors for acute myeloid leukemia in adults: a hospital-based case-control study

Objective To determine risk factors of environment and lifestyles involved in acute hematology departments of 29 secondary-care and tertiary-care hospitals in Shanghai. There were 206 hospitalized patients with de novo AML during June 2003 to April 2007 meeting the diagnostic criteria for AML by the World Health Organization, excluding those with definite history of radiotherapy or chemotherapy, and 412 age- and gender-matched controls with non-hematological other diseases from the same hospitals. All the participants were interviewed face-to-face using a standard structured questionnaire,including personal medical history, family medical history, history of medications, traditional Chinese herb medicines, exposure to occupational hazards, lifestyle factors, etc. in the past five years prior to onset of the disease. Conditional univariate and multivariate logistic regression analyses were performed to identify risk factors for AML. Results Logistic regression analysis showed that taking traditional Chinese herb medicine might be a protective factor for AML, with an odds ratio (OR) of 0. 39 and its 95% confidence interval (CI) of 0. 16-0. 98. Potential risk factors for AML included history of diabetes and taking hypoglycemic agents ( OR: 1.39, 95% CI: 0.67 -2. 87), occupational exposure to metal ( OR: 1.73, 95% CI: 0. 77 -3. 91 ), glue, paint and other coating materials, etc. ( OR: 1.72, 95% CI: 0. 93 - 3.2), raising animals (OR: 1.33, 95% CI: 0. 79 -2. 24). No association of living within a distance of 100 meters from high voltage power transmission lines, home renovation and decoration in the past year, hair dyeing, smoking,alcohol drinking with AML in adults was found. Conclusions Factors mentioned above such as occupational exposure to metal, glue, paint and other coating materials potentially increase risk for AML in adults,however taking traditional Chinese herb medicine is possibly a protective factor for it. Key words: Leukemia, myeloid; Risk factor; Questionnaire

The Study on Anti-Icing Critical Current of Overhead Conductors

Preventing high-voltage power transmission lines ice-covered is ensure to power system the important guarantee of safe and reliable operation in the extreme weather. The size of anti-ice critical current is reasonable or not will directly affect the anti-ice effect. This paper conducts a comprehensive analysis of thermal balance process of the wire surface, and proposes a critical current model to anti-ice. In this paper, the minimum melting ice current of under the ultra-thin ice cover (0.05mm) circumstance is regarded as the anti-ice currents. Finally, by the model established in this article, calculating critical current of some typical wires in Hunan electric power grid, and the result is compared with result of existing literature made the critical current model, verified accuracy of model.

Are these data real? Comments on “No effects of intermittent 50 Hz EMF on cytoplasmic free calcium and on the mitochondrial membrane potential in human diploid fibroblasts.” by Pilger et al. (Radiat Environ Biophys 43:203–7 (2004))

Sir, Two papers (Diem et al. 2005; Schwarz et al. 2008) by the group of Hugo Rudiger, former head of the Division of Occupational Medicine, Medical University Vienna, on the effects of high-frequency mobile phone electromagnetic fields on DNA molecules have been questioned with regard to the origin of the data (Vogel 2008; Tuffs 2008). Although these papers have not yet been retracted, the editors of the International Archives of Occupational and Environmental Health (IAOEH) published an ‘‘Expression of Concern’’ (Drexler and Schaller 2009) in which they ‘‘apologize to the readers of IAOEH for publishing this paper’’. The editors of Mutation Research published an editorial (Baan 2009) in which they stated not to retract this paper, but to ‘‘...leave this issue open for scientific debate’’. COPE (Committee on Publication Ethics) considered a complaint against both journals and asked Elsevier to alter the title of the editorial to ‘‘Letter of concern’’ which has been published meanwhile (Baan 2010). This organization has more than 4,000 members (mainly Editors-in-Chief, but also Elsevier and Springer, which are the publishers of Mutation Research and IAOEH, respectively). The clear regulations, to which COPE members must adhere, also define the procedures once readers of published articles approach Editors with concerns about the validity of research data. The group in Vienna published not only data on the effects of electromagnetic fields on DNA but also a series of papers describing the same sort of effects caused by lowfrequency magnetic fields which are produced, for example, by household appliances or high-voltage power transmission lines (Ivancsits et al. 2002, 2003a, b, 2005; Pilger et al. 2004). Also here, the extent of the effects and the low variability of the data, respectively, were remarkable. In this respect, the data on DNA damage in the paper by Pilger et al. (2004) in this journal are record-breaking with regard to the magnitude of effect and the extremely low standard variations, respectively. For the sake of clarity, the figure (Fig. 1) was redrawn from the data given in the original paper (in the text and in Fig. 1). The standard deviations of the mean comet tail factors are barely visible. When calculating the coefficients of variation (standard deviation divided by the mean), these are below 1% for the sham-exposed group and below 0.5% for the exposed group. In other words, the individual data (n = 5) of each group are virtually identical. These extremely low standard deviations of ‘‘five independent series of exposure’’ are suspicious for a number of reasons. It was argued earlier that the very low standard deviations shown in two of the publications (Diem et al. 2005; Ivancsits et al. 2005) would be extremely sensitive to counting one single cell more or less in the respective categories (Vijayalaxmi et al. 2006). In addition, all other inevitable variations, such as cell cycle, exposure conditions, biochemical analysis, and time course of effect, should result in a much bigger variability in the data. To further clarify this important point on the incomprehensibly low standard deviations, some data are given in the following section. The authors (Pilger et al. 2004) refer in ‘‘Materials and Methods’’ to a paper from the same group (Ivancsits et al. 2002). In that paper, a detailed description of the comet assay and the calculations to get the tail factors are given. First, the cells’ comets were estimated in the following way: for each individual data point, 1,000 DNA spots were microscopically inspected, manually classified into five categories (A–E), and the A. Lerchl (&) School of Engineering and Science, Jacobs University Bremen, Campus Ring 6, 28759 Bremen, Germany e-mail: a.lerchl@jacobs-university.de

Integration of IC/EC systems in ITER

The RF heating and current drive (H&CD) systems that are to be installed in ITER during the construction phase, are the electron cyclotron (EC) and ion cyclotron (IC) systems. They are complex assemblies of high voltage power supplies (HVPS), RF generators, transmission lines and antennas. Their design and integration are constrained by many interfaces, both internal, between the subsystems, and external, with the other ITER systems. In addition, some components must be compatible with a nuclear environment and are classified as Safety Important Component. This paper describes the processes implemented in ITER to ensure proper integration.

Visible Human Utilization to Render Induced Electric Field and Current Density Images Inside the Human

The external and internal exposure to power frequency electromagnetic field, generated by high-voltage power transmission lines, raises serious safety concerns. Since we cannot measure the induced electric fields and current densities inside the human body, we used the Visible Human (VH) to investigate the induced electric fields and currents in human body tissues and organs of a worker standing 2 m away from conductor phase C of a double-circuit 132 kV transmission line. The double circuit 132 kV 60 Hz transmission line has a power rating of 293 MVA and a maximum recorded peak load current of 603 A. Charge simulation method and the Biot-Savart law have been used for computation of external electric and magnetic fields. Finite-difference time-domain technique was used to calculate the organs' internal induced electric field and circulating current densities in more than 40 different tissues of the VH with 3 mm voxel size. The simulation indicates that, at 2 m away from a 132 kV transmission line, the computed external electric field is 6.485 kV/m and the external magnetic field is 66.4 muT, which are below the limits set by the IEEE standards for external exposure for live-line workers. The maximum induced electric fields in the brain and heart are 23 and 14 mV/m, respectively. These values are below the IEEE standard recommended limits of 53 mV/m for the brain and 943 mV/m for the heart. The VH data allowed us to obtain two- and three-dimensional images of the induced electric field and current density distribution in different organs, tissues, and cross-sections of the human body.