Power Line Conditions Research Articles

Analysis of transient inductive interference in underground pipelines due to faults on nearby power lines

PurposeThe purpose of this paper is to present a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of power lines in close proximity.Design/methodology/approachBased on finite difference‐time domain method, an improved method is proposed to calculate transient inductive interference in underground metallic pipelines due to a fault in nearby power lines. The frequency‐dependent problem in the analysis of transient interference is solved in phase domain. Compared with the traditional method, the disposal of phase‐modal transformation matrices’ frequency‐dependent characteristic is avoided and the calculation is simplified by using vector fitting approach and recursive algorithm greatly in the proposed method.FindingsA novel improved method is proposed to calculate transient induced voltage distribution along underground metallic pipelines due to a fault in nearby power lines. Results show that the peak value of transient induced voltage at the most critical point is about 1.15 times of the magnitude in the steady state without the fault removed and the analysis of transient inductive interference is necessary in the fault‐to‐ground case of power lines.Practical implicationsIn order to mitigate the interference from power lines to nearby pipelines, pipelines should be good grounded and positioned as far away from the power line as possible. In high soil resistivity areas, the common corridor should be avoided.Originality/valueThe paper presents a method to calculate the transient induced voltages along the underground pipelines and analyze the transient interference generated in the pipelines due to the inductive coupling in the fault‐to‐ground condition of nearby power lines. The proposed method is general and can also be applied to other transient interference studies such as crosstalk problems of communication networks and interference between power lines and aboveground pipelines or communication cables. Effects of various parameters upon the inductive interference generated in underground pipelines due to a fault in nearby power lines are analyzed to be a guide for controlling the inductive interference.

New rotating transformation for efficient DSP control of active power-line conditioners

This paper presents a new rotating transformation for the control of APLC (active power line conditioners). APLC is a power electronic inverter which is designed to suppress power line distortion caused by nonlinear loads. Existing control methods for the APLC such as the popular instantaneous power transformation, are based on measurements of both power line voltage and current to estimate the required compensation for the power line distortion. These methods are quite sensitive to the power line voltage distortion that can introduce control errors. This paper presents a new simple transformation method for the APLC which determines the correct power line compensation using the line current measurement only. This method simplifies the existing control processing and reduces the power line measurement requirements. The accuracy of the new method is not affected by the power line voltage distortion and therefore, it is reliable for all power line conditions. A 10 kVA prototype APLC has been developed to verify the accuracy and efficiency of the new method.

Total least squares and discrete-time line models in HV distance protection

This paper discusses the applicability of the parameter estimation procedure known as total least squares, to the distance protection of high voltage transmission lines. The TLS based algorithm presented in the paper uses a two parameter discrete-time model for the line to be protected. The procedure is able to provide precise results (within specifications) in shorter time than other well known procedures, showing an improved dependability/security compromise. Two algorithms designed for different power line conditions, provide the procedure with adaptive behavior. Trip orders are provided in minimum time, according to the noise level in the current and voltage signals.

送電線周辺磁界におよぼす電力線電流条件の影響

送電線周辺磁界におよぼす電力線電流条件の影響

A token passing network for powerline communications

The AC powerline is the ideal communications medium for enabling control and monitoring applications in the home. The authors describe a low-level network architecture for reliable powerline communications. It uses a robust token passing protocol that supports network access and device response under worst-case powerline impairments. The approach is hierarchical, building upon both a spread-spectrum physical layer enabling short-duration powerline transmissions and adaptation to changing powerline conditions and upon a packet structure designed for error correction.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Study on grounding in the vicinity of the work site on 1000‐kV power transmission line. Part 2. Electromagnetic induction and its protection

AbstractIn order to clarify the grounding conditions for protecting workers on a de‐energized circuit from induction from a live circuit and to determine the required current capacity of the grounding conductor for a 1,000 kV double‐circuit power transmission line, the phenomena caused by electromagnetic induction resulting from a live circuit are discussed. The electromagnetic induction current Ig flowing through the body of a worker and the electromagnetic induction current IgO flowing through the grounding conductor can be analyzed by dividing the various power line conditions into three main factors, and using electromagnetic induction current calculations for a power line of infinite length. The zone where Ig does not exceed 1 mA is within 1 km of the grounding point on the de‐energized circuit owing to the grounding resistance (0.1 Ω) of the substations at the ends of the line and the difference in the phase configurations on the line when the current I1 of the live circuit is a constant 1 kA through the line. Similarly the value of IgO is determined by the grounding resistance of the substations at the ends of the line and the difference in the phase configurations on the line. IgO is approximately 10 A per 1 kA of I1. The currents Ig and IgO produced by electromagnetic induction are additive, allowing Ig and IgO in the actual power line to be evaluated by summation.

A study on grounding in the vicinity of the work site on 1000‐kV power transmission line. Part 1. Electrostatic induction and its protection

In order to clarify the grounding conditions for protecting workers on a de-energized circuit from induction from a live circuit and to determine the required current capacity of the grounding conductor for a 1,000 kV double-circuit power transmission line, the phenomena caused by electromagnetic induction resulting from a live circuit are discussed. The electromagnetic induction current Ig flowing through the body of a worker and the electromagnetic induction current IgO flowing through the grounding conductor can be analyzed by dividing the various power line conditions into three main factors, and using electromagnetic induction current calculations for a power line of infinite length. The zone where Ig does not exceed 1 mA is within 1 km of the grounding point on the de-energized circuit owing to the grounding resistance (0.1 Ω) of the substations at the ends of the line and the difference in the phase configurations on the line when the current I1 of the live circuit is a constant 1 kA through the line. Similarly the value of IgO is determined by the grounding resistance of the substations at the ends of the line and the difference in the phase configurations on the line. IgO is approximately 10 A per 1 kA of I1. The currents Ig and IgO produced by electromagnetic induction are additive, allowing Ig and IgO in the actual power line to be evaluated by summation.