Double-circuit Power Transmission Line Research Articles

Short-Circuit Detection in Case of the Cascade Shutdown of a Disabled Circuit in a Double-Circuit Power Transmission Line

Short-Circuit Detection in Case of the Cascade Shutdown of a Disabled Circuit in a Double-Circuit Power Transmission Line

Распознавание короткого замыкания при каскадном отключении повреждённой цепи в двухцепной линии электропередачи

The article supplements the previously published analysis of the informational contribution of a cascade disconnection of a power line to the recognition of a short circuit (SC) that has occurred in it. The determination of the short circuit in one-way observation of the line increases due to the disconnection of the opposite side, but there is still a need to attract full information about the phase values, including, which is undesirable, their components of the zero sequence. The article shows that in the case of a double-circuit power transmission line, including bypass communication, cascade disconnection of the damaged circuit opens up a fundamentally new opportunity to evaluate the voltage and current on its unobservable side. The situation is very much, though not in all, reminiscent of two-way observation of a damaged circuit. The main thing is that quasi-two-sided observation, like ordinary two-way observation, can be carried out in two-wire channels of phase quantities that are freed from the components of the zero sequence. The efficiency of dividing zero - free phase currents into two components is shown: the normal one, determined in the model of an undamaged line, and the local one, operating in channels shunted on both sides. The measurement based on which the location of the fault is recognized is characterized by a priori dependence on the line coordinate. The theoretical provisions are illustrated by examples of two-chain lines, including real power transmission with branches.

Development of the wave method of calculation operational parameters of a double-circuit power transmission line with known values of output voltages and currents at the end of the line

Electrical energy from the place of its generation is transmitted to consumers of various capacities. The distance from the source of electrical energy to the consumer can vary from several meters to several thousand kilometers. In this regard, the accurate determination of the operating parameters of the power transmission line (PTL) is a mandatory and necessary condition for the PTL normal functioning. In the current-carrying parts of the double-circuit PTL there are six incident and six reflected waves of the electromagnetic field. They determine voltages and currents. A scheme is proposed for the distribution of these waves along linear wires of a homogeneous section of a double-circuit PTL. This scheme shows that the current-carrying parts of the adjacent wires have a significant impact on voltages and currents in one wire. This scheme illustrates the distribution of the amplitude values of electromagnetic field waves, defined as the integration constant. Using the integration constants, the propagation constants of electromagnetic waves along the linear wires of the PTL and the corresponding wave impedances, one can obtain the amplitude values of the incident and reflected waves at any point of the double- circuit PTL, and hence the currents and voltages in the double-circuit PTL. The article presents a method for determining the currents and voltages in a double-circuit PTL according to the load. The proposed method will allow determining the qualitative and quantitative indicators of electrical energy (induced voltage) appearing from each wire separately and provide the possibility of their elimination, which will improve the quality of electrical energy.

Assessment of reliability of an overhead transmission line with a split back-up phase

Transmission of electrical energy is the most important component of an electric power system. Optimization, modernization of the electric power transport system, increasing the capacity, as well as variability of connection arrangements, while maintaining the required level of reliability and safety, is regarded today as an urgent task for the energy industry as a whole. The article is devoted to the problem of determining the efficiency of the circuit design solution for a double-circuit three-phase power transmission line with an additional mode of operation — «with a split back-up phase» and determining its main reliability indicators. A circuit design solution for a double-circuit power transmission line with expansion of operating modes is presented in detail. The functional redundancy of the transmission line in accordance with the circuit design solution is based on switching of a conventional double-circuit power transmission line in the emergency mode to the single-circuit split-phase mode, which is the second working circuit. The ways of increasing the natural power of a double-circuit power transmission line are considered. The results of calculation of the capacity of a line with a split back-up phase and a comparison of the main parameters of overhead transmission lines with an additional mode of operation — with a split back-up phase — and power lines in conventional modes of operation, are presented. The results of calculations of reliability indicators are presented, such as the probable relative number of hours of interruption of power supply and the undersupply of electrical energy. A comparison of options have shown that the probable relative under-supply of the electric power of a double-circuit overhead transmission line with an additional operating mode — with a split back-up phase, is lower by approximately 13% than that of a conventional double-circuit power line, which will positively affect the maneuverability and reliability of the entire system.

A Successive Geometric Segmentation Approach Applied to Double-Circuit Transmission Lines Fault Classification and Location

This paper presents a new approach to address both fault classification and location in double-circuit power transmission lines. Fault diagnosis is achieved by using an algorithm based on the successive geometric segmentation approach. The proposed technique is able to generate both the topology and the weighting of neural networks. The input parameters are the magnitudes of phase voltages and currents measured in only one bus of a double-end fed transmission line. In order to validate the methodology, a comprehensive dataset of cross-country faults was simulated using a mathematical model. The results indicate high accuracy rate to fault diagnosis in double-circuit transmission lines compared to other ANN-based approaches found in the literature.

Fault analysis of Ar–Cs segmented-loading disk magnetohydrodynamics generator connected to electric power system

The authors study numerically an interconnecting system between the segmented-loading Ar–Cs closed cycle disk magnetohydrodynamics (MHD) generator and an infinite bus through the line-commutated inverter system and double-circuit power transmission line when faults occur at the inverter system and the power transmission line. Simulation results at the inverter fault condition show that misfiring of the inverter at not only the downstream but also the upstream results in a large disturbance at the downstream in various quantities of the generator. The firing angle control is very important to recover the operating condition of the MHD generator. Simulation results at the power line fault condition show that the inverters become out of operation, and ionization instability of the plasma is induced in the MHD generator when the fault occurs. When the fault is removed, the MHD generator can be recovered by means of the firing angle control of the inverters.

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.