Fault identification of double-circuit transmission lines on the same pole based on EEMD energy ratio

In order to improve the sensitivity and reliability of traveling wave protection, on the basis of analyzing the relationship of the anti-traveling wave current amplitude in the window after the internal/external failure of the double circuit line on the same tower, a fault identification method based on EEMD energy ratio is proposed. Use EEMD decomposition to decompose the anti-traveling wave current in a time window after the fault into 7 scales, and extracts the EEMD energy ratio at each scale at both ends to form a feature vector. Then it is sent to the particle swarm optimization support vector machine (PSO-SVM) for training and testing, and the internal and external faults are identified. Experiments show that the algorithm has good fault identification ability, the fault accuracy is 95% and the method sensitivity is high.

Utilization of Six-Phase Systems to Reduce Technical Losses in Subtransmission Networks of Power Distribution Companies

The objective of this work is to find solutions for the reduction of energy losses in the distribution systems, focusing on the number of phase conductors. In the transmission segment, there are many surveys with six-phase systems. Due to the current regulatory framework in Brazil, the economic viability of this solution is highly restricted. In the distribution segment, the situation is different and there is little research on this alternative. The segment’s valuation model (PRICE-CAP) enables greater technical and economic viability. The main objective of this work is to demonstrate the reduction in technical losses by transforming a three-phase double circuit line into a six-phase line. The work presents: the regulatory framework that shows the advantage of investing in the distribution segment; and performs simulations considering OpenDSS to illustrate the reduction of technical energy losses.

Analysis of Six-Phase Transmission Lines for Increasing Power

In the India, especially in metropolitan areas, transmission infrastructure is congested due to a combination of increasing load demands, declining investment, and aging facilities. It is anticipated that significant investments will be required for new construction and upgrades in order to serve load demands. This paper explores higher phase order systems, specifically, six-phase, as a means of increasing power transfer capability, and provides a comparison with conventional three-phase double circuit transmission lines. Line parameters calculations performed in this thesis show that line impedances in six-phase lines have a slight difference, compared to three-phase double circuit line. The electric and magnetic fields calculations show that, ground level electric fields of the six-phase lines decline more rapidly as the distance from center of the lines increase. The six-phase lines have a better performance on ground level magnetic field. Based on the electric and magnetic field results, right of way requirements for the six-phase lines and three-phase double circuit line were calculated. The calculation results of right of way show that six-phase lines provide higher power transfer capability with a given right of way.

Simulation and Analysis of Induced Current of HV Parallel Reactor Disconnector for 500kV Double Circuit Line on the Same Tower

The 500 kV double circuit line with HV parallel reactors has a long outage time in ice melting operation.In this paper, we discussed the possibility of directly switching HV parallel reactor disconnector under the cold standby state,in order to further optimize the operation mode of DC ice melting line.We calculated the induced current of the HV parallel reactors disconnector in the 500kV LG A and B lines, and analyzed the related factors. We also calculate the overvoltage level of the HV parallel reactor disconnector, and put forward the parameter requirements, which provides reference for the type selection.

Uplift Behavior of Belled Short Piles in Weathered Sandstone

Field pull out test results of 500 kV double-circuit line of Luping-Fule are presented in this paper to investigate the uplift bearing behavior of rock-socketed belled short piles. A calculation model of rock-socketed belled short pile has been proposed. During the initial stage of loading test, uplift load is shared by even section and bell of the pile, and the bell continues to bear uplift load after the lateral resistance of even section pile reaches the limit. A different performance has been found on the case of long belled pile. At the ultimate state, the uplift resistance provided by bell accounts for about 54.9% and 34.7% of the total uplift capacity for the 6.0 m long and 7.0 m long piles, respectively. Increasing pile length has been found to noticeably increase the ultimate uplift bearing capacity, while it has less effect on the displacement of pile top. The uplift capacity of even section pile is associated with the shear strength of rock mass around the pile, and the test results demonstrate that the ultimate resistance can be equal to the shear strength. The calculation method proposed in this paper is proven to be able to accurately predict the ultimate uplift bearing capacity of the rock-socketed belled short piles.