Backup Protection for Six-Phase Transformer Based on Six-Sequence Components

2013 ◽  
Vol 385-386 ◽  
pp. 1127-1130 ◽  
Author(s):  
Hai Jiang Wang ◽  
Yan Xia Zhang ◽  
Zhong Yuan Deng
Keyword(s):  
Theoretical Analysis ◽  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Simulation Experiments ◽  
Backup Protection ◽  
System A ◽  
Sequence Components ◽  
Zero Sequence ◽  
Phase Transmission

The six-phase transmission can improve the power transmission density of the transmission lines effectively, and save line corridor. To save the problem that the sensitivity of the traditional transformer backup protection is low in six-phase transmission system, a backup protection for six-phase transformer was proposed. An over-current protection criterion is proposed for interphase short circuit and opposite zero sequence over-current protection criterion is proposed for ground faults, based on the six-sequence components relationship, and the existence of six-sequence components in different fault types. Theoretical analysis and EMTDC simulation experiments prove that the scheme is feasible.

Study on Phase Comparison Pilot Protection for Six-Phase Transmission Lines Based on Six-Sequence Transformation

2012 ◽  
Vol 433-440 ◽  
pp. 2394-2399 ◽  
Author(s):  
Yan Wang ◽  
Dan Zhou ◽  
Song Xiao Xu
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Transmission System ◽  
Heavy Load ◽  
Load Current ◽  
Operating Current ◽  
Sequence Components ◽  
Phase Transmission ◽  
Current Sequence ◽  
Pilot Protection

Six-phase transmission system occupys a narrow line corridor, and it can also effectively improve power transmission density, so it gains more and more attention. A new scheme of phase comparison protection suitable for six-phase transmission lines was proposed in this paper. Because both ends of electrical quantities on six-phase transmission line are decoupled into six separate sequence components, of which opposite positive fault sequence component is independent with load current in typical six-phase transmission system, the scheme utilizes the sum of forementioned fault sequence components and same positive current sequence component and opposite negative current sequence component in proportion as the operating current in phase comparison pilot protection. The theoretical analysis and result of simulation confirm that the new scheme can correctly reflect any fault of the six-phase transmission lines, and it can overcome the disadvantages of the conventional protection under conditions of power swing, heavy load current and high transition resistances, and it can improve the sensitivity of phase comparison pilot protection and be used on six-phase transmission lines as main protection.

scholarly journals An Optimized Coordination Strategy between Line Main Protection and Hybrid DC Breakers for VSC-Based DC Grids Using Overhead Transmission Lines

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1462 ◽  
Author(s):  
Zheng ◽  
Jia ◽  
Gong ◽  
Zhang ◽  
Pei
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Short Circuit ◽  
Power Grids ◽  
Fault Line ◽  
Long Distance ◽  
Coordination Strategy ◽  
Overhead Transmission Lines ◽  
Depth Analysis ◽  
Dc Breaker

Compared with alternating current (AC) power grids, the voltage-sourced converter (VSC)-based direct current (DC) grid is a system characterized by “low damping”, as a result, once there is a short-circuit fault on the DC transmission line, the fault current will rise more sharply and the influence range will be much wider within the same time scale. Moreover the phenomenon that a local fault causes a whole power grid outage is more likely to occur. Overhead transmission lines (OHLs) have been regarded as the mainstream form of power transmission in future high-voltage, large-capacity and long-distance VSC-based DC grids. However, the application of overhead transmission lines will inevitably lead to a great increase in the probability of DC line failure. Therefore, research on how to isolate the DC fault line quickly is of great significance. Based on the technology route for fault line isolation using DC breakers, on the basis of in-depth analysis of traditional coordination strategy, an optimized coordination strategy between line main protection and a hybrid DC breaker for VSC-based DC grids using overhead transmission lines is proposed in this paper, which takes the start-up output signal of line main protection as the pre-operation instruction of the corresponding hybrid DC breaker. As a result, the risks of blockage of the modular multilevel converter (MMC) closer to the fault position and of damage to power electronic devices in main equipment can be reduced effectively. Finally, the proposed coordination strategy was verified and analyzed through simulation.

scholarly journals Computational Tool for Determining the Model in Sequence Components of Overhead Transmission Lines

2021 ◽  
Vol 2135 (1) ◽  
pp. 012008
Author(s):  
Luis Imbachi Guerrero ◽  
Fredy Jiménez Rubio ◽  
Mario Rodríguez Barrera ◽  
Diego Giral Ramírez
Keyword(s):  
Transmission Line ◽  
Transmission Lines ◽  
Distribution Systems ◽  
System Analysis ◽  
Power Transmission ◽  
Computational Simulation ◽  
Maximum Error ◽  
Computational Tool ◽  
Sequence Components ◽  
Electromagnetic Pollution

Abstract An indispensable element in addressing the current problem of non-ionizing electromagnetic pollution in the environment is a review of the levels of exposure to the electric and magnetic fields produced by the lines of electric power transmission and distribution systems. In order to establish the exposure levels, it is necessary to determine the model of the lines. Considering that a computational simulation is a helpful tool for power system analysis, this article presents a computational tool developed in Matlab App Designer for the model-in-sequence components of the parameters that make up a transmission line. This tool allows the user to work in a friendly and parameterizable environment according to the performed tests. In order to verify the tool’s performance, two case studies are implemented. The first one is for a transposed transmission line and the second one for a non-transposed transmission line. The results obtained are compared with commercial software, acquiring a maximum error of 0.16402 %.

scholarly journals Power quality in high voltage mains supplying mainline railroads’ traction substations

2019 ◽  
Vol 114 ◽  
pp. 04001
Author(s):  
Yu.N. Bulatov ◽  
A.V. Kryukov ◽  
A.V. Cherepanov
Keyword(s):  
Power Quality ◽  
Transmission Lines ◽  
Large Scale ◽  
Power Transmission ◽  
Short Circuit ◽  
Far East ◽  
Power Transmission Lines ◽  
Quality Factors ◽  
Significant Deterioration ◽  
Traction Substations

The increase in the trains weight and their operation speeds leads to considerable growth of abrupt-variable, non-linear and one-phase traction loads. This, in its own turn, leads to significant deviations, unsymmetry and voltage harmonic distortions in 110-220 kV mains adjacent to traction substations of AC railroads. Significant deterioration in power quality factors is observed in Siberian and Far East regions where 110-220 kV main power transmission lines are immediately adjacent to Transsib traction substations; in this case, in points with lower levels of short circuit power, power quality factors exceed by far the permissible levels. The articles provides the results of studies aimed at solution of power quality enhancement is-sues for mains adjacent to traction substations of Trans-Siberian Railway. To enhance power quality in mains supplying traction substations, smart grid technologies can be used together with multiagent control systems. Technical solutions, based on the results obtained, are proposed that allow to bring the power quality factors to the regulatory values. Due to a big investments amount, an implementation of tar-get program is needed to resolve the large-scale issue of enhancing power quality in mains adjacent to traction substations of AC railroads.

scholarly journals Allocation of 0.4 kV PTL Sectionalizing Units under Criteria of Sensitivity Limits and Power Supply Reliability

2021 ◽  
Vol 11 (24) ◽  
pp. 11608
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Andrey Izmailov ◽  
Alexey Dorokhov ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Short Circuit ◽  
Reducing Power ◽  
Power Transmission Lines ◽  
Electrical Networks ◽  
The Cost ◽  
The Impact ◽  
Supply Reliability

Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.

scholarly journals Application of the MQ RBF-FD method to calculating transient voltages of power transmission lines

2016 ◽  
Vol 19 (2) ◽  
pp. 5-15
Author(s):  
Anh Pham Lan Vu ◽  
Viet Quoc Le ◽  
Tu Phan Vu
Keyword(s):  
Finite Difference ◽  
Transmission Lines ◽  
Power Transmission ◽  
Power Transmission Lines ◽  
Finite Difference Approximations ◽  
Transient Problems ◽  
Benchmark Circuit ◽  
Three Phase ◽  
Phase Transmission ◽  
Transient Voltages

This paper presents an application of the Radial Basis Function – Based Finite Difference Method (RBF-FD) to solving the electrical transient problems defined by the time-dependent ordinary differential equations. In this method, the finite difference approximations of first- and second-order derivatives in time domain are formalated the same as those in space domain based on the MQ (Multiquadrics) function presented in [1]. The MQ RBF-FD method are for the sake of evaluating the accuracy, effectiveness and applicability used to compute the transient voltages on the benchmark circuit and 220 kV three-phase transmission line of Viet Nam. Our numerical results are compared with those obtained by the analytical method, the traditional FD method and ATP/EMTP software. The compared results have been shown that the MQ RBF-FD method has accuracy that is higher than ones of the traditional numerical methods, especially with the optimal shape parameter.

scholarly journals Distance backup protection using supply currents on a line with several branches

Vestnik IGEU ◽  
2019 ◽  
pp. 49-59
Author(s):  
L.M. Kolesov ◽  
V.V. Mozhzhukhina
Keyword(s):  
Transmission Lines ◽  
Short Circuit ◽  
Impedance Measurement ◽  
Total Power ◽  
Distance Protection ◽  
Backup Protection ◽  
Response Characteristics ◽  
Mode Recognition ◽  
Urgent Task ◽  
Short Circuits

The third step of distance protection is used as backup protection against phase-to-phase short circuits on 110–220 kV transmission lines. The main problem when using these protections on a line with several branches is to ensure the effectiveness of distant backup protection in case of phase-to-phase short circuits behind branch transformers of substations. The effective solution to distant backup protection is possible to provide by expanding the information base of protection. Currently, backup protection of lines with branches is being developed with control of currents and their components when using a communication channel, and based on algorithmic models of the facility. In this regard, the urgent task is to develop an algorithm for the distance protection ensuring the required sensibility during short circuits on the lower voltage side of the branch transformers. Analytical methods of determining the impedance measurement and simulation in Simulink and SimPowerSystems of the Matlab modeling system are used. The effectiveness of distant backup protection can be evaluated on the basis of recognition possibility of short circuit modes behind the branch transformers. Analytical expressions have been obtained to determine the impedance measurement during phase-to-phase short-circuits behind a branch transformer and under load conditions. Criteria have been developed to assess the proposed protection possibility to recognize the mode of phase-to-phase short circuits behind the branch transformer. Studies have shown that the main factor determining the possibility of mode recognition is the ratio between the protected transformer power and the total power of the branches loads. The use of several impedance measuring elements with their own response characteristics for branches with transformers of different capacities provides mode recognition for any possible correlation of power of branch substations. The use of the distance protection implementation option developed by the authors allows providing the required sensitivity for short circuits behind branch transformers and to solve the problem of distance backup line protection on a line with several branches. The reliability of the data obtained is confirmed by the correspondence of analytical research and simulation results.

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