Flexible direct current distribution system fault positioning method based on traveling wave

Abstract

The invention discloses a flexible direct current distribution system fault positioning method based on a traveling wave, and belongs to the technical field of the distribution system fault positioning method. The invention presents a multi-port looped network type flexible direct current system fault positioning method based on the minimum fault time of the travelling wave specific to a complex structure of a multi-port flexible direct current system and the transmission characteristics of the travelling wave. The network topology of the complex multi-port flexible direct current system is expressed by a picture. And then it can be judged if the fault happens on a radiation line or the inner part of the looped network. For the fault at the inner part of the looped network, the fault starting moment when every line goes wrong is calculated and compared, thus the fault branch is found, and the fault point is calculated. The flexible direct current distribution system improves the calculation speed of the algorithm on the basis of guaranteeing the calculation precision; it is very important to the direct current network of which response time is much more than that of the alternating current system.

Description

technical field [0001] The invention specifically relates to a fault location method for a flexible DC power distribution system based on traveling waves, and belongs to the technical field of fault location methods for power distribution systems. Background technique [0002] With the rapid development of power electronics technology, the extensive access of new energy in the power grid, and the continuous increase of DC loads such as electric vehicles, information equipment and semiconductor lighting systems, DC power grids have achieved technical and economic advantages in many aspects . After a fault occurs in the line of the flexible DC transmission and distribution system, quickly and accurately locate the fault point, which is not only of great significance for quickly repairing the faulty line, ensuring the reliability of power supply and reducing power loss, but also for ensuring the safe, stable and economical operation of the entire power system. All have a very ...

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Problems solved by technology

Paper: DC Fault Protection Scheme for Multi-terminal Flexible DC System [J]. Chinese Journal of Electrical Engineering, 2016, 36(0): 1-10, Paper: Research on Fault Isolation Technology of Multi-terminal Flexible DC Power Grid [J]. Chinese Journal of Electrical Engineering, 2016 ,36(1):87-95, the above papers researched the protection and isolation of multi-terminal ring flexible DC systems, which promoted the research process of flexible DC systems, but did not mention the method of fault location

Paper: Wavelet-based protection strategy for DC faults in multi-terminal VSC HVDC systems[J]. IET Generation, Transmission & Distribution, 2011, 5(4), 496-503, by selecting two out of three monitoring standards, Increased reliability, but with a corresponding increase in redundancy

Paper: New faultlocation approach using voltage measurements[C] / / Proceedings 2007IEEESoutheastCon, March 407-412, 2007, Richmond, VA, by combining the voltage information at the busbar with the network results to form the busbar impedance matrix technology for fault location, although this method It can also achieve high accuracy, but for different fault types, different matrices are required to solve, and judging the fault type is also a difficult point

Paper: Fault location on multi-terminal DC systems using synchronized current measurements[J].International Journal of Electrical Power&Energy Systems,2014,63:779-786, Paper: A Traveling-Wave-Based Methodology for Wide-Area Fault Location in Multiterminal DC Systems [J].IEEE Transactions on Power Delivery,2014,29:2552-2560, the research results of the above two papers are based on the traveling wave method to first determine the fault interval, and then determine the fault point, and can get good results , but these methods need to divide the network topology in advance, and for the number and location of detector installations, when the fault occurs in some divided areas, the fault section determination method is not applicable

[0005] When a fault occurs in the DC system, the response time is relatively short, so fast protection actions are required, and the impedance method based on transient electrical quantities is slower than the traveling wave method and has lower accuracy

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