Large-scale photovoltaic power station's collection system fault location method

Abstract

The invention belongs to the technical field of new energy grid-connected power generation technology, in particular to a large-scale photovoltaic power station's collection system fault location method. The method, based on the control of the inverter in an actual photovoltaic power plant, through the utilization of the characteristics of a photovoltaic power generation unit of not outputting negative sequence current under an asymmetrical voltage condition and the combination of the node negative sequence voltage equation corresponding to the sparse measurement point after an asymmetric fault occurs in the photovoltaic power station's collection system and the compression perception theory, and through the assistance of an improved Bayesian compression perceptual reconstruction algorithm, solves the node negative sequence injection current vector to locate a fault. Of all node negative sequence injection current amplitude vectors in a data window, the nodes corresponding to the largest element and appear at the most frequency are regarded as problematic ones. According to the invention, all the method requires is the non-synchronized measurement information of sparse measurement spots. And the method is free of impacts of fault types and transitional resistors. Due to its strong ability to combat noise and its high precision, the method can be practically used to meet the application requirement of large scale photovoltaic power stations.

Description

technical field [0001] The invention belongs to the technical field of new energy grid-connected power generation, and in particular relates to a method for locating faults in a collection system of a large-scale photovoltaic power station. Background technique [0002] Large-scale centralized photovoltaic power plants are composed of a large number of photovoltaic power generation units, and overhead lines and buried cables coexist in the collection system. The collection system generally does not have an automatic reclosing device, and manual troubleshooting is required after a fault trips. The photovoltaic array area occupies a large area and has a small appearance distinction, which makes line inspection difficult, resulting in a long time for the disconnected photovoltaic system to restore power generation and loss of power generation efficiency. Therefore, accurately and quickly locating the fault location in the collection system is helpful to improve the power gener...

AI Technical Summary

Problems solved by technology

Among the existing fault location methods based on multi-point measurement information, the method based on information interaction between measurement points needs to synchronize measurement information, which requires high communication

However, most of the methods based on voltage sag cannot avoid the cyclic traversal process of possible fault points in the entire network. When the network scale is large, the calculation process will be very long and the positioning accuracy will be poor.

When considering distributed power access, existing methods simply equate distributed power into constant current sources or controllable sources at the system frequency, and distributed and centralized photovoltaic grid-connected power generation systems have differences in topology and control. Significant differences lead to large differences in fault current characteristics, the original equivalent method is difficult to apply, and the penetration rate of photovoltaic power in the collection system reaches 100%, and the control characteristics of photovoltaic inverters cannot be ignored

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