Grid-connected fault model and analysis method of photovoltaic power station with neutral point grounded by resistance

Abstract

The present invention provides a photovoltaic power station grid-connected fault model and analysis method of neutral point grounding through resistance. Based on an inversion power supply fault equivalence model with low-voltage crossing control strategy, a photovoltaic power station grid-connected system comprising neutral point grounding through resistance is subjected to modeling, and fault calculation models are respectively established aiming at the features of the system line of the grid-connected system and a collection line in a station. Each sequence network equation of the line fault calculation model and corresponding fault boundary conditions are combined to obtain a fault network multi-web nonlinear equation group, and the Newton-Ralfsnn's method is employed to construct an iteration correction equation to obtain a convergence solution so as to realize fault analysis. The grid-connected photovoltaic state employs a mode of the neutral point grounding through little resistance to solve the problem of fault modeling of the system, especially provide the possibility for the completion analysis of line faults through establishing of the collection line fault calculation model in the station, fully consider the influence of the neutral point grounding through resistance on the system zero sequence network and provide basis for a following protection design.

Description

technical field [0001] The present invention relates to the technical field of solar photovoltaic power generation and power transmission, in particular to a grid-connected fault model of a photovoltaic power station whose neutral point is grounded through resistance. analysis method. Background technique [0002] With the continuous integration of large-scale photovoltaic power plants into the grid, the failure rate of the power system will inevitably increase, and the short-circuit current of the transmission line will also increase, and may exceed the maximum current carrying capacity of some power components, thereby causing cascading failures . Therefore, the construction and improvement of the power grid must be carried out according to the maximum short-circuit current that may occur after the large-scale photovoltaic power station is connected to the grid. Therefore, fault calculation including large-scale photovoltaic power plants has become one of the most import...

AI Technical Summary

Problems solved by technology

[0003] Traditional fault analysis has relatively little research on the grid-connected situation of large-scale photovoltaic power plants, and most of them do not consider the fault control strategy of photovoltaic power plants and the situation that the neutral point is grounded through a resistor, which inevitably leads to limitations in fault calculations

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