Method for protecting collection system line in large-scale photovoltaic power station

Abstract

The invention belongs to the technical field of new energy electricity generation and grid connection, and particularly relates to a method for protecting a collection system line in a large-scale photovoltaic power station. The method comprises the following steps: deriving a unified expression of fault currents under different control targets aiming at a positive and negative sequence bisynchronous rotating coordinate system current controller which is widely adopted by a centralized photovoltaic inverter and the influence on characteristics of a power supply of a photovoltaic cell panel on a direct current side; on the basis of the unified expression, analyzing the current protection performance of a 35kV collection line in the photovoltaic power station; providing a distance protection replaced new configuration scheme aiming at the situation that current protection on a downstream photovoltaic side of an overhead line cannot act correctly. The method is not influenced by the factors of a photovoltaic output condition and operating power; the problem about setting calculation of a short circuit current threshold value on the photovoltaic side is avoided; the operating safety and reliability of the photovoltaic system in the power station are improved.

Description

technical field [0001] The invention belongs to the technical field of grid connection of new energy power generation, and in particular relates to a method for protecting a collection system line in a large-scale photovoltaic power station. Background technique [0002] In order to solve the increasingly severe energy crisis and environmental problems, grid-connected photovoltaic power generation technology has been developed rapidly. Most of the photovoltaic power stations adopt the system of decentralized inverter, local boost and centralized grid connection. A large photovoltaic power station needs hundreds of photovoltaic power generation units to gather together. The collection system in the station contains multiple collection lines, and the accurate operation of its protection is directly related to the power generation efficiency of the photovoltaic power station, which has important research significance. The technical specifications for connecting photovoltaic po...

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Problems solved by technology

[0007] Step 3. Aiming at the problem that the current protection of the photovoltaic side downstream of the overhead line in the station cannot operate correctly, combined with the characteristics of the fault current in the station, a configuration scheme for distance protection to replace the current protection of the photovoltaic side downstream of the overhead line is proposed

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