A distributed photovoltaic protection system and protection method

Abstract

The invention provides a distributed photovoltaic protection system and protection method. The distributed photovoltaic protection system comprises a transformer area transformer, a transformer area load collection cabinet, a photovoltaic protection platform, and one or more home photovoltaic grid-connected power generation systems. The home photovoltaic grid-connected power generation system comprises an intelligent electric meter, a photovoltaic inverter and a photovoltaic grid-connected protection controller. An early-warning threshold is set on the photovoltaic protection platform. The tidal current distribution of a transformer area is forecasted through tidal current calculation. If the early-warning threshold is reached, photovoltaic power generation is removed in the priority order. According to the invention, for online intelligent protection of the entire transformer area, the tidal current change of a transformer in the transformer area is monitored; if the tidal current reaches the early-warning threshold, the system automatically shuts down some photovoltaic terminals; after the early-warning is released, the system automatically turns on the photovoltaic terminals to prevent an islanding effect; and under the condition that power outage of a power grid is prevented, power is still transmitted to a power supply and consumption grid.

Description

technical field [0001] The invention relates to the field of photovoltaics, in particular to a distributed photovoltaic protection system and protection method. Background technique [0002] In recent years, distributed photovoltaic technology has become more mature and has been deployed on a large scale. Photovoltaic distributed power generation is a new type of power generation and comprehensive utilization of energy with broad development prospects. It advocates the principles of nearby power generation, nearby grid connection, nearby conversion, and nearby use. It can not only effectively increase the power generation of photovoltaic power plants of the same scale , At the same time, it also effectively solves the problem of power loss in boosting and long-distance transportation. [0003] However, with the large-scale access of distributed photovoltaic power generation, especially household photovoltaics, and direct access to the grid, it will have a greater impact on ...

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Problems solved by technology

[0003] However, with the large-scale access of distributed photovoltaic power generation, especially household photovoltaics, direct access to the grid will have a greater impact on the distribution network

On the other hand, because the grid-connected photovoltaic power generation system directly inverts the power generated by the photovoltaic array and feeds it to the grid, the grid will stop working due to failure, equipment maintenance or operational errors, etc. When the power supply to the load is stopped, the distributed energy source continues to work in grid connection, so that the partial load of the grid is still in the power supply state, which will lead to an island effect, which will cause damage to the grid and user equipment, and even make some power grids considered to have been disconnected from all power sources. The open line is live, which will bring the risk of electric shock to relevant personnel (such as grid maintenance personnel and users)

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