Building photovoltaic grid-connected system

Abstract

The invention relates to a building photovoltaic grid connected system which comprises a plurality of photovoltaic buildings accessed into a power distribution grid through a plurality of access points, and is characterized by comprising an energy storage station and a power-adjustable photovoltaic power station, wherein an electric energy quality coordinated control system and a plurality of electric energy quality adjustment devices are used for adjusting and controlling electric energy quality input into a plurality of low voltage systems; power distribution grid relay protection devices, anti-islanding protection devices and counting measurement and control devices are arranged in a plurality of low voltage systems; and the anti-islanding protection devices and the counting measurement and control devices are arranged at eahc access point of the photovoltaic buildings. By adopting the building photovoltaic grid connected system, short-time power fluctuation in a power distribution grid region can be relieved, and the stability of a power grid can be improved; furthermore, the harmonic content and the voltage fluctuation degree are reduced, and the quality of electric energy is controlled; the power distribution grid relay protection devices and the anti-islanding protection devices ensure security of equipment and safety of human; and the counting measurement and control devices are distributed for different systems, so that automatic and intelligent running management is realized.

Description

technical field [0001] The invention relates to a building photovoltaic system, in particular to a high-density, multi-access point building photovoltaic system and a grid-connected coordination system of a power distribution network. Background technique [0002] Since the 1990s, Japan, Europe, the United States and other developed regions, under the encouragement of the "Photovoltaic Roof Project", have gradually promoted and applied building photovoltaic systems on a large scale. The area of ​​the distribution network, such as the SMW (3,500 households) solar community in Haierxu Howard, the Netherlands, the 2.2MW (550 households) photovoltaic demonstration area in Ota City, Japan, and the 345kW (144 households) demonstration area in Rocklin, California, USA. Although the application of building photovoltaic systems in my country has just started, it is developing very rapidly. At the end of 2009, the cumulative installed capacity of building photovoltaic systems reached ...

AI Technical Summary

Problems solved by technology

[0005] 1) The high-density photovoltaic system has an impact on the voltage stability of the distribution network, and the photovoltaic system and the distribution network cannot be effectively coordinated;

[0006] 2) The harmonic distortion rate of photovoltaic grid-connected inverters is high under light load conditions. After the high-density photovoltaic system is connected to the user side, it will affect the distribution of reactive power in the distribution network, and will cause voltage fluctuations and three-phase imbalances. And other issues;

[0007] 3) After the photovoltaic system is connected to the user side, the distribution network changes from a single power supply radiation network to a double-terminal and multi-terminal network, which changes the direction, magnitude and duration of the fault current, which may cause traditional relay protection to malfunction or refuse to operate

The protection configuration of the photovoltaic system itself will also affect the system operation and relay protection;

[0008] 4) The photovoltaic system introduces a new power supply to the distribution network, which has a positive effect on meeting the load demand nearby and improving the reliability of power supply. On the other hand, the output power of the photovoltaic system is greatly affected by randomness, and when it reaches a high level have the potential to negatively affect the reliability of power supply;

[0009] 5) The access location and maximum access capacity of photovoltaic systems and energy storage stations are affected by photovoltaic characteristics and grid operation constraints. The current location and capacity planning of photovoltaic systems and energy storage stations is unreasonable

[0016] To sum up, the regional high-density, multi-access point photovoltaic system is a new form of photovoltaic application, and the promotion prospect is very broad. However, there are still many problems in the stability of grid-connected operation, power quality, safety protection, energy management and measurement and control insufficient

Images