Photovoltaic power generation optimal arrangement system

Abstract

The invention discloses a photovoltaic power generation optimal arrangement system, which comprises a photovoltaic module, a direct-current combiner box, a photovoltaic grid-connected DC / DC device, adirect-current metering cabinet and a direct-current power distribution cabinet, wherein the direct-current metering cabinet and the direct-current power distribution cabinet are both arranged in a direct-current power distribution room, and the photovoltaic assembly, the direct-current combiner box and the photovoltaic grid-connected DC / DC device are all arranged on the roof of the direct-currentpower distribution room; and the photovoltaic module is connected with the direct-current combiner box, the direct-current metering cabinet is connected with the direct-current power distribution cabinet through a first cable, the photovoltaic grid-connected DC / DC device is connected with the direct-current metering cabinet through a second cable, and the direct-current combiner box is connectedwith the photovoltaic grid-connected DC / DC device through a third cable. According to the invention, the amplitude and the rising rate of short-circuit current provided by the photovoltaic grid-connected DC / DC device during inter-electrode short circuit can be reduced under the condition that extra electrical equipment is not added, and the probability that the photovoltaic grid-connected DC / DC device provides extremely high short-time overcurrent is reduced.

Description

technical field [0001] The invention relates to the field of electric power layout structure, in particular to a photovoltaic power generation optimization layout system. Background technique [0002] As the problem of fossil energy shortage becomes increasingly prominent, photovoltaic power generation technology, as a renewable power technology, has developed rapidly. Photovoltaic power generation system is a power generation system that uses the photovoltaic effect of solar cells to directly convert solar radiation energy into electrical energy and is electrically connected to the public grid. Its connection with the public grid can be in the form of AC or DC. Since photovoltaic systems adopt DC access to have higher energy efficiency, with the popularization and application of DC power distribution systems, it can be predicted that distributed photovoltaic systems will use DC to connect to DC distribution networks in the future. [0003] Since the current DC power grid ...

AI Technical Summary

Problems solved by technology

[0007] From the simulation calculation results, it can be seen that the shortcomings of the prior art 1 mainly include the following aspects: 1. Since the photovoltaic grid-connected DC / DC device is too close to the DC power distribution cabinet, the electrical distance is short and the impedance is small, when the feeder poles are short-circuited At this time, the port capacitance of the grid-connected DC / DC device will discharge quickly and provide a huge short-circuit current, which will easily cause protection malfunction and even damage the equipment

2. Any short-circuit of the inter-pole feeder will cause the grid-connected DC / DC device to quickly discharge and provide a huge short-circuit current. Therefore, for the occasion with many feeders, the probability of the grid-connected DC / DC device providing a very short-term overcurrent will be greatly reduced. Increase

But this method also has the following disadvantages: 1. It is difficult to select the current limiting reactor

Iron-core reactors are easy to saturate under high current and lose their current-limiting effect; air-core reactors have large magnetic flux leakage, which is easy to affect peripheral equipment, and they are large in size and require a large footprint

2. The addition of a piece of equipment will increase the project cost and land occupation accordingly

Especially when the rated current is large, in order to facilitate the heat dissipation of the reactor, the volume of the reactor is large

3. The inductance value of the current limiting reactor should not be determined

If the inductance value is too small, the current limiting effect is not obvious; if the inductance value is too large, the reactor volume is large, and it is easy to cause system instability

In addition, the reactor may also resonate with the capacitors in the system, etc.

Images