Evaluation method and device for accessible capacity of distributed photovoltaic power sources

Abstract

The invention discloses a method and device for evaluating the accessible capacity of a distributed photovoltaic power source, wherein the method includes: identifying the voltage level of the location where the photovoltaic power is connected, and obtaining the system parameters on the backside of the photovoltaic power supply; The impedance of the downstream line, and obtain the current protection parameter configuration information; according to the voltage level, backside system parameters, impedance and current protection parameter configuration information, obtain the maximum capacity of photovoltaics that can be connected under the current relay protection configuration. According to the evaluation method of the embodiment of the present invention, it can effectively avoid the huge damage to the distribution network or even the transmission network caused by the relay protection malfunction or failure to reach the required protection range, improve the power supply reliability of the power system, and effectively ensure Power quality improves user experience.

Description

technical field [0001] The invention relates to the technical field of power supply, in particular to a method and device for evaluating the accessible capacity of a distributed photovoltaic power supply. Background technique [0002] At present, distributed energy refers to the joint generation of electric energy by multiple or even various forms of power generation equipment within a certain geographical range, so as to meet the requirements of large-scale electricity consumption on the spot. As a distributed energy source, photovoltaic has the characteristics of clean and environmental protection, two-way power supply, and local consumption. However, as the penetration rate of photovoltaic equipment in the distribution network system continues to increase, when the system fails, the short-circuit current provided by the photovoltaic power supply is also increasing, which will affect the reliability and sensitivity of the original protection. . [0003] In the related te...

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Problems solved by technology

However, as the penetration rate of photovoltaic equipment in the distribution network system continues to increase, when the system fails, the short-circuit current provided by the photovoltaic power supply is also increasing, which will affect the reliability and sensitivity of the original protection.

[0003] In the related technology, most of the relay protection configurations of the existing 10kV distribution network are the overcurrent section I and the overcurrent section III, and the setting values ​​are all set according to the power load before the photovoltaic connection; After the conventional energy is connected, it will affect the correct operation of the existing relay protection. For example, the reverse current of photovoltaics will cause the protection malfunction without directional elements, and the protection cannot reach the required protection range. With the improvement of capacity, this effect is also increasing. Given that there is a maximum accessible photovoltaic capacity, when the photovoltaic capacity connected to the system exceeds the maximum accessible photovoltaic capacity, it will cause the existing relay protection to malfunction. Action or fail to reach the required protection range, which will cause great harm to the distribution network and even the transmission network, greatly reduce the power supply reliability of the power system, and reduce the power quality, which needs to be solved urgently

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