Anti-islanding protection system for distributed grid-connected system and protection method of anti-islanding protection system

Abstract

The invention relates to an anti-islanding protection system for a distributed grid-connected system and a protection method of the anti-islanding protection system based on wave carrier communication and decentralized detection technology. The anti-islanding protection system comprises a decentralized detection device, a central detection device and a communication device. The decentralized detection device is used for acquiring the electrical capacity of the system and judging whether a public supply network loses power or not by data processing and logical judgment for the electrical capacity. The central detection device receives information from the decentralized detection device and logically judges the information to protect a common connection point of the distributed grid-connected system, and transmits a control instruction to a distributed power supply grid-connected point switch. The communication device is used for transmitting the information of the decentralized detection device to the central detection device and transmitting the control instruction of the central detection device to the distributed power supply grid-connected point switch. An upper carrier acquires the information of the supply network for islanding discrimination, a lower carrier controls the distributed power supply grid-connected point switch on a user side, a distributed power supply is cut off, islanding effects are prevented, and reliability and safety of the distributed grid-connected system are improved.

Description

technical field [0001] The invention relates to the technical field of distributed power generation, in particular to an anti-islanding protection system and a protection method for a distributed power generation grid-connected system. Background technique [0002] In recent years, the development of new energy power generation has been accelerated to cope with the energy crisis and the pressure brought by energy conservation and emission reduction. In the development of new energy power generation, distributed power generation including solar power generation, wind power generation, and biomass power generation has developed rapidly. A large number of distributed power sources are connected to the distribution network, which effectively improves the reliability of the distribution network, improves the power quality of regional power supply, and reduces network loss at the same time, resulting in significant economic benefits. However, the grid-connected operation of distr...

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Problems solved by technology

[0004] 1. Endanger the life safety of electric maintenance personnel;

[0005] 2. Affect the protection switch action program on the power distribution system;

[0006] 3. The unstable nature of the power supply voltage and frequency in the isolated island area will cause damage to the electrical equipment;

[0007] 4. When the power supply is restored, the voltage phase out of sync will generate surge current, which may cause tripping again or cause damage to the photovoltaic system, load and power supply system;

[0008] 5. Photovoltaic grid-connected power generation system due to single-phase power supply causes the problem of under-phase power supply of the three-phase load of the system

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