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Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device

A technology of distributed power supply and intelligent switch, applied in emergency protection circuit devices, circuit devices, electrical components, etc., can solve problems such as impacting power grid protection devices, affecting the action procedure of protection switches in power distribution systems, and phase asynchrony.

Inactive Publication Date: 2015-05-27
STATE GRID ZHEJIANG HAIYAN POWER SUPPLY
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Problems solved by technology

[0003] Once the island is generated, it will endanger the safety of maintenance personnel and the public on the transmission line of the power grid; affect the action program of the protection switch on the power distribution system, impact the power grid protection device; affect the quality of transmitted power, and the power supply voltage and frequency in the power island area will be unstable. ; When the grid power supply is restored, the phases will be out of sync; the single-phase distributed power generation system will cause the three-phase load of the system to be out of phase, so for a distributed power grid-connected system, it must be able to detect the anti-islanding effect and cut off in time off grid

Method used

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  • Anti-islanding grid-connection intelligent switch protection method for distributed type power supply system and grid-connection intelligent switch device

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Embodiment

[0021] Example: figure 1 As shown, the distributed power supply system of the present invention includes the DC power output by wind energy and solar energy, which is converted into AC power through an inverter, and then converted into electric energy of a corresponding voltage level through a transformer, which is incorporated into the distribution network and grid-connected There is a special grid-connected switch DK; in order to prevent the generation of islanding benefits, by controlling the grid-connected inverter, inject certain disturbances into its output power, frequency or phase, such as current disturbance method (dynamic impedance measurement method), frequency deviation Shift, mutation method, voltage offset method, and simultaneously detect the output of the inverter. When the power grid is working normally, due to the balance of the power grid, the disturbance signal is not enough to change the output characteristics of the grid-connected inverter; when the ...

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Abstract

The invention discloses an anti-islanding grid-connection intelligent switch protection method for a distributed type power supply system and a grid-connection intelligent switch device. The distributed type power supply system is converted into alternating current power through an inverter, and the alternating current power is converted into electric energy of the corresponding voltage level through a transformer and is connected into a power distribution network through a grid-connection switch; the grid-connection intelligent switch protection method comprises the following steps: injecting certain disturbance into the output power, the frequency or the phase of a grid-connection inverter by controlling the grid-connection inverter, and detecting the output situation of the inverter, wherein when a power grid works normally, a disturbance signal cannot change the output characteristic of the grid-connection inverter under the balance action of the power grid; when the power grid fails, the output characteristic of the grid-connection inverter can be quickly accumulated and exceed an allowable range under the feedback action of the disturbance signal; if the output current, the output voltage and the output power, detected by injection of the disturbance signal into the grid-connection inverter, of the grid-connection inverter exceed the allowable range, a signal is generated to trigger a protection device of the grid-connection switch immediately to enable the protection device to trip.

Description

technical field [0001] The invention relates to a grid-connected intelligent switching method and a switching device for preventing the islanding effect of a distributed power system, and belongs to the technical field of power system safety protection. Background technique [0002] In the existing technology, when the power grid is out of power due to failure or maintenance, the distributed power generation system (wind power generation, solar power generation) fails to detect the power failure state in time and disconnects itself from the power grid, forming a self-sufficient power supply island. [0003] Once the island is generated, it will endanger the safety of maintenance personnel and the public on the transmission line of the power grid; affect the action program of the protection switch on the power distribution system, impact the power grid protection device; affect the quality of transmitted power, and the power supply voltage and frequency in the power island are...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02H7/26
CPCH02H7/267H02J3/381H02J3/388
Inventor 汪泽州鲍建飞缪金良宓均良篑晓云冯朝力
Owner STATE GRID ZHEJIANG HAIYAN POWER SUPPLY
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