Fault detection method for circuit sent out from wind power plant

A technology for fault detection and sending out lines, applied in emergency protection circuit devices, electrical components, etc., to solve problems such as inaccurate detection results
CN104348144AActive Publication Date: 2015-02-11ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID NINGXIA ELECTRIC POWER COMPANY +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
ELECTRIC POWER RESEARCH INSTITUTE OF STATE GRID NINGXIA ELECTRIC POWER COMPANY
Publication Date
2015-02-11

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Abstract

The invention discloses a fault detection method for a circuit sent out from a wind power plant. The method comprises the following steps: 1 collecting phase current of a circuit sent out from a current wind power plant after a fault appears; 2 building a linear relationship between measurement by using the least squares fitting method, and estimating the frequency of the phase current; 3 when the calculated frequency of the phase current is in a normal frequency range, judging that a crowbar protection circuit is not started, and entering the step 4; or else, judging that the crowbar protection circuit is started, and returning to the step 1; 4, finding out the position of sending out the fault in the circuit through a distance protection element. The fault detection method can be immune to non-power frequency current characteristics sent out from a double-fed wind power plant; the operation characteristics of fault impedance and distance protection can be quickly calculated aiming at various fault types; the protection reliability and selectivity are greatly improved.
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Description

technical field

[0001] The invention belongs to the technical field of fault detection, in particular to a fault detection method for a transmission line of a wind farm. Background technique

[0002] At present, doubly-fed wind turbines have been widely used in the field of new energy power generation. Distance protection, as one of the mainstream backup protections, plays an extremely important role in the safe operation of wind farm transmission lines. When the grid voltage drops and the rotor overcurrent is caused by the doubly-fed wind turbine, in order to protect the converter on the rotor side, the crowbar (crowbar) protection circuit will be put into operation. At this time, the stator terminal will send a non-power frequency fault current to the grid. It has brought many practical engineering problems to relay protection, one of which is that the distance protection element based on Fourier algorithm cannot accurately calculate the impedance from the fault point to t...

Claims

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