A transformer differential protection method and device based on current transformer disconnection
A current transformer and differential protection technology, which is applied to emergency protection circuit devices, electrical components, etc., can solve problems such as differential protection misoperation and differential protection refusal
Active Publication Date: 2019-07-23
XUJI GRP +3
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[0004] The purpose of the present invention is to provide a transformer differential protection method and device based on current transformer disconnection, which is used to solve the problem that the differential protection may malfunction after the current transformer is disconnected and the differential protection refuses to operate when a fault occurs again
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[0079] The present invention will be described in further detail below in conjunction with the accompanying drawings.
[0080] The transformer differential protection method based on the disconnection of the current transformer is mainly used in the transformer protection device of the smart grid. The protection equipment sends out an alarm signal to notify the dispatcher to cut off the power of the transformer for maintenance through load reversal, so as to avoid the tripping of the main transformer caused by the disconnection of the secondary circuit of the current transformer. If the differential current of the line increases to the setting value of open differential protection for disconnection, an alarm signal will be issued and the differential protection will be opened to remove the fault and avoid the expansion of the accident.
[0081] Taking the 220kV transformer as an example, the main wiring diagram is as follows figure 1 shown. During normal operation, the circu...
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The invention relates to a transformer differential protection method and device based on a current transformer disconnection. The transformer differential protection method comprises the steps of judging whether a current transformer disconnects; if the current transformer disconnects, judging whether differential protection is started; if the differential protection is started, instantaneously determining that the current transformer disconnects, or otherwise, delaying to determine that the current transformer disconnects; after determining that the current transformer disconnects, judging whether disconnection locking differential protection is used; if the disconnection locking differential protection is not used, alarming the current transformer disconnection and opening the differential protection, and if the disconnection locking differential protection is used, judging whether a differential current is greater than a set value; if the differential current is greater than the set value, alarming the current transformer disconnection and opening the differential protection; and if the differential current is not greater than the set value, alarming and locking the differential protection. The transformer differential protection method and device related by the invention can reliably detect whether the current transformer disconnects; and the problems that the differential protection is likely to be mistakenly operated after the current transformer disconnects, and the differential protection refuses operation when a failure reoccurs are effectively solved.
Description
technical field [0001] The invention relates to a transformer differential protection method and device based on a disconnection of a current transformer, and belongs to the technical field of electric power system relay protection. Background technique [0002] "Electrical Industry Safety Work Regulations" stipulates that it is strictly forbidden to open the circuit when the secondary circuit of the live current transformer is working. The current transformers used in large units and ultra-high voltage equipment have a large number of secondary winding turns and a high open circuit voltage. The higher secondary voltage may not only damage the insulation of the secondary winding and secondary equipment, but also burn the iron core due to overheating, and even threaten personal safety. Therefore, the current regulations and countermeasures require that the transformer current transformer disconnect It is usually recommended not to block the differential protection for the li...
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IPC IPC(8): H02H7/045
CPCH02H7/045
Inventor 邓茂军樊占峰姚武倪传坤王攀峰胡叶宾马和科姚东晓李宝伟李旭李文正程天保冯秋芳王莉
Owner XUJI GRP