Differential protection device based on sudden change impedance principle
A differential protection device and sudden change technology, which is applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of high synchronization requirements, large data volume, and low synchronization requirements, and achieve low synchronization requirements and low data volume. small effect
Inactive Publication Date: 2015-08-12
NANHUA UNIV
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Problems solved by technology
Amplitude comparison differential protection (sampling value differential can also be classified into this category) has high requirements on the synchronization of the currents participating in the differential, and requires a large amount of data; phase comparison differential protection requires synchronization Not high, the use of the electromagnetic transformer linear transmission area can also reduce or even overcome the influence of CT saturation, but the traditional bus connection current comparison type bus difference protection and current phase comparison type bus difference protection have outflow currents for faults in the area powerless
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[0012] The present invention will be further described below in conjunction with the accompanying drawings of the description.
[0013] Such as figure 1 As shown, a differential protection device based on the principle of sudden change impedance, a differential protection device based on the principle of sudden change impedance, is provided with n branches connected to the bus, and each branch detects a branch fault The output unit, the branch fault detection output unit includes a first AND gate, a second AND gate, a first OR gate and a second OR gate, and the action of the positive direction element and the non-action of the reverse direction element of each branch pass through the first After the AND gate, it is output to the first OR gate, and the positive direction element and the reverse direction element of each branch are not activated and then output to the first OR gate after passing through the second AND gate, and the n first OR gates are simultaneously output to t...
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A differential protection apparatus based on a break variable impedance principle. N branches are connected on a bus, and each branch is corresponding to a branch fault detection output unit. Each of the branch fault detection output units comprises a first AND gate, a second AND gate, a first OR gate, or a second OR gate. Positive direction element actions and negative direction element inactions of each branch pass through the first AND gate and then are output to the first OR gate. Positive direction element inactions and negative direction element inactions of each branch pass through the second AND gate and then is output to the first OR gate, or to n first OR gates or are simultaneously output to the third AND gate. Positive direction actions of n way of branches are simultaneously input to the second OR gate, the second OR gate outputs the inactions to the third AND gate. The third AND gate outputs a differential protection signal. The apparatus uses break variable impedance relays as positive and negative direction elements, and sets an action range on a fixed value. An internal fault can be determined when positive direction elements of all branches connected to the bus act while negative direction elements do not act or neither of the positive nor negative direction elements act.
Description
technical field [0001] The invention relates to a differential protection device, in particular to a differential protection device based on the principle of abrupt change impedance. Background technique [0002] The implementation of current differential protection can be roughly divided into two categories: amplitude comparison current differential protection and phase comparison current differential protection. Amplitude comparison differential protection (sample value differential can also belong to this category) has high requirements on the synchronization of the currents participating in the differential, and requires a large amount of data; phase comparison differential protection requires synchronization Not high, the use of the electromagnetic transformer linear transmission area can also reduce or even overcome the influence of CT saturation, but the traditional bus connection current comparison type bus difference protection and current phase comparison type bus ...
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IPC IPC(8): H02H7/22
CPCH02H7/22
Inventor 曾铁军文杰
Owner NANHUA UNIV