High voltage line longitudinal zero sequence direction discrimination method and device
A high-voltage line, zero-sequence direction technology, applied in fault locations, fault detection by conductor type, etc.
Active Publication Date: 2016-04-27
STATE GRID CORP OF CHINA +2
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[0006] The embodiment of the present invention provides a method for judging the zero-sequence direction of the longitudinal connection of high-voltage lines, which can solve the problems in the prior art by comparing the relative angle difference between the zero-sequence current on both sides of the high-voltage line and the voltage of the same phase in the three-phase voltage. Technical problems existing in judging the phase comparison results of the zero-sequence voltage and zero-sequence current on one side of the high-voltage line
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[0061] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
[0062] The existing longitudinal zero-sequence directional protection for high-voltage and extra-high-voltage lines in power systems is used to protect single-phase high-resistance grounding faults in the power system. However, this method is susceptible to insufficient zero-sequence voltage sensitivity, PT disconnection, and the conventional zero-sequence direction misjudgment in the case of weak current and strong magnetic connection on the same...
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The invention discloses a high voltage line longitudinal zero sequence direction discrimination method and a device. The high voltage line longitudinal zero sequence direction discrimination method comprises steps of determining a first relative angle difference between zero sequence current on one side of the high voltage line and a phase voltage and determining a second relative angle difference between the zero sequence current on other side of the high voltage line and same phase voltage, wherein if the difference value of a first relative angle difference and a second relative angle difference is in a preset angle difference range, the direction of the longitudinal zero sequence direction is a positive direction, otherwise the longitudinal zero sequence direction is the negative direction. When one phase voltage has PT disconnection, the other phase voltage can be utilized to perform determination in order to avoid the locking zero sequence direction protection problem when the three-phase PT is disconnected. In high resistance fault, the invention avoids the problem that the zero sequence voltage is small and the sensitivity is not enough, which causes the incorrect operation of the zero sequence direction member and solves the problem of the false operation of the zero sequence direction protection caused by the non-faulted line affected by the faulted zero sequence mutual inductance which is related to the weak current and strong magnetic.
Description
technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method and device for judging the zero-sequence direction of a high-voltage line longitudinal connection. Background technique [0002] At present, the longitudinal zero-sequence directional protection of high-voltage lines is mainly used to protect single-phase high-resistance grounding faults. When the leading zero-sequence voltage direction is 90°, the longitudinal zero-sequence direction is considered to be the positive direction, and the longitudinal zero-sequence protection can operate. The use of zero-sequence directional elements for longitudinal zero-sequence directional protection has the characteristics of high sensitivity, but there are also the following problems: [0003] Generally, when a PT (Potential Transforme, voltage transformer) secondary circuit disconnection fault occurs in the protection device, the longitudinal zero-seque...
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IPC IPC(8): G01R31/08
CPCG01R31/085
Inventor 倪传坤李宝伟靳东晖樊占峰李顺昕聂文海刘丽朱正甲张嵩
Owner STATE GRID CORP OF CHINA