A Disconnection Identification Method for Adjacent Lines of Double-circuit Transmission Lines on the Same Tower
A transmission line, double-circuit technology on the same tower, applied in the direction of measuring electricity, measuring electrical variables, instruments, etc., can solve the problems of tripping, unconsidered how to monitor the disconnection of adjacent lines, and the expansion of power outage range, so as to avoid misoperation Effect
Active Publication Date: 2018-12-21
NR ELECTRIC CO LTD +2
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Problems solved by technology
In a large-current grounding system, if a longitudinal fault occurs in one of the double-circuit transmission lines on the same tower and is not grounded, the longitudinal zero-sequence directional protection of adjacent transmission lines adopts the conventional zero-sequence directional protection with zero-sequence voltage compensation When using the measurement method, it may cause the zero-sequence power direction on both sides of the non-broken transmission line to be judged as a positive direction action trip, thereby causing the scope of power outage to expand
[0003] In the line protection devices of some foreign manufacturers, components with line disconnection monitoring function are configured, but the fundamental purpose of such components is to monitor broken transmission lines, and how to Monitor the disconnection of adjacent lines
Method used
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[0025] The technical solutions of the present invention will be described in detail below in conjunction with the accompanying drawings.
[0026] Such as figure 1 As shown, the present invention provides a method for identifying the disconnection of adjacent lines of double-circuit transmission lines on the same tower, including the following steps:
[0027] Step 1, collect the three-phase current and three-phase voltage at the place where the line protection is installed;
[0028] In this embodiment, it is assumed that the collected three-phase currents are respectively The three-phase voltages are
[0029] Step 2, calculate the zero-sequence current and zero-sequence voltage at the place where the line protection is installed;
[0030] Specifically, the method for calculating the zero-sequence current and zero-sequence voltage at the line protection installation is:
[0031] Zero sequence current:
[0032] Zero sequence voltage:
[0033] Step 3. Calculate the ...
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The invention discloses a recognition method of breaking of an adjacent line of a double-circuit transmission line on a same tower. The method includes following steps: step 1, acquiring a three-phase current and a three-phase voltage at a line protection installation position; step 2, calculating a zero-sequence current and a zero-sequence voltage at the line protection installation position; step 3, calculating a virtual zero-sequence voltage according to the zero-sequence voltage and the zero sequence current of the line protection installation position and a zero-sequence impedance of the transmission line; and step 4, comparing the phase relationship between the zero-sequence voltage at the line protection installation position and the calculated virtual zero-sequence voltage, and determining the fact that the adjacent line of the line protection installation line breaks if the phase of the zero-sequence voltage at the line protection installation position is greater than that of the virtual zero-sequence voltage by 180 degrees. According to the method, in the double-circuit transmission line at the same tower, non-breaking line relay protection misoperation is avoided.
Description
technical field [0001] The invention belongs to the field of relay protection of electric power systems, and in particular relates to a method for identifying disconnection of adjacent lines of double-circuit power transmission lines on the same tower. Background technique [0002] Double-circuit transmission lines on the same tower are widely used in EHV transmission networks. In a large-current grounding system, if a longitudinal fault occurs in one of the double-circuit transmission lines on the same tower and is not grounded, the longitudinal zero-sequence directional protection of adjacent transmission lines adopts the conventional zero-sequence directional protection with zero-sequence voltage compensation When the measurement method is used, it may cause the zero-sequence power direction on both sides of the non-broken transmission line to be judged as a positive direction action trip, thereby causing the scope of power outage to expand. [0003] In the line protecti...
Claims
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IPC IPC(8): G01R31/02
CPCG01R31/50
Inventor 谢华赵青春戴光武徐晓春朱晓彤张洪喜
Owner NR ELECTRIC CO LTD