A method for detecting capacitance current to ground
A technology of ground capacitance current and detection method, applied in the field of medium voltage power transmission and distribution, can solve the problems of equipment damage, system and measurement influence, etc., to achieve the effect of high practicability, small system influence, and simple method
Active Publication Date: 2022-03-11
ANHUI ELECTRICAL ENG PROFESSIONAL PROFESSIONAL TECHN COLLEGE +4
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Problems solved by technology
However, the injection method needs to inject harmonics into the system, which will affect the system and measurement. The impedance method and extreme value method need to repeatedly adjust the arc suppression coil, which will cause damage to the equipment.
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Embodiment Construction
[0043] One proposed according to the present invention, the earth capacitance current detection method, the main steps of: constructing large_capacity neutral ground circuit, and then to the current source from the voltage source is converted to parallel arc suppression coil adjustable initial conductance value Conductance calculating the current through the neutral point, and Petersen coil parallel conductance change value calculating again the current through the neutral point, the capacitance value finally obtained by computing system. The following sequentially describes the steps of the method:
[0044] Step ①, constructed neutral point arc suppression coil grounding circuit
[0045] Such as figure 1 , The conductance G L and the capacitance branch admittance circuit in parallel connection to ground.
[0046] in, Are A phase, B phase, C phase power source voltage; L is Petersen coil inductance, G is adjustable parallel conductance Petersen coil; C A , C B , C C Grid A phase,...
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The invention discloses a detection method for ground-to-ground capacitance current, which relates to the technical field of medium-voltage power transmission and distribution. Construct the grounding circuit of the neutral point through the arc suppressing coil, and then transform from the voltage source to the current source, calculate the current through the neutral point with the initial conductance value of the arc suppressing coil parallel adjustable conductance, and then change the parallel conductance value of the arc suppressing coil to calculate again The current passes through the neutral point, and finally the capacitance value of the system to ground is obtained through calculation. The invention proposes a method for calculating the capacitance current of the system to ground by changing the resistance value of the neutral point, respectively measuring the value of the overcurrent of the neutral point before and after changing the resistance value. Among them, the current value flowing through the neutral point can be obtained directly from the neutral point current transformer, that is, the zero-sequence current transformer, and the value is 3 times of the zero-sequence current. The measurement signal of the method is easy to obtain, the method is simple, the influence on the system is small, the practicability is high, and the precision is high.
Description
Technical field [0001] The present invention relates to lose pressure distribution art, in particular, to a method for detecting the capacitive current pair. Background technique [0002] Of 35kV power distribution system and the multi-point non-effectively grounded neutral mode in which a wide arc suppression coil neutral point grounding applications. The kind of system, the most common single-phase ground fault, when the single phase, the ground capacitance current neutral point reactor Petersen coil compensated, limits the size of the ground current, reduced recovery voltage, the arc extinguishing easy to avoid arcing renewed, harm reduction circuit. Of the grid system, the non-effective grounding of the neutral point, allowing the occurrence of a short single-phase ground fault allowed 2 hours to effectively reduce the grounding fault current embodiment harm. [0003] Currently, the main method used has a maximum value of the earth capacitance current detection method, the si...
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IPC IPC(8): G01R31/08G01R19/00G01R27/26
CPCG01R31/086G01R31/088G01R19/0092G01R27/2605
Inventor 周锐夏俊雅于传杨春玲
Owner ANHUI ELECTRICAL ENG PROFESSIONAL PROFESSIONAL TECHN COLLEGE