Method and system for monitoring three-phase unbalance degree of power system
A power system and balance technology, applied in the power field, can solve problems such as the adverse effects of capacitor neutral point zero-sequence voltage protection, three-phase imbalance, and affecting the safe operation of power systems
Active Publication Date: 2016-08-17
GUANGZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD
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[0004] Based on this, it is necessary to provide a monitoring of the three-phase unbalance degree of the power system in view of the problem that the three-phase unbalance in the power system will adversely affect the zero-sequence voltage protection of the capacitor neutral point and affect the safe operation of the power system. method and system
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[0064] see figure 1 , figure 1 It is a schematic flowchart of the first embodiment of the method for monitoring the three-phase unbalance degree of the power system of the present invention.
[0065] The method for monitoring the three-phase unbalance degree of the power system in this embodiment includes the following steps:
[0066] Step 101, acquire the three-phase capacitance of the Y-connection compensation capacitor of the power system through off-line measurement, and acquire the three-phase voltage loaded on the Y-connection compensation capacitor by the power system.
[0067] Step 102, converting the three-phase capacitance into a three-phase reactance of the Y-connection compensation capacitor.
[0068] Step 103: Transform the three-phase capacitive reactance into a delta equivalent capacitive reactance of the Y-connected compensation capacitor through star-delta transformation.
[0069] Step 104, converting the three-phase voltage into three line voltages of the ...
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The invention discloses a method and system for monitoring the three-phase imbalance of an electric system. The method includes the steps that the three-phase capacitance of a Y-connection compensating capacitor of the electric system is acquired through offline measurement, and a three-phase voltage, loaded by the electric system, to the Y-connection compensating capacitor is also acquired; the three-phase capacitance is converted into the three-phase capacitive reactance of the Y-connection compensating capacitor; the three-phase capacitive reactance is converted into the delta equivalent capacitive reactance of the Y-connection compensating capacitor through Y-delta transformation; a line voltage, a line current, a phase current and a neutral-point three-phase voltage are calculated according to the delta equivalent capacitive reactance and the three-phase voltage; a neutral-point zero-sequence voltage is calculated according to the neutral-point three-phase voltage; the three-phase imbalance of the electric system is monitored according to the neutral-point zero-sequence voltage. By means of the method and system for monitoring the three-phase imbalance of the electric system, the three-phase imbalance of the electric system can be quickly and accurately monitored, and it can be guaranteed that the neutral-point voltage of the capacitor is within a safety range.
Description
technical field [0001] The invention relates to the field of electric power technology, in particular to a method and system for monitoring three-phase unbalance degree of an electric power system. Background technique [0002] With the development of science and technology, people's demand for electric energy is increasing day by day, and at the same time, the requirements for electric energy quality are also getting higher and higher. Power quality is usually expressed by indicators such as frequency, offset, flicker, collapse, peak, harmonic, three-phase unbalance, and high-frequency interference. Three-phase unbalance is an important indicator of power quality. System failure, system component parameter asymmetry, load asymmetry, etc. will cause the three-phase imbalance of the system. [0003] However, when the three-phase unbalance of the system exceeds a certain range, it will cause the parameter change of the Y-connection compensation capacitor of the power system,...
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IPC IPC(8): G01R29/16
Inventor 徐强超刘威葳江文东曾文斐沈石兰许雪丽
Owner GUANGZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD