A Line Disconnection Protection Method Based on Comparing the Line Voltage Amplitude Difference on Both Sides of Line
A technology of disconnection protection and line voltage, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of transformer three-phase voltage asymmetry, damage to electrical equipment, motor lack of phase operation, etc., to achieve the effect of safe and stable operation
Active Publication Date: 2021-02-19
STATE GRID JIANGSU ELECTRIC POWER CO ZHENJIANG POWER SUPPLY CO
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[0002] At present, there are 3~66kV (including 3, 6, 10, 20, 35, and 66kV) line disconnections in various power grids. The disconnection causes the transformer powered by the line to run without phase, which makes the three-phase voltage of the transformer asymmetrical and supplies power to the load. If there is an impact, it may damage electrical equipment, such as causing damage to the motor due to lack of phase operation, etc.
In the prior art, there is no relay protection device and method specifically for 3-66kV line disconnection
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[0052] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0053] First, take the 35kV line disconnection as an example to analyze the fault characteristics:
[0054] 1.1 Ungrounded or grounded system through arc suppression coil
[0055] 1.1.135kV line disconnection
[0056] Such as figure 1 It is a schematic diagram of a 35kV disconnection primary system, taking the phase A short line as an example. The 35kV side of the superior substation is not grounded or grounded through the arc suppression coil, and the 35kV neutral point of the load side 35kV substation transformer is not grounded. Assume that the power potential of the 35kV side of the upper substation is E A ,E B ,E C , U N It is the 35kV neutral point voltage of the substation transformer on the power supply side. If the line is broken at α, then the ground capacitance from the broken line to the upper substation busbar side is αC, an...
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The invention discloses a line disconnection protection method for comparing the line voltage amplitude difference on both sides of the line. The invention fully utilizes the fault characteristics of the secondary voltage of the power supply terminal and the load terminal substation bus PT when the line is single-phase disconnected, and compares the two sides of the line. The voltage amplitude difference of the terminal bus line is different, and the single-phase disconnection of the line is identified, and the load-side substation adopts the closing and unlinking operation to transfer the load and supply power, which is simple and easy. The present invention transmits the voltage information on both sides of the line through the line optical fiber channel, compares the line voltage amplitude difference on both sides of the line to identify line disconnection, and the load-side substation adopts the ring closing operation to transfer the load power supply, so that the transformer that lost the power supply can be restored to the backup power supply The power supply relay protection scheme can effectively prevent the impact of transformer lack of phase power supply on the power grid and load power supply, which is conducive to the safe and stable operation of the power grid.
Description
technical field [0001] The invention relates to a line disconnection protection method for comparing line voltage amplitude differences on both sides of the line, and belongs to the technical field of protection and control of power transmission and distribution networks. Background technique [0002] At present, there are 3~66kV (including 3, 6, 10, 20, 35, and 66kV) line disconnections in various power grids. The disconnection causes the transformer powered by the line to run without phase, making the three-phase voltage of the transformer asymmetrical, and supplying power to the load. If there is an impact, it may damage the electrical equipment, such as causing damage to the motor due to lack of phase operation. In the prior art, there is no relay protection device and method specifically for disconnection of 3-66kV lines. The present invention will propose a method that transmits the voltage information on both sides of the line through the line optical fiber channel i...
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IPC IPC(8): H02H7/26
CPCH02H7/26
Inventor 刘昶胡浩汤勋孙东杰杨静朱文韬姜正驰杜炜凝戴星宇
Owner STATE GRID JIANGSU ELECTRIC POWER CO ZHENJIANG POWER SUPPLY CO