A method to reduce the depth of voltage sag by three-phase reclosing sequence
A voltage sag and reclosing technology, which is applied in the direction of AC network voltage adjustment, electrical components, circuit devices, etc., can solve the problems of the second voltage sag and the depth of the second voltage sag, so as to avoid losses, The effect of avoiding off-grid accidents and reducing economic costs
Active Publication Date: 2020-03-31
南京首风智慧电力研究院有限公司
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Problems solved by technology
2) Reclosing occurs on a permanent fault, the protection operates again, and the reclosing fails
When reclosing fails, it may cause a second voltage sag
A large number of simulations show that when the two sides of the line are respectively used as the non-voltage detection side, the depth of the second voltage sag is different.
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[0019] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.
[0020] In the present invention, the fault component voltage ΔU of the sensitive load node is calculated when the two sides of the line are respectively used as the non-voltage detection side. pi , ΔU pj , compare ΔU pi , ΔU pj , select the side with the smaller value as the non-pressure side. Such as: |ΔU pi |>|ΔU pj |, then the side j is determined as the non-pressure side. If side j coincides with the fault, side i will no longer coincide, causing the voltage sag of the sensitive load bus to be only ΔU pj . If side j is successful, then side i will pass the check for synchronous coincidence.
[0021] The IEEE 39 node model established in PSCAD / EMTDC, such as figure 2 shown.
[0022] The present invention proposes a method for reducing voltage sag depth through three-phase reclosing sequence, according to grid information and ope...
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The invention discloses a method for reducing the voltage sag depth by a three-phase reclosing time sequence. According to grid rack information and operation data, fault component voltages of a sensitive load are calculated respectively when different sides of each line overlap a permanent fault by using a fault component concept; and one side of a small fault component voltage value is determined to be a no-voltage-detection side and the other side is determined to be a synchronization detection side, so that a three-phase reclosing time sequence of each line is determined. Therefore, when line protection overlap the permanent fault, the sensitive load losses under the condition of voltage sag can be reduced or even avoided; and no cost increases. The voltage and electric energy qualityis improved; occurrence of wind power generation and photovoltaic power generation off-grid accidents is avoided; and the economic costs are lowered effectively.
Description
technical field [0001] The invention belongs to the technical field of power systems, and relates to a method for reducing voltage sag depth through three-phase reclosing sequence. Background technique [0002] In recent years, with the widespread use of computers, programmable control devices, etc., voltage sag has become one of the main problems affecting user power quality. Analysis and research on the characteristics of voltage sag and its control measures have become a research hotspot. The causes of voltage sag include short-circuit fault, lightning strike, switch operation, switching of transformer and capacitor bank, etc. Among them, the short-circuit fault of the transmission line is the main cause of the voltage sag. At present, the depth of voltage sag is reduced by costly methods and measures such as reducing the failure of the public power grid, installing compensation devices, and changing the power supply mode. [0003] For double-sided power transmission li...
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IPC IPC(8): H02H3/06H02H7/26H02J3/12
CPCH02H3/063H02H7/262H02H7/263H02J3/12
Inventor 梁振锋张清张惠智
Owner 南京首风智慧电力研究院有限公司