| Abstract: |
| Out-of-step oscillation separation devices based on apparent impedance angle trajectory are widely used in the
power grid in China, and their reliability is of great importance. In this paper, the influence mechanism of series
compensation on apparent impedance angle trajectory is analyzed. It reveals that series compensation capacitors
reduce the equivalent impedance angle and consequently the apparent impedance angle cannot pass through all
four zones, resulting in the risk of failure for the separation devices. A revised method of apparent impedance angle
based on compensation principle is discussed, and then an improved out-of-step oscillation detection criterion is
proposed. In view of the fact that the apparent impedance angle at the moment of maximum current is equal to the
equivalent impedance angle during an oscillation process, a practical algorithm based on the compensated apparent
impedance angle is proposed. RTDS tests are conducted to verify the effectiveness of the new criterion, considering
transmission lines with a high series compensation level. |
| Key words: Out-of-step oscillation separation, Series compensated line, Apparent impedance angle, Compensated
impedance angle |
| DOI：10.1186/s41601-022-00242-1 |
|
| Fund:This work was supported by the science and technology project of State
Grid Corporation of China (Security Protection Technology of Embed
ded Components and Control Units in Power System Terminal, No. |
|
