基于改进型锁相环和混沌振子的配电网故障选线

Fault line selection of distribution network based on improved phased-loop and chaotic oscillator

当小电流系统发生故障时,各线路零序电流特征呈现出复杂的非线性和非平稳性,并且故障点的电流非常小,给故障选线带来一定的困难,对此给出一种改进锁相环和混沌振子相结合的检测方法,改进型锁相环不但可以准确的跟踪特定频率的信号,而且不需要进行dq变换和αβ变换;混沌振子系统对于与本身内驱动力同频的信号具有较高的敏度,外加信号不同时,Duffing系统的相图轨迹不同。首先用改进型锁相环锁定零序电流中的五次谐波,将此信号作为混沌系统的待测信号,通过Duffing振子系统检测此信号,正常线路和故障线路的待测信号通过混沌系统表现出来的相图状态是不一致的,由此判断出故障线路。对不同故障条件进行模拟,验证了算法的可靠性。

When the fault occurs in the small current system, the characteristics of zero-sequence current of each line show complex nonlinearity and nonstationarity, and the current at the fault point is very small, which brings some difficulties to the fault line selection. This paper presents an improved detection method of PLL and chaotic oscillator. The improved PLL can not only accurately track the signal of specific frequency, but also do not need to dq transform and αβ transform. The chaotic vibration subsystem has a high sensitivity to the signal with the same frequency as the internal driving force, and the phase diagram of the Duffing system is different from the external signal at the same time. Firstly, the fifth harmonic in the zero-sequence current is locked by the improved phase-locked loop, and the signal is used as the signal to be measured in the chaotic system. The signal is detected by the Duffing oscillator system. The state of phase diagram of the signal tested by the chaotic system is inconsistent with that of the normal line and the fault line, and the fault line can be judged from the state of the phase diagram. Different fault conditions are simulated to verify the reliability of the proposed algorithm.