基于随机子空间和最小二乘法的介质损耗角检测方法

Measurement Algorithm of Dielectric Loss Angle Based on SSI-LS

介质损耗角是判断高压设备绝缘状况的有效参数之一,而准确地提取基波电压和电流信号是检测介损角的关键。为精确检测介损角,提出基于随机子空间辨识(stochastic subspace identification,SSI)与最小二乘(leastsquare,LS)法的介损角检测方法。该方法可以准确提取基波电压和电流分量,得到基波电压和电流的相位,从而实现介损角的准确检测。当介损角真实值、电压频率、3次谐波、直流分量、采样频率、采样点数以及白噪声等状态变化时,对SSI-LS法基本无影响;当白噪声的信噪比>25 dB时,其计算结果满足介损角的误差精度;经与谐波分析法进行比较分析可知,此算法的速度和精度较优。仿真分析结果验证了该方法的可行性与有效性。

Dielectric loss angle is the effective means to determine the status of the high voltage apparatus insulation. The key to detect dielectric loss angle is correct extraction of the fundamental wave of voltage and current signal. We introduced a novel method based on the stochastic subspace identification（SSI） and least square（LS） method. The method can accurately extract fundamental wave of voltage and current signal, and gets the phase of fundamental wave, then obtains the accurately dielectric loss angle. Simulation is validated in the variety of real values of dielec- tric loss angle, frequency fluxion, third-harmonics, direct bias, sampling frequency, sampling dot number and white noise ,and is compared with harmonic analysis method. Simulation results show the feasibility and effectiveness of this method.