基于正交信号和延迟采样周期的电网序分量实时检测方法

A Real-time Detection Method for Power System Sequence Components Based on Orthogonal Signal and Delayed Sampling Period

随着我国新能源装机容量逐渐增加,电网稳定运行能力受到了巨大挑战。而新能源系统主动支撑电力系统运行技术的关键是在不对称电网环境下快速准确地检测电网序分量。据此,该文从数学上推导出一种基于正交信号和延时采样周期的序分量开环检测方法。首先,使用正交信号构造法在同步旋转坐标系下构建电网电压的正交信号,之后将电压延时采样信号、电网电压及其正交信号使用提出的数学运算规则,实现快速准确地提取序分量。其次,为了消除检测方法在动态响应时间内造成的波动,提出一种计算误差规避方法,通过判断电网电压信号实时状态来规避计算误差。当电网电压不对称时,该方法可实现快速精确地提取正、负序分量的幅值和相位,动态响应时间小于3ms。最后,仿真实验结果证明了所提出方法的正确性和实用性。该方法具有响应速度快、精度高、易于实现的特点,为新能源系统主动支撑电网提供了保障。

With the continuous growth in the installed capacity of new energy,the stable operation of the power system has been greatly challenged.The key for the new energy system to actively supporting the stable operation of the power grid is to quickly and accurately detect the sequence components of the power system under the unbalance condition.Accordingly,this paper mathematically deduces an open-loop detection method for sequence components based on the orthogonal signal and delayed sampling period.First,the orthogonal signal construction method is used to construct the orthogonal signal of the grid voltage in the dq frame.Subsequently,the delayed sampling signal,the grid voltage and its orthogonal signal are used to extract the sequence components quickly and accurately using the mathematical operation rules.Secondly,in order to eliminate the fluctuation caused by the detection method in the dynamic response time,this paper proposes a calculation error avoidance method,which avoids the calculation error by judging the real-time state of the grid voltage signal.When the grid voltage is unbalanced,this method can quickly and accurately extract the amplitude and phase of the positive and negative sequence components,and the dynamic response time is less than 3ms.Finally,the results of the simulation experiments prove the correctness and practicability of the proposed method.The fast response,high precision and easy implementation of this method provide a guarantee for the new energy system to actively support the power grid.