从现有波动量法出发,研究用户波动与背景谐波变化对公共联结点谐波电流、谐波电压的影响,提出一种基于用户主导波动量筛选原理的用户谐波发射水平估计方法。提出公共连接点(point of common coupling,PCc)谐波波动伏安特性比的概念,研究系统侧、用户侧谐波波动对其变化的影响;利用统计学筛选方法从PCC点谐波电流测量值中筛选出用户主导谐波电流波动量,以此估计系统谐波阻抗;采用用户谐波电压发射水平修正公式消除背景谐波的影响。对理论模型和实际工程算例的仿真证明该文方法的正确性和有效性。
Based on the existing fluctuation method, this paper investigates the influences of harmonic changes occurring in customer and system sides at the point of common coupling (PCC), and proposes an estimation method for customer harmonic emission level based on the dominant fluctuation filtering principle. The concept of harmonic volt-ampere characteristic ratio at the PCC is proposed. And its varying rules with the harmonic changes occurring in system and customer sides are studied. The filtering principle used in statistics is introduced to determine the customer dominant harmonic current fluctuation and then the system harmonic impedance is estimated. A modified formula for the estimation of customer harmonic emission level is used to eliminate the influence of the background harmonics. The simulation results on the theoretic model and practical project show that the proposed method is valid and accurate.