基于改进粒子群优化算法的CVT杂散电容参数估计方法

杂散电容是影响电容式电压互感器(CVT)谐波测量取值的不确定因素,通过分析CVT内部结构和杂散电容计算公式,发现杂散电容是具有随机性特点的区间型参数。为提高CVT谐波传递特性曲线的拟合精度,提出一种基于改进粒子群优化算法的CVT杂散电容参数估计方法。该方法以输入参数的置信区间为条件,以计算结果的误差最小为目标,在满足幅值、相移最小误差要求以及尽量多置信区间的条件下确定杂散电容的参数组合。通过建立电能质量综合试验平台,以某35 kV阻容分压式电压互感器二次侧输出的谐波电压值为基准,分析TYD35 3(1/2)-0.02HF型CVT实际谐波电压值和利用幅频曲线校正后的谐波电压值分别相对基准值的误差,验证了所提方法的有效性和可行性。

Parameter Estimation Method of Stray Capacitance of Capacitive Voltage Transformer Based on Improved Particle Swarm Optimization Algorithm

Stray capacitance is an indeterminate factor affecting the harmonic measurement of capacitive voltage transformer (CVT). By analyzing the internal structure of CVT and the calculation formula of stray capacitance, it is found that the stray capacitance is a random interval-type parameter. In order to improve the fitting precision of harmonic transfer characteristic curve of CVT, this paper proposes a method based on improved particle swarm optimization (PSO) algorithm for parameter estimation of stray capacitance of CVT. The method takes the confidence interval of the input parameters as the condition, and the minimum error of calculation result as the goal. The parameter combination of the stray capacitance is determined under the condition that the requirements of the minimum errors of amplitude and phase shift are satisfied and the confidence intervals are as much as possible. Through the establishment of a comprehensive power quality test platform, the harmonic voltage value of the secondary side of a 35 kV resistive capacitive divider voltage transformer (RCVT) is used as a reference to analyze the error of the actual harmonic voltage value of the TYD35/-0.02HF CVT and the harmonic voltage value corrected by the amplitude-frequency curve relative to the reference value. The validity and feasibility of the proposed method are verified.