计及一次电压波动的电压互感器误差状态在线评估方法

On-line Error Evaluation Method of Instrument Voltage Transformers Considering Primary Voltage Fluctuations

电压互感器测量准确性直接影响电网的安全稳定和经济运行。针对一次电压波动下高维随机矩阵评估方法无法可靠评估电压互感器误差状态的问题,提出一种基于差分间距自适应的差分处理(differential processing of adaptive differential interval,DP-ADI)和同相测量一致性(measurement consistency of same phase,MCSP)的电压互感器误差状态评估方法。该方法按照时间序列理论,将一次电压波动分为由确定因素引起的非平稳波动与随机因素引起的微小缓慢平稳波动,同时提出了基于差分间距自适应的平稳化方法与基于同相测量一致性的差异性评价指标,分别削弱一次电压波动中的非平稳波动与微小缓慢平稳波动对状态评估的影响。仿真实验及现场应用结果表明:改进后的高维随机矩阵评估方法能够可靠地评估电压互感器0.1%的误差异常状态。

Measurement accuracy of instrument voltage transformers directly affects the safety,stability and economic operation of the power grid.In fact,the existing evaluation methods based on large-dimensional random matrix cannot reliably evaluate transformers due to the influence of primary voltage fluctuations,this paper proposes a method for evaluating the error condition of voltage transformers based on differential processing using adaptive differential interval(DP-ADI)and measurement consistency of same phase(MCSP).According to the time series theory,the primary fluctuation is divided into non-stationary fluctuations caused by definite factors and stable small stationary fluctuations caused by random factors.Moreover,a stabilized method based on adaptive differential interval is put forward to weaken the influence of non-stationary fluctuations.In addition,a difference evaluating indicator based on the measurement consistency of same phase is established to diminish the influence of stationary fluctuations.The simulation experiments and field application results suggest that 0.1%error of voltage transformers can be estimated by using the improved evaluation method based on large-dimensional random matrices.