Letizia Palma Sara, Signorino Davide, Crotti Gabriella
Istituto Nazionale di RIcerca Metrologica, INRIM, 10135 Torino, Italy.
Sensors (Basel). 2022 Mar 15;22(6):2270. doi: 10.3390/s22062270.
This paper analyzes the impact of typical DC transient events occurring in railway grids on the frequency performance of instrument transformers (ITs) installed onboard trains and in AC substations for power quality (PQ) applications. PQ monitoring in railway systems is an issue of great interest because it plays a key role in the improvement of energy efficiency. The measurement chain for the PQ measurements, at 15 kV at 16.7 Hz and 25 kV at 50/60 Hz, commonly includes ITs to scale the voltage to levels fitting the input of the measurement units. Nevertheless, the behavior of ITs in the presence of PQ phenomena represents an open issue from a normative point of view, even for those installed in conventional AC power supply systems. In this context, the paper presents a possible definition of DC transient disturbances test waveforms, a measurement procedure, and a setup to assess the impact of these disturbances on the harmonic performances of ITs for railway systems. Preliminary experimental tests carried out on two commercial ITs under wide ranges of variation for the amplitude and the time duration of DC disturbances show that, in some cases, the error introduced in harmonic measurements can exceed 100%.
本文分析了铁路电网中典型直流瞬态事件对列车上以及用于电能质量（PQ）应用的交流变电站中安装的仪用互感器（IT）频率性能的影响。铁路系统中的电能质量监测是一个备受关注的问题，因为它在提高能源效率方面起着关键作用。用于在16.7Hz下15kV以及50/60Hz下25kV进行电能质量测量的测量链通常包括仪用互感器，以便将电压缩放至适合测量单元输入的电平。然而，从规范的角度来看，即使对于安装在传统交流电源系统中的仪用互感器，其在电能质量现象存在时的行为仍是一个未解决的问题。在此背景下，本文提出了直流瞬态干扰测试波形的一种可能定义、一种测量程序以及一种设置，以评估这些干扰对铁路系统仪用互感器谐波性能的影响。在直流干扰的幅度和持续时间的广泛变化范围内，对两个商用仪用互感器进行的初步实验测试表明，在某些情况下，谐波测量中引入的误差可能超过１００％。
