841 / 2022-05-11 10:58:46

Inverse calculation of the terminal voltage of electromagnetic voltage transformers based on LabVIEW

inverse calculation,terminal voltage,electromagnetic voltage transformers,LabVIEW

IEEE ICHVE 2022 / 1-PAGE ABSTRACT

Inverse calculation of the terminal voltage of electromagnetic voltage transformers based on LabVIEW

Junhao Lei, Ming Yang, Binyang Zou, Jialong Lin, Wenxia Sima, Shuhao Liu

State Key Laboratory of Power Transmission Equipment & System Security and New Technology

Chongqing University, Chongqing, China

junhaolei@cqu.edu.cn



Purpose/Aim

Electromagnetic voltage transformer (EVT) is a piece of crucial voltage measurement equipment in power systems. However, the core of EVT may suffer from deep saturation with the excitation of power-frequency overvoltage, ferroresonance, DC bias, and energization. Once the core is deeply saturated, the secondary voltage of the EVT might be distorted, and the error can step up to 60%. Thus, the system voltage can not be correctly recorded using EVTs. In this paper, we propose a method the calculate the primary voltage of EVT using its distorted secondary voltage, inspired by the inverse problem.

Experimental/Modeling methods

Based on the National Instrument (NI) platform, we design a monitoring system based on LabVIEW, which inverts the secondary side distorted voltage information into the primary side with high accuracy. First, we build a forward circuit model considering core saturation and propose a parameter identification method. Then, we establish an electromagnetic simulation platform based on ATP-EMTP, which is expected to analyze the error of the simulation to verify the accuracy of the proposed inverse calculation method. Finally, a simulation is carried out using the recorded waveforms from a hardware platform to verify the accuracy of the forward circuit model and the proposed inverse calculation method.

Results/Discussion

The results show that the maximum relative difference of the monitoring system using the proposed inverse calculation method based on LabVIEW does not exceed 8.2%, which could meet engineering requirements.

Conclusions

The proposed method could accurately correct the secondary voltage of EVTs when they suffer from deep saturation. The built monitoring system using LabVIEW provides a competitive solution to measuring most distorted voltage in power systems caused by the deep saturation of the EVTs' core.