Modelling Overvoltage Protection Components: Verilog Simulations of Combined MOV and GDT Arresters

Overvoltage protection systems are used to protect sensitive electrical and electronic equipment from voltage surges and lightning strikes. These systems are mostly based on the use of gas discharge tubes (GDTs) and metal-oxide varistors (MOVs), which are utilised individually or in various combinations. Adequate computer simulations play an important step in the process of designing overvoltage protection systems and selecting adequate parameters. In this paper, the modelling of low-voltage GDT and MOV components is performed using the Verilog-A hardware description language. The presented models are designed for integration with other overvoltage protection system components to form an integrated overvoltage protection system. The current–voltage characteristics of the GDTs and MOVs are highly nonlinear and frequency dependent. The developed Verilog-A mixed behavioural and structural models of GDTs and MOVs ensure a stable convergence of numerical processes during the simulations of circuits with these elements. The simulations of overvoltage protection systems were completed using a TINA circuit simulator. Two laboratory tests were performed using GDT and MOV components. In the first test, the time responses of the current and voltage on a GDT and MOV serial connection were measured in the laboratory. In the second test, the response of the GDT and MOV serial connection was tested in a power line network environment, where a surge current impulse and power line voltage of 50 Hz existed simultaneously. The dynamic response of the GDT and MOV serial connection obtained through the simulations agrees well with the measurement results.