Numerical modeling of the voltage sensors for quench detection in the TPX TF and PF conductors

The voltage sensors in the TPX superconducting TF and PF magnets are designed to pick up the resistive voltage once the conductor quenches and becomes normal. This is one of the quench detection systems needed to protect the rather expensive magnets. Because the magnets are operating in a high-noise environment, the sensors would experience inductive voltages (noise). It is important to estimate the noise level and design a system with high signal to noise ratio. The numerical model described in this paper includes 3-D eddy currents assuming the worst condition, i.e., plasma disruption. The voltages induced in both parallel and helical cowound sensors are calculated. Several differencing schemes to eliminate the noise levels are compared and a new scheme is suggested.