The power quality is denoted by the deviation of voltage, current or frequency, which makes electric equipments not work proper.
电能质量是指引起用电设备故障或不能正常工作的电压、电流或频率的偏差。
2
The second order ion trajectories in crossed toroidal electric and inhomogeneous magnetic fields are derived by means of the Fermat's principle and expressed in energy deviation.