No abstract

Anti-misoperation locking device is a locking device for control operation circuit and primary equipment. At present, three faults of relay protection often occurs in the secondary cabinet of substation. There will be a lot of safety threats if the secondary cabinet is lack of locking device. Therefore, in this study effective improvement strategies will be put forward in the aspect of technology and further analyze the technology of the secondary cabinet safety measures locking device and then replace the traditional setting mode of the secondary safety measures so that to technically prevent the violation of regulations in secondary maintenance and effectively prevent the occurrence of three fault events of relay protection. This technology can be applied to the secondary work site of power industry which is significant to ensure the safe operation of power grid. This study illustrates the application effect of the technology of the safety measures locking device for secondary panel cabinet in substation with specific cases which could provide help for the the relevant staff.

Both electric vehicle PMSM drive system and grid connected photovoltaic (PV) power generation need voltage source inverter (VSI). The dead time should be set properly when the power switches are turned on and off in the same bridge arm of VSI. During the dead time, the load is out of control, which will cause the abnormal output voltage amplitude and phase. However the influence of dead time on the output fundamental voltage phase has not been paid much attention to and studied. Firstly, in the paper, the phase shift of output fundamental voltage caused by dead time is simulated and analyzed for three-phase VSI - resistance inductance series (RL) load system under several conditions such as variable switching frequency, modulation index, output fundamental frequency and dead time. Secondly, take three-phase VSI - permanent magnet synchronous motor (PMSM) drive system for instance, the simulation analysis of output fundamental voltage phase shift and rotor positioning error caused by dead time are also performed, and an off-line method to compensate the fundamental voltage phase based on αβ coordinate is given. The above work provides a reference for further understanding the influence of dead time on fundamental voltage phase shift in VSI, so as to improve the monitoring and control precision of electric vehicle drive system. The analysis approach can be applicable to the grid connected photovoltaic (PV) power generation PMSM servo system.