This paper analyses the synchronization problem of a generator onto power system without satisfying synchronization condition. The main focus of the paper is on the impact of the dc component of the current in the hig...This paper analyses the synchronization problem of a generator onto power system without satisfying synchronization condition. The main focus of the paper is on the impact of the dc component of the current in the high voltage circuit breaker during its close-open operating cycle. Using real time measurements of currents/voltages and angles during the close-opening cycle of high voltage generator circuit breaker and the impact of the dc component of current in context of interrupting large magnitude of current from the circuit breaker. In addition, the paper describes a study case model and the results of simulations performed using the software EMTP-ATP of an actual incident that occurred during the inadvertent synchronization of a large 339 MW, 24 kV generator to the grid.展开更多
This paper presents a novel precision delay circuit design for high-speed data acquisition systems. Many studies have suggested that various advanced electronic measurement apparatuses require that the delay circuit s...This paper presents a novel precision delay circuit design for high-speed data acquisition systems. Many studies have suggested that various advanced electronic measurement apparatuses require that the delay circuit should have a high precision and a short delay interval. Practically, however, such measurement apparatuses are low in preci- sion and long in delay interval at present. The structure and function of a data acquisition system is introduced first; then the principle of ramp-based precision delay circuits and the digitally programmable delay generator is studied and the precision delay circuit is designed. The authors also demonstrated 8-bit programmable delay circuits with a timing pre- cision of 10 ps. Therefore the programmable precision delay circuit here presented has a higher precision, shorter inter- val and more detectable function than any other precision delay circuit.展开更多
文摘This paper analyses the synchronization problem of a generator onto power system without satisfying synchronization condition. The main focus of the paper is on the impact of the dc component of the current in the high voltage circuit breaker during its close-open operating cycle. Using real time measurements of currents/voltages and angles during the close-opening cycle of high voltage generator circuit breaker and the impact of the dc component of current in context of interrupting large magnitude of current from the circuit breaker. In addition, the paper describes a study case model and the results of simulations performed using the software EMTP-ATP of an actual incident that occurred during the inadvertent synchronization of a large 339 MW, 24 kV generator to the grid.
文摘This paper presents a novel precision delay circuit design for high-speed data acquisition systems. Many studies have suggested that various advanced electronic measurement apparatuses require that the delay circuit should have a high precision and a short delay interval. Practically, however, such measurement apparatuses are low in preci- sion and long in delay interval at present. The structure and function of a data acquisition system is introduced first; then the principle of ramp-based precision delay circuits and the digitally programmable delay generator is studied and the precision delay circuit is designed. The authors also demonstrated 8-bit programmable delay circuits with a timing pre- cision of 10 ps. Therefore the programmable precision delay circuit here presented has a higher precision, shorter inter- val and more detectable function than any other precision delay circuit.
