For solving the dynamic instability problem of Yunnan Provincial Power System (YNPS) and the South China Interconnected Power System (SCIPS), Lubuge Hydropower Station was chosen to install Power System Stabilizer (PS...For solving the dynamic instability problem of Yunnan Provincial Power System (YNPS) and the South China Interconnected Power System (SCIPS), Lubuge Hydropower Station was chosen to install Power System Stabilizer (PSS). This paper introduces the principles and methods of parameter selection for PSS, in addition to field test. The test results show that the PSS installed can significantly improve the system damping.展开更多
In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator a...In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.展开更多
A frequency mixing and phase locking system is designed, in which electromagnetic shielding, microwave coupling, and intermediate frequency (IF) measurement arrangements are in- cluded. In lieu of liquid nitrogen, a p...A frequency mixing and phase locking system is designed, in which electromagnetic shielding, microwave coupling, and intermediate frequency (IF) measurement arrangements are in- cluded. In lieu of liquid nitrogen, a pulse tube cryo- cooler is used to cool the whole system. With Jo- sephson grain boundary junction as the mixing ele- ment, the 96th harmonic frequency mixing at 3 mm waveband is obtained, and phase-locked voltage- controlled oscillator (VCO) is realized.展开更多
文摘For solving the dynamic instability problem of Yunnan Provincial Power System (YNPS) and the South China Interconnected Power System (SCIPS), Lubuge Hydropower Station was chosen to install Power System Stabilizer (PSS). This paper introduces the principles and methods of parameter selection for PSS, in addition to field test. The test results show that the PSS installed can significantly improve the system damping.
文摘In this research paper,we have presented variable area type capacitive sensor signal conditioning system for angular displacement measurement and for this purpose we have used timer LM555 based astable multivibrator and universal frequency to digital converter (UFDC). Due to variation in angular displacement in the variable area type capacitor which is connected in the timer based astable circuit,capacitance changes which in turn changes the time period of the timer circuit output. The time period of the timer output waveform is linear with the capacitance and hence linear with angular displacement. The timer output is further processed with UFDC for the measurement. The experimental results show that the time period is linear with the angular displacement in the range of 0- 180° and the uncertainty we should associate it with this average time period value is the standard deviation of the mean,often called the standard error (SE),which is ± 0.023 μs. Because of the simplicity,this measurement system can be used in both electronic and industrial instrumentation.
基金supported by the National Natural Science Foundation of China(Grant Nos.10474036&10534060)the National Basic Research Program of China(2006CB601006).
文摘A frequency mixing and phase locking system is designed, in which electromagnetic shielding, microwave coupling, and intermediate frequency (IF) measurement arrangements are in- cluded. In lieu of liquid nitrogen, a pulse tube cryo- cooler is used to cool the whole system. With Jo- sephson grain boundary junction as the mixing ele- ment, the 96th harmonic frequency mixing at 3 mm waveband is obtained, and phase-locked voltage- controlled oscillator (VCO) is realized.
文摘Y98-61452-261 9914966电机定子绕组在线局部放电测量用的敏感度增加的电容耦合器=Capacitive couplers with increased sensitivityfor on-line PD measurement in stator windings[会,英]/Zhu,H.& Green,V.//1998 IEEE International Sym-posium on Electrical Insulation,Vol.1.—261～265(AG)用于测量旋转电机在线局部放电(PD)的传统的电容耦合器的电容有80PF,最近发现增加电容可提高耦合器的检测灵敏度。文中介绍了用比传统80PF
