James H “Transformers 3” The Electric Power Engineering Handbook docx

... to the heat sources through which the cooling medium can flow such that the heat can be effectively removed from the trans- former. The natural circulation of oil through a transformer through ... the industry. The magnitude of this reactance is a function of the number of turns in the windings, the current in the windings, the leakage field, and the geometry of the...

Ngày tải lên: 05/03/2014, 16:20

... of the best known is the Pacific HVDC Intertie, which interconnects southern California with Oregon. Another DC system is the ±400 kV Coal Creek-Dickenson lines. Another famous HVDC system is the ... also used. The line has a single conductor in each phase. Post insulators hold the conductors without metal cross arms. One grounded shield conductor on the top of the tower shield...

Ngày tải lên: 05/03/2014, 16:20

... a thermal generating plant and range in size from fractional horsepower to several thousand horsepower. These motors may be supplied with the equipment they drive or they may be specified by the ... ground. The method used to limit the phase to ground fault current to a value equal to or less than the three-phase fault current is determined by the way the generator is connected t...

Ngày tải lên: 05/03/2014, 16:20

... exist on the left-hand side of the equations while 18 degrees of freedom exist on the rig ht-hand side. Therefore, for the relationship between the voltages in the abc frame of reference and the voltages ... voltage phase angles at the system buses. The input to the state estimator is the active and reactive powers of the system, measured either at the injection site...

Ngày tải lên: 21/03/2014, 12:11

... transfer mechanism to cool the arc and to elongate the arc through a grid (arc chutes), allowing extinguishing of the arc when the current passes through zero. In other designs, the arc heats the SF6 ... use the gas as a cooling mechanism to cool the arc and to use the pressure to elongate the arc through a grid (arc chutes), allowing extinguishing of the arc when the...

Ngày tải lên: 21/03/2014, 12:12

... self-impedances of the phase conductor and the tape shield as well as the mutual impedance between the phase conductor and the tape shield. The resistance and GMR of the phase conductor are found ... a temperature of 50°C. The diameter of the tape shield d s is given in inches and the thickness of the tape shield T is in mils. The GMR of the tape shield is given by:...

Ngày tải lên: 21/03/2014, 12:12

... proportional to the product of the source voltage, the line current, and the cosine of the phase angle between the two. Thus, the torque is also proportional to the power in the metered circuit. The device ... interval shown, the integrated area under the power curve represents the energy consumed during the interval. This energy, divided by the length of th...

Ngày tải lên: 21/03/2014, 12:12

... exist on the left-hand side of the equations while 18 degrees of freedom exist on the right-hand side. Therefore, for the relationship between the voltages in the abc frame of reference and the voltages in ... LLC (8.29b) (8.29c) The circuit synthesis of Eq. (8.29a) through (8.29c) is illustrated in Fig. 8.9. Particular notice should be taken of the fact the response of ea...

Ngày tải lên: 21/03/2014, 12:12

... pickup when the tension across the voltage element gets above a high-set threshold. For an external fault with CT saturation, the saturated CT will constitute a low-impedance path in which the current ... relays. The basic principle behind the concept of supervising the overcurrent relay by voltage is that a fault external to the generator and on the system will have the e...

Ngày tải lên: 21/03/2014, 12:12

... LLC Here, h p and r p are the height and radius of the phase conductor, h s and r s are the height and radius of the shield wire, d p′s is the distance from the shield wire to the image of the ... to the diameter of the r s -cylinder of the shield wire. Raising the shield-wire height further will then be actually detrimental. In this case, either the insulat...

Ngày tải lên: 21/03/2014, 12:13