Sequential switching

In this countermeasure, the faulted phase is opened instantly, but healthy phases are opened about 10 s later when the dc component is decayed enough. When this countermeasure is applied near a generator, especially when the cable line offers radial path to the generator, it is necessary to evaluate the negative-sequence current capability of the generator, as Countermeasure (3) causes an unbalanced operation for a prolonged duration. 

In Countermeasure (5), a resistance is connected in series to shunt reactors when a cable line is energized. The resistance needs to be sized so that the dc component decays fast enough. After the cable line is energized, the resistance is bypassed in order to reduce losses. Considering the additional cost for the resistance, this countermeasure is more suited for HV cable lines than EHV cable lines. 

Countermeasure (6) cannot always be applied especially, it is difficult to apply to long EHV cables due to the steady-state overvoltage. 

The zero-missing current is observed only in a healthy phase (phase a). The current in the faulted phase (phase b) crosses zero point as it contains a large ac component due to the fault current. Hence, the line breaker of the faulted phase can interrupt the fault current. 

In Step 2, shunt reactors are tripped before line breakers of healthy phases. It is necessary to trip shunt reactors of only healthy phases. At this time, it is not necessary and recommended to trip shunt reactors of the faulted phase, since the current through shunt-reactor breakers of the faulted phase does not cross the zero point. 

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Step control A control method in which a multiple switch assembly sequentially switches on or off various stages of a device, such as a heater battery. 

The technique was made practical for personnel screening applications by incorporating sequentially switched linear antenna arrays to improve the data collection speed to near real-time rates [ 17,27-31 ]. The linear arrays allowed one axis of the two-dimensional planar aperture to be scanned electronically at very high speed (on the order of several microseconds per element). This reduced total data collection for practical systems to human body is not transparent to millimeter-waves, personnel will need to be inspected from multiple aspects (front and back at a minimum). 

Several other examples for potential application of reverse-flow operated catalytic reactors are described in Ref. 9. Also, other potential techniques of forced unsteady-state operation which allow for combining chemical reaction and heat exchange in a fixed catalyst bed are discussed. One such technique is sequential switching between inlet and outlet ports of the reaction gas between two or more packed beds (Fig. 2(c)). In this case, the thermal wave travels continuously through a series of packed beds in one direction, as if along a closed ring. However, this operation is more complex and requires more catalyst than the reverse-flow operation. 

Brinkmann, V., Muller, S. and Heusser, C.H. (1992). T cell dependent differentiation of human B cells direct switch from IgM to IgE, and sequential switch from IgM via IgG to IgA production. Mol. Immunol. 29, 1159-1164. 

Mandler, R., Finkelman, F.D., Levine, A.D. and Snapper, C.M. (1993). IL-4 induction of IgE class switching by lipopolysaccharide-artivated murine B cells occurs predominantly through sequential switching. J. Immunol. 150, 407-418. 

Zhang, K., Mills, F.C. and Saxon, A. (1994b). Switch circles from IL-4-directed epsilon class switching from human B lymphocytes. Evidence for direct, sequential, and multiple step sequential switch from mu to epsilon Ig heavy chain gene. J. Immunol. 152, 3427-3435. 

The simulated moving bed reactor (SMBR) based on the simulated moving bed (SMB) process is a practical alternative for implementing counter-current continuous reactors. Counter-current movement of the phases is simulated by sequentially switching the inlet and outlet ports located between the columns in direction of the liquid flow (Fig. 8.4). As with the SMB process, two different concepts are known to realize the counter-current flow. One is based on switching the ports and the other on the movement of columns. However, both require elaborate process control concepts to realize the movement. Owing to the periodical changes of the set-up the pro-... 

Fig. 12.30 Release profiles of phloroglucinol plotted against the square root of time, upon sequential switch in the pH of the excess solution from pH 7 -> pH 2 -> pH 7. (Taken from [108])...

Scriber, J. M. (1979b) The effects of sequentially switching foodplants upon the biomass and nitrogen utilization by polyphagous and stenophagous Papilio larvae. Ent. exp. appL, 25, 203-15. 

Figure 3.25 shows the time sequence of sequential switching when the cable line is energized from Substation A. In Step 1, the line breaker of phase b is opened at 60 ms after the fault and the fault is cleared by tripping this CB. Since the fault is already cleared by the opening of the phase b line breaker, some time can be allowed before opening the line breakers of other healthy phases. 

Zero-missing phenomenon with sequential switching. 

Usually, long EHV cable lines are compensated by shunt reactors that are directly connected to the cable. When the compensation rate is high enough, the leading current interruption capability is not a concern. If sequential switching is applied to a cable line as a... 

Specific multi-element monitoring is possible in various ways. Sequential switching between elemental wavelengths of a monochromator is useful if speed is compatible with peak elution rates [5]. However, the most widely utilized multi-element detection has been by means... 

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