Parallel switching

Let us refer to equation (23.13) for the inrush current, / on parallel switching. If we can increase the impedance of the switching circuit by introducing a resistance R or inductance L, or both, we can easily control this current to a desired level. 

Parallel switching of capacitor banks (i) Inrush current... 

Consider the scheme of Example 23.4 having an automatic parallel switching. If we assume the closing sequence cycle to be 30 seconds, the recommended value of discharge resistance for each 20 kVAr capacitor bank having a capacitance of 120 fiF can be determined as follows ... 

Achieved NotoI °pi>cal memory, photon-mode spatial light modulation, ulttafast optical parallel switching, optical enhancement of nonlinear optical properties, etc... 

We know intuitively (and also from the capacitor equation) what happens to a capacitor when we attempt to suddenly discharge it (by means of the parallel switch). Therefore, we can now easily guess what happens when we suddenly try to discharge the inductor (i.e. force its current to zero by means of the series switch). 

Each of the six switches would likely include a parallel diode or, perhaps, a parallel switch, which would enable the battery to supply and absorb VARs. 

Controller/data processor Photo diode array Columns Parallel switching valve... 

In either version, cells of the bipolar type assembled to batteries of the filter-press t5q)e can be used. The version with circulating electrolyte is also feasible for building monopolar ( jai -type) cells that are cheaper than bipolar types (as they do not require expensive bipolar plates) and offer a highly flexible series-parallel switching within the battery to accommodate specific user needs. 

The account begins with binary arithmetic, moves on to on-off (flip-flop) electronic switches, then to serial and parallel processing, and finally to computers/transputers. 

In an effort to identify materials appropriate for the appHcation of third-order optical nonlinearity, several figures of merit (EOM) have been defined (1—r5,r51—r53). Parallel all-optical (Kerr effect) switching and processing involve the focusing of many images onto a nonlinear slab where the transmissive... 

Eliminate flame arrester or use dual (parallel) flame arresters with on-line switching capabilities... 

These are unidirectional and uncontrollablet static electronic devices and used as static switches and shown in Figure 6.14. A diode turns ON at the instant it becomes forward biased and OFF when it becomes reverse biased. By connecting them in series parallel combinations, they can be made suitable for any desired voltage and current ratings. Whether it is a transistor scheme or a thyristor scheme, they are used extensively where a forward conduction alone is necessary and the scheme calls for only a simple switching, without any control over the switching operation. They are used extensively in a rectifier circuit to convert a fixed a.c. supply to a fixed d.c. supply. 

Thus, only three of the five interrupting devices can be switched at a time as required without causing a parallel operation between any of the two incomers. 

The schemes are logical and simple and have been drawn, to ensure that no two supply sources can ever be switched in parallel. The scheme prevents to switch an interrupter, that may cause it to operate in parallel with another, unless the first source is opened first. This is illustrated in the following schemes ... 

Parallel operation of capacitor bank C2 with an already switched capacitor C,... 

If we are able to provide an inductance of this value with each capacitor bank of 60 kVAr the problem of excessive inrush transient current can be overcome and the component ratings as chosen above will be sufficient to switch a parallel circuit. 

In TSCs the thyristors are used in anti-parallel to switch a capacitor bank ON or OFF but without any phase angle control. A TSC therefore does not by itself generate any harmonics, unlike a TCR. 

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