Closing resistor effect

Effect of closing resistors on maximum overvoltages, (a) Closing surge, (b) Reclosing surge residual voltages (-1, -1, 1 pu). 

Figure 2.25 shows the effect of a closing resistor on a statistical distribution. It is clear how the closing resistor is effective in reducing the overvoltage in both the closing and reclosing... 

It is a common practice to adopt a closing resistor into a CB on EHV and UHV systems in Japan. Figure 2.16 shows the effect of resistor closing on a closing surge on an untransposed vertical double-circuit line of Figure 1.25... 

Proper calibration of the DSC instruments is crucial. The basis of the enthalpy calibration is generally the enthalpy of fusion of a standard material [21,22], but electrical calibration is an alternative. A resistor is placed in or attached to the calorimeter cell and heat peaks are produced by electrical means just before and after a comparable effect caused by the sample. The different heat transfer conditions during calibration and measurement put limits on the improvement. DSCs are usually limited to temperatures from liquid nitrogen to 873 K, but recent instrumentation with maximum temperatures close to 1800 K is now commercially available. The accuracy of these instruments depends heavily on the instrumentation, on the calibration procedures, on the type of measurements to be performed, on the temperature regime and on the... 

In Chapter 1 we had discussed a simple series resistor-capacitor (RC) charging circuit. What we were effectively doing there was that by closing the switch we were applying a step voltage (stimulus) to the RC network. And we studied its response — which we defined as... 

Note that the unprotected circuits of the control had substantial drift of the three that did not fail during the test run. Failures were evident upon inspection of the part as occurring from disintegrated resistors. Dip coated PSS and HMDS had fewer failures and less drift. The best protection from moisture was offered by the plasma-polymerized HMDS. The indicated 1.7% drift is close to the acceptable limits of the design for power-on thermal aging effects. 

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