Short-circuit tests panels

Figure 13.23 Oscillograms of an actual short-circuit test carried out on a power distribution panel (Courtesy ECS)...

For more clarity we have reproduced in Figure 14.3 an actual test circuit and in Figure 14.4, the oscillograms of the test results of a short-circuit test successfully carried out on an LT power distribution panel (Figure 14.8) for a system fault level of 50 kAfor 1 second, at CPRI (Central Power Research Institute). From a study of these oscillograms (Figure 14.4), we can infer the following test results ... 

It is permissible to lest just one panel of a multi panel-assembly so long as the construction of other panels is similar and busbar arrangement and supports are the same. The value of the prospective short-circuit current may be determined from a calibrated oscillogram. The test current in any phase should not vary by more than 10% of the average in the three phases and must be applied for a predetermined time of I or. 1 seconds. Unless specified otherwise, this should be considered as to be I second. 

Test for electrical connections between panels with a multimeter or ohmmeter. If there are short circuits, check for and remove stray fabric strands that could be bridging the gap between anode segments. This step is critical to ensuring that each panel is electrically isolated. 

At the foundry level, quality control tests may be performed diuing incoming inspection of the ceramic materials. Finished-product inspection may range from limited testing (e.g., shorts and opens to ensure that the product was built to print) to additional functional performance testing on each substrate. Test coupons on each panel may be used for electrical performance checks (e.g., impedance, resistance), and destructive mechanical tests for feature size conformance. The extent of testing at this level is determined by the functional complexity of the circuits, final assembly testing, and economics. 

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