Busbars testing

During the test the main busbars are fed at the rated current, for which the switchgear assembly is designed. They are heated naturally and therefore no resistance of the main bus need be measured. The busbars are shorted at one end and the current is fed from the other through a variable-current injection set at a reduced voltage of 3-10 V, or enough to achieve the rated current. The arrangement saves on power requirement and consum-... 

Locate the RTDs at the likely hot spots, as at the joints of the busbars. Figure 14.2 illustrates the likely locations of the RTDs. The test may be carried out as noted earlier and temperature readings tabulated at 30-minute or l-hour intervals, whichever is more appropriate. The temperature rise, estimated with the highest temperature recorded by any of the RTDs, would refer to the ambient... 

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. 

In LT assemblies, when the test is conducted on busbars, the length ofbusbars should be minimum 2 m. If it is less than this, short-circuit may be created at the ends of the busbars. 

If the busbars consist of more than one section in cross-section, or different distances between the supports or the busbars, the test may be conducted separately on each section. 

Supply source Busbar section, Test circuit Cable... 

These are generally the same as the routine tests. No field test as regards the power frequency voltage withstand or HV lest is normally prescribed on a bus system, which has already been tested at the manufacturer s works. Repealed application of high voltage may deteriorate the insulating properties of the insulation system and its life unless modification has been carried out at site or where the insulation of joints between the busbars can be completed only after erection at site. In such cases, if this test becomes essential it can be conducted,... 

Moulded-in busbars 6 Isolator blades with moving contacts 7 Hinged front door 8 Door interlocked with isolator 9 Flameproof window for instruments, indicator lights and operation counter 10 Flameproof windows for visual isolation 11 Fault reset and/or earth fault test push-buttons under covers 12 Static protection unit ... 

Bus-zone protection is recommended to be of the high-speed balanced voltage type. Each section of busbars should be protected as one zone. There are other options available that are technically more complex and hence more expensive. It is normal practice to overlap adjacent zones at bus-section and bus-coupler circuit breakers. The bus-zone protection scheme can also be provided with a test facility that can be used while the switchboard is in its normally energized state. 

It does not seem possible to provide a figure of merit for a fluid that possesses these sundry needs, but (see Sect. 6.6) the linear traverse mechanism will demonstrably test total capability in that respect [115]. In this device, two contra-rotating, high-inertia, constant-velocity rotors provide motion somces with HT (high tension) and earth busbars , the excitation being controlled via switches. 

The status of electrical systems is also indicated satisfactorily except for the position of breakers. They can be set in a test position in which the component (pump) is not able to fulfil its SF. However, this position is not indicated in the MCR. That is why the test procedures are written in a very detailed way, ensuring that the component breaker remains in the operating position after the test. Independent checking of the status of the breakers is done in busbar cabinets during operation. Correction of this deficiency is included in the upgrading programme. 

In the A1 industry, the creep values are interesting for heat insulation materials in reduction cells, because their service is in permanent relatively high pressure and permanent pressure (due the weight of carbon blocks with busbars and the weight of A1 melt and the bath). It s likely that 50-h tests are essential. 

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