Forum Replies Created
-
Posts
-
Fast acting fuses are better option when we require to couple a low Short circuit rated network to an infinite bus or network with high short circuit rating. IS limiting fuses are also desirable when coupling two or more LV networks with moderately high short circuit rating where the combined Short circuit rating of the coupled network exceeds technically feasible values. In such cases by inserting fuses with proper clipping current characteristics, we can limit the short circuit rating of the coupled networks.
No..the energy saving is by reducing the losses in the system also. However, saving from Max demand reduction may be higher than the saving by reduction in losses in case of small installations.
@Smithy said:Just a point to watch. I have seen a number of people install power factor correction equipment in the hope of making savings and see next to no saving in their electricity costs simply because they were on a kW tarrif rather than a kVA tarrif. There should be something in the calculator to alert people to thoroughtly understanding their tarrif structure.
LV fuses are more suitable for Short circuit protection where speed of arc clearance is too small by the Circuit breakers or in other words Fuses are the only option when you want to limit the short circuit currents to not more than 1/2 cycles or even less. A typical example is given below
An electrical Power system employing 8 Alternators of 2000KVA @690V 3 Ph 60 Hz and Xd” of 20%. is required to feed electrical Variable speed drive. Unfortunately, the availability of drives in market is limited to a maximum KA of 65KA. Therefore it is not possible to feed VSD directly from 690V Switchboard (fed from 8 Alternators). How do we solve this problem.
1. By splitting the 690V bus in to two Sections, each supplied by 4 alternators
2. Bus coupling is achieved by employing a Short circuit limiter which limits the short circuit flow between two buses to 10KA
By employing above arrangement, we can limit the shirt circuit level of 690V bus.
