Question

please explain in detail in one page UPS(uninterrupted power supply ) redundancy impact on cable dimension and Automatic transfer switches.in power design.

Answer 1

I am dividing this question into two parts:

1.UPS(uninterrupted power supply ) redundancy impact on cable dimension: There are various design configuration of UPS for eg: N,isolated redundant,distributed redundant,N+1,2N,2N+1 where N is simply defined as the need of load so the different ups design configuration will have different impact on cable dimension.

N capacity system: This system is compromised of single ups module or a paralleled modules whose capacity is matched to the critical load projection.It is 400 kW single ups module or two 200 kW ups module paralleled onto a common bus so according to simplicity of this system we can comment on the cable dimension hence there is no isolation in the circuitry and extra circuity to protect the load in case ups failures so the dimension of cable will be comparatively less than other systems.

isolated redundant : This system is sometimes also known as N+1 system although it does not follow the parallel system.In this system primary system feeds the load.The isolation feeds the static bypass of the primary ups module.This configuration requires the separate input for static bypass circuit,plus at least one additional circuit breaker is also require so the additional circuitry will definitely increase the dimension requirement of cable.

N+1 system: In this system two ups module are paralleled onto to a common bus this system is quite useful just in case if one system does not work other will work just fine so this system have some advantages over N system and the dimension requirement of the system is more than N system.

Distributed redundant system : This system is also known as tri-redundant, are commonly used in big organizations This system uses 3 or more ups modules with independent input and output feeders.So this is quite a complex system but very costly and additional circuitry for protection and failure mode analysis but due to the complexity of the system dimension of cable is more than rest of the system.

2.UPS(uninterrupted power supply ) redundancy impact on Automatic Transfer Switches : These switches are required to divert the data center load b/w source and emergency power these switch are similar static transfer switch but they have additional mechanical relay to make the switch.ATS works at different frequency range and it is decided on various parameter for example insertion loss,isolation loss etc so dimension of these switches will totally depend on frequency and losses in the system.