The HESSCO approach..... Before deciding upon one of the above options we ask the following questions:
System Operation
a)
Are there likely to be electrically skilled staff available at all times to interpret /act upon the status of the system?
b)
If skilled staff are available, are they permanent long term employees or transitory ( i.e. each new one likely to require training/system familiarisation? )
c)
What would be the tolerable outage time if a low cost totally manually dependent system ( i.e. Castell interlocks or manual changeover switch ) were to be installed?
Degrees of Criticality
a)
How critical are the loads to be maintained?
b)
Are there primary maintained and secondary maintained loads?
c)
d)
Is automatic non-essential load-shedding to be part of the scheme?
Is sequenced reinstatement of secondary maintained loads desirable.
e)
Will primary essential loads be UPS maintained and for how long?
f)
What, if any, routine/planned maintenance periods are possible ( i.e. night times, summer/Xmas shut down, or is it a totally 24/7 situation?
