On average, modern ships require more power than their predecessors; they simply have more onboard equipment that needs electricity, from navigation and rudder control to pumps, winches, and scrubbers. This also means that onboard power cannot be allowed to fail, and yet it sometimes does: In 2017, a safety study by the Finnish Safety Investigation Authority found that deficient backup and emergency systems played a role in all cases investigated.
Integration or segregation?
To keep power flowing, ships need power management systems (PMS). To control all equipment on board, they also have automation systems (sometimes called alarm and control systems). It can be tempting to integrate power management in the automation system – your crew only needs to deal with one centralised system, and purchasing everything from one supplier means that the cost of procurement, installation, training, and parts can be relatively low.
However, if your vessel has a complex or high-powered system, or if it operates with stringent requirements on operational safety, there are greater benefits to be had by segregating your PMS from your automation system. The most important of these benefits is a higher degree of safety.
Higher degree of safety
A segregated PMS is particularly resilient if it is based on a distributed control system (DCS) architecture. Such an architecture consists of a network of connected controllers, each of which is capable of controlling the entire network in addition to the unit or component it is meant to manage. For example, there could be a DCS controller for each generator, for the bus tie breaker (BTB), and for all other important power sources and breakers in the system. One of these controllers is the master controller which also controls the entire network; if it fails, control is automatically assigned to another controller on the network.