REDUNDANT AND SUPERVISED SERIAL AND PARALLEL CONTACTS TO INCREASE RELIABILITY ON A VESSEL

Abstract

One of the goals of control systems in autonomous ships and unattended engine room
of a ship is the minimization of potential breakdowns, because there is no crew onboard to solve
these situations. This is especially important in IMO type three autonomous ships, i.e., remote
controlled vessels with no crew onboard that are operated from land.
For the correct control of an electrical installation, it is essential that connections for electrical
manoeuvres do not fail. These connections are the ones that connect different auxiliary
electrical generators and various automation equipment. There are two main connections for
electrical manoeuvres: serial contact connection and parallel contact connection. In a ship
engine room, we can find many serial and parallel connection contacts. Some of them are
important to ensure correct operation. Others are essential for critical equipment, main engine
or electric auxiliary. A suitable design of the electrical installation has to minimize the risk of
failure but it also has to allow the early detection of problems and guarantee the continuity of
the operation even if a failure takes place.
In this work, several types of serial and parallel contact connections are proposed with the aim
to ensure correct operation at different levels of the electrical systems in the engine room,
preventing failures and allowing early alarms to detect potential future problems. For each type,
serial and parallel, three different configurations are presented, each one more robust than the
previous one, depending on the requirements and criticality of the particular electrical system
to be controlled. The advantages and shortcomings of each configuration are presented and
discussed.