Automation and rules for constructing the logic of equipment operation?

Question

Automation

Hello.
I came across a task with a bias towards a new steppe for me, a lot of things are new.
Task: Automation of the existing hydroelectric power station and all equipment (with a comprehensive replacement of it) with digitally compatible ones.
At this stage, the operation scheme of all components of the technological level station is analyzed. Sheets with equipment interaction diagrams, operation logic, alarms, operational interlocks, etc. are available.
Because the entire technological system is completely analog equipment, there is not even developments in the direction of "ACS", it is necessary to delve into the operation of each specific apparatus and, based on the construction schemes and logic of operation, assign each specific component the correspondence of input and output signals, the connection between them, and the like.
For example, there is a control complex for turbine brake pads, when a signal is given from a pressure gauge that a dangerous oil value in the turbine bearings is reached, an alarm lamp lights up somewhere and in parallel with this, the process of stopping the turbine begins. Accordingly, the pressure gauge gives a signal, an "analogue" lamp lights up somewhere (which will most likely remain an analog lamp, but will also acquire a digital double on the AWP monitor), the automation will start the stop algorithm. This chain, starting from the pressure gauge, needs to be analyzed, input / output signals should be called somehow, logic should be built on CFC ...
A request to readers.Perhaps links to similar experience, literature, rules and standards for the design of work. The situation will be complicated by the fact that the interaction between the elements will be built on the IEC-61850 communication standard, which seems to exclude the complete integration of ready-made solutions (for example, from the same Siemens). Thanks for reading all of this ;)