Elegant Retirement of Ship Power Plants: In-depth Analysis of Automatic Generator Unwind and Shutdown

In the process of ship navigation, the generator set “parallel” is the charge of blood, and “unlisting” is the wisdom of the retreat. When the load of the grid is reduced or the unit has a slight “micro-illness”, how to let the running generator set safely and smoothly withdraw from the grid? This is not only a test of the logic of the PMS system, but also a mandatory test point for the practical operation of the electronic electrician (ETO).

I. Why unlist? --More than just turning off a switch

Disconnecting“ commands from automatic power plants are usually based on two core logics:

1. Principles of economic operation: The total load of the grid is reduced, and single-unit operation is more fuel-efficient and emission-reducing than dual-unit low-load operation.

2. Principles of safe changeover: When a unit has a non-fatal fault such as “high cooling water temperature”, the system will adopt the strategy of “merge first and solve later” - first start the standby machine to merge, and then let the faulty machine exit.

II. Core processes: the “relay run” of loads”

The core of the de-listing operation does not lie in the “disconnection” but in the **“Transfer ”**. After the command is issued, the automatic load distributor will gradually reduce the active power to be shut down through the governor like a relay race, while increasing the power of the machines on the grid to ensure that the sink frequency and voltage are always rock-solid.

Third, ETO practical demonstration: the standard four-part series of interpretation

If you are evaluating on an emulator, follow these steps closely:

1. Creating conditions for solving problems

Gradually reduce the power plant load. It was observed that the load was reduced from 80% of the rated power of the stand-alone machine to 20% or less At that time, the system starts counting down.

2. Monitoring the transfer process

Keep a close eye on the power meter! You'll see the needle on the to-be-disconnected machine slowly fall back while the needle on the running machine steadily rises. Record the residual load at the moment of breaking (usually close to zero) and about 1 minute. of the analog delay.

3. Responding to unexpected challenges: the discontinuation of deconstruction

This is the link that best demonstrates professional quality. If the load suddenly increases due to automatic startup of the air compressor or pump during the de-listing process, the system will immediately execute the **“Abort de-listing ”** and the unit will return to the equalized load state.

Specialty Points: Never force an unlisting when the load fluctuates dramatically, safety above all else.

4. Cooling and shutdown

The diesel engine will not shut down immediately after a successful shunt. To prevent damage to the supercharger due to localized overheating, the unit will enter approximately 1-minute delay for no-load operation (cooling operation)The machine then stops automatically.

🛠️ Hands-on Assessment Checklist

• [ ] Delayed recording: Are the two critical delays from the issuance of the command to tripping and from tripping to shutdown recorded?

• [ ] Logical judgment: Do you know that the system will automatically block the unlisting command when a “heavy load alarm” occurs?

• [ ] Security Confirmation: Did you check the status of the “Ready for Start” indicator after the shutdown?