Failsafe Operation For Paralleled Generator Sets

Cat® Emcp 4.4 Control System Ensures Continued Safe And Stable Operation, Load Sharing And Load Response After Loss Of A Communication Link.

Ed Schroeder
Senior Engineering Specialist
Caterpillar Electric Powers

Keith Folken
Senior Engineering Specialist
Caterpillar Innovation and Technology Development

October 2016
INTRODUCTION

In facilities with a high demand for power, such as a hospital or data center, communication among generator sets is crucial for maintaining power levels. In these types of applications, generator sets can be electrically connected to help manage the large power need. Called paralleling generator sets, this configuration helps ensure more efficient load sharing and load response within a network.

One way to operate power systems with paralleled generator sets is to use dedicated multi-function engine generator set controllers with integrated paralleling controls on board the generator set. With Cat® EMCP 4.4 control system, the individual controllers communicate with each other by way of an Ethernet backbone, synchronizing the generator sets through a connection to a single Ethernet switch.

This approach to paralleling is cost-effective, as it integrates the function of discrete paralleling control devices and programmable logic controllers with the generator set controls and reduces switchgear footprint, leading to lower project capital cost. However, the approach has raised questions among power system designers and users:

What happens if the Ethernet switch fails and the generator sets no longer can communicate?

What happens if the link from one or more generator sets is broken and those units are cut off from communication?

Under such conditions, will the power system continue to operate, share load, and respond to load changes in a safe and stable manner?

For generator sets equipped with EMCP 4.4 control and Multiple-Generator Data Link (MGDL), the answer is an unequivocal yes. Caterpillar’s patented strategy called Failsafe Adaptive Load Sharing/Droop Operation is programmed into the EMCP 4.4 system to intelligently switch units to a control scheme that enables uninterrupted, stable operation for as long as it takes for full communication to be restored. The communication loss also triggers an alarm that alerts operating personnel to the condition so that repairs can be expedited.