Intelligent Monitoring in the Modern Central Office

OVERVIEW

The power components in a Central Office or Critical Facility are designed to overcome a single failure. Power to the load often traverses two separate, but identical paths (A/B). Rectifiers are operated with N+1 or better redundancy, are fed from diverse AC sources and are backed up by parallel strings of batteries that supply power during a short-term AC power outage. Standby generators provide power when the outage lasts more than a few hours. Data centers take a different tack, foregoing the DC approach in favor of large, 3-phase UPS systems backed up by redundant generators. For the most part, these offices are almost always on, except in the worst case manmade or natural disasters.

The various power components– the incoming AC service, power conversion systems, battery backup, generators and distribution networks – form an interdependent ecosystem that ensures reliable and resilient network operation. But for all its success, the power system is still basically reactive. Alarm conditions observed at the office or a Network Operations Center (NOC) result in a technician being dispatched to resolve the failure condition. There is very little predictive analysis or maintenance with these critical power systems. Battery monitoring is sometimes provided, and modern power conversion systems usually include intelligent controllers. But there is little ability to assess the performance of the entire power ecosystem in the office because the components are not connected to each other under a common monitoring and control platform.

This paper proposes an intelligent monitoring and control network that can improve the overall power ecosystem performance. It discusses how the user can benefit from the new concept. The paper sets the stage with background information on how current power networks are configured in Central Offices and Critical Facilities, and how the various components report alarms and performance. It also presents the main communications protocols in use today. Finally, it ties all this together with a proposal on the requirements for intelligent monitoring and control for power system networks.