Power Quality & Chillers ... SP 2007 Conf.

[Dennis Cronin]

• We have experienced several power outages, voltage sags, transistents etc from our Utility Company. These power issues have resulted in shutting down all of our York centrifugal chillers at the same time. Automation tries to restart the chillers in once instance, in another each chiller's VSD had to be reset before the chiller was allowed to recover from the outage. Do we just accept the way the chillers react in these instances and add procedures to respond accordingly?
Richard A. Reyher, Cushman & Wakefield SPRING 2007 Conference Question
REPLY:
The following comments are by Doug Sandberg, Dir. of Operations at ASCO
Critical Mechanical loads should be sequenced back to prevent overloading. Load management is important. If chiller loads are fed via ATS, load management can be easily accomplished via controls in place at the ATS and / or Engine Generator control system. Aside from that, a control system (PLC) can be designed to interface directly with Chiller controls or electrically operated breakers, which feed them. The resetting issue should be addressed by the manufacturer of the equipment. First they should be able to explain the sequence of operation and under what conditions a “reset” is required. Second, they may be able to develop a solution which automatically resets the controls. You will need collaboration here between all entities. A good consultant is you best bet to thoroughly identify the issues and work to resolution with all involved parties.

[Ethan Thomason]

Do you know what the chillers shutdown on? Over voltage, Under voltage... Do you have any power quality monitoring on the feed to the chillers? In order to figure out what the problem is you need information. The machine should shutdown to protect itself if truly needs to but steps can be taken from the operations/engineering point of view to minimize the frequency of this occuring.

[glenfoxman]

be aware of the power quality standards prevailing in your area. your POCO follows a set of PQ standards and you should be able to match them with the PQ requirements of your equipment. having equipment that wont match with the POCO standard means trouble.
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