The Role of Distributed Generation in Power Quality and Reliability

voltage situations have a significant impact on production and require manual corrections to
optimize capacity.
A second plastics facility reported a similar story, in a different utility service region. They never
lost all of their power, but would lose one phase (typically L3). Motors would trip when there
was a phase drop off. The utility denied the problem at first, but later made the necessary
repairs. The cable under the street was upgraded and voltage is now consistent, except when the
facility attempted to bring on a new machine.
A hospital reported that flickering lights, surges, spikes and transients have become more
frequent. The local utility does not warn the site when maintenance and testing of feeders is
scheduled. On the contrary, a communications facility noted that the local utility did give them
advance notice of testing and maintenance procedures and warned them of plans for voltage
drops (brownouts).
The tolerances to power quality variations and the amount of losses involved vary greatly across
the interviewees. In a couple of instances we interviewed businesses that required extremely
high grade power. These businesses made huge investments in preventative measures. One of
these businesses experiences approximately 15-20 incidents (spikes, transients) on any given day
that could affect their operations, but the business has invested in a system of protections that
minimize the impacts of these problems.
3.2 Costs Incurred Due to Power Quality and Reliability Problems
The diverse group of customers interviewed as part of this study experienced a variety of costs
due to power quality and reliability problems. The costs included the value of lost production,
increased labor costs, damage to work-in-process with resulting reduced value or costs of
reworking, value of lost materials, equipment damage, revenue (opportunity) loss due to failure
to perform contracts, transaction processing losses and the need to ration services to customers.
The costs of disruptions are not typically quantified, with a few exceptions. In one instance a
plastics business reported that when its machines were down due to power quality problems, it
suffered the indirect cost of lost production but also incurred the direct cost of paying all line
workers even though no product was being made. Another plastics business reported
documenting $16,500 in equipment damage costs in a single month. This figure was said to be
quite conservative as it only included the direct costs to repair damaged equipment that could be
directly linked to poor power quality. The company did not document and account for “softer,”
though no less real costs, such as the value of lost production, losses to work-in-progress and
other costs.
In another continuous manufacturing process costs incurred due to poor power quality included
losses when a machine trips out while raw materials are on the line. This would require reprocessing
the materials input, could require overtime pay premiums of $35 to $40/hour, might
involve damage to the machinery that was working the input material, down time and
Energy and Environmental Analysis / Pace Energy 12 The Role of DG in Power Reliability