Abstract :
1. Good power quality
2. Poor power quality
» Good power quality
can be used to describe a power supply that is always available, always within
the voltage and frequency tolerances and has a pure noise-free sinusoidal wave
shape to all equipment, because most equipment was designed on that basis.
Unfortunately, most of the equipment that is manufactured also distorts the
voltage on the distribution system, leading to what is known as poor power
quality. And thus affecting other equipment that was designed with the
expectation of consistent undistorted voltage, and are thus sensitive to power
disturbances resulting in reduced performance and will cause equipment miss
operation or premature failure.
» The cost of power
quality problems can be very high and include the cost of downtimes, loss of
customer confidence and, in some cases, equipment damage. Indeed, power quality
is an important point in the relationship between suppliers and consumers but
might become a contractual obligation that stress on improving voltage quality,
availability, performance and efficiency and these improvements will have:
Benefits for industrial customers (customized and flexible availability) and
for suppliers utilities.
The
Problem:
» Power
quality is a worldwide issue, and keeping related standards current is a
never-ending task. It typically takes years to push changes through the
process. One of the most important developments in the power quality arena is
the increased emphasis on coordinating IEEE standards with international
standards developed by the International Electrotechnical Committee (IEC).
» Although
utilities keep on trying to improve the reliability of the grid, sensitivity of
industrial equipment to Power Quality (PQ) disturbances increases as automation
and electronics become more ubiquitous in industry. Unfortunately, utilities
cannot guarantee 100% availability in the power supply.
COST OF
POOR POWER QUALITY :
Poor Power
Quality can be described as any event related to the electrical network that
ultimately results in a financial loss. Possible consequences of poor Power
Quality include:
»
Unexpected power supply failures (breakers tripping, fuses blowing). Equipment
failure or malfunctioning.
» Equipment
overheating (transformers, motors etc.) leading to their lifetime reduction.
» Damage to
sensitive equipment (PC’s, production line control systems etc.).
»
Electronic communication interferences.
» Increase
of system losses.
» Need to
oversize installations to cope with additional electrical stress with
consequential increase of installation and running costs and associated higher
carbon footprint.
» Penalties
imposed by utilities because the site pollutes the supply network too much.
»
Connection refusal of new sites because the site would pollute the supply
network too much.
»
Impression of unsteadiness of visual sensation induced by a light stimulus
whose luminance or spectral distribution fluctuates with time (flicker).
» Health
issues with and reduced efficiency of personnel.