Ferroresonance also called as neutral instability is an
abnormal condition wherein unstable high voltage occurs on 3 phase electrical
systems that could potentially cause the failure of equipment.
Ferroresonance generally refers to a wide variety of
interactions between capacitors and iron-core inductors that result in unusual
voltages and/or currents Ferroresonance In power system context occurs when a
nonlinear inductor is fed from a series capacitor.
Ferroresonance can occur when an unloaded 3-phase system
consisting mainly of inductive and capacitive components is interrupted by
single phase means. In the electrical distribution field this typically occurs
on a medium voltage electrical distribution network of transformers (inductive
component) and power cables (capacitive component).
Below are chosen links to further explain the phenomenon of
Ferroresonance.
Cahier Technique: Ferroresonance
Ferroresonance is a non-linear resonance phenomenon that can
affect power networks. The abnormal rates of harmonics and transient or steady
state overvoltages and overcurrents that it causes are often dangerous for
electrical equipment. Some unexplained breakdowns can be ascribed to this rare,
non-linear phenomenon.
The purpose of this “Cahier Technique” is to help readers
understand ferroresonance. The methods described ensure credible prediction and
evaluation of the risk of ferroresonance in existing and future installations.
Practical solutions designed to avoid or eliminate ferroresonance are also
given. Read more...
Investigation of Ferroresonance and Switching Surge
Phenomena on the Power Switchyard
When the structure of power system is changed or facing
external disturbances, many unstable transient phenomena may occur during the
transient period. This transient process may lead to overvoltage situation and
will have some impacts on the power system.
Depending on the frequency of transient process, the
transient phenomena can be broadly classified as high, medium and low frequency.
The switching and lightning surges belong to a high-frequency overvoltage
phenomenon. Read more...
Ferroresonance during Single-Phase Switching of
Distribution Transformers
After single-phase switching-on of the first phase of an
unloaded distribution transformer two identical series circuits arise each
consisting of the no-load inductance of the transformer and the earth
capacitance of the still open phases. These circuits are fed in parallel by the
phase voltage Us.
The saturation of the no-load inductance of the transformer,
however, limits the over-voltage. Resonance phenomena in such a series circuit
with non-linear inductance are described by the ferroresonance theory and
characterized by a 'jump' effect. Read more...
Ferroresonance Phenomenon in Power Transformers - Experimental
Assessment
This paper reports on the results of recent research and
development efforts to study and assess various impacts of ferroresonance
phenomenon on operating performance of power transformers and to investigate
ways to mitigate the effects of such phenomenon.
Three-phase core-type transformers are used in the study.
The results of the technical investigation and the associated ferroresonance
experimental work performed showed that ferroresonance can cause dangerous
overvoltages and overcurrents in three-phase core type transformers. Read more...
Determination of the Characteristics for Ferroresonance
Phenomenon in Electric Power Systems
Ferroresonance is an electrical phenomenon in nonlinear
character, which frequently occurs in power system due to transmission line
faults and single or more-phase switching on the lines as well as usage of the
saturable transformers.
In this study, the ferroresonance phenomena are investigated
under the modeling of the West Anatolian Electric Power Network of 380 kV in
Turkey. The ferroresonance event is observed as a result of removing the loads
at the end of the lines. Read more...
FERRORESONANCE IN THREE-PHASE POWER DISTRIBUTION
TRANSFORMERS: SOURCES, CONSEQUENCES AND PREVENTION
Ferroresonance is a phenomenon that involves high distorted
levels of overvoltage and overcurrents. During the last decades, the
three-phase ferroresonance research has suffered several changes due to the
continuously changing equipment and network.
This paper analyses every main factor that is somehow
related with the origin, consequences and the preventive decisions that may
lead us to avoid the three-phase ferroresonance to appear. Besides this, it
gives the opportunity to get a quick identification of such a complex
phenomenon. Read more...
Ferroresonance Experience in UK: Simulations and
Measurements
Ferroresonance is a complex non-linear electrical phenomenon
that can cause dielectric & thermal problems to the transmission plant and
switchgear. Electrical systems exhibiting ferroresonant behaviour are nonlinear
dynamical systems.
The application of conventional linear mathematics is
therefore not fully appropriate for the study of ferroresonance. Read more...
BEST PICK on FERRORESONANCE TUTORIAL is this SITE
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