The Effects of Harmonics on Capacitors include additional heating - and in severe cases overloading, increased dielectric or voltage stress, and unwanted losses. Also, the combination of harmonics and capacitors in a system could lead to a more severe power quality condition called harmonic resonance, which has the potential for extensive damage. Consequently, these negative effects will shorten capacitor life.
Thursday, May 31, 2012
Static Synchronous Series Compensator (SSSC) is a modern power quality FACTS device that employs a voltage source converter connected in series to a transmission line through a transformer. The SSSC operates like a controllable series capacitor and series inductor. The primary difference is that its injected voltage is not related to the line intensity and can be managed independently. This feature allows the SSSC to work satisfactorily with high loads as well as with lower loads.
Monday, April 30, 2012
Ferroresonance Prevention Tutorials deal with strategies that electric utilities and end-users could implement to minimize occurrence of the power quality phenomenon. These practices are based from the fact that ferroresonance usually happens with lightly loaded three-phase transformer, having one or two phases open either intentionally or accidentally. Common strategies for managing ferroresonance include: Preventing open phase condition, limiting overvoltages, damping resonance with secondary load, limiting cable length, switching at transformer terminals and grounding transformer primary.
Saturday, March 24, 2012
Ferroresonance and Transformer Connections are related as such that the latter is a significant factor to the occurrence of the former during loss of phase or open phase conditions. There are certain transformer configurations that are more susceptible to ferroresonance. Generally, ferroresonance phenomenon becomes highly probable if the primary windings of the three-phase transformer are ungrounded.
Wednesday, February 29, 2012
Ferroresonance is usually described as an irregular and chaotic type of resonance. This phenomenon occurs because of the nonlinear characteristic of iron-core (saturable) inductors - ferromagnetic material such as a transformer. Ferroresonance is often times associated with unwanted and destructive overvoltages, but has found some helpful applications in Constant Voltage Transformers, which can mitigate power quality problems like voltage sags.
Sunday, January 29, 2012
Voltage Notching is described by IEEE as a recurring power quality disturbance due to the normal operation of power electronic devices (i.e. rectifier), when current is commutated from one phase to another. Conventionally, the current waveform is used as the starting point for harmonic analysis, and voltage notching is simply derived from the IZ drops of the harmonic currents.
- I am an Electrical Engineer with a Masters Degree in Business Administration. My interest is in Power Quality and Protective Relaying. I have been working in an electric distribution utility for about seven years now as a Planning & Design Engineer. I handle PQ studies, power system analysis and capital budgeting for company projects.