Power Quality In Electrical Systems

EFFECTS OF HARMONICS ON CAPACITORS

2012-06-17T01:24:00.000-07:00

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. Capacitors are typically installed in the electrical power system – from...

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STATIC SYNCHRONOUS SERIES COMPENSATOR (SSSC)

2012-05-31T08:39:00.000-07:00

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. The...

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FERRORESONANCE PREVENTION TUTORIALS

2012-04-30T07:58:00.000-07:00

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...

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FERRORESONANCE AND TRANSFORMER CONNECTIONS

2012-03-24T18:18:00.000-07:00

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. Susceptible Transformer Connections Ferroresonance is more likely to happen with...

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POWER QUALITY BASICS: FERRORESONANCE

2012-02-29T06:47:00.000-08:00

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. Basically, ferroresonance involves...

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POWER QUALITY BASICS: VOLTAGE NOTCHING

2012-01-29T05:25:00.000-08:00

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. In addition, voltage notching characterizes an unusual case that falls between harmonics and transients. This is...

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EFFECTS OF HARMONICS TO ELECTRONIC EQUIPMENT

2011-12-31T22:52:00.000-08:00

The Effects of Harmonics to Electronic Equipment are experienced in various ways depending on the type of device - from slight to serious consequences. Ironically, it is a known fact that most electronic equipment is prone to misoperation due to harmonic distortion, even though it is a harmonic generator itself. In this post, these common effects will be briefly discussed. Power Electronic Equipment This equipment is reliant upon accurate determination of voltage zero crossings or...

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DELTA CONVERSION ONLINE UPS

2011-11-02T07:12:00.000-07:00

Delta Conversion Online UPS is a modern innovation that eliminates the disadvantages of the traditional double conversion online UPS. The enhancements are based on having a delta inverter and allowing bidirectional power flow. Today, this design is the only major uninterruptible power supply technology protected by patents and is unlikely to be offered from a broad range of UPS suppliers. Also, delta conversion online units are available in the market from 5 kVA to 1 MVA. Similarities and...

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MOTOR-GENERATOR (M-G) SET FOR IMPROVED RIDE-THROUGH

2011-10-30T08:41:00.000-07:00

Motor-Generator (M-G) set is basically a combination of a motor and generator, although it is physically different from an ordinary electric motor that is attached to a separate generator. It has many practical functions that generally involve converting voltage, frequency and phase of power. However, this post will focus on its power quality applications, as it is a mature technology used for isolating sensitive and critical loads from voltage sags and interruptions. Also, it is available in...

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EMTP-RV: REFERENCE FOR POWER SYSTEM TRANSIENTS

2011-10-26T23:26:00.000-07:00

EMTP-RV is a powerful and dedicated software for the simulation and analysis of transients in power systems. It provides an extensive variety of system modeling capabilities covering electromagnetic and electromechanical oscillations ranging in duration from microseconds to seconds. EMTP-RV is the most comprehensive analysis and simulation program for power system transients. EMTP-RV has gained a reputation of being a super-fast computational engine that gives improved solution methods for...

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