FERRANTI EFFECT

Ferranti Effect is the rise in receiving-end voltage (V_R) as compared to the sending-end voltage (V_S) of a transmission line. It was first noticed by Sebastian Ziani de Ferranti on a project involving underground cables in a 10 kV distribution system in 1887, and was eventually named after him.

STATCOM (STATIC SYNCHRONOUS COMPENSATOR)

STATCOM or Static Synchronous Compensator is a shunt device, which uses force-commutated power electronics (i.e. GTO, IGBT) to control power flow and improve transient stability on electrical power networks. It is also a member of the so-called Flexible AC Transmission System (FACTS) devices. The STATCOM basically performs the same function as the static var compensators but with some advantages.

STATIC VAR COMPENSATORS (SVC) IN THE POWER SYSTEM

Static Var Compensator (SVC) is a power quality device, which employs power electronics to control the reactive power flow of the system where it is connected. As a result, it is able to provide fast-acting reactive power compensation on electrical systems. In other words, static var compensators have their output adjusted to exchange inductive or capacitive current in order to control a power system variable such as the bus voltage.

MITIGATION OF FLICKER AND VOLTAGE FLUCTUATIONS

There are several techniques available for Flicker Mitigation. However, since flicker is caused by voltage fluctuations, these methods should be based on reducing such power quality phenomenon. It must be noted that the effects of voltage fluctuations are dependent on both its amplitude and the rate of their occurrence. Generally, mitigation measures are focused on limiting the amplitude of the voltage fluctuations. 

UIE/IEC FLICKERMETER FOR FLICKER MEASUREMENT

The UIE/IEC Flickermeter is the standard for flicker measurement. Its main function is to provide assessment of the flicker perception caused by voltage fluctuations. Therefore, the flickermeter should be designed to have the capability of transforming the input voltage fluctuations into an output parameter proportionally related to flicker perception. This is done by simulating the process of physiological visual perception, which is the lamp–eye–brain chain.

EFFECTS OF VOLTAGE FLUCTUATIONS ON ELECTRICAL EQUIPMENT

The undesirable effects of voltage fluctuations on electrical and electronic equipment are briefly described here. This post aims to give an overview of these effects, which are more obvious with light sources. Nonetheless, other sophisticated devices subjected to voltage fluctuations could malfunction and have reduced efficiency, which are costly in terms of downtime and rejects.

POWER QUALITY BASICS: VOLTAGE FLUCTUATIONS AND FLICKER

Voltage Fluctuations are described by IEEE as systematic variations of the voltage waveform envelope, or a series of random voltage changes, the magnitude of which falls between the voltage limits set by ANSI C84.1. Generally, the variations range from 0.1% to 7% of nominal voltage with frequencies less than 25 Hz. Subsequently, the most important effect of this power quality problem is the variation in the light output of various lighting sources, commonly termed as Flicker. This is the impression of instability of the visual sensation brought about by a light stimulus, whose luminance fluctuates with time.

ETAP TUTORIALS: MODELING A SHUNT REACTOR

A Shunt Reactor is not yet included in the list of ETAP elements in its Edit Toolbar as of its latest version (ETAP 11). Nonetheless, it doesn’t mean that we can’t model a shunt reactor in our one-line diagram and simulation. Modeling a shunt reactor in ETAP is easy using a simple technique.

ALESSANDRO VOLTA – ELECTRICAL ENGINEERING MASTER OF THE MONTH

Alessandro Volta made one of the greatest electrical discoveries of all time in 1796. He was able to produce continuous electric current for the first time, through his voltaic pile. Basically, it was the first electric battery and the first source of direct current (DC).