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UPFC consist of two back to back converters named VSC1 and VSC2, are operated from a DC link provided by a dc storage capacitor. These arrangements operate as an ideal ac to ac converter in which the real power can freely flow either in direction between the ac terminals of the two converts and each […]

Voltage Source Converter (VSC) technology has been selected as the basis for several recent projects due to its controllability, compact modular design, ease of system interface and low environmental impact. Following are few factors which increase use of Voltage Source Converter in transmission system. Independent control of reactive and active power. Reactive control independent of other terminal(s). Simpler

A Synchronous Condenser is a device that control voltage on an electric utility’s transmission or distribution system. Voltage is the “pressure” needed to deliver electricity through such a system. Another device that controls voltage is a capacitor. Capacitors have no moving parts. Their simple design keeps their cost and maintenance requirements low. Synchronous Condensers have

Use of thyristor control in series capacitors potentially offers the following little-mentioned advantages: 1. Rapid, continuous control of the transmission-line series-compensation level. 2. Dynamic control of power flow in selected transmission lines within the network to enable optimal power-flow conditions and prevent the loop flow of power. 3. Damping of the power swings from local

Let us consider the case of two platinum electrodes dipped in dilute sulphuric acid solution. When a small potential difference is applied across the electrodes, no current is found to flow. When, however, the applied voltage is increased, a time comes when a temporary flow of current takes place. The H+ ions move towards the cathodes and

PRIMARY CONTROL: Primary control consists of changing a generating unit’s power versus the frequency, according to its static generation characteristic as determined by the speed governor settings. The objective of primary control is to re-establish a balance between generation and demand within the synchronous area at a frequency different from the nominal value. This is

A power system can be referred to as an islanding system when it is disconnected from other systems and does not exchange power through tie-lines. Due to the fact that frequency is the same within the entire system, frequency control in an islanding system can be achieved in a relatively simple way. The turbine speed

The main difference between a STATCOM and an SVC is the way they operate: a STATCOM works as a controllable voltage source while an SVC works as a dynamically controllable reactance connected in parallel. Compared with an SVC, a STATCOM offers the possibility of feeding the grid with the maximum available reactive current even at

It depends on what is limiting the power flow and how much of an increase is needed to solve the problem. In most circumstances, power flow limits are the result of concerns over electrical phase shift, voltage drop or thermal effects in lines, cables or substation equipment. SURGE IMPEDANCE LOADING LIMITS As power flows along

In order to prevent over voltages at light loads, it is necessary to have devices for absorbing reactive power (like shunt reactors) not only at either end of a long line but even at intermediate points. Generators connected at the ends of the line have limited reactive power absorption capability as defined by their capability