The problem of waveform distortion of the power system terminal voltage is becomin a critical problem especially for computers and otfey sensitive loads. Elimination of this distortion requires the ability to generate the compensating pulses of energy in times much less than the source period. This paper presents the theory and the experimental implementation of a new device called the Static Voltage Controller (SVC) which can eliminate waveform distortion and provide a sinusoidal volt age.
Increasing the power transfer across the existing power transmission lines and compensating for the voltage drops across these lines are two major challenges which will have great effects on the existing power networks and on the construction of new transmission lines.The Instantaneous Voltage Controller (IVC), the theory of which was presented in [1,2,3,4]
, was initially operated on Current Source Inverter (CSI) principle to modulate the transmission line reactance. Modulation of the transmission line reactance has great effects on controlling the power flow across the power transmission lines and subsequently on the stability of power transfer and on voltage drop across the power lines. This paper investigates the operation of IVC as Voltage Drop Compensator (VDC) for power transmission lines based on Voltage Source Inverter (VSI) instead of CSI. The voltage drop compensation presented in this paper is based on switching the VSI to act on the voltage error between the load voltage and a sinusoidal reference voltage. The voltage on the load is maintained equal to the reference sinusoidal voltage by inclusion afeedback from the voltage error into the power module capacitor. The voltage instability associated with increased load demand caused by inability of power systems to meet demand for reactive power [5] can also be solved using Voltage Drop compensation. The computer simulation of this design shows that the VDC is effective in preventing the voltage instability by reducing the inductive reactance of the line and by that allowing the transfer of more active reactive power across the line.
Reactance modulation of power transmission lines has great effects on load voltage control and on the stability of power transmission. Steady state voltage control can be easily achieved with conventional control devices such as switchable capacitors and reactors, while transient voltage control requires faster and more effective means of control [1]. In this paper, the transient voltage control is achieved by modulation of the net reactance of the transmission line using Voltage Drop Compensator (VDC) through hysteresis switching of a dc current from Voltage Source Converter (VSC) to charge/discharge a capacitor in series with the line. Modulation of the capacitor voltage by dc current from VSC improves the voltage control of the load, reduces the voltage drop on the transmission line, and improves the stability of the power transfer [2][3][4]. High frequency switching of the capacitor through charging/discharging process ensures faster response to transients in the input voltage and prevents it from appearing in the load. Fast response to variation in the input supply is done by comparing the load voltage to a sinusoidal reference voltage every time this voltage deviates from a fixed hysteresis window. Under this method of capacitor voltage control, no control is exerted on the dc current from VSC which can reach hundred amperes. In this paper a dc current controller is introduced to limit the dc current from VSC to a any value desired or to any other value necessary to keep the load voltage sinusoidal.
Power generation scheduling to cover the load economically is an important issue, especially with ever growing increased fuel costs. The effective power plant management has to give the economic factor of fuel cost and technical characteristics of the machines an outstanding importance. Input /Output characteristics of the power plants must be taken during economic dispatching of load. In addition, the fuel cost variation driven by the fuel market must be taken into consideration for economic operation of the power plants. In this paper, a study of the economic scheduling of generating plants of the Southern Electrical Network (SEN) of Saudi Arabia using input / output characteristics of the plants and the fuel costs is conducted. Results show that a substantial savings can be obtained from operation of these plants following variation in the fuel cost.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.