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In power engineering, the power-flow study, or load-flow study, is a numerical analysis of the flow of electric power in an interconnected system. A power-flow study usually uses simplified notations such as a one-line diagram and per-unit system, and focuses on various aspects of AC power parameters, such as Voltage, voltage angles, real power and reactive power.
Voltage levels and reactive power flow must be carefully controlled to allow a power system to be operated within acceptable limits. A technique known as reactive compensation is used to reduce apparent power flow to a load by reducing reactive power supplied from transmission lines and providing it locally. For example, to compensate an ...
For power systems engineers, a load flow study explains the power system conditions at various intervals during operation. It aims to minimize the difference between the calculated and actual quantities. Here, the slack bus can contribute to the minimization by having an unconstrained real and reactive power input.
A unified power flow controller (UPFC) is an electrical device for providing fast-acting reactive power compensation on high-voltage electricity transmission networks. It uses a pair of three-phase controllable bridges to produce current that is injected into a transmission line using a series transformer. [1] The controller can control active ...
reactive power causes heating in the generators and the transmission lines, thermal limits will require restricting the production and the flow of real power; injection of reactive power into transmission lines causes losses that waste power, forcing an increase in power supplied by the prime mover .
Currents that flow solely in reaction to these properties, (which together with the resistance define the impedance) constitute reactive power flow, which transmits no power to the load. These reactive currents, however, cause extra heating losses. The ratio of real power transmitted to the load to apparent power (the product of a circuit's ...
From the above equations, it can be seen that there are three variables that affect real and reactive power flow on a Transmission Line: [12] the voltage magnitudes at either bus, the line reactance between the buses, and the voltage phase-angle difference between the buses. All FACTs devices operation on the fundamental principal that changing ...
Electrical loads consuming alternating current power consume both real power and reactive power. The vector sum of real and reactive power is the complex power, and its magnitude is the apparent power. The presence of reactive power causes the real power to be less than the apparent power, and so, the electric load has a power factor of less ...