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Thread: Reactive power Information

  1. #1

    Reactive power Information

    How reactive power is helpful to maintain a system healthy We always in practice to reduce reactive power to improve system efficiency. This are acceptable at some level, if system is purely resistively or capacitance it make cause some problem in Electrical system. AC systems supply or consume two kind of power: real power and reactive power. Real power accomplishes useful work while reactive power supports the voltage that must be controlled for system reliability. Reactive power has a profound effect on the security of power systems because it affects voltages throughout the system. Find important discussion regarding importance about Reactive Power and
    how it is useful to maintain System voltage healthy. COVERED TOPICS:

    Need of Reactive Power
    Voltage control in an electrical power system is important for proper operation for electrical power equipment to prevent damage such as overheating of generators and motors, to reduce transmission losses and to maintain the ability of the system to withstand and prevent voltage collapse. In general terms, decreasing reactive power causing voltage to fall while increasing it causing voltage to rise. A voltage collapse occurs when the system try to serve much more load than the voltage can support.

    When reactive power supply lower voltage, as voltage drops current must increase to maintain power supplied, causing system to consume more reactive power and the voltage drops further . If the current
    increase too much, transmission lines go off line, overloading other lines and potentially causing cascading failures.

    If the voltage drops too low, some generators will disconnect automatically to protect themselves. Voltage collapse occurs when an increase in load or less generation or transmission facilities causes dropping voltage, which causes a further reduction in reactive power from capacitor and line charging, and still there further voltage reductions. If
    voltage reduction continues, these will cause additional elements to trip, leading further reduction in voltage and loss of the load. The result in these entire progressive and uncontrollable declines in voltage is that the
    system unable to provide the reactive power required supplying the reactive power demands.

    Importance of Present of Reactive Power
    Voltage control and reactive-power management are two aspects of a single activity that both supports reliability and facilitates commercial transactions across transmission networks. On an alternating-current (AC) power system, voltage is controlled by managing production and absorption of reactive power. There are three reasons why it is necessary to manage reactive power and control voltage.

    First, both customer and power-system equipment are designed to operate within a range of voltages, usually withiną5% of the nominal voltage. At low voltages, many types of equipment perform poorly; light bulbs provide less illumination, induction motors can overheat and be damaged, and some electronic equipment will not operate at High
    voltages can damage equipment and shorten their lifetimes.

    Second, reactive power consumes transmission and generation resources. To maximize the amount of real power that can be transferred across a congested transmission interface, reactive-power flows must be minimized. Similarly, reactive-power production can limit a generator’s real-power capability.

    Third, moving reactive power on the transmission system incurs real power losses. Both capacity and energy must be supplied to replace these losses.

    Voltage control is complicated by two additional factors. First, the transmission system itself is a nonlinear consumer of reactive power, depending on system loading. At very light loading the system generates reactive power that must be absorbed, while at heavy loading the system consumes a large amount of reactive power that must be
    replaced. The system’s reactive-power requirements also depend on the generation and transmission configuration.

    Consequently, system reactive requirements vary in time as load levels and load and generation patterns change The bulk-power system.

  2. #2

    Re: Reactive power Information

    thank you for this pdf

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