Regulators with improved energetic characteristics are considered for powering airfield lighting equipment (LE). The regulators used now have low power factors and high levels of current disturbance. Thus, a new regulator structure is proposed based on six-phase rectifiers and a two-inverter cascade with PWM control. In general, the LE includes several independent electric lines with the lamps connected in series via an isolation current transformer that form the so-called 'cable loop (CL)'. The CL is powered by an AC multistep regulator-stabilizer called a 'brightness regulator (BR)'. The CL is a complicated nonlinear, nonstationary load with a substantial inductive component, which varies depending on the number of working lamps in the CL. For example, a fault in a 200-W lamp causes the CL inductance to increase by 51 mH and the active resistance to decrease by 4.6 ohms. If all of the lamps are operable, then the CL inductance will be within the range of 0.8 mH to 13 mH and the resistance will be within the range of 46 ohms to 460 ohms depending on the length of the CL and the number of lamps. The brightness of the light will be regulated by steps of 100 %, 30 %, 10 %, 3 %, and 1 % of the nominal value. Regulation in BRs currently in use is performed by an inverse-parallel thyristor unit connected directly to the primary source and a transformer with the CL connected to its secondary coil. During development and operation at aisfields there is a need to reduce load asymmetry as it arises. It is necessary to reduce the distortion of the consumed current with the purpose of lowering the influence of the nonharmonicity of the current on the rate of the degradation of the electrical equipment and the decrease in the durability. In order to stabilize the CL current under the reduced (by 15 %) voltage, a thyristor regulation angle reserve of about 85 to 100 is provided in the control system. A significant increase in the number of semiconductor devices in the proposed BR as compared to thyristor devices makes it necessary to estimate the efficiency of the system, i.e., the ratio of the effec tive power (the power consumed by the load) to the total power. Power losses are caused mainly by heat dissipation in the switch elements. Because CLs can differ significantly in their power consumption, the problem arises of matching the CL voltage to the output voltage of their common transformer. The control system solves this problem because the proposed BR is based on totally controlled elements, which makes it possible to apply the high-frequency, pulse-width modulation (PWM) technique, which results in the harmonicity of the CL current, the reduction of CL losses, and the extension of the service life of the equipment.


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    Title :

    Brightness regulators for airfield lighting equipment with improved energetic characteristics


    Additional title:

    Beleuchtungsregelung mit verbesserter Energie-Effizienz für einen Flugplatz


    Contributors:

    Published in:

    Publication date :

    2008


    Size :

    6 Seiten, 6 Bilder, 1 Tabelle, 8 Quellen




    Type of media :

    Article (Journal)


    Type of material :

    Print


    Language :

    English




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