Methods and Means of Improving the Dynamic Characteristics of Brushless Excitation Systems
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Vol. 54, No. 4, November, 2020
METHODS AND MEANS OF IMPROVING THE DYNAMIC CHARACTERISTICS OF BRUSHLESS EXCITATION SYSTEMS A. L. Komkov,1 N. Yu. Filimonov,2 and A. A. Yurganov3 Translated from Élektricheskie Stantsii, No. 5, May 2020, pp. 40 – 46.
Possibilities of improving the dynamic characteristics of brushless excitation systems are considered. A technique for choosing the value of the additional resistance in the excitation winding of a reverse synchronous generator, the gain of the hard negative feedback and the excitation-forcing ratio of the exciter by voltage has been developed. The reasons for the appearance of high-frequency pulsations in the excitation voltage of a reverse synchronous generator are considered. The technique was applied when choosing the means of improving the dynamic characteristics of the BVD-4600-1500 brushless exciter, operating with the TVV-1000 – 4 generator. Keywords: synchronous generator; excitation control; brushless excitation system; hard feedback; excitation system response; dynamic characteristics; frequency distortions; high-frequency pulsations.
verse synchronous generator (RSG) with an excitation winding in its stationary part on the stator and with an armature, as well as an uncontrolled diode rectifier (DR) on the rotor [1]. The connection between the movable and stationary parts is provided by means of electromagnetic field. Excitation systems of this type, as a result of using the RSG with its own time constants and the armature response on load changes, have got a significant weak point — the inertial dynamic characteristics. The block diagram of the brushless excitation system (BES) is shown in Fig. 1. To improve the dynamic characteristics of BES, the following measures are taken: — introduction of hard negative feedback (HNF) on the excitation voltage of the main generator or on the excitation current of the RSG; — increased values of the excitation-forcing ratio of the RSG by voltage; — installation of an additional resistance Radd in series in the circuit of the excitation winding of the RSG. It is known that all the above methods lead to an improvement in the dynamic characteristics, but the literature
Synchronous generators of large unit rating power are becoming more and more widespread as part of the unified electric power system of Russia. Correct operation of excitation systems and their automatic controllers (AEC) has a significant effect on the stability of parallel operation of generators, increases the reliability and survivability of the power system. With an increase in the unit rating of the aggregates, it is necessary to get larger excitation currents, which should be transferred from a stationary thyristor converter to the excitation winding of a rotating rotor of a synchronous machine. The brush-contact device of Russian turbomachines at nominal speeds of 1500 and 3000 rpm provides long-term and reliable operation at currents, as a rule, not exceeding 5 kA. For the transmission of large currents on synchronous generators manufactured in Russi
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