Dusan Joksimovic

Voltage Controller for a Synchronous Generator with Exciter

In this paper, the excitation controller for a synchronous generator (SG) with an exciter is presented, based on novel stabilization feedback actions comprising the SG rotor current and rotor voltage measurements. The novel stabilizing feedback actions are used to compensate the dynamic lag introduced by the exciter machine, and to improve the overall excitation systems dynamic performance without employing differential control actions. Namely, by avoiding differential control actions, an improved level of performance can be achieved without compromising the control systems sensitivity in relation to the measurement noise. Also, compared with the existing solutions based on a different set of stabilizing feedback signals, the controlling structure proposed in this paper enables a more stable and faster dynamic response, which is illustrated in the paper by means of the system frequency response analysis. The performance of the proposed solution is verified through the set of simulation and experimental ...

Control of rotary exciter with series and separetly excitation windings excitation system of generator a2 at power plant “Kostolac A”

In this paper, the excitation control with rotary exciter of generator A2 in Thermal Power Plant “Kostolac A” is presented. Excitation system under consideration consists of a main exciter, an auxiliary exciter and power semiconductor rectifiers. The main exciter is a synchronous-reluctance generator with windingless toothed rotor. That excitation system is specific due to the fact that the main exciter has three excitation windings and three phase output a.c. windings, all located at stator. Series excitation is serially connected with rotor winding of the synchronous generator, while other two separate excitations are realized by independent windings, each of them generating the flux pointing in opposite direction. In the main three phase a.c. windings the 500 Hz frequency currents are induced. Auxiliary exciter is a 400 Hz permanent-magnet synchronous generator. It supplies separate excitation windings of the main exciter by means of thyristor rectifier bridges. The main aim of the control algorithm is to accomplish the magnetomotive force balance of all three excitation windings in order to regulate generator terminal voltage. In addition to the main outer voltage control loop, the inner local stabilizing current loop is added in order to achieve the satisfactory transient performance of the regulation. Control algorithm sets the values of the firing angle of the thyristors in two three-phase rectifier bridges, in order to produce corresponding excitation currents of separate excitation windings.

Modernization, reconstruction and development of excitation systems for synchronous generators

This paper presents the previous results of work and development of excitation systems with digital automatic voltage regulators regarding their design, development, manufacturing and commissioning. A special attention was paid to the characteristics of excitation system voltage regulator.