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... Brushless Excitation (SBE) system includes an inverted synchronous generator called the Exciter Machine (EM) and a uncontrolled rotating diode bridge rectifier that excites the synchronous generators. Fig. 1 shows a representation of a synchronous generator (SG) with brushless excitation system. The main advantage of this structure is the elimination of the power ring-brush system on the rotor winding of the SG, which reduces maintenance costs. Some papers [1], [2], [3] have shown that the performances of SBE systems are limited by the ...
Context 2
... The PID parameters are adjusted to give a compromise between stability and temporal performance. In this tests, proportional and derivative constants are given by P=100, D=0.6 and N=500, respectively. Under Fig. 9. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.8 power factor. Fig. 10. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.3 power factor. conditions herein, as can be observed, the proposed ABE structure with de-excitation closed-loop PID control for voltage overshoot enhances, greatly, the terminal voltage Fig. 11. r.m.s voltage (p.u.) ...
Context 3
... power with a 0.8 power factor. Fig. 10. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.3 power factor. conditions herein, as can be observed, the proposed ABE structure with de-excitation closed-loop PID control for voltage overshoot enhances, greatly, the terminal voltage Fig. 11. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.6 power factor. performance of the SG during the load shedding tests. Table III shows a sum up of the improvement obtained with ABE system. Thus, the controlled non linear discharge resistor considerably improves the ...
Context 4
... Brushless Excitation (SBE) system includes an inverted synchronous generator called the Exciter Machine (EM) and a uncontrolled rotating diode bridge rectifier that excites the synchronous generators. Fig. 1 shows a representation of a synchronous generator (SG) with brushless excitation system. The main advantage of this structure is the elimination of the power ring-brush system on the rotor winding of the SG, which reduces maintenance costs. Some papers [1], [2], [3] have shown that the performances of SBE systems are limited by the ...
Context 5
... The PID parameters are adjusted to give a compromise between stability and temporal performance. In this tests, proportional and derivative constants are given by P=100, D=0.6 and N=500, respectively. Under Fig. 9. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.8 power factor. Fig. 10. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.3 power factor. conditions herein, as can be observed, the proposed ABE structure with de-excitation closed-loop PID control for voltage overshoot enhances, greatly, the terminal voltage Fig. 11. r.m.s voltage (p.u.) ...
Context 6
... power with a 0.8 power factor. Fig. 10. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.3 power factor. conditions herein, as can be observed, the proposed ABE structure with de-excitation closed-loop PID control for voltage overshoot enhances, greatly, the terminal voltage Fig. 11. r.m.s voltage (p.u.) during step load change (shedding), a load that consumes the 100% of the apparent power with a 0.6 power factor. performance of the SG during the load shedding tests. Table III shows a sum up of the improvement obtained with ABE system. Thus, the controlled non linear discharge resistor considerably improves the ...
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Citations
... • A negative excitation controller used to control the IGBT via the control machine. The controller selected is a PID one based on the supervision of the generator terminal voltage [18]. ...
... During normal operation, the SG voltage is generally regulated to the rated value by the positive voltage regulator. Consequently, the PID output will saturate to "1" and the IGBT will be always ordered to close [18]. The IGBT is controlled to open during transient states when the terminal voltage tends to be higher than 105%. ...
The main weakness of the brushless excitation system in a synchronous generator (SG) is the slow de-excitation response obtained during a load rejection. That is why voltage overshoots may be observed on the generator terminals. This behavior is mainly due to the exciter machine response time and the rotating diode bridge which is not able to quickly de-excite the generator by negative excitation voltages. This paper presents a new brushless de-excitation structure able to perform a quick de-excitation of the generator by providing controlled negative excitation voltage to the generator main field winding. The proposed structure is based on a new brushless de-excitation machine, called a control machine, and mounted on the same shaft of the generator and the brushless exciter. The brushless control machine is a low power one and used to transfer the orders from the voltage regulator to the discharge system located on the rotor side of the main generator. The dynamic performance of the proposed de-excitation system is evaluated in terms of system stability, voltage regulation response times and voltage overshoots during different load rejection tests. The proposed system is compared to the conventional brushless excitation system without the proposed de-excitation structure. In addition, a comparison is done with the static excitation system. The simulation tests are realized on an experimentally validated model of 11kVA synchronous generator developed in Matlab/Simulink.
A new de-excitation system for advanced brushless excitation based on a synchronous generator is presented. The proposed system uses a discharge resistor in series with a freewheeling diode of a buck chopper. It improves the reliability of the entire power plant and can be used on several excitation systems. It can be used in case of programmed shutdown of the generator and also shows good results in voltage regulation without destroying the efficiency of the excitation system under nominal operation. An analysis of the system has allowed us to suggest a methodology to obtain the appropriate value of the discharge resistance to be used. The validation of the proposed system has been done through simulations in the Matlab/Simulink environment, supported by experimental tests.
