del sistema de turbina-generador instalado. Producción. Nuestro centro de producción (Orléans, Francia) está equipado con máquinas de tecnología punta. Los generadores síncronos constituyen el equipo más costoso en un sistema de potencia. Como consecuencia de los posibles fallos que se presentan tanto. CONTROL DE FRECUENCIA EN GENERADORES SÍNCRONOS Carol Sánchez Mateo Rodríguez Fredy Salazar Luz Dary Garcia Universidad.
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This paper focuses on the application of the third harmonic principle and is devoted to present a comparative analysis and an improvement of three different approaches. The behavior of the third harmonic voltage is described by curves as shown in figure 14 [7, 10]. Decentralized parallel operation of inverters sharing unbalanced and nonlinear loads. In the proposed test system, the normal operating ranges were determined for both the third harmonic of voltage at the neutral Vn and at the terminals Vtby varying the load from zero to the nominal value.
In the case of the overvoltage of the third harmonic scheme 2there is not possible to detect any ground fault because the overlapping of the normal operation range values of the third harmonic and those values measured in case of faults. Theoretical evaluation of the non-faulted and faulted models.
GENERADORES SINCRONOS by Jorge Rosas on Prezi
Finally, the alternative which uses the ratio of the third harmonic components scheme 3 as it is presented from equation 1 to 3due its high sensibility to the voltage variations could detect high resistance faults.
From the results obtained in a real synchronous generator there are advantages of the scheme based on the ratio of the voltages measured at terminals and neutral, in the case of using the voltage threshold strategy.
Ground faults at the synchronous machine stator are common and these cause current flows through the neutral conductor.
The normal operating intervals for the third harmonic voltage measured at the neutral is [ Figure generadorss Third harmonic voltage typical variations caused by changes in the output active power. In such cases where the curve which relates the normal value of the third harmonic voltages and the generator load is not available, the voltage threshold based strategy helps to implement a very constrained application using the undervoltage scheme.
The obtained results shows small variations in the maximum fault resistance detected, showing the reduced dependence of the proposed protection strategy and the synchronous generator load condition.
Finally, the alarm-trip logic proposed helps to deal with the variation in the magnitude of the third harmonic of voltage caused by load changes as it is presented in figures 23 and First, the basic aspects of the analyzed methods sinfronos presented.
In this method, the third harmonic voltage is measured at the neutral.
System and method for commutating a motor using back electromotive force geenradores. The use of the proposed alarm-trip logic is an interesting alternative which helps to improve the protection performance, making possible the detection of high impedance faults in all of the three third harmonic based schemes.
Figure 13 Alarm-trip logic used for the undervoltage scheme 1 or overvoltage scheme 2 of the third harmonic component. Modulation and control of three-phase paralleled Z-source inverters for distributed generation applications.
Schemes 2 and 3 Overvoltage and ratio of the third harmonic components, respectively have a better performance according to the analyzed cases, because the capability to detect high fault resistances is higher than in the case of scheme 1. Following, from figure 9 and using the proposed equations presented in 4 and 5 it is possible to obtain the impedances at the terminal and neutral nodes, respectively.
Using the classical thresholds strategy to determine the maximum fault resistance to be detected in the case of the undervoltage scheme, different fault sinccronos were analyzed using the circuit presented in figure Where i indicates the imaginary operator and f is the power frequency. Finally, Cn corresponds to Cgwhile Ct genetadores equivalent to 1-k Cg. Then the third harmonic voltage produced by the synchronous generator is distributed between the terminal and the neutral shunt impedances governing the generaadores.
EST3 – Generadores síncronos estáticos – Google Patents
Improvement of the third harmonic based stator ground fault protection for high resistance grounded synchronous generators. The first strategy is based on the determination of the normal values of the third harmonic of voltage at the terminals and the neutral of the synchronous generator.
The results help to validate the system behavior by a comparison of the values obtained for the third harmonic voltage measured at the ground connection Vn and these measured at the machine terminals Vt with those obtained by using equations 6714 and 15 considering the real machine parameters given by table 1.
The first model is the equivalent scheme of the system under normal condition operation while the second one is equivalent to the system working under fault conditions. Fault resistance estimation using the voltage thresholds The first strategy is based on the determination of the normal values of the third harmonic of voltage at the terminals and the neutral of the synchronous generator. Figure 4 Protective scheme used to detect under voltage of the third harmonic Figure 5 Protective scheme using over voltage of the third harmonic Ratio of the third harmonic components Scheme 3 This method is based on the comparison of third harmonic voltages using several mathematic relations which should make the protective device more susceptible to the variation of these voltages.
According to preliminary test performed in the proposed real synchronous generator, the obtained values for the maximum fault resistances which are detectable by using each one of the three proposed schemes are presented in table 2.
Fault resistance estimation using the voltage thresholds. According to the results, it is shown that the scheme 1 Undervoltage of the third harmonic component has a lower capability to detect the abnormal behavior in case of high resistant faults.
Finally, the different schemes were tested in the case of nine values of third harmonic voltage nine different load conditions to cover all variation range.
The logic used to determine the presence of trip or alarm for both, under and overvoltage of the third harmonic component schemes 1 and 2, respectivelyis presented in figure 13, and it is based on the comparison of the values of the third harmonic of the voltage measured denoted with the additional subindex m and those normal values as the present in figure A stator ground fault close to the neutral point is not immediately catastrophic because: This characteristic is desirable because it is useful to detect possible problems in the insulation level of the synchronous generator.
Figure 7 Equivalent synchronous generator model considering non fault conditions. Revista Tecnura – U. Validation of the proposed third harmonic generator models.
Electric Machinery Company – Generadores Sincrónicos
Impact generadoree FACTS controllers on the stability of power systems connected with doubly fed induction generators. The high impedance method is frequently used because in the case of faults the current magnitude is relatively low [1, 2].
However, the ratio based scheme helps to obtain the best performance in high impedance fault determination. Figure 10 Equivalent synchronous generator model considering fault conditions.