Any type of power system must be guaranteed to operate at rated voltage. Therefore, keeping the voltage constant is one of the important indicators of power quality. However, in fact, the voltage always changes frequently. Compared with the onshore power grid, the ship's power grid is more severe due to the smaller capacity. In order to ensure the normal operation of the power system, the synchronous generator automatic voltage regulator plays an important role. The requirements are: simple and reliable, high sensitivity and stability, good steady state, good dynamic characteristics, certain forced excitation ability, reasonable and stable distribution of reactive power. The new power station simulator in our hospital simulates the ship's power system according to the actual ship conditions, so that students can better understand the composition and principle of the ship's power system during training, and master the various operations and functions. However, according to the use situation, its simulation of dynamic characteristics is greatly distorted, which makes students difficult to understand in training. In this paper, the author establishes its mathematical model based on the analysis of the dynamic process of synchronous generators, using CSSF language programming. Try to make its dynamic characteristics achieve better simulation results.
1 The establishment of the mathematical model of the power system, whether it is large disturbance or small disturbance, makes the ship power station transition from one steady state to another, and thus undergoes a dynamic process. The entire system and its components, such as synchronous generators, excitation regulators, prime movers, governors and loads, will undergo a dynamic process, including an electromagnetic transition process and an electromechanical transition process. For the various disturbances of the ship's power system, it is generally the first to cause the electromagnetic transition process, and then the electromechanical transition process. When discussing the dynamic characteristics of the power system, it can be roughly considered that the rotational speed is constant, so that the control process of the speed control system can be ignored. |1 1.1 Mathematical Model of Synchronous Generator Park first applies the d-q coordinate with the rotation of the rotor to the equation of the synchronous motor, eliminating the coefficient of the motor equation over time and simplifying the motor equation. The synchronous motor pattern after coordinate transformation is shown as |2丨, and its equivalent circuit is shown as 2.
Assuming that the synchronous generator studied is an ideal motor, that is, regardless of the influence of the motor hysteresis eddy current, the Parker equations of the synchronous generator can be written according to the equivalent circuit diagram, but such an equation will be applied in engineering. Inconvenience, so all parameters are expressed in relative units with the reference value (ie, the standard value)|3丨 In the process of research on the dynamic state of the generator, the following assumptions can also be made: 1) Because the machine is 万 万 (1970-) Male, engineer is engaged in the research of turbine simulator. A11. "JU1. + group can be simplified as: where: Ud, Uq, Uf - vertical, horizontal axis armature, excitation circuit voltage; id, iq, if a vertical, horizontal axis armature, excitation circuit current; Xd , Xq, Xf* longitudinal, horizontal axis armature, flux linkage of the excitation circuit; resistance of ra, Rf armature, excitation circuit; Xd, Xq, Xad, Xf - mutual inductance and self-inductance of the corresponding circuit; P - synchronization time Differential symbol.
In practical applications, a more intuitive generator mathematical model, often represented by a transfer function block diagram or block diagram, is often used. Therefore, according to the above equation, a block diagram of the simplified mathematical model of the synchronous generator can be obtained, as shown in the transfer function structure diagram of the phase compounding device.
1. Mathematical model of phase compound excitation synchronous generator According to the previous analysis, the mathematical model of the phase compound excitation synchronous generator can be obtained, as shown. The model consists of three parts: synchronous generator, phase compounding device and load. The single-machine operation is considered here, regardless of the fluctuation of the rotational speed, the load impedance is constant, and the transition process of the stator is not considered.
2 Simulation and Analysis of Results In recent years, the digital simulation technology of control systems has received extensive attention and application. Many simulation languages ​​such as dynamo, CSMP, GPSS, GASP, SIMSCRIPT, DDS, CSSF and so on have appeared. According to the structure shown, the block type table is compiled using the CSSF simulation language. The parameter of the generator is Un 1.08. The initial state is that the generator is unloaded, and the generator voltage is not adjusted. When the rated load of cosT=0.4 is suddenly added, the simulation result is as follows.
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