Study on reinforcement of longitudinal power system by power electronics

在这项研究中，我们研究了一个异常电压的静止无功补偿器（SVC）和一个次同步谐振的晶闸管控制的串联电容器（TCSC）。主要研究成果如下：1）SVC电压异常的研究SVC由电容器和晶闸管控制电抗器（TCR）组成。推导了TCR频率响应的理论方程。通过将频率的小电压叠加到基频电压，然后导出频率的电流变化来获得响应。我们可以很快地计算出频率响应。不同的射击方式，其反应也不同。对于电压过零法，TCR电导在某些频率范围内取负值。另一方面，对于基于基波电压的点火方法，电导总是正的。接下来，我们表明，电压振荡模式变得不稳定的纵向电力系统与SVC。原因是TCR电导为负。特雷福 ...更多信息 如果我们应用锁相环（PLL），则电压模式变得稳定。TCSC的次同步谐振研究TCSC与SVC的结构相同，但作用方式不同。如果我们在一个频率上施加一个小电压，就会有许多电流分量流过TCR。在TCSC中，这些元件使电容器循环，然后产生许多电压分量。这些分量再次影响电流分量。我们推导出一个线性代数方程对这些组件。我们求解这个方程，得到TCSC的频率响应。同样，不同的发射方法，反应也不同。接着，我们计算了具有TCSC阻抗的发电机的阻尼转矩系数。阻尼系数变为负值，TCSC也会引起SSR。然而，与串联电容器相比，它的值很小，因此SSR得到了缓解。过零触发方式下阻尼系数的峰值随触发角的增大而移动，而基波触发方式下阻尼系数的峰值随触发角的增大而减小。这表明后一种方法对于抑制SSR是上级的。少

In this study, we investigated an abnormal voltage by static var compensator (SVC) and a subsynchronous resonance by thyristor controlled series capacitor (TCSC). The results are summarized as follows;1) Study of abnormal voltage by SVC SVC consists of a capacitor and a thyristor controlled reactor (TCR). We derived a theoretical equation for frequency responses of TCR. The response is obtained by superimposing a small voltage of a frequency to a fundamental frequency voltage, and then deriving current change of the frequency. We can caluculate the frequency response very quickly. The responses vary with firing method. For the voltage zero crossing method, TCR conductance takes negative values in some frequency ranges. On the other hand, for the firing method based on the fundamental voltage, the conductance is always positive. Next, we showed that a voltage oscillation mode becomes unstable in a longitudinal power system with SVC. The cause is that TCR conductance is negative. Therefo … More re, if we apply phase-locked-loop (PLL), then the voltage mode becomes stable. Numerical simulations verified this consideration.2) Study of subsynchronous resonance by TCSC Though the structure of TCSC is same as SVC, its action is different. If we superimpose a small voltage of a frequency, many current components flow through TCR. In TCSC, these components circulate the capacitor, and then produce many voltage components. These components influence the current components, again. We derived a linear algebraic equation on these components. We solve this equation to obtain the frequency responses of TCSC. The responses differ with the firing method, again. Next, we calculated a damping torque coefficient of a generator with TCSC impedance. The damping coefficient becomes negative, so TCSC causes SSR, too. However, its value is small compared with a series capacitor, so SSR is mitigated. The peak of the damping coefficient moves with the firing angle in the zero crossing firing method, but its value gets smaller in the firing method based on the fundamental voltage. This shows that the latter method is superior to suppress SSR. Less