A unified Newton-Raphson technique for AC-DC power flow analysis with thyristor controlled series capacitor

This paper presents a unified Newton-Raphson method to solve an AC power flow problem with the presence of a DC link and a tyristor controlled series capacitors (TCSC). A DC link provides an economical way to interconnect areas with long-distance separation or those with different frequencies or incompatible frequency control. A TCSC, a series capacitor bank shunted by a thyristor-controlled reactor, provides fast and reliable power flow control. The presence of a DC link and a TCSC introduces complexity in power flow calculation. It is therefore proposed in this paper the unified Newton-Raphson technique for solving the AC part, the DC part and the TCSC part simultaneously. The methodology is demonstrated by a modified IEEE 14-bus power system with result and discussion.