Computer controlled passive networks for control of power flow on the interconnected grid

Conventional wisdom says that a solid-state AC/DC/AC power conversion system must be used between tie points if systems are nonsynchronized, or if they are synchronized but the angles between the two would allow an unacceptable power flow. This paper shows that interconnecting points of a synchronized system through computer controlled passive networks allows arbitrary power flow control in either direction which can be continuously changed as needed. Network design criteria are developed. A sample case is discussed. The flow diagram of a computer program is presented that gives predetermined power flows in either direction. Only static capacitors and continuously variable inductors are required because a variable inductor plus a static capacitor can be made to represent a variable capacitor. Design criteria for MVAr sized variable inductors utilizing computer controlled variable air gaps are presented. Application of this technology would provide much greater flexibility in load dispatching as well as the optimization of existing transmission lines. It is particularly relevant in an era of deregulation where power sources and transmission systems may be independent.