Section I: ABCD Parameters
Consider the power system shown in Fig. 2.1. In this the sending and receiving end voltages are denoted by VS and VR respectively. Also the currents IS and IR are entering and leaving the network respectively. The sending end voltage and current are then defined in terms of the ABCD parameters as
 |
(2.1) |
 |
(2.2) |
From (2.1) we see that
 |
(2.3) |
This implies that A is the ratio of sending end voltage to the open circuit receiving end voltage. This quantity is dimension less. Similarly,
 Ω |
(2.4) |
i.e., B , given in Ohm, is the ratio of sending end voltage and short circuit receiving end current. In a similar way we can also define
 mho |
(2.5) |
 |
(2.6) |
The parameter D is dimension less.
Fig. 2.1 Two port representation of a transmission network. |
