Section VI: Sequence Networks

The sequence circuits developed in the previous sections are combined to form the sequence networks. The sequence networks for the positive, negative and zero sequences are formed separately by combining the sequence circuits of all the individual elements. Certain assumptions are made while forming the sequence networks. These are listed below.

1. Apart from synchronous machines, the network is made of static elements.
   
2. The voltage drop caused by the current in a particular sequence depends only on the impedance of that part of the network.
   
3. The positive and negative sequence impedances are equal for all static circuit components, while the zero sequence component need not be the same as them. Furthermore subtransient positive and negative sequence impedances of a synchronous machine are equal.
   
4. Voltage sources are connected to the positive sequence circuits of the rotating machines.
   
5. No positive or negative sequence current flows between neutral and ground.

Example 7.5