# 6-Bus System (System III)

I. Introduction:

$$\bullet$$ The network of this test case is shown in the figure given below, where the near-end $$3\phi$$ fault is considered. The generating units are connected to bus-1 and bus-6 through power transformers, while the loads are not shown in the diagram.
$$\bullet$$ This system has same number of directional overcurrent relays (DOCRs) as compared with the first 8-bus test case. This is because the two additional buses are connected to the generating units and then feed the network through two transformers without using DOCRs on that two buses. It is supposed that the generators and transformers will be protected by their own protection systems.
$$\bullet$$ It can be observed from the given primary/backup (P/B) relay pairs that the ($$R_7/R_{13}$$) pair is relaxed.
$$\bullet$$ The CT ratios ($$CTRs$$) are not given, but they are supposed to be similar to that used for the first 8-bus test case and the second 6-bus test case.
$$\bullet$$ Also, the elements specifications are different; as can be seen in Table 1.
$$\bullet$$ The step of variations of $$PS$$ and $$TMS$$ are $$0.25 A$$ and $$0.05$$, respectively.
$$\bullet$$ The $$3\phi$$ short-circuit current for each P/B pair of relays, the side constraints of each variable, and the coordination time interval ($$CTI$$) are given below (click on them for bigger size):

II. Single-Line Diagram:

$$\bullet$$ This single-line diagram was drawn by Ali R. Alroomi in Sept. 2015.

III. Files:

$$\bullet$$ Tables Source Codes (LaTable Format) [Download]

IV. References (Some selected papers that use this system):

[1] Davood Solati Alkaran, et. al., "Overcurrent Relays Coordination in Interconnected Networks Using Accurate Analytical Method and Based on Determination of Fault Critical Point," IEEE Transactions on Power Delivery, vol. 30, no. 2, pp. 870–877, April, 2015.