*4.2.1 Simulation results under the normal condition*

In this case, the mechanical power input of the generator within 1–2 seconds differs from 0.6 to 0.7 pu, at the under normal circumstances the observed state is shown in **Figure 10**, and the relay does not trip.

## *4.2.2 Simulation results under the faulty condition*

In this case, the mechanical power input in 2–3 seconds from 0.7 to −0.1 pu. Relay responds to this change after 0.15 second for safe, and the relay is triggered, where the fault occurred at 2 seconds as shown in **Figure 11**. Input Mechanical Power (pu).

The reverse current adjustment knob and the delay time are shown in **Table A2** of the Appendix, and then the trip is confirmed with the minimum reverse current in the range of 2–20%. The trip time delay setting range is 0–20 seconds.

*Telecommunication Systems – Principles and Applications of Wireless-Optical Technologies*

As shown in **Figure 9**, the simulation design uses 200 MVA /11 kV, with a synchronous generator connected to a transmission line 25 kV through an 11/25 transformer, 60 Hz, Load10 MW, and 3 Mvar. Relays are tested in a variety of situa-

tions. The conditions and results of the discussion are as follows.

*Model of a reverse power relay in an electrical power system.*

*(a) Performance of input-output power; and (b) relay status.*

**4.2 Simulation results**

**212**

**Figure 10.**

**Figure 9.**
