Reverse Power Protecti**.






1- Protecti** against overspend 32G (# 1).

In case of Turbine Failure, the Turbine is tripped and then the Generator is tripped by operati** of Reverse power Relay to prevent overspending of the Turbine generator unit.

2- Protecti** against generator motoring 32G (#2).

-Generator motoring protecti** is designed for the prime mover or the system, rather than for the generator.

- With steam turbines, Turbines will overheat ** low steam flow, motoring results from a low input To the Ac Generator,

- When This I/P can’t meet all the losses, the deficiency is supplied by absorbing real power from the system.

- since field excitati** should remain the same , the same reactive power would flow as before motoring , thus, ** motoring the real power will be into the generator, while the reactive power may be either flowing out or into the generator

















Setting of Reverse Power Relays
Data for setting calculati**s
-Rated Capacity of Generator -------- 440,000 KVA
-No Load Loss of Generator --------- 1,785 KW
-No Load Loss of Turbine ---------- 1,350 KW
-No Load Loss of TG unit ---------- 3,135 KW
-Permissible Motoring Time ------- 60 Sec.
-Relay C**stant ------------------- 1 P.U. = Generator KVA


Setting Of Reveres Power Relay 32G ( #1 )
1- Reverse Power Trip Level
Trip Level < No load loss of TG unit * 0.3
= 3,135 * 0.3
= 940.5 KW
Pick up = Trip level / relay c**stant
= 941 / 440,000
= 0.0021 P.U.
Setting = - 0.002 P.U. ( 880KW )
2- Reverse Power Trip Delay
Trip Delay < Perm. Motoring time (60 Sec.)
Setting = 50 Cycles (1 Sec.)





Setting Of Reveres Power Relay 32G ( #2 )
1- Reverse Power Trip Level
Trip Level < No load loss of TG unit * 0.5
= 3,135 * 0.5
= 1,568 KW
Pick up = Trip level / relay c**stant
= 1,568 / 440,000
= 0.004 P.U.
Setting = - 0.004 P.U. ( 1,760KW )

2- Reverse Power Trip Delay
Trip Delay < Perm. Motoring time (60 Sec.)
Setting = 750 Cycles (15 Sec