1. 660 MW SUPERCRITICAL TURBINE " GOVERNING & PROTECTION SYSTEM"

2. Topics of Presentation
Overview of Turbine
Concept of Governing System
Functioning of EHC Circuits
Turbine Start Up Procedure
TSI & TSC System
Turbine Protection System

3. OVERVIEW OF
TURBINE

4. Turbine Block Diagram

5. Turbine Extractions Ext. No Source Of Extraction
Destination Equipments 1
13th stage of HPT
HPH-8 2
CRH
HPH-7 3
3rd stage of IPT
HPH-6 *
TDBFP 4
6th stage of IPT
DEAERATOR 5
8th stage of IPT
LPH-4 6
11th stage of IPT
LPH-3 7
2nd stage of LPT
LPH-2 8
4th stage of LPT
LPH-1

6. Turbine Components Turbine: HPT, IPT, LPT1 and LPT2
Turbine Bearings: 08
Generator / Exciter Bearings: 04
Turbine Stop Valves: 04 (HPSV-1&2, IPSV-1&2)
Turbine Control Valves: 08 (4 HPCV & 4 IPCV)
CRH Check Valves: 02 ( With Bypass lines for warm up)
Motor driven Shut Off valve in non-stabilized oil line to Check Valve
Motor driven warm up Shut Off valves for HPCV-3 & 4
Governing Box

7. Overview of Governing Box

8. Governing Box Components
Motor operated Control Gear to generate resetting / protection oil & control oil for S.V./ Summators
Two Manual trip devices
Two Over Speed Governor Slide valves (110 % & 111 %)
Two Remote Trip Solenoids
Slide Valve for ATT with two solenoids

9. CONCEPT OF
GOVERNING
SYSTEM

10. Governing System Combination of throttle & nozzle governing
IP Turbine has throttle governing – all four control valves open simultaneously
HP Turbine has nozzle governing – all four control valves open in preset sequence
Resetting of Turbine is done by Control Gear operation
Operation of Stop & Control Valves and CRH Check Valves are done by spring type hydraulic servomotors
Servomotors are closed by spring action during loss of oil pressure

11. Governing System
HPT control valves open only after achieving preset load (12% of 660 MW)
Opening time of control valve is 1.5 sec
Closing time of Stop valve in case of operation of protection is 0.3 sec
Turbine maximum speed is restricted to 108% in case of generator disconnected from grid
Over speed protection system stops steam supply in HPC in < 0.5s
Speed Controller Droop is adjustable from 2.5% to 8% (with dead band of 0.04%)

12. Resetting of Turbine

13. Resetting of Turbine
Stabilized oil pressure of 50 Ksc is supplied to Control Gear
The control gear (AE001) is moved from closed position (0 degree) to open position (90 deg)
Oil is first supplied to reset the over speed governor slide valves
Subsequently Protection Oil is generated and supplied to protection devices
Finally, Control Oil for Stop Valves servomotors & Control Oil for EHC-summators are generated

14. Operation of Stop Valve

15. Operation of Stop & Control Valves
Control Oil pressure in S.V. servomotor moves up slide valve, providing Header Pressure Oil under the piston for S.V. opening
Header Pressure Oil is supplied to C.V. valve servomotors via locking pilot valve & traction/bush arrangements. Opening of C.V. is governed by Control Oil from EHC-Summator
During loss of Header Pressure Oil, the servomotors are closed by spring action
During loss of Control Oil pressure, Bush & Traction of Pilot valve travels up shutting off head pressure oil supply to C.V. servomotors, resulting control valve closing
During S.V. ATT, bush & Traction do not travel up due to slide valve downward movement by ATT motor

16. Components of EHC 1. Speed Controller 2. Pressure Controller
EHC comprises of following controllers:
1. Speed Controller
2. Pressure Controller
3. Load Controller
4. Position Controller

17. Interesting, right?
This is just a sneak preview of the full presentation. We hope you like it! To see the rest of it, just click here to view it in full on PowerShow.com. Then, if you’d like, you can also log in to PowerShow.com to download the entire presentation for free.