1. DISASTER PREPAREDNESS: A case of Masinga Flooding
Presented by: Charles Ogugo
2017 4th COPI-EH FORUM, KSSC MATENDENI
16thMarch, 2017

2. Presentation Outline Introduction & Background
Flooding: Causes and Effect
Flooding: Improvement works/remedial actions
Recommendation & Conclusion

3. Introduction & Background
Masinga power station has two (2) Kaplan hydro turbine generators rated at 20Mw each.
The station was commissioned in 1981
On 10th April 2013, the station was flooded as a result of entry of storm rain water into the power house, Generator area and Turbine floor
The flooding was culmination of unprecedented torrential rains that lasted a approximately two-hours
Entry of storm water into the power house was through holes drilled through the concrete wall for cable entry
Turbine floor area was flooded with storm water getting through cable entry points on the generator floor

4. Introduction & Background Cont.-Photos
Storm water run off upstream of the last culvert to Masinga Power Station
Storm water run off upstream of the last culvert to Masinga Power Station

5. Introduction & Background Cont.-Photos
Signs of erosion after heavy rains. Upstream of the last culvert to Masinga Power Station
Directional indication of surface run off flow. Towards Masinga Power Station main gate

6. Flooding: Causes
Blocked drainage channels along Kaewa-Masinga road. Runoff was not adequately directed through the culverts across the road. Blocked culverts by contractor who laid parallel KITWASCO water line
Depressed drainage capacity of the drainage system around the power station area
Blocked storm drains around the power station area

7. Flooding: Causes, photos
Blocked drainage culverts along Masinga-Kaewa road
Blocked drainage culverts along Masinga-Kaewa road

8. Flooding: Causes, photos Cont…
Blocked drainage culverts along Masinga-Kaewa road. Note the new parallel water line laid by the contractor
Blocked drainage culverts along Masinga-Kaewa road

9. Flooding: Causes, photos Cont…
Blocked drainage culverts along Masinga-Kaewa road. Note deposits of eroded soil

10. Flooding: Effect………… Unit 1:
Loss of generation: The unit was out for hours
Generator and electrical auxiliaries were affected: Cleaning, drying and other restoration works done. Tested and commissioned.
Replacement of turbine bearing oil due to water ingress
Staff costs incurred

11. Flooding: Effect Cont……
Unit 1:
Stator IR Values at 2.5 kV after inspection and cleaning
15 sec
60 sec
3 min
10 min PI
R-YBE
595 MΩ
2.12 GΩ
Y-RBE
610 MΩ
2.26 GΩ
B-YRE
605 MΩ
2.20 GΩ
RYB-E
232 MΩ
820 MΩ
1.94 GΩ
3.98 GΩ
4.85
Stator temp was 30.3 degrees C

12. Flooding: Effect Cont……
Unit 2:
Water ingress in unit 2 was higher than in unit 1
Loss of Generation: The unit was out for hours
Generator initial IR Value was 0 ohms after flooding
Generator was thoroughly cleaned with special quick drying white spirit and dried with hot air blowers.
IR Value measured after above restoration activities was unsatisfactory. The unit was rolled at speed no load condition to aid in further evacuation of any moisture

13. Flooding: Effect Cont……
Unit 2:
Some damage occurred on the stator wedge stoppers at the windings overhang (Insulation had peeled off). This was noticed after the spinning operation
Water ingress occurred in combined and turbine bearing oil. The oil was replaced
Staff costs incurred

14. Flooding: Effect Cont……
Stator IR Values at 2.5 kV after inspection and cleaning with quick drying white spirit cleaning
15 sec
60 sec
3 min
10 min PI
RYB-E
208 MΩ
640 MΩ
1.49 GΩ
Stator temp was 25 degrees C
Stator Final IR Values at 2.5 kV after unit spinning to further evacuate moisture and repair work
15 sec
60 sec
3 min
10 min PI
R-YBE
628 MΩ
2.14 GΩ
Y-RBE
614 MΩ
2.01 GΩ
B-YRE
1.87 GΩ
RYB-E
256 MΩ
737 MΩ
1.61 GΩ
3.88 GΩ
5.30
Stator temp was 26 degrees C

15. Flooding: Drainage System improvement
JOH-KGN JvW-X1
Flooding: Drainage System improvement
Opening up blocked culverts along Kaewa-Masinga road. This was meant to direct flow to the other side of the road.
Re directing surface runoff away from the power station area. Construction of new drainage system
Upgrading existing drainage system to accommodate increased flow
Strengthening the walls of the open drainage channels.
Blocking cable entry points through which storm water accessed the power house

16. Flooding: Drainage System improvement
Storm water flow into the last drainage culvert before Power Station main gate
Storm water flow exit the last drainage culvert before Power Station main gate

17. Flooding: Drainage System improvement
Re directed flow of surface run off in the open chanel after initial construction stages.
Surface run off exit culvert and flows through open chanel after initial construction stages.

18. Flooding: Drainage System improvement
Re directed flow of surface run off along Masinga Kaewa road after the junction to the power station.
New culvert constructed along Masinga-Kaewa road to direct flow across the road. Culver constructed using old penstock pipes from Tana.

19. Flooding: Drainage System improvement, reinforcement.
Due to continued heavy rains and resultant runoff experienced, new open drainage channels could not contain increased flow volume hence damaging the walls.
Gabion boxes (Rheno gabions) were used to reinforce culvert wings and back walls of open channels.

20. Flooding: Drainage System improvement, reinforcement-Photos
Damaged walls of the new open channel before reinforcement with Gabion boxes.
Start of reinforcement works

21. Flooding: Drainage System improvement, reinforcement-Photos Cont…
Allowance for gradual overflow
Reinforced walls of the open channel.
Reinforced walls of the open channel. Note: Allowance for gradual over flow incase of increased volume of surface run off

22. Recommendation & Conclusion
Drainage system around the power station still require further improvement works
Existing old open drainage channels will have to be expanded, stone pitched and reinforced
There was remarked improvement in the flow of storm water runoff along Kaewa-Masinga road
Much of the runoff is currently diverted across the road before getting to the power station area
Other stations can learn from Masinga experience

23. THANK YOU