etc gdpr 01a power system design
TRANSCRIPT
-
7/31/2019 ETC GDPR 01a Power System Design
1/32
-
7/31/2019 ETC GDPR 01a Power System Design
2/32
2
TOPIC OBJECTIVES
Better understanding of:
why and how the Power system design have influence on the securityof the system
possible causes of faults on lines, transformers, busbars or equipmentin switchyards
switchgear arrangements - maintainability and reliability
hardware and software of fault clearance and control system
specifics about Electric Power System of Nigeria
-
7/31/2019 ETC GDPR 01a Power System Design
3/32
-
7/31/2019 ETC GDPR 01a Power System Design
4/32
4
Transmission lines design
Voltage level
Overhead line or cable Single or double circuit
Insulator chain design
Towers design
Shield wires
Tower footing earthing
Conductor thermal capability
-
7/31/2019 ETC GDPR 01a Power System Design
5/32
5
Faults on transmission line possible causes
Lightning
Switching
Pollution
Salt storms
Growing trees
Bush fires Damage or sabotage
The most often!
-
7/31/2019 ETC GDPR 01a Power System Design
6/32
6
Power transformers design
Voltage level Insulation level
kV kV0.4 0.42
0.415
1
6 7.2
10 12
11 12
15 15.75
20 24
33 36
35 38
66 72
110 123
132 145
220 245
330 362
400 420
750
1000
EHV
Group
LV
MV
HV
Purpose and capacity
Step up or step down, ratio
Insulation levels
Neutral point earthing
Tap changing (off/on load)
Dry or oil immersed
Cooling system
Single phase or three phase
Two/three windings or autotransformer
Efficiency (loses)
Impedance
Vector group
-
7/31/2019 ETC GDPR 01a Power System Design
7/32
7
Power transformers vector groups
N
A
B
C
a
b
c
YNd11
N
A
B
C
ma
mb
mc
b
c
a
YaNd11
ZNyn1NA
B
C
a
b
c
n
EARTHING TRANSFORMER
POWER TRANSFORMER 132/33 KV INTERCONECTION AUTOTRANSFORMER330/132 KV
TERTIARY WINDING
-
7/31/2019 ETC GDPR 01a Power System Design
8/32
8
Power transformer faults possible causes:
Deterioration and ageing of insulation
Mechanical damage of insulation Damage of conductor, poor contact in joints
Tap-changer, wear, mechanical failure
Tap-changer switching during overcurrent condition
Transient overvoltage , e.g. at lightning or switching
Contaminated oil Corona discharge
Mechanical forces on windings and bushings
Heavy current during external faults, switching-in, or at resonance
Overheating
High load current or circulation current between parallel transformers Reduced or lost cooling, sustained through-fault current
Overexcitation or voltage rise with transformer core saturation
-
7/31/2019 ETC GDPR 01a Power System Design
9/32
9
Power transformer faults
IEEE statistics about transformer faults
Earth fault
Short circuit Turn-to turn fault
Flash over from HV to LV winding
Core fault
Tank fault
External fault
-
7/31/2019 ETC GDPR 01a Power System Design
10/32
10
Switchyard design
In many cases there is a tendency to have richly equippedswitchyards.
The reason for this is often to have high dependability for the
fault clearance, have a high probability of fault disconnection.
We have to keep in mind that more equipment we have , thehigher probability for faults in the equipment we get!
-
7/31/2019 ETC GDPR 01a Power System Design
11/32
11
Switchyard design: HV equipment
Busbar conductors and drop off connections, fittings
Isolators/disconnectors
Circuit breakers
Current transformers
Voltage transformers
Surge arrestors Earthing switches
Line (wave) traps
The most important is typeof switchgear arrangement
and the placement of HVequipment
-
7/31/2019 ETC GDPR 01a Power System Design
12/32
12
Switchyard design:Single breaker - single busbar
Cheap, simple, in distribution sector
-
7/31/2019 ETC GDPR 01a Power System Design
13/32
13
For more feeders and incomers
Bus section
Switchyard design:Single busbar with bus section
-
7/31/2019 ETC GDPR 01a Power System Design
14/32
14
No feeder outage during maintenance of CB
Switching logic of tripping to Line CB or Transfer bay CB
Transfer bus
Transfer bay
Switchyard design:Single busbar with transfer bay
-
7/31/2019 ETC GDPR 01a Power System Design
15/32
15
Switchyard design: Double busbar
The most common arrangement
Bus coupler
-
7/31/2019 ETC GDPR 01a Power System Design
16/32
16
SWITCHGEAR ARRANGEMENTS: Breaker and a half
For two lines Three breakers =3/2 = 1 1/2
-
7/31/2019 ETC GDPR 01a Power System Design
17/32
-
7/31/2019 ETC GDPR 01a Power System Design
18/32
18
Single busbar +
Reserve busbar
13%
Single busbar
27%
Double busbar
42%
Poligone (ring)
busbar
1%Double busbar with
2 breakers
2%
Double busbar with
1.5 breaker
4%
Triple busbar
4%
Double busbar +
Reserve busbar
7%
SWITCHGEAR ARRANGEMENTS
CIGRE statistics about applied switchgear arrangements
-
7/31/2019 ETC GDPR 01a Power System Design
19/32
19
SWITCHGEAR ARRANGEMENTS: Busbar faults
Fault causeType and number of faults
Total %PE PPE 3P Unknown
Flash over on busbar insulators 20 6 1 27 21%
Circuit Breaker failure 16 2 2 20 16%
Insulation on switching devices 19 2 1 22 17%
Other on insulation 4 1 4 9 7%
Current transformers 3 3 2%
Disconnector opening on load 8 1 6 15 12%
Not removed temporary earthing 6 1 8 15 12%
Contacts (birds and other) 9 1 2 1 13 10%
Misc. and unknown 2 1 1 1 5 4%Total 87 15 24 3 129
% 67% 12% 19% 2%100%
CIGRE statistics for 400 kV busbars 91-96.
-
7/31/2019 ETC GDPR 01a Power System Design
20/32
20
PROTECTION
EQUIPMENT
TRIP
COIL
TELE
COM
DC SYSTEM
FAULT
VOLTAGE
TRANSFORMER
CURRENT
TRANSFORMER
CIRCUIT BREAKER
FAULT CLEARANCE SYSTEM
-
7/31/2019 ETC GDPR 01a Power System Design
21/32
21
PROTECTION
EQUIPMENT
TRIP
COIL
TELE
COM
DC SYSTEM
FAULT
VOLTAGE
TRANSFORMER
CURRENTTRANSFORMER
CIRCUIT BREAKER
FAULT CLEARANCE SYSTEM
HARDWARE DC supply system Current transformers Voltage transformers Protective relays Switching devices Telecommunication equipment Wiring
SOFTWARE
Design Construction (installation) Configuration of the protection relays Setting of the protection relays Maintenance
-
7/31/2019 ETC GDPR 01a Power System Design
22/32
22
CONTROL SYSTEM
Control commands(open, close, raise, lower )
Indications(position, status )
Alarms (protection trips, alerts, warnings)
Metering(current, voltage, power, temperature )
Synchro-check
OLTCvoltage control
Katampe 330/132 kV s/sCONTROL BOARD
-
7/31/2019 ETC GDPR 01a Power System Design
23/32
23
Specific characteristics of Power system of Nigeria
Still in development
Waste area with very different population density and consumption
Still unable to supply the nations demand for electricity needs to build new
generating plants and rehabilitate existing but not operational capacities
Hydro generation in middle belt (Kainji, Jebba and Shiroro)
Thermal generation on south (Egbin, Sapele, Afam, Delta)
Total energy loses are still very high (about 30 %) Long lines needs to build new substations
Radial lines needs to build new lines to close the loops
Parallel SC lines, double circuits lines
Low reliability of plants due to insufficient maintenance
Low security and transient instability
Persistent and frequent black-outs
Deregulation and privatization in power sector goes very slow
-
7/31/2019 ETC GDPR 01a Power System Design
24/32
-
7/31/2019 ETC GDPR 01a Power System Design
25/32
25
KAINJI HPP
JEBBA HPP
JEBBA SHIRORO HPP
OSHOGBOKATAMPE
KADUNAKANO
JOS
GOMBEBIRNIN KEBBI
157 km 3 x SC
5,6 km DC
AIYEDE
IKEJA WEST
EGBIN TPP
251 km SC
280 km DC
62 km DC
119 km SC
137 km
2 x SC
BENIN
AJAOKUTA
195 km 2 X SC
SAPELE TPP
AKANGBA
AJA
50 km DC
ONITSHA NEW HAVEN
ALAOJI
25 km DC
AFAMALADJA
DELTA IV TPP
G
G
81km 2XSC
310 km SC
244 km 2XSC
G
230 km SC
197 km SC
265 km SC
96 km 2XSC
144 km DC
G
G
G
G
137 km 2 X SC
95 km SC
138 km
SC175 km
SC
107 km
17 km
63 km
5 x 90 MVA
2 x 150
MVA
4 x 150
MVA
2 x 150 MVA
G
6 x 220 MW
60 MVA
90 MVA150 MVA
90 MVA
2X60 MVA
2 x 90
MVA
2 x 150
MVA
2 x 150
MVA
2 x 150MVA
2 x 150
MVA
2x150 MVA
4 x 150 MW
4 x 200 MVA
2x 120 MW
2 x 100 MW
4 x 80 MW
6 x 90 MW
2 x 150
MVA
6 x 120 MW
4 x 71.25 MW
6 x 140 MVA
2 x 168.5 MVA
3 x 50
MVA
2 x 150
MVA
2 x 150
MVA
2 x 90
MVA
150 MVA
90 MVA
60 MVA
17 km DC
16 km DC
256 km SC
330 kV Transmission Power Network of Nigeria
-
7/31/2019 ETC GDPR 01a Power System Design
26/32
26
Historical growth of NEPA generation
Not suppressed power demand is 12,000 MW (unofficially)
-
7/31/2019 ETC GDPR 01a Power System Design
27/32
27
Generated energy in NEPA Power plants
-
7/31/2019 ETC GDPR 01a Power System Design
28/32
28
Status of NEPA Hydro power plant (2004)
89 %
-
7/31/2019 ETC GDPR 01a Power System Design
29/32
29
Status of NEPA Thermal power plant (2004)
-
7/31/2019 ETC GDPR 01a Power System Design
30/32
30
Status of NEPA Thermal power plant (2004)
-
7/31/2019 ETC GDPR 01a Power System Design
31/32
-
7/31/2019 ETC GDPR 01a Power System Design
32/32
32
New power plants up to 2007
Okpai Power Project(Agip) 450 MW
Afam VI (Shell) 700 MW
Geregu (Siemens) 414 MW
Papalanto (Chinese Gov.) 335 MW
Omotosho (Chinese Gov.) 335 MW
Alaoji 400 MW Shell PDC Afam 700 MW
3334 MW
By Plan in 2007
8500 MWIn total will be connected on network