TransformersHansDeKeulenaer

Report
Energy Saving Opportunities for
Transformers
Hans De Keulenaer
Outokumpu Tara Mines
Energy Efficient Motors & Transformers Workshop
May 7, 2002
Content
•
•
•
•
•
Introduction
Technical issues & standards
Economic equations
Ecological equations
The business case for high efficiency
transformers
• Conclusion
15-May-02
2
Why transformer efficiency is an
issue?
• All electricity passes through several stages of
transformation
• Savings potential of 22 TWh / year for EU
• Technology exists
• Economic potential
• Many pieces to the sustainable energy puzzle
15-May-02
3
Losses in distribution
transformers
• No load loss, or iron loss (Po)
• Load loss, or copper loss (Pk)
– DC loss
– Extra losses
• eddy current loss in windings
• stray loss
• Other losses (ventilation, …)
15-May-02
4
Losses in distribution
transformers
Extra loss
Load loss
Extra loss due to
harmonics
Resisitive loss
Conventional load
loss excl harmonics
No load loss
Unloaded
15-May-02
Rated load
Actual load
(excl harmonics)
Actual load
(incl harmonics)
5
Iron loss
• Occurs 24 hours / day, 365 days / year
• Example: 1,600 KVA, Po = 2,600 W
– Annually
2,600 W * 8,760 hrs
– 30 yrs
– Emissions (0.4 kg CO2 / kWh)
– 5 c / kWh
15-May-02
= 22.8 MWh / yr
= 684 MWh
= 274 tonnes
= 34,200 €
6
Historical evolution in the
production of magnetic steel
YEAR
(a p p ro x .)
C O R E M A T E R IA L
1895
1910
1950
1960
1965
1970
1975
1980
Iro n w ire
W a rm ro lled F eS i
C o ld ro lled C G O
C o ld ro lled C G O
C o ld ro lled C G O
C o ld ro lled H iB
A m o rp h o u s m eta l
C o ld ro lled C G O
C o ld ro lled H iB
L a ser trea ted H iB
C o ld ro lled C G O
P la sm a trea ted H iB
C h em .E tch ed H iB
1983
1985
1987
1991
15-May-02
T H IC K N E S S
(m m )
0 .3 5
0 .3 5
0 .3
0 .2 7
0 .3
0 .0 3
0 .2 3
0 .2 3
0 .2 3
0 .1 8
0 .2 3
0 .2 3
E P S T E IN V A L U E
(W /k g a t 5 0 H z)
6
2
1
0 .9
0 .8 4
0 .8
0 .2
0 .7 5
0 .7 0
0 .6
0 .6 7
0 .6
0 .6
(1 .0 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .3 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
(1 .5 T )
TYPE
M 6x
M 5x
M 4x
M 0H
M 3x
M 0H
ZDKH
M 2x
P la sm a P J
PDR
7
Evolution of magnetic steel since the
introduction of cold-rolled magnetic steel
15-May-02
8
Copper loss
• Occurs only when transformer is loaded
• Varies quadratically with the load
• Example: 1,600 kVA, Pk = 17 kW, 50% loaded
– Annually
17 kW * 8,760 hrs * 0.5^2
– 30 yrs
– Emissions (0.4 kg CO2 / kWh)
– 5 c / kWh
15-May-02
= 37.2 MWh/yr
= 1.11 GWh
= 444 tonnes
= 55,500 €
9
Loading
• Case 1:
– 30% of time 80% load
– 70% of time 10% load
• Case 2:
– 8 hours @ 80%
– 8 hours @ 40%
– 8 hours @ 10%
15-May-02
10
15-May-02
2 9 /1 0 / 0 1 1 2 :4 5
2 9 /1 0 / 0 1 8 :1 5
2 9 /1 0 / 0 1 3 :4 5
2 8 /1 0 / 0 1 2 3 :1 5
2 8 /1 0 / 0 1 1 8 :4 5
2 8 /1 0 / 0 1 1 4 :1 5
2 8 /1 0 / 0 1 9 :4 5
2 8 /1 0 / 0 1 5 :1 5
2 8 /1 0 / 0 1 1 :4 5
2 7 /1 0 / 0 1 2 1 :1 5
2 7 /1 0 / 0 1 1 6 :4 5
2 7 /1 0 / 0 1 1 2 :1 5
2 7 /1 0 / 0 1 7 :4 5
2 7 /1 0 / 0 1 3 :1 5
2 6 /1 0 / 0 1 2 2 :4 5
2 6 /1 0 / 0 1 1 8 :1 5
2 6 /1 0 / 0 1 1 3 :4 5
2 6 /1 0 / 0 1 9 :1 5
2 6 /1 0 / 0 1 4 :4 5
2 6 /1 0 / 0 1 0 :1 5
2 5 /1 0 / 0 1 1 9 :4 5
2 5 /1 0 / 0 1 1 5 :1 5
2 5 /1 0 / 0 1 1 0 :4 5
2 5 /1 0 / 0 1 6 :1 5
2 5 /1 0 / 0 1 1 :4 5
2 4 /1 0 / 0 1 2 1 :1 5
2 4 /1 0 / 0 1 1 6 :4 5
2 4 /1 0 / 0 1 1 2 :1 5
2 4 /1 0 / 0 1 7 :4 5
2 4 /1 0 / 0 1 3 :1 5
2 3 /1 0 / 0 1 2 2 :4 5
2 3 /1 0 / 0 1 1 8 :1 5
2 3 /1 0 / 0 1 1 3 :4 5
2 3 /1 0 / 0 1 9 :1 5
2 3 /1 0 / 0 1 4 :4 5
2 3 /1 0 / 0 1 0 :1 5
2 2 /1 0 / 0 1 1 9 :4 5
Typical load profile
k W (1 5 a vg )
800
750
700
650
600
550
500
450
400
k W to T 1
350
k W to T 4
300
k W to t
250
200
150
100
50
-5 0
0
11
Results
• Energy transformed:
– 1,600 kVA * 0.5 * 8,760 = 7,008 MWh / year
• Efficiency
–  = 7,008 / (7,008 + 22.8 + 37.2) = 99.2%
• Lifetime cost:
– Transformer:
– Iron loss:
– Copper loss:
–
Total
15-May-02
10,000 €
34,200 €
55,500 €
99,700 €
10%
35%
55%
100%
12
Transformer efficiency
100%
99%
98%
97%
96%
95%
94%
93%
92%
91%
90%
400 kVA,
efficiency
level A-A’
(HD428)
0%
15-May-02
25%
50%
75%
100%
13
Efficiency @ low load
100%
95%
90%
400 kVA,
efficiency
level A-A’
(HD428)
85%
80%
75%
0%
15-May-02
5%
10%
15%
20%
25%
14
Efficiency standards
• Two approaches
– European approach: specify Po and Pk
• CENELEC HD428 (oil)
Po class A’, B’, C’
Pk class A, B, C
(nine combinations)
• CENELEC HD538 (dry) one class for Po, Pk
– US approach: specify efficiency at average load
(typically 35-50%)
15-May-02
15
Distribution transformer
efficiency standards
L oad L osses for D istribution T ransform ers
RATED
O IL -F IL L E D (H D 4 2 8 ) U P T O 2 4 kV
2)
N o-L oad L osses for D istribution T ransform ers
DRY TYPE
2)
DRY TYPE
(H D 5 3 8 )
POW ER
L IS T A
L IS T B
L IS T C
(H D 5 3 8 )
L IS T A ’
1 2 kV
P R IM A R Y
kV A
O IL -F IL L E D (H D 4 2 8 ) U P T O 2 4 kV
L IS T B ’
L IS T C ’
1 2 kV
3)
P R IM A R Y
3)
W
W
W
W
W
W
W
W
50
1 ,1 0 0
1 ,3 5 0
875
N /A
190
145
125
N /A
100
1 ,7 5 0
2 ,1 5 0
1 ,4 7 5
2 ,0 0 0
320
260
210
440
160
2 ,3 5 0
3 ,1 0 0
2 ,0 0 0
2 ,7 0 0
460
375
300
610
250
3 ,2 5 0
4 ,2 0 0
2 ,7 5 0
3 ,5 0 0
650
530
425
820
4 ,6 0 0
6 ,0 0 0
3 ,8 5 0
4 ,9 0 0
930
750
610
1 ,1 5 0
6 ,5 0 0
8 ,4 0 0
5 ,4 0 0
7 ,3 0 0
1 ,3 0 0
1 ,0 3 0
860
1 ,5 0 0
6 ,7 5 0
8 ,7 0 0
5 ,6 0 0
7 ,6 0 0
1 ,2 0 0
940
800
1 ,3 7 0
1000
1 0 ,5 0 0
1 3 ,0 0 0
9 ,5 0 0
1 0 ,0 0 0
1 ,7 0 0
1 ,4 0 0
1 ,1 0 0
2 ,0 0 0
1600
1 7 ,0 0 0
2 0 ,0 0 0
1 4 ,0 0 0
1 4 ,0 0 0
2 ,6 0 0
2 ,2 0 0
1 ,7 0 0
2 ,8 0 0
2500
2 6 ,5 0 0
3 2 ,0 0 0
2 2 ,0 0 0
2 1 ,0 0 0
3 ,8 0 0
3 ,2 0 0
2 ,5 0 0
4 ,3 0 0
400
6 3 0 /4 %
1)
6 3 0 /6 %
Source: CENELEC
15-May-02
16
Extreme cases
High loss >> AA’
15-May-02
Low loss >> CC’
17
Comparison of efficiency at 50% load
99.5%
HD428 BA'
HD428 CC'
NEMA TP1
China S9
HD428 AA'
C-Amorphous
98.5%
15-May-02
Rating (kVA)
20
00
15
00
75
0
63
0
40
0
25
0
16
0
11
2.
5
75
45
15
97.5%
18
Conductor materials
• Cu and Al transformers can be built to comply
to the same performance and quality standard
• Smaller ratings are typically cheaper with Cu
• In general, use of Cu leads to:
– heavier, but more compact windings
– a smaller core
– a smaller, more compact transformer
– a lower noise level
– less oil-content
15-May-02
19
Copper and Aluminium Designs
for the same efficiency
1600 KVA AA' design
130%
130%
120%
120%
Cu design
110%
Al design
100%
Cu-ref = 100
Cu-ref = 100
400 KVA AA' design
90%
Cu design
110%
Al design
100%
90%
cost
total mass
noise
volume
cost
130%
130%
120%
120%
Cu design
110%
Al design
100%
15-May-02
90%
Cu-ref = 100
Cu-ref = 100
noise
volume
1600 KVA CC' design
400 KVA CC' design
cost
total mass
Cu design
110%
Al design
100%
20
90%
total mass
noise
volume
cost
total mass
noise
volume
Dry-type versus oil-filled
transformers
•
•
•
•
•
•
higher initial cost
higher no-load losses
lower load losses
harmonics cause less extra heating and ageing
better fire protection
no oil spilling container
15-May-02
21
Full load losses in a
100kVA C-C’ transformer
9%
12%
Resistance
Magnetic
Eddy Current
79%
Total loss = 1685 W
15-May-02
22
Harmonic profile of a typical
Personal Computer
Desktop System
0.6000
0.5000
Current (A)
0.4000
0.3000
0.2000
0.1000
0.0000
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
Harmonic
15-May-02
23
Full load losses in a
100kVA C-C’ transformer
53%
41%
Resistance
Magnetic
Eddy Current
6%
15-May-02
Total loss = 3245 W
24
Effect of additional losses on
life-time
Working
temp  t 
Pk
 90  1 . 93  173  C
Pf
Life  time  T  2
 t 


 10 
Life  time  T  2
 Pk  P f

 t
Pf


10










 40  2
 8 .3
 0 . 13 years
where T is working temperature at rated fundamental power, Pf,, Pk is the total
power and T is the rated life-time in years
15-May-02
25
/1
0/
23 0 1
/1 2 0
2 3 0 /0 : 3 0
1
/
2 3 1 0 / 2 :0
/1 0 1 0
2 3 0 /0 7 :3
/1 1 1 0
0/
3
24 0 1 :00
/1 1 8
2 4 0 /0 : 3 0
1
/
2 4 1 0 / 0 :0
0
/1
1 0
2 4 0 /0 5 :3
1
/1
1 0
2 4 0 /0 1 : 0
/1 1 1 0
0/
6
25 0 1 :30
/1 2 2
2 5 0 /0 : 0 0
1
/
2 5 1 0 / 3 :3
/1 0 1 0
2 5 0 /0 9 :0
/1 1 1 0
0/
4
26 0 1 :30
2
/1
0
2 6 0 /0 : 0 0
1
/
2 6 1 0 / 1 :3
/1 0 1 0
2 6 0 /0 7 :0
/1 1 1 0
2 6 0 /0 2 : 3
/1 1 1 0
0/
8
27 0 1 :00
/1 2 3
27 0/ :3
/1 0 1 0
2 7 0 /0 5 :0
/1 1 1 0
2 7 0 /0 0 : 3
/1 1 1 0
0/
6
28 0 1 :00
/1 2 1
2 8 0 /0 : 3 0
1
/
2 8 1 0 / 2 :0
/1 0 1 0
2 8 0 /0 7 :3
/1 1 1 0
0/
3
29 0 1 :00
/1 1 8
2 9 0 /0 : 3 0
1
/
2 9 1 0 / 0 :0
0
/1
1 0
2 9 0 /0 5 :3
1
0
/1
0/ 11
0 1 :0
16 0
:3
0
15-May-02
22
Harmonic culture
T H D a n d K -fa c to r (3 0 m in . a ve ra g e )
60
50
40
V1 HD THD SD
30
I1 H D T H D S D
I1 H D K F T D
20
10
0
26
Economic evaluation
• 2 approaches to buy a transformer
– Specify Po and Pk
– Specify A & B factors
Ct = Purchase price + A * Po + B * Pk
(1  i )  1
n
A
i  (1  i )
(1  i )  1
n
B 
15-May-02
i  (1  i )
n
n
With
 C kW h  8760
 I 
 C kW h  8760   l 
 Ir 
2
I = interest rate
n = lifetime
CkWh = cost / KWh
Il/Ir = loading
7%
30 yrs
0.05 c
50%
27
Example
• 1600 KVA, 50% load, oil-cooled:
• (A = 5.4 euro / Watt; B = 1.3 euro / Watt)
– Efficiency
– Purchase
– Load loss
– No load loss
– Total
15-May-02
AA’
9,700 €
22,100 €
(1.3 * 17,000)
14,040 €
(5.4 * 2,600)
45,840 €
CC’
10,300 €
18,200 €
(1.3 * 14,000)
9,180 €
(5.4 * 1,700)
37,680 €
28
A and B values for selected
countries
E u ro / W a tt
A (N L L )
B (L L )
N e th e rla n d s
4 .0
1 .2
G e rm a n y (8 6 ) 4 .0
1 .0
G e rm a n y (9 3 ) 1 1 .3
4 .0
CH
7 .5
1 .9
C h in a
5 .0
0 .7
Sw eden
4 .0
0 .5
15-May-02
29
Lifetime owning cost
400 kVA oil-cooled
35,000
Total owning cost
30,000
25,000
20,000
15,000
10,000
5,000
0
A-A'
A-A'
C-C'
C-C'
A-AMDT
C-AMDT
Design
Total owning cost NL
Total owning cost China
Investment costs
15-May-02
Total owning cost D 86
Total owning cost CH
Total owning cost D 93
Total running cost Sweden
30
Beyond the magic of A & B
A fa c to r
1 4 ,0 0
R e n te p e rce n ta g e
3%
4%
5%
6%
7%
8%
9%
10%
11%
12%
A facto r (eu r o /W ) b ij elektriciteitstarief = 100 E u r o /M W h
1 2 ,0 0
1 0 ,0 0
8 ,0 0
6 ,7 5
6 ,0 0
4 ,0 0
2 ,0 0
0 ,0 0
1
15-May-02
2
3
4
5
6
7
8
9
10
11
ja re n
12
13
14
15
16
17
18
19
20
31
Example - revisited
• 1600 KVA, 50% load, oil-cooled:
– Efficiency
– Purchase
– Load loss
– No load loss
– Result
• Payback
• IRR
15-May-02
AA’
9,700 €
1,850 € / yr
1,140 € / yr
CC’
10,300 €
1,533 € / yr
745 € / yr
10 months
119% @ 30 years
32
Ecological evaluation
• 1600 KVA, 50% load, oil-cooled:
– Efficiency
– Energy
transformed
– No load loss
– Load loss
– Emissions
– Emission savings
15-May-02
AA’
210 GWh
CC’
210 GWh
684 MWh
1,110 MWh
718 tonnes
447 MWh
921 MWh
547 tonnes
171 tonnes
33
Soft benefits
•
•
•
•
•
•
•
Save energy
Save emissions
Noise?
Reduced heating
Improved lifetime
Reliability?
More robust against harmonics
15-May-02
34
What’s the catch?
•
•
•
•
Increased capital outlay
Commercial policy of suppliers
Small amounts
Risk of being a pioneer
15-May-02
35
Energy & emission savings potentials
related to transformers & standby power
R e g io n
E n e rg y sa vin g s
T W h / yr
C O 2 S a vin g s
M illio n to n n e / yr
22
9
T H E R M IE
5
5
ECI
US
45
34
C h in a
47
52
Japan
24
T o ta l
143
EU
C&EE
15-May-02
S o u rce
IIE C
T o p ru n n e r
100
36
More information
• www.efficient-transformers.org
– electronic library
– calculation tools
• K-Factor & Factor K
• Investment evaluation spreadsheet
• www.supertrafo.com
– daily, on-line measurement of energy saving for 4
high efficiency transformers installed in Poland
15-May-02
37
15-May-02
38
15-May-02
39
Super-trafo demonstration
15-May-02
40
Conclusions
• Evaluate transformers for lifetime cost
– oil-cooled
• Buy only CC’ or higher
• Evaluate transformer with 15-20% less loss than CC´
– dry-type
• if you need the advantages
• evaluate transformer with 15% less loss than HD538
• Check harmonic culture
• Consider replacement of veteran transformers
15-May-02
41

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