Overview and Applications
SIPROTEC 5
7UT8x
© Siemens AG 2013 All rights reserved. Answers for infrastructure and cities.
SIPROTEC 5
Transformer differential protection devices
Two winding transformers 7UT82
(2 sides, 2 measuring points)
non expandable HW
ƒ 1 differential protection for standard
and auto transformers
ƒ 2 restricted earth fault protections
ƒ Number of measuring points (MP)
ƒ 2 three phase current MPs
ƒ 2 single phase current MPs
ƒ 1/3 Device with IO103
© Siemens AG 2012. All rights reserved.
Page 2 Energy Automation Sector Infrastructure & Cities
SIPROTEC 5
Transformer differential protection devices
Two winding transformers 7UT85
(2 sides, 4 measuring points)
expandable
ƒ 1 differential protection for standard
and auto transformers
ƒ 2 restricted earth fault protections
ƒ Number of measuring points (MP)
ƒ 4 three phase current MPs
ƒ 3 single phase current MPs
ƒ 2 three phase voltage MPs
© Siemens AG 2012. All rights reserved.
Page 3 Energy Automation Sector Infrastructure & Cities
SIPROTEC 5
Transformer differential protection devices
Three winding transformers 7UT86
(3 sides, 6 measuring points)
expandable
ƒ 1 differential protection for standard
and 2 for autotransformers
ƒ 3 restricted earth fault protections
ƒ Number of measuring points (MP)
ƒ 6 three phase current MPs
ƒ 4 single phase current MPs
ƒ 3 three phase voltage MPs
© Siemens AG 2012. All rights reserved.
Page 4 Energy Automation Sector Infrastructure & Cities
SIPROTEC 5
Transformer differential protection devices
Multiple winding transformers 7UT87
(7 sides, 9 measuring points)
ƒ Multiple winding differential protection
expandable
ƒ 3 differential protections for standard and
autotransformers
ƒ 5 restricted earth fault protections
ƒ Number of measuring points (MP)
ƒ 9 three phase current MPs
ƒ 5 single phase current MPs
ƒ 3 three phase voltage MPs
© Siemens AG 2012. All rights reserved.
Page 5 Energy Automation Sector Infrastructure & Cities
SIPROTEC 5
Transformer differential protection devices
Protection functions
7UT8x
ƒ Transformer Differential protection
ƒ Restraint characteristic and fast trip stage
ƒ Flexible vector group adaptation
ƒ Inrush and over excitation detection
ƒ CT saturation detection
ƒ Motor differential protection
ƒ Restricted earth fault protection
ƒ Thermal overload protection
ƒ Sensitive E/F protection
© Siemens AG 2012. All rights reserved.
Page 6 Energy Automation Sector Infrastructure & Cities
SIPROTEC 5
Transformer differential protection devices
Protection functions
7UT8x
ƒ Directional O/C protection
ƒ Voltage and frequency protection
ƒ Distance protection
ƒ Tap changer
ƒ Voltage regulator
ƒ Adaptive differential protection (considering the tap position)
ƒ Line Differential protection (together with 7SD8, 7SL8, 7UT8)
© Siemens AG 2012. All rights reserved.
Page 7 Energy Automation Sector Infrastructure & Cities
Integrated Line Differential Protection
7UT
8x
87 T
Protection
interface
87 L
7SD
8x
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Page 8 Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Improved restraint algorithm
ƒ High sensitivity also at low fault currents Idiff IMP1 IMP2
requirement
Customer
ƒ Sensitivity at 1,5 CB application with
small power transformers
trip area
ƒ High stability against external faults
IMP3
ƒ 87T uses the conventional restraint
restraint
Siemens
solution
characteristic with modified settings Idiff> Idiff = |Ρ IMP |
area
ƒ New is the calculation of the restraint Irest = Max {ΗMP|
Irest
current (Maximum of the phase currents)
ƒ 87T restraint characteristic has three ƒ Higher sensitivity in 1,5 CB
straight lines application
ƒ Flexible setting of the characteristic ƒ More stability at signal distortion
functions
Benefits
Device
(e.g. CT saturation)
ƒ Increased system availability
⇓ Increased system availability
© Siemens AG 2012. All rights reserved.
Page 9 date Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Improved Idiff- fast stage
ƒ Short tripping time at high internal fault IMP1 IMP2
requirement
Idiff
Customer
currents
ƒ Robust at CT saturation (internal faults) trip area
ƒ Stable at external faults in 1,5 CB appl. Idiff>>
k=0,8 IMP3
ƒ 87T fast stage evaluates instantaneous
values of the differential current i(t)diff = |Ρ iMP(t) |
Siemens
solution
ƒ New: Fast differentiation between i(t)rest = Max {iMP(t)|
internal and external fault based on few Irest
idiff, irest trajectory
samples (proven busbar prot. method) evaluation
ƒ 87T fast stage in addition to the ƒ Fast tripping time at internal faults
standard restraint characteristic also at saturated currents
ƒ Adaptive algorithm for differential ƒ Stable at heavy external faults with
functions
Benefits
Device
current evaluation: first instantaneous CT saturation (transverse currents
values and after 1 cycle filtered values in 1,5 CB application)
⇓ Increased system availability
© Siemens AG 2012. All rights reserved.
Page 10 date Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Improved inrush stabilization
ƒ Stable at inrush currents (switching ON
requirement
Customer
of a transformer)
ƒ Stable at sympathetic inrush currents
(switching ON of a parallel transformer) IMP1 IMP2
Method 1: I2,Harm/I1,Harm > 15%
ƒ Inrush detection function blocks the Method 2: CWA ⇓ Flat area evaluation
Siemens
solution
differential protection
ƒ New is the one out of two decision of
two different inrush algorithms
ƒ Inrush detection function with two ƒ Avoiding of false trip in the case of
different measuring principles an inrush or sympathetic inrush
ƒ Second harmonic evaluation with ƒ Increased system availability
functions
Benefits
Device
the cross block option
ƒ Curve waveform analysis (CWA)
ƒ At high VTR blocking of the differential
protection with the 5th harm. current
⇓ Increased stability at inrush currents
© Siemens AG 2012. All rights reserved.
Page 11 date Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Faster detection of external faults
ƒ Protection must be stable at external Idiff
requirement
Customer
faults with CT saturation
ƒ CT requirements regarding transient CT = ?
trip area
performance must be as low as possible
IMP1 IMP2
ƒ New algorithm based on instantaneous
Siemens
solution
values detects very fast external faults Idiff> Add-on Stabilization
ƒ Missing samples due to saturation are
Irest
predicted via an estimation method
ƒ Add-on stabilization characteristic for ƒ Stable at external faults with CT
external fault detection with CT saturation
saturation ƒ Lower CT requirements
functions
Benefits
Device
ƒ Handling of evolving faults (if after an ƒ Secure handling of evolving faults
external fault an internal occurs) ƒ Increased system availability
ƒ Reduced transient dimensioning factor
(Ktd = 2; SIP4-factor was 3
⇓ Cost reduction through lower CT requirements
© Siemens AG 2012. All rights reserved.
Page 12 date Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Wide range of CT mismatching
ƒ Using of protection on 3-wind. with a low
requirement
Customer
power tertiary winding or 2- wind. transf.
with high ISC on the busbar
ƒ Matching transformers must be avoided I CT
< 10
I OBJECT
ƒ High resolution of the measured phase
Siemens
solution
currents via 24 ADC
ƒ Each measured current can be adapted
ICT
to a reference current < 0,104
I OBJECT
ƒ No limitation regarding CT mismatching ƒ Improved transient CT
performance via lower burden
⇓ No matching transformer
functions
Benefits
Device
ƒ Flexible applications
⇓ Increased application flexibility
© Siemens AG 2012. All rights reserved.
Page 13 date Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Two winding transformer
Requirement
ƒ Two winding transformer differential protection
ƒ additional functions
ƒ Protection with one device only
ƒ Flexible hardware and communication
Solution
ƒ Transformer differential device 7UT85
ƒ Standard hardware (base module)
ƒ Application template: Two winding basic
ƒ Communication modules
Benefit
ƒ One device for different applications, easy adaptation
ƒ Simplified engineering, reduced wiring, shorter
commissioning
© Siemens AG 2012. All rights reserved.
Page 14 Energy Automation Sector Infrastructure & Cities
Application template:
Two winding transformer basic
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Page 15 Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Two winding transformer and REF
Requirement
ƒ Two winding transformer differential protection
ƒ additional functions
ƒ High sensitivity at 1-phase ground faults
ƒ Protection with one device only
Solution
ƒ Transformer differential device 7UT85
ƒ Functions 87T and 87T N
ƒ Standard hardware (base module)
ƒ Application template: Two winding with REF
Benefit
ƒ One device for different applications, easy adaptation
ƒ Simplified engineering, reduced wiring, shorter
commissioning
© Siemens AG 2012. All rights reserved.
Page 16 Energy Automation Sector Infrastructure & Cities
Application template:
Two winding transformer with REF
© Siemens AG 2012. All rights reserved.
Page 17 Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Two winding transformer in 1.5 CB
Requirement
ƒ Two winding transformer differential
protection in 1.5 CB application
ƒ High sensitivity at 1-phase ground faults
ƒ Protection with one device only
Solution
ƒ Transformer differential device 7UT85
ƒ Functions 87T and 87T N
ƒ Standard hardware (base + expansion
module)
ƒ Application template: Two winding for 1,5
CB application
Benefit
ƒ One device for different applications, easy adaptation
ƒ Simplified engineering, reduced wiring, shorter
commissioning
© Siemens AG 2012. All rights reserved.
Page 18 Energy Automation Sector Infrastructure & Cities
Application template:
Two winding transformer 1,5 CB
52 52
B-QA A-QA FG Transformer side 1 FG Circuit breaker A-QA
MP
I-3ph I-3ph 50BF
I-3ph 1
49 87N Ctrl
MP
I-3ph 2 Measured values
BI
CB
BO
FG Transf. neutral point 1 FG Transformer 1 FG Circuit breaker B-QA
I-1ph I-3ph 50BF
MP
50N 51N 87 Ctrl
I-1ph 1
Measured values
BI
CB
BO
FG Transformer side 2 FG Circuit breaker C-QA
MP
I-3ph I-3ph 50BF
I-3ph 3
50 51 Ctrl
52 C-QA Measured values
BI
CB
BO
© Siemens AG 2012. All rights reserved.
Page 19 Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Three winding transformer
Requirement
ƒ Three winding differential protection for different
vector groups
ƒ Protection with one device only
ƒ Flexible hardware and communication
Solution
ƒ Transformer differential device 7UT86
ƒ Standard hardware (base + expansion module)
ƒ Application template: Three winding basic
Benefit
ƒ One device for different applications, easy adaptation
ƒ Simplified engineering, reduced wiring, shorter
commissioning
© Siemens AG 2012. All rights reserved.
Energy Automation Sector Infrastructure & Cities
Transformer differential protection 7UT8
Three winding transformer in 1,5 CB
Requirement
ƒ Three winding differential protection for 1,5 CB
application
ƒ High sensitivity at 1-phase ground faults
ƒ Protection with one device only
ƒ Flexible hardware and communication
Solution
ƒ Transformer differential device 7UT86
ƒ Standard hardware (base + expansion module)
ƒ Application template: Three winding for 1,5 CB
application
Benefit
ƒ One device for different applications, easy adaptation
ƒ Simplified engineering, reduced wiring, shorter
commissioning
© Siemens AG 2012. All rights reserved.
Energy Automation Sector Infrastructure & Cities
7UT86- Application template
Three winding transformer for 1,5 CB application
52 52
B-QA A-QA FG Transformer side 1
MP
I-3ph
I-3ph 1 FG Circuit breaker A-QA
49 87NT
MP I-3ph 50BF
I-3ph 2
V-3ph 59 81 Ctrl
MP
Measured values
V-3ph 1 BI
CB
BO
FG Transf. neutral point 1 FG Circuit breaker B-QA
MP
I-1ph I-3ph 50BF
I-1ph 1
50N 51N Ctrl
Measured values
BI
CB
BO
FG Transformer side 2 FG Transformer 1 FG Circuit breaker C-QA
MP
I-3ph I-3ph 50BF
I-3ph 3
Ctrl
87T
Measured values
BI
CB
BO
FG Transformer side 3 FG Circuit breaker D-QA
MP
I-3ph I-3ph 50BF
I-3ph 4
Ctrl
52 52
Measured values
D-QA C-QA BI
CB
BO
© Siemens AG 2012. All rights reserved.
Page 22 Energy Automation Sector Infrastructure & Cities