Technical Requirements for Subsea High Voltage Direct

Transcription

Open Industrial Workshop
Technical Requirements for Subsea High Voltage
Direct Current Connectors
RPSEA Project 12121-6302-01
GE Global Research
Nov 19, 2014
Imagination at work.
Safety Minute
RPSEA Project 12121-6302-01, Subsea DC Connectors
© 2014 General Electric Company - All rights reserved
2
Agenda
Date: November 19, 2014 (Houston)
7:15 – 7:45
Welcome (Coffee and light breakfast)
Qin Chen/Jeff Sullivan (GE) James Pappas (RPSEA)
7:45 – 8:15
Project introduction
Qin Chen (GE)
8:15 – 9:45
Update on preliminary study (UDW requirement, electrical system, connector specs)
Qin Chen (GE)
Xu She (GE)
9:45 – 10:00
10:00 – 11:00
11:00 – 11:30
11:30 – 12:30
12:30 – 13:15
13:15 – 14:15
14:15 – 15:00
Break
Discussion – General needs for subsea processing
Discussion – Electrical systems
Lunch & GE introduction
Discussion – Electrical systems (continued)
Discussion – Connector requirements
Wrap up
All participants
All participants
Jeff Sullivan (GE)
All participants
All participants
All participants
3
Participants
Organization
Name
BP
Michael Scroggins
Chevron
Lyndon Bowen, David Wendt (DORIS)
ExxonMobil
Xiaolei Yin, Kevin Corbett
GE Oil & Gas
Svend Rocke, Aslaug Melbo, Gorm Sande, Jan Erik Elnan-Knutsen
Paul Doucette (GE Corporate)
GE Global
Research
Qin Chen, Jeff Sullivan, Di Zhang
Xu She, Rui Zhou, Joe Suriano, Weijun Yin, Konrad Weeber, Ibrahima
Ndiaye, Liwei Hao, Rob Sellick, Pat Irwin, Gary Yeager, Chris Calebrese
Michael Vanderwerken
NETL
Roy Long, Bill Fincham, Gary Covatch
RPSEA
James Pappas
Shell
David Liney
Statoil
Jeswin Joseph
TOTAL
Khalid Mateen
4
Acknowledgement
The material contained in this presentation is based upon
work supported by the Department of Energy, and RPSEA
under RPSEA Subcontract 12121-6302-01 and DOE Prime
Contract DE-AC-07NT42677
5
Contacts
Principal Investigator:
Qin Chen
GE Global Research
[email protected]
518-387-7960
Project Manager:
Bill Fincham
[email protected]
304-285-4268
Technical Coordinator:
James Pappas
[email protected]
(281) 690-5511
6
Project Introduction
DC for subsea processing:
Drivers for subsea
processing
• New Fields
Gas/ Oil
Power
Control
Chemicals
• Long offsets
• Deeper waters
• Complex reservoir
• Brown fields
• Increased production rates
• Increased recovery
• Removal of topside facilities
• DC for long distance, high
power, …
• Subsea DC connectors
• Subsea – available (AC
connectors)
• DC – available (land-based)
• Subsea + DC – not available
8
70
88 kV 185 m m 2
88 kV 240 m m 2
60
88 kV 300 m m 2
88 kV 400 m m 2
50
Power [MW]
Cable
Transmission capability (MW)
DC for long distance and high power
40
Voltage
limit
30
20
10
0
0
10
20
30
40
Dista nce [m i]
50
60
70
Length of the cable (mile)
Example of AC Power transfer capability vs Distanc
*Cable too long -> most of the AC current needs to charge/discharge cable
capacitor
Two ways to reduce/eliminate transmission loss are:
Additional compensation for reactive power
Make ω0: LF AC or
DC
9
Subsea cable connectors: AC vs. DC
Insulation
AC Insulation
DC Insulation
Field is capacitive graded, i.e.,
determined by dielectric constant,
which for typical ac insulation, is
nearly independent of field &
temperature : 
Field is resistive graded, i.e.,
determined by electric conductivity,
which is strongly (and nonlinearly )
field- & temperature- dependent: (E,T)=
0eT+E
Field distortion by space charge is Space charge (both trapped and mobile
a secondary effect
charges) could significantly alter local
field, and might lead to early insulation
failure
Aging and life data available for
AC insulation, including field
experiences with subsea
installations
Limited aging and life data available for
DC insulation, especially under
influence of subsea conditions; lacking
field data
Electrical stress distribution in
Electrical stress distribution in
connector can be highly sensitive to
connector is insensitive to cable
cable properties
properties
Mechanical challenges
cannot be
overlooked!
10
Types of connectors
Dry Mate Connector (DM)
• Submerged in sea water
• Connected/disconnecte
d at topside
• Typically the split is
made between a barrier
part and a cable
termination part (wall of
the power consumer is
not opened)
Wet mate connector
Wet Mate Connector
(WM)
• Submerged in sea
water,
• Connected/disconnecte
d in a submerged
condition.
Penetrator (PEN)
• Enables HV conductors to pass
through a partition such as a wall
or a tank
• The means of attachment flange
or fixing device, to the partition,
forms part of the penetrator.
• Includes bulkhead mounted
connector assembly
components.
• Includes a cable termination,
attaching the cable to the
penetrator. Connection typically
Example of arrangement
made in a controlled
(with topside VSD):
environment.
PEN
WM
PEN WM
DM
DM
PEN
11
Electric field in wet mate connector – AC vs.
DC
Cable termination
AC
Steel = ground
Oil
DC
Equipotential lines
(denser -> higher
field)
Epoxy
Copper
Cond.
Rubber =
ground
rubber
XLPE
Copper = high voltage
Wet-mate
chamber
AC
Steel = ground
Epoxy
axis
DC
Oil
axis
Copper = high voltage
axis
• Challenge with field control in wet-mate chamber
• Beyond field control -- challenges of contamination, surface discharge,
…
12
Wet-mate chamber configurations
Clean environment
•
Power
conducto
r
•
DC conduction & breakdown are sensitive to
contaminants – cleaner is better
“Zig-zag” path helps prevent DC surface
breakdown
Oil
Ground
Solid
insulation
Oil
Water=Ground
Unmated
Mated
High
voltage
Stab type
•
Power
conducto
r
Rubber
bellow
Easier DC breakdown along straight
interfaces
Oil
Solid
insulation
High
voltage
Water=Ground
Unmated
Mated
Ground
13
Subsea High Voltage Direct Current
Connectors
Project overview:
Major deliverables:
• Objective: develop electrical
prototype mock-up, retire DC +
subsea technical risks
• Phase 1:
• Funding: $2.9 MM (with 20% GE
costshare)
• Phase 2:
 Technical requirements
 Technical gap analysis
• Duration: 06/20/14 to 09/30/16
 Dry-mate (DM) & Wet-mate (WM)
connector electrical design
(tentative 50kV DC)
 Phase 1: 06/14 to 02/15, $800K
 WM electrical prototype mock-up
 Phase 2: 03/15 to 09/16, $2100K
 Ambient condition test results
 Simulated subsea condition test
results
14
Subsea High Voltage Direct Current
Connectors
Past work:
Scope highlight:
•
Electrical focus: (new) DC
electrical + (existing) AC
mechanical
•
•
• RPSEA MSDC project (081212901-01), DC connector task
• 50kVDC WM conceptual design,
basic materials tests
Wet-mate focus:

DC cable termination

Wet-mate chamber
Rating: 50kV/500A DC
Termination
L~2m
D ~ 0.25 m
Wet-mate
chamber
50kV/500A DC WM electrical conceptual design:
compatible with geometry & tooling for MECON
36kV/500A 3-phase AC
15
Team Introduction
GE Global Research
Working Project Group
NAME
Chris Calebrese
Di Zhang
Dong Dong
Gary Yeager
Ibrahima Ndiaye
Jeff Sullivan
Konrad Weeber
Liwei Hao
Michael VanderWerken
Pat Irwin
Phil Cioffi
Qin Chen
Rob Sellick
NAME
Xiaolei Yin (Champion)
David Liney
Edouard Thibaut
Herve DE‐NAUROIS
Khalid MATEEN
Kevin Corbett
Gorm Sande
Svend Rocke
James Pappas ‐ Technical Coordinator
Roy Long
Bill Fincham – Program Manager
Qin Chen – PI
Rui Zhou
Weijun Yin
Xu She
Role
Materials Scientist
Power Electronics Engineer
Chemist
HV Engineer
Manager - Dielectrics Lab
Chief Engineer
HV Engineer
Business Development Manager
HV & VPI Systems Initiatives Leader
Power Electronics Engineer (Mechanical)
Electrical Engineer, PI
Manager - HV lab
Manager - High power conversion systems
lab
Principle Engineer
GE Subsea Systems (in GE Oil and Gas)
NAME
Aslaug Melbo
Gorm Sande
Jan Erik Elnan‐Knutsen
Kristin Elgsaas
Svend Rocke
Role
Engineering Manager
Principle Engineer
Engineering Manager
Senior Product Manager
Chief Consulting Engineer
COMPANY
Exxon Mobil
Shell
TOTAL
TOTAL
TOTAL
Exxon Mobil
GE Subsea Systems
GE Subsea Systems
RPSEA
DOE NETL
DOE NETL
GE Global Research
• University of Connecticut
(subcontractor; team leader: Prof. Yang
Cao)
• Dr. Steven Boggs (technical consultant)
16
Phase I approach
Example of subsea DC electric power system
1.
Technical requirement




2.
Oil & Gas industry application
needs & regulations
Power system design options
(electrical performance, fault
protection, packaging)
Derive connector requirements
Industrial workshop No. 1
Technical gap




Assess state of the art
Estimate development need
Preliminary technical evaluation
Industrial workshop No. 2
Example of subsea AC connectors (GE
MECON)
WM 36kV/500A, 3-phase
DM 36kV/700A
DM 145kV/700A
17
Phase II, stage gate 2-1: design &
construction
Preliminary 50kV/500A DC WM connector design
1. Design
 Electrical design analysis (WM &
DM connectors)
 Assessment of compatibility with
subsea mechanical design
 Qualification test method
 Design test on small coupons and
down-scaled geometries
2. Construction
 To be coordinated by GE Subsea
Systems (AC connector
experiences; established
fabrication methodology; quality
assurance)
Structure of WM connector
Voltage distribution
36kV/500A MECON WM (AC) prototype under assembly
18
Phase II, stage gate 2-2: ambient condition
test
 As-fabricated prototypes

Test system to be assembled

Short term electrical tests (e.g. capacitance &
loss, resistance, hi-pot, partial discharge)

Long term DC electrical test
 Cable loop
 Excessive DC voltage for acceleration
Outline of long term DC test system
 Rated load current & load cycles
 Transient DC waveforms (e.g. polarity
reversal)
 Superimposed impulses
 Detailed test conditions to be designed &
reviewed

Sub-component tests
Example of subcomponent electric measurement
19
Phase II, stage gate 2-3: simulated deep sea
condition test

Simulated subsea conditioning
 WM chamber exposed to high pressure
sea water
 Flushing by processing liquids
 Expose to processing liquids at high
pressure
 Assemble with termination chambers
 In-situ measurement of electrical
parameters

Conditioning process design supported by
materials tests (e.g. diffusion, surface
absorption)

Short term & long term DC electrical test

Sub-component tests
20
Project schedule
Tasks
2014
2015
2016
7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9
Tech. requirement
Collect VOC
Gap analysis
1st design
Design analysis
Modeling study
Revised
design
1st prototype
Construction
2nd
prototype
Materials and simple geometry tests
Dry Test 1st
prototype
Experiment
Dry Test 2nd
prototype
Simulated deep sea test
Project
start
1st open
worksho
p
2nd open
workshop
GO/NO-GO
Prototyping & drytest report out
GO/NO-GO
Project
end
Note: parallel tasks arranged due to shortening of performance period
21
Technical Requirement –
Preliminary Studies
Contents
• Definition of technical requirements
• Subsea processing – needs from the industry
• Subsea DC electrical systems
• Challenges and requirements for DC
connectors
23
Technical requirements for subsea DC
connector
•
•
•
•
•
•
Operational conditions (depth, temperature, etc)
Electrical ratings (focus on DC)
Mechanical ratings
General requirements (life, maintenance-free, etc)
Specific requirements for wet/dry mate connectors and
penetrators
Test requirements (to be finalized in Phase II)
Focus on defining requirements related to DC electrical operation
24
Summary – key connector electrical ratings
Parameter
RPSEA
prototype
Governing factor
Rated voltage
± 50 kV
System power, distance
Rated current
500 A
Overvoltage
2.5 × U0
Cable ground fault, with high
impedance grounding
Short circuit
current
15 × I0 (0.5 sec)
Cable ground fault
DC system short circuit
Protection mechanism
Polarity
reversal
Full reversal in 1
msec
System ground fault
25
Technical requirements - Approach
General requirements
•
•
•
Connectors will
also set
requirements for
system specs
Distance
Power
Depth, etc.
Electrical system
•
•
System topology
Fault analysis
Connector requirements
•
•
Electrical requirements
Non-electrical
requirements
26
Typical subsea processing systems
Boosting
Increase oil recovery and
production rate from maturing
subsea wells
Pump
Separation
Remove water from oil stream
at the seabed – and re-inject
back into reservoir
Pump + Separator
Compression
Drive gas from matured
subsea wells to host
Pump + Separator +
Compressor
27
Power ratings for subsea power systems
System
Max. Power
(kW)
Voltage
(kV)
Current
(A)
Frequency
(Hz)
15
1.2 - 7.2
10
162/3-60
Small pump
1,000
3.6 – 12
100
0 – 60
Large pump
5,000
7.2 – 12
500
0 – 200
Compressor
15,000
7.2 – 12
1900
0 – 400
Transmission
& Distribution
2,500 –
70,000
12 – 145
20 –
2000
0,
162/3/50/60
Control
systems (incl.
all electric)
Data based on existing systems … Future perspectives?
28
Overview of subsea power system
Deployed
Pilot-tested,
not deployed
Higher Power rating
Depth: up to several kms
New system,
similar concept
New concept
Top side
Subsea
M
M
Top side AC
M
M
M
Subsea AC
Subsea AC
Subsea DC
50/60Hz Low frequency
Longer step out
* Data from “2014 subsea electrification survey”
29
Example of subsea AC system
30
Example of subsea DC system
31
Subsea electrical network components
Cable
AC transformer (pressure compensated)
Source: wikipedia
(http://upload.wikimedia.org/wikipedia/commons/3/3c/Wolf
e_Island_Wind_Project_Submarine_Power_Cable.jpg)
DC converter (1 atmosphere)
Cable connectors
145kV AC, single-conductor DM connector
Other components: motors, switches,
…
32
Electrical system analysis for DC connector
requirements
• Focus on generic system, instead of a
specific system with detailed design
• Focus on transmission side – more
challenging for connectors than distribution
side (distribution voltage is lower, and system
protection will be coordinated to meet current
ratings for connectors)
33
Generic models - voltage source system
Centralized source and load
Centralized source and stacked load
Stacked source and centralized load
Stacked source and load
Source controls voltage, load determines current
34
Generic models - current source system
Centralized source and load
Centralized source and stacked load
Stacked source and centralized load
Stacked source and load
Source controls current, load determines voltage
35
DC transmission options for subsea
On shore
Sending end - centralized
or stacked structure
Off shore
Receiving end stacked structure preferred
Stacked subsea receiving end – Rationale:
1. Redundancy leads to higher reliability
2. Smaller packaging size
3. Easier installation and individual module retrieval
High voltage wet
mate DC connector
needed
Source
Load
36
Fault scenarios under investigation
4
2
2
3
1
Voltage source system
Current source system
Transmission side fault scenarios:
1. Cable ground fault
2. DC voltage short circuit fault
3. Ground fault between the stacked modules
4. Fault within the individual modules
37
Studied voltage source DC system
System parameters:
Parameters
Value
DC voltage
150kV (+/-75kV)
Dry mate connector
Load power rating
60MW
Wet mate connector
Step out distance
180km
Source
Load
Generic system architecture under study
•
•
•
Connector locations for illustration only; actual locations depends on
system architecture and mechanical packaging.
Grounding schemes affect fault behavior, only selected cases
presented.
No protection is considered in generic system architecture.
38
Mechanism of over-voltage
Model under study
Overvoltage at ground fault
Vao=2Vdc
Vbo=0
Voltage doubling under worst case system
design
39
Ground fault of the cable
Current: kA
IRE
Time: sec
Wet mate DC connector current (1.4X)
Generic model
Voltage: kV
VC1
Overvoltage due to ground fault
Time: sec
Current path under fault
Wet mate DC connector voltage (~2.1X)
(common mode voltage may see polarity reversal)
*Note: fault response depends on cable impedance
40
Mechanism of over-current
Ifault
L
r
Vdc
Short the capacitance, e.g. cable capacitance
Dynamic response determined by:
⋅
⋅
0
Loop inductance value will affect the transient current
41
Ground fault next to DC connector
Overcurrent due
to ground fault
Current: kA
IRE1
IRE25
Time (sec)
Wet mate DC connector current (5X)
Vin1
Voltage (kV)
Generic model
Vin2 to Vin5
Time (sec)
Differential voltage of connector (1.25X)
*Note: Fault response dependent on cable impedance and receiving module
inductance
42
Ground fault within the module
Current: kA
IRE1
Time: sec
Generic model
Voltage: kV
Vin1
Vin2 to Vin5
Time: sec
Differential voltage of connector (1.4X)
* Note: Fault response dependent on cable impedance and receiving module
inductance
43
Current: kA
Transmission DC short circuit fault
DM connector
overcurrent due
to short circuit
ISE
0.16pu inductance in the source
Time: sec
Dry mate DC connector current (9X):
Break in 5ms: >4x, Break in 50ms: >7x
Generic model
Current: kA
IRE
Time: sec
•
•
Wet mate DC connector current
Short circuit current depends on total inductance in the loop and available breaker technology.
Wet mate connector is very unlikely to experience this current
44
Studied current source DC system
System parameters:
Dry mate connector
Parameters
Value
DC voltage
150kV (+/-75kV)
Load power rating
60MW
Step out distance
180km
Wet mate connector
Generic model (MSDC system)
• Connector locations are for illustration only; actual locations depend on system
architecture and mechanical packaging.
• Grounding schemes will affect the fault behavior, only selected cases are
presented.
45
Ground fault of transmission cable
VPCM
RE1
Polarity reversal
due to ground fault
SE1
RE2
SE2
Source
SE6
VNCM
Load
RE8
Generic model
Common mode voltage of connector
Differential voltage
surge (not concern
for singleconductor
connectors)
Differential mode voltage of connector
(3.5X, voltage reverse)
*Note: Overvoltage highly dependent on receiving module inductance
46
Bypass event of one module
0.7
Icon1-Icon4
ICON (kA)
0.6
0.5
0.4
0.3
0.2
Generic model
1
1.02
1.04
1.06
Time (sec)
1.08
1.1
Wet mate DC connector current (1.7X)
40
Vcon2-Vcon3
VCON (kV)
35
30
25
20
1
1.01
1.02
Time (sec)
1.03
1.04
Differential voltage of DC connector (1.4X)
*Note: Overcurrent dependent on the distribution cable and other impedance.
47
Ground fault within the module
IRE
RE1
I1
SE1
RE2
SE2
Source
Load
SE6
I2
I3
RE8
Generic model
Fault current is highly dependent on the transmission cable
48
Summary – subsea electrification general
needs
• Total system power: 20 - 70 MW (>100 MW future)
• Loads – pumping, boosting, water injection, compression
• Unit load power : up to 5 MW for pumps; up to 15 MW for
compressors
• Distance: up to 400 km (>600 km future)
• Depth: up to 3000 m
49
Summary – need for connectors
Receiving end module
1
2
3
Power
electronics
(from top side)
Transmission cable
Transmission network
4
5
(to loads)
Distribution cable
Distribution network
Location
Type
AC or DC?
Voltage
Current
1
Dry-mate
DC
High
Medium
2
Wet-mate
DC
High
Medium
3
Penetrator
DC
High
Medium
4, 5, … …
(distribution side)
Dry-mate, wetmate, penetrators
DC and AC
Low to
Medium
High (but not
exceeding AC
connectors)
50
Summary – electrical system
• Transmission system rating
– Voltage & current depend on power & distance, cost vs. technical
challenge tradeoff
– Example: 60MW, 180 km  ±75 kV, 400 A (or ± 50kV, 600 A)
• Modularized subsea DC power conversion
– Redundancy -> high reliability
– Smaller packaging (easier cooling, easier deployment, cost)
– Individual retrieval
• Greatest electrical challenge: wet-mate connector at
transmission voltage level
51
Summary – electrical system fault analysis
• Generic voltage-sourced and current-sourced system
models analyzed
• Focus on transmission-side risks, due to high voltages
& stored energy
• Fault response dependent on system design, protection
schemes, & system fault tolerance
• Major impact on connectors:
– Overvoltage
– Short circuit current
– Polarity reversal
52
Summary – key connector electrical ratings
Parameter
RPSEA
prototype
Future need
Governing factors
Rated
voltage
± 50 kV
± 150 kV
Rated
current
500 A
200 – 1000 A
2.5 × U0
Cable ground fault, with
high impedance grounding
15 × I0 (0.5 sec)
Cable ground fault
DC system short circuit
Protection mechanism
Overvoltage 2.5 × U0
Short
circuit
current
15 × I0 (0.5
sec)
Polarity
reversal
Full reversal Full reversal in 1
in 1 msec
msec
System ground fault
53
DC connector technical requirement
Operational requirements (for WM/DM/Penetrator)
No. of connection
Maximum water depth
External temperature range
Internal temperature range
Storage temperature
Service life
Maintenance need
Min. onshore storage time
Min. subsea storage time
No. of water sealing barriers between seawater and
live parts
Electrical Rating (for WM/DM/Penetrator)
Voltage rating (U0)
Current rating (I0)
Maximum transient current
Duration of transient current
Short circuit current
Duration of short circuit current
Overvoltage
Polarity reversal time
Requirements for WM Connectors
No. of matings
Orientation during operation
Tolerence against deposits
Tolerence against contaminations
Tolerence against cleaning
Requirements for DM Connectors
Value
10
3000
-5 to 20
-5 to 60
-25 to 60
25
Maintenance free
1
1
Unit
times
m
deg C
deg C
deg C
years
year
year
2
± 50 – 150 kV
200-1000
2.5*I0 (to be updated)
(to be updated)
15*I0
0.5
2.5x U0
1
kV
A
A
sec
A
sec
kV
msec
50
horizontal, vertical, tilted
calcium deposit, marine growth, debris
sand, silt
acidic cleaning (e.g. citric acid), mechanical brushing
times
Tolerence against harsh offshore environment (e.g. humidity,
salt)
Mating environment
Requirements for Penetrators
Differential pressure rating (ISO 10423 standard)
+/- 10 (with pressure compensation)
Up to 300 (no pressure compensation, depending on water
depth)
bar
54

Technical Requirements for Subsea High Voltage Direct

Transcription

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