Download Temperatures

Transformer Asset
Management
Selwyn Braver
Dynamic Ratings Pty Ltd
Melbourne, Australia
August 10, 2017
Changing
Environment
• Utilities have entered an era where cost and
competitiveness are business drivers
• The capacity in existing assets must be
driven harder than in the past without loss of
customer service or reliability
• Networks have expanded and become more
difficult to operate
• Asset Managers, Planners, Operators and
Maintenance staff need better tools management based on facts, not
assumptions
August 10, 2017
Justification for
Online Control &
Monitoring
• Increase the availability and capacity of
power transformers
• Redirection of time and/or operational
based maintenance to condition based
maintenance
• Asset and life management
• Failure cause analysis
August 10, 2017
Equipment
Categories: Gauges
• Temperatures
August 10, 2017
TMS TEMPERATURE
MONITOR
VS
CONVENTIONAL WTI OTI
August 10, 2017
• Temperatures
Transformer
Management System
(TMS)
• Cooling System
• LTC Monitoring/Control
• Load Monitoring
• Connection to other
IEDs
August 10, 2017
Evolution of
Transformer Controls
Control House
Control
Alarms
Temp
Temp
Expert
Software
Protocol
Converters
Oil
Level
LTC
Control
LTC
Paralleling
Communications
Sudden
Pressure
August 10, 2017
Data
Logging
Event
Recording
Condition Monitoring
LTC
Monitoring
DGA
Moisture
Direct
Winding
Temp
Other
Monitoring
Input
Overview of TMS
• Integrated microprocessor-based system
with:
– Dynamic Rating - real time thermal limit predictive
loading capacity-real time aging
– Monitoring -data acquisition & storage of all data for
the entire transformer
• Operating data: volts, amps, watts, vars, tap position,
temperatures - ambient, oil and winding hot spot, etc
• Condition monitoring probes - DGA, water in oil, bushing and
OLTC condition
– Control –Voltage(OLTC) and Cooling
– Communication –Web server(at sub or LAN / WAN),
IU, SCADA, modem, TCP/IP, DNP 3.0, Modbus
August 10, 2017
Converting Data into
Information
Dynamic Transformer Rating
60
50
40
30
Thermal Model
Ambient
Top Oil Temp
Cooling System Health
August 10, 2017
2 Hr Overload
FA
FA
OA
Tuned to this specific S/N Transformer
Actual Ambient
Starting Top Oil Temp
Fans/pumps/breakers/contactors
August 10, 2017
What is Dynamic
Rating?
• Real-time on-line calculation of loadability
• Based on thermal model (modified IEC /
IEEE) Guide for Loading Mineral-OilImmersed Transformers IEEE C57.91,IEC354
• Transformer thermal parameters from design
or test
• Retrofits, thermal model from recorded site
data and mathematical modeling
• Uses measured ambient & top oil
temperatures, tap position & load current
• Can typically enable 20% increased loading
August 10, 2017
with reduced risk and number of outages
Collecting the Data
• Data typically collected
– Top Oil Temp
– Winding Hot Spot (if fibre probes)
– Load
• Amps per phase
• Voltage
– Ambient Temperature
– Cooling Status
•
•
•
•
Operating Status
Amp Draw
Contactor Operation
Control Switch Positions
– Alarm Contacts & Ancillaries
•
•
•
•
Sudden Pressure
Pressure Relief
Main Tank Oil Level
Nitrogen Pressure
August 10, 2017
– LTC (OLTC)
•
•
•
•
•
•
•
Position
Temperature
LTC Motor Current
Oil Level
Sudden Pressure
Vacuum Bottle Fail
Filter clogged/excessive pressure
The following if equipment fitted
– DGA
– Dissolved Moisture, MIO
– Direct Winding Temperatures
– Bushing PF
– Partial Discharge
Converting Data into
Information
• Information typically calculated/determined
–
–
Winding Hot Spot (for all windings)
Forecasted Temperatures
•
•
–
–
–
–
Max Load
Max Time
“What If”
Amps*
Voltage*
Watts
Vars
Cooling Status
•
•
•
•
Cooling Efficiency Problem
Fan or Pump Fail
Contactor Fail
Control Switch Not In Auto
August 10, 2017
Oil Leak
Nitrogen Leak
LTC (OLTC)
•
•
•
•
•
•
•
•
Load
•
•
•
•
Alarm Contacts & Ancillaries
•
•
Insulation Loss of Life
Dynamic Rating
•
•
•
–
Ultimate WHS
Ultimate Top Oil Temp
–
Time Since Last Through Neutral
LTC Delta T
LTC Counter Total
LTC Counter Per Tap Position
LTC Contact Wear (I Squared)
LTC Drive System Fail
Oil Leak
Filter clogged/excessive pressure
–
Internal Transformer
Problem/Threshold monitoring
•
•
•
•
•
DGA
Dissolved Moisture, MIO
Direct Winding Temperatures
Bushing PF
Partial Discharge
Insulation Aging Rate
IEEE vs IEC Age Rate
100000
10000
1000
Age Rate (pu)
100
10
1
0
20
40
60
80
100
120
140
160
180
0.1
0.01
0.001
0.0001
August 10, 2017
WHS
IEEE
IEC
200
Cooling System
Features
• Cooling Control
- dynamic predictive control of the operation of fans and
pumps
• Cooling System Monitoring
– Continuously confirms operation of each fan and
pump.
• Cooling System Exercise
– Exercises cooling system and checks the operation of
fans & pumps.
• Run Hour Meter for Each Cooling Stage
– Ensures equal mechanical wear on all fans/pumps.
August 10, 2017
Voltage Control
Modes
•
•
•
•
•
•
Independent
Master Follower-(fibre optic comms)*
Circulating Current-(fibre optic comms)*
VAr Sharing
Reverse Reactance
SCADA control and SCADA set points
*between transformers/DRMCCs
August 10, 2017
Gathering Downstream Data,
Storage, Interpretation &
Communication
• Condition Monitoring Equipment
-DGA
-MIO
-PD
-Tan Delta
-Fibre optic temperature
Getting the Right
Information to the Right
People
August 10, 2017
SUGGESTED
SCENARIO
Retrofit cubicle
SCADA Control centre
Fibre optic cable and Comms
Utility intranet
Condition sampling device
Transformer
Control room
Management
Environment
August 10, 2017
Substation
August 10, 2017
August 10, 2017
August 10, 2017
Benefits of TMS
• Major cost savings possible by deferring
plant upgrades-achieved using dynamic
rating to work assets harder
• Further large cost savings by reducing risk
and frequency of unplanned outages,
achieved using dynamic rating and condition
monitoring together to avoid plant failures,
expensive repairs, loss of revenue
August 10, 2017
Benefits (cont)
• Longer life of assets, achieved by
reliability centred maintenance based
on condition monitoring
• Reduced maintenance costs, avoiding
unnecessary maintenance inherent in
fixed interval scheduling
• Objective data for planning
• Insurance premium reductions
August 10, 2017