Transformer Asset Management Selwyn Braver Dynamic Ratings Pty Ltd Melbourne, Australia April 20, 2017

Overview Equipment Categories Collecting the Data Gauges Electronic Temperature Monitors (ETM) Transformer Management Systems (TMS) Collecting the Data Temperatures: Methods of measurement Converting Data to Information Getting the Right Information to the Right People Converting Information into Benefits April 20, 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 The environment in which we work is becoming increasingly more complex. Not only from a technical perspective, but also due to financial and regulatory pressures. Engineers operating in electricity utilities are facing different issues from the past. Some of the major issues are: Cost competitiveness is becoming increasingly important. mouse As a utility, we cannot afford to lower our standards of customer service and reliability of supply and yet at the same time we MUST drive the assets which we have harder. In other words, we want to use our existing expensive assets (like transformers) for longer and to their full capacity. We need to manage our assets better and know more about their operating history. Because we are loading our transformers higher than ever before in day to day operations, our networks are becoming harder to operate and our previous experience of the operating life of assets on the network will have to be re-examined. Everyone involved in operating the network will need better tools if we are going to drive the assets harder and return better results for our shareholders and stakeholders. Importantly as well, all the major players the planners, operators and maintenance staff must be running the network process with the same strategies. It would be far from ideal if the planners in the utility were utilising highly sophisticated computer models for the rating of transformers and the operators of the network had the relatively unsophisticated tools of the past. For example they may have no tools at all or perhaps a simple analogue or two from a SCADA system. next slide April 20, 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 April 20, 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 April 20, 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 April 20, 2017

Equipment Categories: Gauges Temperatures April 20, 2017

TMS TEMPERATURE MONITOR VS CONVENTIONAL WTI OTI April 20, 2017

Electronic Temp Monitoring (ETM) “Basic” Temperatures April 20, 2017

Electronic Temp Monitoring (ETM) “Advanced” Temperatures Cooling System LTC Monitoring April 20, 2017

Transformer Management System (TMS) Temperatures Cooling System LTC Monitoring/Control Load Monitoring Connection to other IEDs April 20, 2017

Evolution of Transformer Controls Control House Control Alarms Communications Temp Expert Software Protocol Converters Data Logging Event Recording Temp LTC Control Oil Level Condition Monitoring LTC Monitoring DGA Moisture Direct Winding Temp Other Monitoring Input LTC Paralleling Sudden Pressure April 20, 2017

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 April 20, 2017

Converting Data into Information Dynamic Transformer Rating 60 2 Hr Overload 50 FA 40 FA 30 OA OA/ FA/FA = 30/40/50 (ONAN/ONAF/ONAF) PTLoad (software to calculate overload) DRMCC is specifically tuned to each transformer, as apposed to an average transformer of same value. Actual ambient is measured. Top oil temp is monitored. DRMCC will automatically derate loading if a cooling bank/pump/fan motor is lost. Thermal Model Tuned to this specific S/N Transformer Ambient Actual Ambient Top Oil Temp Starting Top Oil Temp Cooling System Health Fans/pumps/breakers/contactors April 20, 2017

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What is Dynamic Rating? Real-time on-line calculation of loadability Based on thermal model (modified IEC / IEEE) Guide for Loading Mineral-Oil-Immersed 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 with reduced risk and number of outages April 20, 2017

Collecting the Data Data typically collected LTC (OLTC) Top Oil Temp 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 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 April 20, 2017

Converting Data into Information Information typically calculated/determined Alarm Contacts & Ancillaries Oil Leak Nitrogen Leak LTC (OLTC) 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 Filter clogged/excessive pressure Internal Transformer Problem/Threshold monitoring DGA Dissolved Moisture, MIO Direct Winding Temperatures Bushing PF Partial Discharge Winding Hot Spot (for all windings) Forecasted Temperatures Ultimate WHS Ultimate Top Oil Temp Insulation Loss of Life Dynamic Rating Max Load Max Time “What If” Load Amps* Voltage* Watts Vars Cooling Status Cooling Efficiency Problem Fan or Pump Fail Contactor Fail Control Switch Not In Auto April 20, 2017

Accurate WHS Determination Methods of Winding Hot Spot (WHS) Measurement Simulated (inaccurate, local EM or analog measurement) Calculated (via DRMCC using the customized thermal model) Direct Measurement (fibre probes in coordination with DRMCC) The DRMCC “calculated” and the “direct measurement” methods complement each other in specific conditions April 20, 2017

Insulation Aging Rate April 20, 2017

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. April 20, 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 April 20, 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 Connect to the front with serial cable using terminal server. Connect to the LAN/WAN with ethernet using internet explorer Connect to SCADA using DNP, or Modbus using RS-232, RS-485 or fiber Other options: Modem (Pacificorp has an installation in UT monitored from OR via modem). Wireless from Xformer to control room. April 20, 2017

SUGGESTED SCENARIO Management Substation Environment April 20, 2017 SCADA Control centre Utility intranet Control room F ibre optic cable and Comms Retrofit cubicle Transformer Condition sampling device Management Environment April 20, 2017

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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 April 20, 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 April 20, 2017