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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