Raben Naidoo, Technology days, May 21-22th, 2014, Cape Town, South Africa, Enhanced availability of transformers via transformer remote monitoring - TEC ABB Power Products Service
Why a session on availability? Top utility concerns Source: Black & Veatch s 2011 Strategic Directions Survey Results May 27, 2014 Slide 2
Our every day necessities Areas of power consumption reflected on the earth s surface More than ever, the need of energy efficient products and reliable grids. ABB s transformers support the systems that keep our world running. Ever growing population Energy consumption to double within 30 years Sustaining a power-hungry world Ensure the reliability & availability of an ageing grid infrastructure Concern about climate change Green solutions - providing energy efficient products and service Economic environment May 27, 2014 Slide 3
Utility and Industry challenges Asset management with new challenges Probability 0.1 0.08 0.06 0.04 0.02 0 Failure probabilities (Network Transfor.) 1 6 11 16 21 26 31 36 41 46 51 56 Age (years) Move towards Condition Based Maintenance / Reliability Centered Need for tools to decide based on technical & economical criteria Ensure high reliability of aged assets Avoid unplanned power outage Optimize assets performance Increase production output Optimize capital expenditure and increase return on assets Reduce Life Cycle Costs Lowest operation and maintenance costs Extend lifetime of existing assets while looking for sustainability Delay investments while considering green solutions May 27, 2014 Slide 4
How to enhance availability? Avoid unexpected failures Plan maintenance and repair during low load periods Efficient maintenance actions reducing downtime Solutions to shorter repair time Retrofit solution to increase personal and asset safety Green footprint Financial benefits May 27, 2014 Slide 5
Condition based maintenance Assess the condition / withstand capability Source: CIGRE Thermal ageing Temperature Moisture Oxygen Mechanical ageing Delta temperature Over current Vibration / Number of operation Electrical ageing Over voltage Over current Harmonics - VFT May 27, 2014 Slide 6
Assessing the condition Needs for a structured analysis process Input Data Risk Categories Risk of Failure (RoF) May 27, 2014 Slide 7
Condition Assessment Three steps: Optimize ratio Accuracy / Costs, Time May 27, 2014 Slide 8
Electrical tests and DGA Diagnostic matrix Overall condition Oil, DGA, Furans Mechanical condition Frequency Response Analysis (FRA) Thermal condition Dielectric Frequency Response (DFR) Electrical condition Partial Discharge Analysis (PDA) Accessories Bushing Power Factor OTC Vibration May 27, 2014 Slide 9
Transformer condition assessment Typical output and recommendations Plant 1 - Results of condition assessement and action plan Mechanical Electrical Thermal Accessories Overall Risk Mitigation - Actions TFO 2 Winding Arcing Heating 95 Visual Inspection and repair in factory / rewinding TFO 5 Tank OLTC heating 80 Repair on site and OLTC overhaul TFO 1 Aged oil Bushing 70 Oil regeneration / filtration and advanced diagnosis / change HV bushing TFO 6 Arcing Thermometer 50 Exchange TopOil - thermometer / on line monitoring of DGA TFO 3 Silicagel 40 Exchange Silicagel TFO 7 25 Standard maintenance actions and controls TFO 8 15 Standard maintenance actions and controls / 10 % overload capabilities May 27, 2014 Slide 10 TFO 4 10 Standard maintenance actions and controls / 15 % overload capabilities
Transformer Service Success Story Utility, ZA Belhar and Dinaledi Substation Pilot Installation Utility, South Africa, Western Cape & North West Year: 2012 Customers need Lower shutdown periods Reduce OLTC maintenance scheduling Trouble-free operation ABB s response Vacuum On-load tap changer Immediate prognosis allowing to take appropriate actions before a problem occurs Customers benefits Lower life cycle costs, less maintenance needs, and increased time in operation because of a radical reduction in contact wear. Routine inspection takes place in a cleaner environment which reduces downtime. Only the diverter switch mechanism differs which means that the unit is completely interchangeable, thus no redesign of the transformer is necessary. Operation of the transformers has become more efficient allowing overloading and aging forecasting on-line. Online Monitoring has increased the availability of the transformers May 27, 2014 Slide 11
Monitoring Infrastructure from sensor to repair or upgrade Monitoring enables smart grids for: Fleet assessment Optimum control Consulting Service Transformers Asset Health Management Grid integration Asset Health Center Fleet Screening / Assessment Data Aggregation Monitoring data storage, local service and control remote control TEC Upgrades Transformers Substations Optimum Grid Control and Dynamic Overload Control Integration - Load Forecast - Temperature algorithms Sensor Technologies Basic and advanced sensors. Local display and preparation for remote connection Enable smart transformer management May 27, 2014 Slide 12
Online Transformer Monitoring Voltage, Current, Oil and Ambient Temperature, On load Tap Changer, Gases and Bushing, etc, ABB monitoring system (converts raw data into useful informations) Communication system May 27, 2014 Slide 13
Online Transformer Monitoring Control Room May 27, 2014 Slide 14
TEC platform key benefits User friendly web interface no additional software needed on users computer Based on a microprocessor and Modular design, possible to add the sensors that the customer requests with additional hardware Very strong mechanical stability and temperature endurance => Long lifespan Reliable and proven technology (longest serving unit has >10 years in the field) Compact and easy to install Support for standard communication protocols, including IEC 61850 (certified by SGCC) May 27, 2014 Slide 15
User friendly interface No special computer is needed Dual language support May 27, 2014 Slide 16
Display interface Important information available at the transformer in real-time ALARM WARNING NORMAL Press to see next value Press and hold (> 3 sec) to see active events May 27, 2014 Slide 17
Design data fingerprint concept RI2 losses high voltage winding kw 89.5 32.2 RI2 losses low voltage winding kw 131.0 47.2 RI2 losses tertiary winding kw N/A N/A Eddy losses in high voltage winding kw 8.3 3.0 Eddy losses in low voltage winding kw 9.55 3.4 Eddy losses in tertiary winding kw N/A N/A Calculated values for type test AF AN (When applicable) Top oil temperature rise C 56.5 58 Average oil temperature rise C 41.5 49 No load loss at test kw 124 124 Load losses at test - 764 275 Tap-changer position - -2X2.5%(2) -2X2.5%(2) Current high voltage winding A 510.5 306.3 Current low voltage winding A 1600 960 Current tertiary voltage winding A N/A N/A Hot-spot temperature high volt. wind. C 74.3 67.5 Hot-spot temperature low volt. wind. C 75.3 67.5 Hot-spot temperature tertiary volt. wind. C N/A N/A Temperature gradient high volt. wind. C 17.8 (3) 9.5(3) Temperature gradient low volt. wind. C 18.8(3) 9.5(3) Temperature gradient tertiary volt. wind. C N/A N/A Mass parameters Cu-Mass of high voltage winding kg 4461 kg/limb Cu-Mass of low voltage winding kg 3337 kg/limb Cu-Mass of tertiary winding kg N/A Free oil kg 99915 Oil in insulation kg 4000 Core steel mass kg 89049 Other steel mass (tank, yoke plate, etc.) kg 67000 Paper mass kg 438 Type test values AF AN (When applicable) Ambient temperature C Top oil temperature rise C May 27, 2014 Slide 18
Web interface graphs with data May 27, 2014 Slide 19
Intelligent cooling control Signal from CT T Top Oil T Bottom Oil TEC Cabinet ON CABINET Display ALARM WARNING NORMAL Algorithms Hot-spot temp Thermometer pocket Enhancements from traditional cooling Control up to 6 cooler groups Starts on top oil, hot-spot and forecast Remote start of coolers possible All cooler groups equally used Logic to exercise motors each week Time in service shown in station interface Time delay between cooler group start Reduced noise level More stable temperature, reduced breathing Up to 6 Cooler Groups can be controlled Group 1 Group 3 Group 2 Group 4 Group 5 Group 6 Traditional top oil thermometer used as back-up start of coolers and for emergency trip May 27, 2014 Slide 20
On load tap changer Contact wear calculation according to theory and experience Contact Wear 7 6 5 4 3 2 1 Wear on: Right side of Fixed Contact 4 Main Contact W = C. I n Position statistics I 7 6 5 4 I c Wear on: Right side on Fixed Contact 4 Left Transition Contact W = C. (I/2-I c ) n Temperature 3 2 1 I May 27, 2014 Slide 21
Hot-spot Temperature Calculation IEC & IEEE IEC-354 Θ h = Θ o + Hg r K y Θ o = Top oil temperature Hg r = Hot-spot to top-oil gradient K = Load factor (load current/rated current) y = Winding exponent No traditional hot-spot thermometer needed Hot-spot temperature calculation HV winding LV winding Tertiary winding May 27, 2014 Slide 22
Thermal Ageing at the Hot-Spot Ageing calculation gives a possibility to compare the thermal ageing of different transformers, for overload or replacement planning Aging Speed IEC, used for normal paper IEEE, used for thermally upgraded paper Calculated age of the transformer Aging Speed at this time 10 1000% 1 100% 0.1 10% 50 100 0.01 1% F 0.001 ~0% T HS 98 = 6 IEC 2 F IEEE = e 15000 ( ) 15000 383 T + HS 273 Hot-Spot Temperature [ C] May 27, 2014 Slide 23
Overload Capability Overload capacity: Displays the loading capability at present conditions May 27, 2014 Slide 24
Transformer Temperature Balance TEC keeps track of the transformer temperatures and compares them with a theoretical model to indicate changes, in the cooling conditions or heat generation, that could place restrictions on the overloading capacity. T Air T Top Oil Cooling from the Tank Losses Cooling from Radiators or Coolers T Bottom Oil May 27, 2014 Slide 25
Gas and moisture measurement To be able to analyze gas readings it have to be correlated with load, temperatures and cooling status in the transformer TEC keeps track of the transformer and helps you analyze gas readings together with all relevant transformer data. To know when an oil sample is needed. Combination of load, temperatures, cooling status and DGA is required to give the complete picture Early warnings for fast developing gas related faults May 27, 2014 Slide 26
TEC few sensors high functionality Cabling One cable to/from transformer Bus communication available on transformer Top oil temperature Hot-spot temperature Load Ageing Temperature balance Cooling control Current transducers Hot-spot temperature Load Ageing Cooling control Contact wear Temperature balance Bottom oil temperature Temperature balance Ambient temperature Sun Shadow On-load tap-changer (OLTC) Position Contact wear Temperature Temperature balance Moisture OLTC Gases and moisture Trends Bubbling temperature May 27, 2014 Slide 27
Connection with customer s network Minimum scope of supply TCP/IP Fiber optic Gas sensor TEC system May 27, 2014 Slide 28
Connection with customer s network TCP/IP TMU 100 Bushing monitoring Capacitance Tan delta Fiber optic DGA device Individual 8 gases Moisture TEC system Thermal Currents Coolers OLTC May 27, 2014 Slide 29
Connection with customer s network May 27, 2014 Slide 30
TEC transformer installation New Transformers Old Transformers Non-ABB Transformers May 27, 2014 Slide 31
TEC cabinet installation 1) Mount TEC on transformer. 2) Connect sensors and power supply according to drawings and connection tables. 3) Start system. Note: The display indicates present status and events. May 27, 2014 Slide 32
Retrofit of the transformer Placing TEC in one existing Transformer May 27, 2014 Slide 33
Retrofit of the transformer Sensors. Can any existing sensors or sensor pockets be used? New sensors, what type should be used? New sensors, where are they best placed? Historical data. To be able to display correct ageing of transformer and contact wear on the tap-changer, it is necessary to program the TEC with historical data. RI2 losses high voltage winding kw 89.5 32.2 RI2 losses low voltage winding kw 131.0 47.2 RI2 losses tertiary winding kw N/A N/A Eddy losses in high voltage winding kw 8.3 3.0 Eddy losses in low voltage winding kw 9.55 3.4 Eddy losses in tertiary winding kw N/A N/A Calculated values for type test AF AN (When applicable) Top oil temperature rise C 56.5 58 Average oil temperature rise C 41.5 49 No load loss at test kw 124 124 Load losses at test - 764 275 Tap-changer position - -2X2.5%(2) -2X2.5%(2) Current high voltage winding A 510.5 306.3 Current low voltage winding A 1600 960 Current tertiary voltage winding A N/A N/A Hot-spot temperature high volt. wind. C 74.3 67.5 Hot-spot temperature low volt. wind. C 75.3 67.5 Hot-spot temperature tertiary volt. wind. C N/A N/A Temperature gradient high volt. wind. C 17.8 (3) 9.5(3) Temperature gradient low volt. wind. C 18.8(3) 9.5(3) Temperature gradient tertiary volt. wind. C N/A N/A Mass parameters Cu-Mass of high voltage winding kg 4461 kg/limb Cu-Mass of low voltage winding kg 3337 kg/limb Cu-Mass of tertiary winding kg N/A Free oil kg 99915 Oil in insulation kg 4000 Core steel mass kg 89049 Other steel mass (tank, yoke plate, etc.) kg 67000 Paper mass kg 438 Type test values AF AN (When applicable) Ambient temperature C Top oil temperature rise C Feedback from coolers. To monitor the coolers, TEC need feedback signal from each cooler when it is active. Are there any free contacts on existing cooler starting contactors? If not, how can the feedback be provided? May 27, 2014 Slide 34