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DEFINITION

New vision regarding the real average load of distribution transformers in Latinamerican electrical grids. The situation and the various paths to a soluction. Arguments based on IEEE C57.91-1995 (R2004). DEFINITION. Demand curve RMS value in kVA

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DEFINITION

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  1. New vision regarding the real average load of distribution transformers in Latinamerican electrical grids.The situation and the various paths to a soluction.Arguments based on IEEE C57.91-1995 (R2004) HJ International Latin America, Inc.

  2. DEFINITION Demand curve RMS value in kVA Cm = ---------------------------------------------------- Nominal kVAvalue of thetransformer HJ International Latin America, Inc.

  3. Regardingcycles of equivalentloadsNote thatthelevels of overload and itsduration are extractedfromtheproper curves of the real load and notfrom a standard…!! The accummulative concept of the loss of life… …day, month, year, all its life… HJ International Latin America, Inc.

  4. Cycles of equivalentloadsIEEE C57.91-1995 A transformer subjected to any one of these 3 cycles will exhibit the same performance in terms of energy While the RMS value of the load curve is below the nominal capacity of the transformer, the loss of life of the unit will be below the maximum permitted!! HJ International Latin America, Inc.

  5. Diagram of temperatures HJ International Latin America, Inc.

  6. Diagram of temperatures Direct measurement (thermocouples) Indirect measurement (resistance) Calculated (recomendations IEEE) HJ International Latin America, Inc.

  7. Regarding the limits of load and temperatureFor operations above the nominal loadPer IEEE C57.91 – Table 6DISTRIBUTION TRANSFORMERS Top oil temperature: 120degC Temperature of the hot spot of the conductor: 200degC Short duration load (1/2 hour or less) 300% HJ International Latin America, Inc.

  8. Regarding the limits of load and temperatureFor operation s above the nominal load Per IEEE C57.91 – Table 7POWER TRANSFORMERS Top oil temperature: 110degC Temperature of the hot spot of the conductor: 180degC Short duration load (1/2 hour or less): 200% HJ International Latin America, Inc.

  9. How a COMPLETE heatrunshouldbe done… HJ International Latin America, Inc.

  10. DEFINITION:Factor regardingenergerizedmedium load • Annualinvoicing in GWh Fcme = -------------------------------------------------- CITD * fp * 24 * 360 CITD: Installedcapacity of DistributionTransformers, GVA fp: Global power factor of thesystem HJ International Latin America, Inc.

  11. Averageloadability of distributiontransformers en thesystem (Example) • The average sizes in the grid can be reduced in factors of 2 to 5!! HJ International Latin America, Inc.

  12. OPTIMUM SIZING Forthelosses and typicallykVAcostthatwefoundthroughouttheLatinamericangrids, theminimumoperativecostfor Cm tobebetween 50% and 75% of the nominal capacity of thedistributiontransformers. HJ International Latin America, Inc.

  13. THE COMPROMISE… WHERE WE ARE AT TODAY: Cm = 15 % WHERE WE HAVE TO BE: Cm = 60 to 75 % HJ International Latin America, Inc.

  14. Determination of the real demand Indirect measurements – CEMIG (Gemini) Compare the energy sold to the end users connected to the transformer to the energy the transformer has the capacity to deliver The real losses at the sight of installation are not accounted for. Administration of actives due to accummulated loss of life HJ International Latin America, Inc.

  15. Directmeasurement of energydeliveredbythetransformer • Thereadingiscomparedtotheenergysoldtotheend-usersconnectedtotheunit. • Ifyou compare theenergydeliveredbythetransformerto a load profile, youwillhave a precise vision of thepercentage of load. (Fuente: Redes de EEPPM) HJ International Latin America, Inc.

  16. Othervariantspracticedcurrently • Digital measurements • Remotereadings • Remotesignals (Fuente: Redes de EEPPM) HJ International Latin America, Inc.

  17. Distribution of loads in a gridwithoptimumsizing • CRITICAL ZONE WITH THE NEED TO ADEQUATE THERMO PROTECTION • Example: Cm/Fd (0.60/0.65 =0.92) HJ International Latin America, Inc.

  18. IS EVERYTHING CLEAR ? HJ International Latin America, Inc.

  19. Factorstoconsiderfortheoptimumsizingbasedontheconsumption of energy • REAL LOAD CURVE OR CHARACTERIZED AND 2 EQUIVALENT CYCLES. • DETERMINE THE RMS VALUE OF THE LOAD CURVE BASED ON THE ACTUAL CONSUMPTION. • LIMIT THE PROJECTION OF THE LOAD CURVE TO NO MORE THAN 5 YEARS. • DEFINED A UNTI SIZE THAT WILL REACH ITS OPTIMUM LOAD IN THE PROJECTED TIME. • SELECT AN APPROPRIATE THERMAL PROTECTION HJ International Latin America, Inc.

  20. Thetype of transformertobeused in anoptimized load environment Tosuccessfullyoperatedistributiontransformers at Cm levelsbetween 50% and 75%, itisconsideredimperativethattheprotectivedevicesusedforthetransformer, identifythoselevels of overload in magnitud and durationthat cause loss of lifeabovethemaximumpermitted. HJ International Latin America, Inc.

  21. Theareas of Over-CurrentProtection in a transformer... HJ International Latin America, Inc.

  22. Thetype of transformertobeutilizedonoptimum load environments and THE DEFINITIONS OF THE PROTECTION TO BE UTILIZED Emphasis on the control of the thermal compartment (following the load currents and the interior temperatures) Assetmanagement of thegrid Reduction of installationcosts. Significantreductions of the global failureindices of transformers in thedistributionsystem. HJ International Latin America, Inc.

  23. Thetype of transformertobeutilized in anoptimum load environment… Lighted signal or Information sent remotely Priviledging the need to interrupt dangerous load y even finding a better solution, we are installing CSP type transformers to provide an exact thermal protection and the capacity to interrupt at the site. HJ International Latin America, Inc.

  24. Thesolutionthatthe CSP transformeroffers… CAJA NEGRA CONVENTIONAL SELF-PROTECTED HJ International Latin America, Inc.

  25. Thesolutionthatthe CSP transformeroffers… HV ARRESTER LV ARRESTER LV BREAKER FUSES HJ International Latin America, Inc.

  26. Thesolutionthatthe CSP transformeroffers… SIGNAL LIGHT HANDLE AND EMERGENCY OVERLOAD LEVER HJ International Latin America, Inc.

  27. Thesignallamp as anelement in providinganeffectivemanagemente of loads and assetsalongwithanimportant role in balancingloads. LIGHT OFF STATUS OF GRID AND LOAD ARE NORMAL LIGHT ON STATUS OF GRID AND LOAD ARE ABNORMAL HJ International Latin America, Inc.

  28. A practicalapplication of theproposedmodel Case CFE – Veracruz District/Division Pilot grid used to size unit with an optimum Cm HJ International Latin America, Inc.

  29. Summary of thepilotprojectachieved in the City of Veracruz - Mexico 1. GRID INSTALLED OPTIMIZED 2. Number of units 39 39 3. Average kVA 43.1 16.8 4. Total KVA 1,722.5 655 5. Kwh./year 1,012,283 1,012,283 6. Fcme 15.2% 39% 7. Capitalized cost US$65.8k US$34.4k units + losses 8. % Capitalized cost. 100% 52.2% 9. Type of units Conventional CSP HJ International Latin America, Inc.

  30. Summary of thepilotprojectachieved in the City of Veracruz - Mexico HJ International Latin America, Inc.

  31. Importantpointsfor a successfulapplication COORDINATION OF PROTECTIVE DEVICES AND REAL EXERCISES OF OVERLOAD PROTECTION HJ International Latin America, Inc.

  32. Whenmakinganeconomicevaluation of a projectusingconventional vs CSP typetransformers THE SIZE OF TRANSFORMER BEING COMPARED ARE DIFFERENT CONVENTIONAL kVA = X kVA = X/2 HJ International Latin America, Inc.

  33. Theexperience in Mexico wasworththeeffort… Letter from the Sub-Director of CFE indicating all the benefits achieved. HJ International Latin America, Inc.

  34. Other recommendations: The case of transformers in Distribution Substations END Primary and secondary distribution cables NATALIA Orlando Giraldo – Sales and Operations Manager - HJ International Latin Americaorlandog@h-jenterprises.com – USA (636) 677 3421 – (Colombia) 57 1 478 4141 HJ International Latin America, Inc.

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