Gestión inteligente de Transformadores estratégicos

Transcripción

1 Gestión inteligente de Transformadores estratégicos CIGRÉ México, 15 de Junio del 2011 Energy Sector Power Distribution Ing. Ricardo Rivero

2 Agenda A) General information B) Regular and Advanced Diagnostic C) Strategic transformer management program D) Monitoring system on line E) References Página 2 15-Jun-2011 Ing. Ricardo Rivero

3 A) General Information Mortality Rate by Age 20 % Failures GSU Network Age of Transformer Source: CIGRÉ Página 3 15-Jun-2011 Ing. Ricardo Rivero

4 A) General Information Transformer failures: Winding insulation Bushings Tap changers Other areas of concern: Pollution, dust & debris affecting bushings & cooling systems Cooling System inefficiency Página 4 15-Jun-2011 Ing. Ricardo Rivero

5 A) General Information Why does insulation break down? Brittle insulation increases failures Overloading increases heat = aged insulation O 2 & moisture in oil break down insulation Short circuits overpower older designs Página 5 15-Jun-2011 Ing. Ricardo Rivero

6 A) General Information Bushings Inherent design (Type U) Tracking (Dust) Tap Changers Mechanical linkages Cooling Systems Blockage leads to heating & inefficiency Transformer not rated to nameplate Página 6 15-Jun-2011 Ing. Ricardo Rivero

7 B) Regular and Advanced Diagnostics Regular and Advanced Diagnostics Routine Electrical Testing FRA (Mechanical movement of the windings) DFR (Dielectric properties of insulation system) ADGA (Dissolved gas analysis using design characteristics) Página 7 15-Jun-2011 Ing. Ricardo Rivero

8 B) Regular and Advanced Diagnostics Routine Electrical Testing Insulation Power Factor Insulation resistance of windings and core Transformer Turns Ratio (TTR) CT ratio & polarity Winding Resistance Winding Excitation Infrared Scanning Página 8 15-Jun-2011 Ing. Ricardo Rivero

9 B) Regular and Advanced Diagnostics Routine Oil Analysis General Chemistry Dissolved Gas Analysis (DGA), Concentrations of H 2, ethane, ethylene, methane, & acetylene Página 9 15-Jun-2011 Ing. Ricardo Rivero

10 B) Regular and Advanced Diagnostics FRA Frequency Response Analysis (FRA) is a method of measuring the transfer function of the windings of a transformer. Changes in the transfer function reveal a wide range of failure modes, for example: Axial Winding Collapse Hoop Buckling Shorted Turns Página Jun-2011 Ing. Ricardo Rivero

11 FRA: Axial Collapse Axial winding collapse is likely to have the following characteristics: Produced within a transformer winding due to excessive axial forces during a fault Failure likely to be catastrophic if transformer continues in service Página Jun-2011 Ing. Ricardo Rivero

12 FRA: Hoop Buckling Hoop buckling is produced within a transformer winding due to excessive compressive forces during a fault. Página Jun-2011 Ing. Ricardo Rivero

13 FRA: Hoop Buckling Página Jun-2011 Ing. Ricardo Rivero

14 FRA: Shorted Turns Shorted turns in transformers are produced by turn-to-turn faults and may have the following characteristics: Adjacent turns lose paper and braze/weld together They result in a solid loop around the core Página Jun-2011 Ing. Ricardo Rivero

15 B) Regular and Advanced Diagnostics DFR The Dielectric Frequency Response (DFR) test is a series of power factor measurements at multiple frequencies. It provides more information about the dielectric behavior of the insulation system. The method be used to diagnose the following conditions in transformers: Moisture in the cellulose insulation High oil conductivity due to aging or overheating of the oil Chemical contamination of cellulose insulation Carbon tracking in cellulose High resistance in the magnetic core steel circuit Página Jun-2011 Ing. Ricardo Rivero

16 DFR Distinguishing Between Aged Oil and Moisture 60 Página Jun-2011 Ing. Ricardo Rivero

17 DFR Fitting the Right Dielectric Parameters 60 Página Jun-2011 Ing. Ricardo Rivero

18 DFR High Core Ground Resistance XV to Ground XV to Ground after Repair Frequency, Hz Dielectric Response Fingerprint Function caused by a High Core to Ground Resistance in Auxiliary Transformer Página Jun-2011 Ing. Ricardo Rivero

19 B) Regular and Advanced Diagnostics Adv DGA Close observation of dissolved gases in the oil and other oil properties provides the most valuable information about transformer health. DGA analysis tools takes the following into considerations: Página Jun-2011 Ing. Ricardo Rivero

20 B) Regular and Advanced Diagnostics 3D Simulation Solutions of Field Problems verifications of hot-spot verification of electric field analysis and solution of overheated bus-duct in large GSU s determining overload-ability. Electrical field distribution over the winding / HV bushing insulation structures Página Jun-2011 Ing. Ricardo Rivero

21 C) Strategic transformer management program A series of assessments to provide optimal asset decisions Phase I Fleet Risk Screening Phase II Condition & Design Evaluation of Critical assets Phase III Life Profiling Phase IV Implementation Prioritization of critical assets Improved capital forecasting Reduced O&M spending Improved availability and reliability Improved operational efficiencies Improved environmental, public safety profile Página Jun-2011 Ing. Ricardo Rivero

22 C) Strategic transformer management program Página Jun-2011 Ing. Ricardo Rivero

23 C) Strategic transformer management program 130 units total Página Jun-2011 Ing. Ricardo Rivero

24 C) Strategic transformer management program Urgent = 10 Priority = 40 Normal = 80 Plot of Risk of Failure versus Importance Página Jun-2011 Ing. Ricardo Rivero

25 C) Strategic transformer management program RISK OF FAILURE PER TRANSFORMER MAINTENANCE $$$ PER TRANSFORMER $ $ $ $ 30-50% OF MAINTENANCE ACTIVITY IS UNNECESSARY (CIGRE-2000) UNDERSPENDING US OS=US - balanced budget OS>US - lower maintenance $$$ OVERSPENDING OS Budget Expenditures vs. Risk TRANSFORMERS Página Jun-2011 Ing. Ricardo Rivero

26 D) Monitoring system on line Página Jun-2011 Ing. Ricardo Rivero

27 D) Monitoring system on line Sistema de Monitoreo Y Gestión de Activos Siemens SMGAS Firewall VPN Gestión de Mantenimiento y Alarma en caso de contingencia Avisos / Alarmas / Informes Acciona Internet Firewall VPN GAS-Guard 8 DNP i F.O. ETHERNET Switch ETHERNET Cuarto de Control Existente Transformador Cromatógrafo de Gases Análisis de Disolución de Gases Página Jun-2011 Ing. Ricardo Rivero

28 D) Monitoring system on line Software WEB UI, con alarma Y recomendación de acciones Sistema de Monitoreo Y Gestión de Activos Siemens SMGAS Firewall VPN Avisos / Alarmas / Informes Acciona Internet Firewall VPN Switch RS485 DNP3 F.O. ETHERNET ETHERNET F.O. ETHERNET Cuarto de Control Existente Transformador Página Jun-2011 Ing. Ricardo Rivero

29 D) Monitoring system on line Respaldo de Monitoreo y en caso extremo respaldo de Control y Operación Hacia Acciona vía VPN Página Jun-2011 Ing. Ricardo Rivero

30 E) References Repair and retrofitting through - Transformer Lifecycle Management Siemens AG 2010 Sitram - Monitoring - Transformer Lifecycle Management Siemens AG 2010 Energy automation Siemens 2011 Service Handbook for Power Transformers ABB 2006 IEEE C IEEE Guide for Failure Investigation, Documentation, and Analysis fro Power Transformers and Shunt Reactor C. Sweeter and T. McGrail, Sweep Frequency Response Analysis A Technical Paper from Doble Engineering, Ver. 1.0 January 2003 McNutt, W.J. CIGRE Survey on maximum Safe Operating Hot Spot Temperature, From EPRI Proceedings on Transformer Overload and Bubble Evolution, EL-5807-SR, Junio 1988, pp Página Jun-2011 Ing. Ricardo Rivero