ABB Switzerland Ltd High Voltage Products PTHG-V / Marta Lacorte Business Development LAM High Current Systems. Generator Circuit- Breaker Systems

Generator Circuit-Breaker? What are we talking about? GCB G G - 2 - Layout without Generator Circuit-Breaker Layout with Generator Circuit-Breaker

Advantages of Generator Circuit-Breakers Simplified operation Improved generator protection Improved main and unit transformers protection Increased power plant availability - 3 - Decreased costs (case dependent)

Advantages of Generator Circuit-Breakers Simplified Operation GCB clear and logical plant arrangement generator starting-up or shutting-down only GCB operates switching operations number reduction - 4 - power plant and the high-voltage grid operation responsibilities clearly defined

Advantages of Generator Circuit-Breakers Generator, main and unit Transformers Improved Protection generator, main and unit transformers differential protection zones maximum selectivity Generator-fed short-circuit currents four cycles interrupted - 5 -

Advantages of Generator Circuit-Breakers Increased Power Plant Availability simplified operation clearly defined operational responsibilities reduced operational errors more reliable generator synchronisation - 6 -

Advantages of Generator Circuit-Breakers Increased Power Plant Availability rapid and selective clearing clearance of all types of faults avoid expensive secondary damage avoid long down repair times main or unit transformer tank bursting generator damper winding thermal destruction turbine-generator mechanical destruction - 7 -

Advantages of Generator Circuit-Breakers Decreased costs (case dependent) associated items of switchgear integration into GCB enclosure simpler and more economic power plant layouts simpler and more economic erection and commissioning elimination of station transformer and associated high-voltage and mediumvoltage switchgear increased power plant average availability 0.3 0.5 % increased operating hours - 8 - higher power plant operator profit

Requirements for Generator Circuit-Breakers GCB requirements transmission and distribution CB requirements GCB high technical requirements Rated current Short-circuit currents (system-source and generatorsource) Fault currents due to out-of-phase conditions - 9 - Fault currents asymmetry, delayed current zeros Recovery Voltages rate-of-rise

Standards IEC 62271-100 / 2001 (former IEC 56) - 10 - Generator circuit-breakers installed between generator and stepup transformer are not within the scope of this standard

Standards IEEE C37-013 1. Scope This standard applies to all ac highvoltage generator circuit breakers rated on a symmetrical current basis that are installed between the generator and the transformer terminals. Pumped storage installations are considered a special application, and their requirements are not completely covered by this standard. NOTE Since no other national or international standard on generator circuit breakers exists, this standard is used worldwide. - 11 -

ABB Generator Circuit Breakers worldwide - 12 - DB 1954-1993 HEC 3-6 1995- DR 1969-1998 HGC 1998- Our business card is nearly 5 500 units installed and operating worldwide HEK 1984-1999 HEC 7/8 2000- Airblast GCB SF 6 GCB > 1900 units > 3450 units HGI 1992- HECS 2003- HECPS 3/5S 2005-

ABB Switzerland Ltd, High Current Systems Design and Manufacturing in Zurich-Oerlikon, Switzerland Approx. 100 Employees Deliveries in 2006: 352 GCB s Market share world-wide: >70% >70% - 13 - January 2007: received orders for almost 3600 GCB s in SF 6 technology (since 1985) Worldwide more than 3000 ABB GCB s (SF 6 ) are already in operation

GCB PORTFOLIO 2006 Short Circuit Current [ka] 210kA 160kA 140kA 130kA HECS-130 (HECPS-5S / HECS-130R) 100kA 80kA 63kA 50kA HECS-100 (HECPS-3S / HECS-100R) HECS- 80 HGI 3 HGI 2 HEC 7S HEC 7 HEC 8-14 - 6300A 8000A 10500A 13000A 18000A 23000A 24000A 28000A (57000A) Rated Current [A]

Development of Generator Circuit-Breaker - 15 - GCB type: HECS (SF 6 )

Generator Circuit-Breaker System Type HECS 8 7 MO 9 3 T (1) (2) (3) (4) Generator Circuit-Breaker Series Disconnector Capacitors Starting Disconnector for SFC 5 4 2 1 6 T 6 G 10 (5) (6) (7) Manuell Short-Circuit Connection Earthing Switches Current Transformers 8 3 G (8) Potential Transformers - 16-7 G (9) (10) Surge Arrestor Motorized Short-Circuit Connection

Generator Circuit-Breaker System Type HECS View into one pole of Circuit-breaker type HECS-130L Current transformer Voltage transformer Interrupting chamber Series Disconnector Surge arrester - 17 -

Interruption Chamber and Disconnector Interrupting chamber of the circuit-breaker type HECS-100L - 18 - Series Disconnector View through the inspection windows of HECS to assure that the disconnect switch is in the open position.

Earthing Switch - HECS Earthing switch Semaphore and key locking - 19 - In CLOSED position

Hydro-Mechanical Spring Drive HMB 4.5-20 - Schematic diagram of the hydraulic spring operating mechanism View of a hydraulic spring operating mechanism

Current Transformer / Voltage Transformer Current transformer Voltage transformer - 21 - According to IEC 60044-1 or IEEE C57.13 According to IEC 60044-2 or IEEE C57.13

ABB GCB advantages Dimensions GCB ABB smaller in width and smaller length less transportation cots and more flexibility for installation transport units GCB totally mounted in the factory, the three phases and the control cubicle mounted in the structure. Shorter commissioning time, less assembling on site, less assembling mistake,higher availability mechanic-hydraulic drive thousands of units installed in the world, approved equipment, without failures maintenance 20 years or 20 000 mechanical operations, until reach one of these limits only supervision services are necessary, without take the GCB out of service arc extinction method self blast extinction, assuring performance in the currents interruption of high amplitude as well as of small current - 22 - type tests performed according to GCB standard IEEE C37.013 and in independent laboratory KEMA out-of-phase type test performed with 180 of phases disagreement

8 19 0 GCB Type "D": South America 0 0 50 DR 36 sc 1750 San Agaton 2 DR 36 t 0500 Planta Centro Unidad 5 1 18 DR 36 t 0500 Planta Centro Unidad 4 1 DR 36 t 0500 Planta Centro Unidad 1 + 2 2 0 43 10-23 - DR 36 t 0500 Planta Centro Unidad 3 DRT24.125 Macagua 2 4 DRT24.125 Macagua 2 2 DRT24.125 Macagua 2 4 DRT24.125 Macagua 2 2 1 South Americaa World 148 1928

15 11 GCB SF6 Type "H": South America 12 6 8 27 HECS-100M Pedro Camejo 2 HEK 4 Macagua 2 5 0 HEK 4 Macagua 2 4 HEK 4 Macagua 2 4 5 13 3-24 - South America World 103 3203

Replacement Northfield Mountain / USA - 25 - Northfield Mountain - After Northfield Mountain. - Before

Replacement Benmore HPP / New Zealand - 26 -

Retrofit TPP Berezovskaja / Belorussia Estonia - 27 -

Retrofit TPP Berezovskaja / Belorussia Estonia - 28 -

TPP Kuala Langat (250MW) / Malaysia - 29 -

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elimination of station transformer and high-voltage bay GCB G G - 31 - Layout without Generator Circuit-Breaker Layout with Generator Circuit-Breaker

Arc resistance effect in GCB 6 5 4 Arc resistance r e s i s t ê n c i a d o a r c o 3 2 T a = X d /{2Πƒ(R a )} 1 0 T a = X d /{2Πƒ(R a + R add )} 0 0. 0 5 0. 1 0. 1 5 0. 2-32 - - 1

Interruption of Generator-Fed Fault Currents Without Generator Circuit-Breaker (Unit Connection) - 33 -

Interruption of Generator-Fed Fault Currents With Generator Circuit-Breaker - 34 -

Simplified Operational Procedures - 35 - Layout without generator circuit-breaker Unit start-up: 1) Run-up unit on station transformer (startup supply) and synchronise generator with high-voltage grid by means of highvoltage circuit-breaker 2) Parallel unit auxiliaries supplies 3) Separate unit auxiliaries from station transformer (start-up supply) Unit routine shut-down: 1) Parallel unit auxiliaries supplies 2) Separate unit auxiliaries from unit transformer 3) Trip high-voltage circuit-breaker and shutdown unit on station transformer Unit emergency shut-down: 1) Trip high-voltage circuit-breaker, unit auxiliaries are isolated 2) Automatic transfer of unit auxiliaries from unit transformer to station transformer (approx. 4 5 cycles) 3) Shut-down unit on station transformer Layout with generator circuit-breaker Unit start-up: 1) Run-up unit on unit transformer and synchronise generator with high-voltage grid by means of generator circuitbreaker Unit routine shut-down: 1) Trip generator circuit-breaker and shutdown unit on unit transformer Unit emergency shut-down: 1) Trip generator circuit-breaker and shutdown unit on unit transformer

Equipment Failures Main Transformer Failures Sequence of events: t = 0 ms: earth fault at HV-side of transformer t = 45 ms: 2-phase short-circuit t = 95 ms: 3-phase short-circuit t 150 ms: explosion of transformer - 36 -

Equipment Failures Short-Time Unbalanced Load Conditions - 37 -

Short Circuit Characteristic G system-source short-circuit asymmetry 74% voltage rate of rise TRV 6 kv/ms G - 38 - generator-source short-circuit currents asymmetry 130% voltage rate of rise TRT 2.2 kv/ms