Transmissão em Corrente Contínua

Transcrição

1 Transmissão em Corrente Contínua Panorama Atual e Perspectivas Futuras no Brasil

2 Madeira HVDC Transmission System Bipole 2 Project and Studies: Relevant Aspects Brazilian SC B4

3 Madeira HVDC Transmission System: LOTE A 44x71,6MW S. Antônio 4x954MCM - TC - 105km Jirau 44x75MW Filtro AC 1575 MVA 1575 MVA Filtro AC Back-to-back I +600kV CC LOTE F Filtro AC 1575 MVA 1575 MVA Filtro AC 400 MVA Rio Branco AbunaUnivers. Pólo MW Pólo MW -600kV CC +600kV CC Pólo MW Pólo MW -600kV CC 3x(-70/100) Mvar S 4x2312MCM 2375km 4x2312MCM 2375km 4x2312MCM 2375km 4x2312MCM 2375km P. Velho Samuel Ariq. J. Paraná P.BuenoVilhena 400 MVA2x954MCM 12 km 41km 150km 165km 118km 160km km 160km 30km LOTE C CE -25/50 Mvar LOTE G LOTE D CE -25/50 Mvar Cuiabá Ribeirãozinho Rio Verde Jauru 364 km 242km 1x750MVA LOTE B 1x136 Mvar 1x750MVA Coxipo MT Trindade Itumbiara Pólo MW Pólo MW LOTE F Pólo MW Pólo MW LOTE C SE Araraquara -120/250 Mvar Araraquara (Furnas) Atibaia 3x1250MVA LOTE E Araraquara (CTEEP)

4 Bipole 2 Configuration: Transmissão em Corrente Contínua Porto Velho 500 kv +600 kv 2625 A 1575 MW Araraquara 500 kv α º 3150 MW γ nom =18.5º 1575 MW -600 kv 2625 A

5 Objectives of the System Engineering Studies: Dimension and specify all the converter station equipment Verify the specified performance requirements of the HVDC transmission system Perform AC and DC protection coordination of the converter station Define the functions and the settings of the control equipment

6 Main System Studies for BP2: Basic Engineering Studies Main Circuit Design Reactive Power Compensation Equipment Design Studies TOV, TRV and Insulation Coordination Circuit Current Requirements AC and DC Filter Rating DC Control and Protection Studies Operation and Control Strategy Switchgear Control and Sequences PSCAD/EMTDC Protection Coordination Study

7 Main System Studies for BP2: Thyristor Valves Studies Valve Electrical and Thermal Design Valve Mechanical Design Redundancies and Reliability System Performance Studies Fundamental Frequency Dynamic Performance (Stability Study) AC and DC Filter Performance (and Inductive Coordination) PSCAD/EMTDC Dynamic Performance Study (DPS) RTDS Dynamic Performance Study (DPS) Subsynchronous Oscillations Radio and Carrier Interference Audible Noise Reliability and Availability (RAM)

8 Main Scheme Parameters: Transmissão em Corrente Contínua Provides the main parameters, the basic steady-state operating modes and the basic control philosophy Quantities determined by the main circuit calculations: Rated power and voltage of the converter transformers Reactances of the converter transformers Range and step size of the LTC of the converter transformers Maximum and minimum values of Vdc, Idc and Pdc for each operating mode, considering measurement errors, control dead-band, etc. Active and reactive power on the AC bus as function of DC current Control angles ranges

9 Main Scheme Parameters: Operating Configurations Transmissão em Corrente Contínua Bipolar (P3 on L3 and P4 on L4) Monopolar with Ground Return (P3/L3 or P4/L4 out of service) Monopolar with Metallic Return (Neutral of P3 on L4) Operating Modes in Bipolar or Monopolar Operation Nominal Voltage (600 kv) Reduced Voltage (420 kv) High Mvar Consumption (High Gamma) Paralleled Converters (P1 // P3 and/or P2 // P4) Paralleled Transmission Lines (L1 // L3 and/or L2 // L4) Crossed Line (P3 on L1 or P4 on L2) Reverse Power

10 Thyristor Valves: Transmissão em Corrente Contínua Type H400 Suspended valves Porto Velho Indoor, air insulated and water-cooled 6 double valves per pole 1 x 12 pulse bridge per pole 7 valve modules in series per valve 83 thyristors per valve (including redundancy) 3 redundant thyristor levels 5 (125 mm) 8.5 kv thyristor with electrical triggering (ETT) Type H400 Suspended valves Araraquara Indoor, air insulated and water-cooled 6 double valves per pole 1 x 12 pulse bridge per pole 7 valve modules in series per valve 78 thyristors per valve (including redundancy) 3 redundant thyristor levels 5 (125 mm) 8.5 kv thyristor with electrical triggering (ETT)

11 H400 Thyristor Valve Module:

12 H400 Thyristor Valve Module: Damping Capacitors Damping Resistors di/dt Reactor Gate Electronics Thyrsitor Clamped Assembly

13 H400 Thyristor Valve Module: Note: Each module comprises 12 or 11 thyristor levels

14 Doublevalve Arrangement: Transmissão em Corrente Contínua 7.5m 5.5m

15 Doublevalve Testing: Transmissão em Corrente Contínua

16 Thyristor Valve Arrangement: 2 poles Porto Velho 6 double valves per pole (12 valves) 7 modules per valve 83 thyristor levels per valve Total = 1992 thyristor leves 2 poles Araraquara 6 double valves per pole (12 valves) 7 modules per valve 78 thyristor levels per valve Total = 1872 thyristor levels

17 Converter Transformers: Transmissão em Corrente Contínua Parameter Winding arrangement Rated power (6-pulse, 3ø) Rated line side voltage Rated valve-winding voltage Tap range Tap step Nominal impedance Design tolerance (absolute) Porto Velho 1-phase, 2-winding 958 MVA 500 kv 258 kv -4.5% to +35.5% 1.25% 0.15 pu ±7.5% Araraquara 1-phase, 2-winding 902 MVA 500 kv 243 kv -6.5% to +33.5% 1.25% 0.15 pu ±7.5%

18 Converter Transformers: Transmissão em Corrente Contínua Porto Velho Y-Y Y Unit

19 Converter Transformers: Transmissão em Corrente Contínua Porto Velho Y-D D Unit

20 Reactive Power Compensation Design: Main Requirements of ANEEL Edital: AC voltage at converter bus: 475 kv < V < 550 kv System frequency: 59.5Hz < f < 60.5Hz Outage of the largest sub-bank of the entire station Reactive power from the AC system (Porto Velho): Limited by a power factor of 0.93 (overexcited) at machines terminals Proportional to the DC power rating of BP2 (3150 MW) Reactive power into the network at Araraquara need to be kept positive Maximum voltage step when switching any reactive power sub-bank: 5%

21 Reactive Power Compensation Design: Questions raised during the project: What should be the available reactive power provided by the AC system at Porto Velho, since the system configuration and important parameters have changed from those of the auction? It was agreed to use the value of the basic design stage, i.e. 705 Mvar How to consider the measurement errors and tolerances? ANEEL Edital is silent on this subject Different approaches have been used for Araraquara and Porto Velho

22 Reactive Power Compensation Design: Questions raised during the project: ANEEL Edital for BP2 (LF-CC) requests that the reactive power compensation considers the outage of the largest sub-bank of the entire station, not of each individual bipole. BP1 should be responsible for the spare sub-bank ANEEL Edital presented no specific requirement for joint operation At low power, a relatively high amount of capacitance for each bipole/b2b independently is required due to harmonic performance restrictions Care should be taken in joint operation to deal with the network capability to absorb this excessive reactive power, self-excitation of generators, etc. Operation restrictions should apply in this case: limit maximum AC voltage, turn-off converters, etc. Joint studies could show that combined performance is satisfactory with lower number of filters (Filter control not in Bipole level, but in Station level)

23 Reactive Power Compensation Design: Porto Velho 247 Mvar HP13/ Mvar HP5/11/ Mvar HP3/13/ Mvar HP5/11/ Mvar HP3/13/40 Total Mvar = 5 x = 1235 Mvar

24 Reactive Power Compensation Design: Porto Velho 662,7 Mvar < 705 Mvar Rdc max Vdcr min within control deadband Vdc error = 0.5% Idc error = 0.5% α error = 1º 1 Xt tol max Vac min f f min

25 Reactive Power Compensation Design: Araraquara 316 Mvar CAP 305 Mvar HP12/ Mvar CAP 305 Mvar HP12/24 Total Mvar = 4 x x = 1852 Mvar 305 Mvar HP12/ Mvar HP12/24

26 Reactive Power Compensation Design: Araraquara ~0 Mvar Rdc min Vdcr min within control deadband Vdc error = 0% Idc error = 0% γ error = 0º 0 Xt tol max Vac min f f min

27 AC Filter Design: Transmissão em Corrente Contínua AC System frequency range: Continuous: 60 ± 0.5 Hz Short duration (20 seconds): 56 to 66 Hz AC voltage range: 475 kv to 550 kv on both terminals AC voltage negative phase sequence: 1% for performance calculations 2% for rating calculations Ambient temperature range: Porto Velho: +18ºC to 36ºC Araraquara: +5ºC to 40ºC

28 AC Filter Design: Transmissão em Corrente Contínua Network impedance was not provided in ANEEL Edital, but after several discussions both BP1 and BP2 have used the same scatter points (but different envelopes) The calculation of Z(w) considered different generation scenarios, single contingencies, system frequency variation, variation of resistance with harmonic frequency, no loads, grouping of adjacent harmonics, etc. Harmonic currents were calculated using non-classical methodology considering AC/DC interaction (ALSTOM s JESSICA) for all harmonics Worst case parameters deterministically combined to maximize the current generation: full range of DC power, AC voltage and control angles; tolerances and asymmetries on converter transformer impedances and control angles; etc. Performance calculated using resonance-method V hc 100 I hc Yfh Ifhc Ynh Inhc ( h ) ( fh + n h ) m a x V m in Y Y Yn Y f Y n11 B f G f -300 Y f 11 n Y Yn11

29 AC Filter Design: Transmissão em Corrente Contínua Harmonic performance requirements: Operating Mode Normal (Bipolar) Reverse Power Parallel Operation Monopolar (metallic or ground return) Reduced voltage (70%) High Gamma (High Mvar) Low ambient Overload Short-time Overload Long-time Overload A B C Requirement AC Network: N and N-1 Filter banks: N and N-1 AC Network: N and N-1 Filter banks: N No requirement

30 AC Filter Design: Harmonic distortion limits: Transmissão em Corrente Contínua Order 3 a Odd Limit (%) Order 0,6% All 0,4% THD = 1,5% Even Limit (%) 0,3% Vh D h = 100% V THD= D h h=2 TIF= 50 h= 1 ( V W ) V 1 h h It was assumed a limit of TIF=50 (not established in ANEEL Edital)

31 AC Filter Design: Transmissão em Corrente Contínua Filter arrangement for Araraquara Relatively strong and welldamped network Low-order filters were not required Broad-band damped filters Capacitors to complement the reactive compensation Common filter design was agreed with BP1 Pre-existing harmonics were considered on rating as harmonic voltage sources

32 AC Filter Design: Transmissão em Corrente Contínua Filter arrangement for Porto Velho 2 x A 247 Mvar 1.84 uf 2.59 uf 12.6 mh 37.7 uf mh 698 Ω 4354 Ω Network with very low damping Wide range of harmonic impedance (90 generators!) Low-order filters were required to avoid severe resonances (mainly at low power) 0.77 uf mh 6822 Ω Use of triple-tuned filters 247 Mvar 3/13/40 Different configuration from BP1 Joint performance was not an issue Rating has considered the differences in filter configuration

33 DC Filter Design: Transmissão em Corrente Contínua ANEEL Edital put responsibility on manfacturer/utility for determining suitable limits of the equivalent disturbing current (Ieq) along the DC line But this is not possible without a detailed inductive co-ordination study (i.e. assess the impact of induced harmonics in all telephone systems) None of the necessary data for this was available at the basic design stage. So the initial Ieq limits were arbitrarily chosen based on previous experience and the DC filters had to be designed according to these limits 1500 ma 2200 ma 4000 ma Bipole operation with all filters available Monopolar, reduced voltage and reverse power operation with all filters available Rare short-time conditions and filter outages A detailed inductive co-ordination study was conducted after filter design and has confirmed the selected limit values of disturbing current assumed for almost all circuits and operating conditions

34 DC Filter Design: DC Harmonic Model Transmissão em Corrente Contínua Return paths for triplen ground-mode currents Three-pulse harmonic model of converters

35 DC Filter Design: Transmissão em Corrente Contínua DC Filter, Neutral Capacitor and Smoothing Reactor Configuration (per pole per station) 50 th filter Common filter filter design design was was agreed agreed with with BP1 BP1 The The smoothing reactor reactor is is split split into into 3 units: units: 1 x 15mH 15mH on on HV HV side side 2 x 150mH 150mH on on LV LV side side Due Due to to the the smoothing reactor reactor arrangement and and to to the the flow flow of of high-order triplen triplenharmonics (noncharacteristics), the the ST50 ST50 filter filter is is (non- connected direct direct to to ground ground

36 DC Filter Design: Transmissão em Corrente Contínua Example of Ieq Profile: Bipolar, 600kV Limit 1500 ma Higher close to the stations Lower away from the stations

37 DC Filter Rating: Transmissão em Corrente Contínua It was noticed that harmonic orders higher than 50th (up to 64th) had an considerable effect on the voltage ratings of reactor L3 of filter Type A (6th/12th/50th) and reactor L1 of filter Type B (50th) This is because both Type A and Type B filters are tuned at 50 th, so higher order harmonics (mainly 63th) have significant impact on the rating Filter Type Reactor Inductance I rss up to 50 th I rss up to 64 th U max up to 50 th U max up to 64 th U cr up to 50 th U cr up to 64 th A (6th/12th/50th) L3 7.9 mh 63 A 63 A 7.3 kvpk 23 kvpk 2.3 kv 11.7 kv B (50th) L mh 34 A 37.5 A 5.1 kvpk 11.8 kvpk 0.9 kv 3.6 kv

38 Basic Control Philosophy: Rectifier Change α to keep constant Idc Transmissão em Corrente Contínua Tap-changer control to keep 10 < α < 16.5

39 Basic Control Philosophy: Transmissão em Corrente Contínua Idc Control Fast Action (a few ms) Rectifier Change α to keep constant Idc Tap-changer control to keep 10 < α < 16.5

40 Basic Control Philosophy: Inverter Transmissão em Corrente Contínua Fast DC voltage control cascaded with slow γ control (γ ORD =18.5º) Tap-changer control to keep kv < Vdcr < kv

41 Basic Control Philosophy: Transmissão em Corrente Contínua Inverter Fast DC voltage control cascaded with slow γ control (γ ORD =18.5º) γ Control Slow Action (hundreds of ms) Tap-changer control to keep kv < Vdcr < kv Vdc Control Fast Action (few ms)

42 Phase Loop Control (Rectifier): I ORDr Normal operating mode V ORD VDCOL I ORDLr LOOP 1 ERR1 Vdc r Idc r Idc AMXORD (165º) LOOP 5 ERR5 α r RVORD (1.1 pu) α Max LOOP 7 ERR7 LOOP SELECTION LOGIC ERR r To the Phase-Locked Oscillator (PLO) Vdc r Vdc Max AORDR (2º) FRAO (120º) 0 >0 Force Retard α r LOOP 8 α Min ERR8

43 Phase Loop Control (Inverter): Normal operating mode To the Phase-Locked Oscillator (PLO)

44 Pole Power Control: Transmissão em Corrente Contínua Power Trim function Short-Time Overload Limiter (STOL) VORD V ORD x P ORD characteristic Current Order Coordination and Telecom Delay I ORD P = V ORD ORD 1 1+ T t s 1 1+ T t s

45 PSCAD Dynamic Performance Study (DPS) Demonstrate that the response of the HVDC scheme to a variety of transient disturbances will ensure stable operation under severe operation conditions Evaluate the dynamic interactions between the HVDC scheme and the associated AC systems Mains aspects of interest: Recovery from faults Commutation failure performance Voltage and frequency control on the AC side Damping of low-frequency oscillations Detail HVDC control system representation, including firing control The study focused on step responses, transformer and filter switching, and AC/DC system faults to demonstrate the recovery capability of the HVDC scheme under minimum and maximum power transmitted conditions

46 PSCAD Dynamic Performance Study (DPS) PSCAD Representation Porto Velho 500kV Converter Bus Porto Velho 230kV Converter Bus Back to Back and 230 kv Network: Model from R2 e1lb e2lb e3lb BTB e1rb e2rb e3rb PV_230kV Porto Velho 230kV AC Araraquara 500kV Converter Bus Port Velho AC System 500kV X Full System A V Bipole 1: Replica of BP2 Bipole 2: Detailed Representation X1A X1B X1C X2A X2B X2C 3150 MW BIPOLE MW AREVA BIPOLE 2 Y1A Y1B Y1C Y2A Y2B Y2C Dynamic Equivalent (17 GVA) Arq2_500 A V Equivalente Araraquara kv

47 PSCAD Dynamic Performance Study (DPS) Bypass inverter during 3ø inverter faults IDCY [H] 1.0 VrmsY 0.6 F3Y 2 T F11Y 2 T F7Y 2 T 0.3 Fault duration t(s) T T T BPY ms 12ms t(s) F9Y 2 2 F2Y T F5Y 2 2 F10Y T F1Y 2 2 F6Y T During commutation failures, inverter is naturally by-passed F8Y 2 T F4Y 2 T F12Y 2 T Controlled by-pass and release improves the performance of commutation and firing pulses synchronization for three-phase faults at inverter [H]

48 PSCAD Dynamic Performance Study (DPS) Bypass inverter during 3ø inverter faults Idc (without Bypass) Idc (with Bypass) Bypass command AR_3Fa.adf: IdcF_Y: Pdc (without Bypass) Pdc (with Bypass) Bypass command

49 PSCAD Dynamic Performance Study (DPS) Gamma Kick based on commutation failure indication Included mainly to deal with remote and non-bolted faults Voltage distortion during the fault period lead to commutation failure during recovery CFY 1 CF duration Gamma kick function extends the commutation margin during voltage recover 0 t(s) γ ord 20 0 Toff=50ms t(s)

50 PSCAD Dynamic Performance Study (DPS) Gamma Kick based on commutation failure indication Pdc (without Gamma Kick) Pdc (with Gamma Kick) ø inverter fault to 70% voltage CFY (without Gamma Kick) CFY (with Gamma Kick)

51 PSCAD Dynamic Performance Study (DPS) Recover from faults to VORD = 0.9 pu VdcX 0.6 VORD Fault duration t(s) Rate = 0.02 pu/s t(s) As part of recovery strategy, DC voltage order (VORD) is recovered to 90% after faults Rump up to 100% is performed slowly Due to frequency control, DC current is increased, which increases overlap and reduces γ With this strategy the inverter remains in DC voltage control to provide more room for damping (rather than γ MIN control) Note: The VORD output is fed only in VDCOL and Phase-Loop Control, not in Pole Power Control

52 PSCAD Dynamic Performance Study (DPS) Power-Frequency Control (PFC) 3 pu/pu f min = 57.5 Hz f max = 63 Hz 6 pu/pu The PFC modulates the DC power order to stabilize the frequency variations at Porto Velho side A high-gain path is added to deal with unsuccessful autoreclosure of faulted lines

53 PSCAD Dynamic Performance Study (DPS) Power-Frequency Control (PFC) Frequency (without PFC) Frequency (with PFC) AR_3F_original.adf: Wmaq_SCF2: Pdc (without PFC) Pdc (with PFC)

54 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara Va Vb Vc AC voltage collapses at inverter side due to solid fault ,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) VLWY:1 VLWY:2 VLWY:3 1,2 1,0 0,8 0,6 CFY A commutation failure starts at the inverter and holds for the whole fault period 0,4 0,2 0,0 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) CFY:1

55 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara 1,50 1,25 1,00 0,75 0,50 0,25 0,00-0, ms PdcX IdcX -0,50 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) PdcF_X:1 IdcF_X:1 Iordrl: IordX AlphaX Idc increases due to commutation failure Inverter control forms a by-pass Rectifier control increases α (over 90 ) DC power reverts due to Vdc reversal Rectifier VDCOL keep Idc flowing during the fault (IMIN=0.5) ,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) Alpha_X:1

56 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara Gamma Kick CFY Inverter control increase γord by 20 (Gamma Kick) ,0 0,4 0,8 1,2 1,6 2,0 AR_3Fa.adf: CFY:1 AR_3Fb.adf: GammaKick_Loop3: GammaY Gamma stays high during power recovery to prevent post-fault commutation failures ,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) Gamma_Y:1

57 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara 1,2 0,9 0,6 0,3 PdcX At fault clearing, no power is being transmitted while filters are still connected. Thus an overvoltage appears. 0,0-0,3-0,6 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) PdcF_X:1 1,3 1,2 1,1 VrmsY During recovery, voltage drops due to increase of DC current and high γ 1,0 0,9 0,8 0,7 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) VrmsY:1

58 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara 63,5 63,0 62,5 62,0 Frequency Due to load rejection, S.Antonio and Jirau machines speed up and frequency rises 61,5 61,0 60,5 60,0 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) Wmaq_SCF2:1 factors: ,2 1,1 1,0 The power-frequency controller (PFC) of HVDC increases Iord to limit the over-frequency The AC voltage drop is aggravated by this increase of DC current 0,9 0,8 0,7 0,6 IordX IordX + PFC 0,5 0,0 0,4 0,8 1,2 1,6 2,0 (file AR_3Fa.adf; x-var Domain) Iordrl:1+DPFC:1 Iordrl:1

59 PSCAD Dynamic Performance Study (DPS) Typical response for a 3ø fault at Araraquara 63,5 62,5 61,5 Frequency After HVDC recovery, voltage and frequency oscillate and stabilize in normal values 60,5 59,5 58, (file AR_3F_original.adf; x-var Domain) Wmaq_SCF2:1 factors: ,5 1,2 VrmsY 0,9 0,6 0,3 0, (file AR_3F_original.adf; x-var Domain) VrmsY:1

60 Conclusions: The converter station equipment has been designed to meet all the performance requirements of the ANEEL Edital and according to the manufacturer practices and international standards The basic project design is under approval process by ONS and the beginning of commercial operation is provisioned to April 2013 Negative aspects of the project: Lack of data, unclear definition of responsibilities and ambiguous requirements of ANEEL Edital Absence of specific requirements for joint operation Difficulty in exchanging models and important information between the manufacturers due to confidentiality aspects The factors above caused many times long-running discussions, re-design during the project and sometimes contractual conflict Besides, important studies such as AC Filters and Dynamic Performance could not be optimized, leaving some degree of risk to the commissioning and commercial operation stage

61 Thank you! Fernando Fernando Cattan Cattan Jusan Jusan Eletrobras Eletrobras Furnas Furnas