Variable Shunt Reactors. Johann Griebichler I EM TR LPT GTC

Transcription

1 Variable Shunt Reactors Johann Griebichler I EM TR LPT GTC Unrestricted Siemens AG Österreich 2017 siemens.at/future-of-energy

2 Capacitive load and reactive power in grid lines demands for compensation by shunt reactors MW km kv Power Generation Transmission Lines Power Consumption Fluctuations in power generation results in voltage fluctuation Capacitive load depending on line or cable lengths and line loading resulting in varying voltage rise Variable loads at Consumer side causing ohmic or inductive loads and varying voltage drop Installation of shunt reactors as absorber of reactive power to protect connected grid assets against overvoltage and stabilization of grid. The design of a conventional shunt reactor is optimized to a constant load and generation condition. But some situations require more flexible solutions Page 2

3 Typical cases which require a more flexible solution for shunt reactors (variable shunt reactors) Future addition of renewable power generation e.g. wind farms, PV sites Future addition of long transmission lines e.g. in subsequent networks Future switch from overhead lines to cable transmission lines Variable load cycles on consumer side e.g. industrial complexes or daily cycles of AC usage Shunt reactors fitting to various ratings Page 3

4 Increasing dynamics in power grid require operators to provide a flexible reactive power compensation Grids exposed to decentralized and volatile power generation, e.g. by fluctuating in-feed of solar- and wind power rapid extension of renewables very different load conditions in the day- or night time and on working days or the weekend considerable future changes of grid or the conditions requirement of flexible spare unit for shunt reactors in different voltage levels future switch from overhead lines to cable networks sudden load shedding incidents and/or networks operating with no load Grid operators require flexible reactive power needed today and be prepared for the future changes precise adaption of reactive power to varying load cycles (daily & seasonally) flexible device for voltage stabilization and to balance out instabilities Reduced losses, reactor losses when reactor operated at part load, transmission losses by reducing line loading due to precise compensation Increased active power capacity of line low space requirements cost effectiveness in comparison to larger grid extension measures robustness and low-maintenance Variable Shunt Reactors are perfectly adapting to changing network conditions and contributing to increased cost effectiveness Page 4

5 Gain flexibility by adding a tap changer to adapt to changing conditions Static Shunt Reactors Variable Shunt Reactors (VSR) Characteristics: Design concept of fixed shunt reactor cheap and easy ON/OFF device BUT: more expensive than VSR when multiple units placed in parallel Fixed number of windings, optimized on specific load and generation conditions; not adaptable to changed conditions stable load & voltage and a fixed line length required Characteristics: Design concept of variable shunt reactor windings equipped with taps to allow parts of the windings to be switched on or off change of the numbers of windings On-Load Tap Changer to change the number of windings, offering up to % regulation range of power rating low maintenance: OLTC maintenance free up to switching operations Page 5

6 Unique regulation ranges optimized for shunt reactors reached for VACUTAP VRG Siemens trusts in high quality VACUTAP of Maschinenfabrik Reinhausen (MR) Siemens and MR collaborated to reach unique regulation range of: 20% - 100% Q max (at 420 kv) Maintenance free operation up to switching events Life time of diverter switch even operations, leading to minimum life cycle costs Safe and reliable operation proven all over the world 0 + K Maximum voltage for equipment 420 kv 550 kv Maximum control range (% of Q max ) ~ % ~ % Increased regulation rage achieved by series connection of diverter switches and voltage optimized tap selector 800 kv ~ % 0 + K VACUTAP VRG II 1302 of MR Page 6

7 Variable Shunt Reactors contribute to the economical success of grid operators in a changing environment Company Benefits Commercial Benefits flexibility on network changes independence of other grid operators higher reliability for spare units cost efficient solution for flexible reactive power supply less purchase of reactive power reduced losses (reactor, line & all equipment) increased active power capacity of line minimal space requirements vs. other solutions Technical Benefits better network voltage control reduced reactive power loading of the grid Less noise emissions than fixed SHR optimized reactive power compensation Variable Shunt Reactors are perfectly adapting to changing network conditions and contributing to increased cost effectiveness Page 7

8 Business Case: Compensation of reactive power from renewable power generation (1/2) 380 kv line NET Tx 380/110 kv 400 MVA 110 kv cable Renewable generation Project characteristics 50 km 110-kV-cable network of DSO to connect wind (115 MW) and photovoltaic generation (270 MW) TSO DSO No significant load centers in 110kV network [MW] / [MVAr] active power Simulation of daily generation shows active power feed-in 65.8 MVAr max. reactive power demand of 110 kv cable under no load conditions TSO operates the 380 kv overhead line network incl. 380/110 kv NET transformers 150 correlated reactive power demand w/o compensation 0 with VSR -50 with fixed SHR ResTime [h] Apr 01.Apr 02.Apr Active Power Reactive Power Page 8 TSO permits reactive power at point of coupling at reactive power price: 6 ct/kvarh if declared in advance 30 ct/kvarh if not declared Non-compensated reactive power will be transferred through 380 kv grid of TSO (causing additional losses)

9 Business Case: Compensation of reactive power from renewable power generation (2/2) Discounted cash flow (DCF) MEUR T 0 6 (1+0.72%)^month Components of BC calculation Additional Invest for variable shunt reactor 110kV / MVAr Cumulated DCF Value DCF Month ,000 EUR (one time vs. fixed SHR) Conclusions key lever for amortization of VSR at DSO is also reduction in reactive power purchase approx. 3 month payback time (at 6ct./kVArh) Once installed the VSR provides solely monetary benefits in operation In case of fluctuating generation the variable shunt reactor is most profitable choice Assumptions Additional investment of variable shunt reactor 110kV/28-70MVAr vs. fixed shunt reactor 110kV/70MVAr Page 9 Reduced losses from variable shunt reactor (vs. fixed SHR) Reduction in reactive power purchase (vs. fixed SHR) Reduced losses in subsequent NET transformer & 380kV line (380 kv line and Tx from 50 Hertz) Total monthly savings -1,260 EUR (per month) -92,400 EUR (per month) -950 EUR (per month) -94,600 EUR (per month) Reduction of 0.7 MWh per day at POC found by network simulation for standard day extrapolated to a full month Power generation costs of 6ct./kWh (av. of Germany) Reduction of 385 MVArh per day at POC found by network simulation for standard day extrapolated to a full month (4d/month corresponds to load factor of ~13%) Reactive power price 6 ct./kvarh (TSO DSO) Reduction of losses of connected NET transformer & 380kV line of MWh per day (vs. SHR) found by network simulation for standard day extrapolated to a full month Power generation costs of 6ct./kWh (average of Germany) Discount factor for DCF calculation: 9% p.a.

10 Reference for compensation of variable load cycles: 132kV MVAr to Electricity Authority of Cyprus Challenges mastered by use of Siemens VSR: Precise adaption of reactive power supply to varying load cycles at consumer side (daily & seasonally) Preparation of network for increasing renewable generation with even higher volatility Low space requirements (similar to fixed SHR) Substantially lower voltage jumps compared to fixed SHR Page 10 Why Customer decided to buy Siemens: Best ratio of performance and price Reliable supplier with lots of references & high quality standard Proven ability to achieve low noise requirements without external sound house State of the art technology Scope of supply: Customer: Electricity Authority of Cyprus Quantity: 2 units variable shunt reactors Voltage: 132 kv (3 ph. units) Rating: MVAr (18 steps) Losses 1) : 150 kw Sound level 2) : 60.2 db 1) Losses measured in test field, w/o DC & w/o harmonics 2) Sound pressure measured with Intensity method at 0,3 m distance in test field, w/o DC & w/o harmonics

11 Reference for compensation of fluctuating generation: 400kV MVAr to Amprion, Germany Challenges mastered by use of Siemens VSR: High compensation demand due to renewable energies and extension of / switch to cable networks Flexibility for further addition of renewable energy and future switch from overhead lines to cable networks High regulation range necessary for black start capability e.g. after a blackout Page 11 Why Customer decided to buy Siemens: Trusted business partner for product development and R&D collaboration References in variable shunt reactors and high power ratings Scope of supply: Customer: Amprion, Germany Quantity: 5 units variable shunt reactors Voltage: 400 kv (3 ph. units) Rating: MVAr Losses 1) : 425 kw (at 250MVAr / 400kV) Sound level 2) : 97 db 1) Losses measured in test field, w/o DC & w/o harmonics 2) Sound power level

12 Reference for rapid net extension & flexible spare unit: 170kV MVAr to Energienet, Denmark Challenges mastered by use of Siemens VSR: Flexibility for future network changes according to Denmark cable action plan Precise adaption of reactive power supply according fluctuating renewable feed-in One standard equipment fitting for several S/S and ratings Less spare units required Why Customer decided to buy Siemens: Best ratio of performance and price Low noise level References in variable shunt reactors Page 12 Scope of supply: Customer: Energienet, Denmark Quantity: 4x units variable shunt reactors Voltage: 170kV kv (3 ph. units) Rating: MVAr (17 steps) Losses 1) : 130 kw (at 100MVAr / 170kV) Sound level 2) : 83 db 1) Losses measured in test field, w/o DC & w/o harmonics 2) Sound power level

13 Variable Shunt Reactors help you to operate the grid with the maximum flexibility and cost effectiveness Increased grid stability during fluctuating load situations Flexible solution to be ready for future network changes Highly profitable due to reduced purchase of reactive power and lower losses during operation with reduced power rating Economical solution as back-up spare for various shunt reactors Master your challenges with Siemens. Page 13

14 Contact Johann Griebichler Head of Offer Engineering Global Technology Centre for Large Power Transformers Elingasse 3 A-8160 Weiz Mobile: johann.griebichler@siemens.com siemens.at/future-of-energy Page 14