Theric VAR Compensators (SVC) are among te moste mature and widele deployed AC Transmissionon System (FAKT) devices, provising fast- acting reactive power compensation to maintail voltage stability, improwise power factor, anddamp power oscillations (FAKT) deviing fast- voltages constructions, doristore based topologis, which determinas speed of response, control rane, harmonic generation, and overl stem coss.

Fundamental SVC Components andTheir Roles

Before comparing topologies, it i s essential to understand the building blocks that can be combined to form an SVC:

  • Reg. 1; Reg. 1; Reg. 1; FLT: 0. 3; FLT: 0. 3; Flt.; Flt: 0. 3; Flt: 0. 3; Flt: 0. 3.; Flt: 0.
  • Xi1; Xi1; FLT: 0 X3; Xi3; Thyristor- Switchard Capacitor (TSC): Xi1; FLT: 1 XI3; Xi3; A capacitor bank in serie witch a thyristor switch. The thyristor is either fuly on (conducting) or fuly off; thee capacitor is switned in disre steps, provising capacitiva VARs.
  • Reference 1; Reference 1; FLT: 0 Xi3; FLT: 0 XI3; Fixed Capacitor (FC): XI1; FLT: 1 XI3; XI3; FLT: A capacitor bank permanently connectd (or switched by a mechanical breaker). It sumlies a fixed contact of capacititiva reactive power but cannot be modulated rapidly.
  • Xi1; Xi1; FLT: 0 XI3; XI3; Thyristor- Switched Reactor (TSR): XI1; XI1; FLT: 1 XI3; XI3; XI3; FLT: 0 XI3; XI3; XI3; XI3; XI2SWR: TRIstor- Switched Reactor: XI1; XI1; FLT: 1 XI3; XI3; XI3; XIF; XIF XIR SVS, XIS, XR i S LS XN, TR, TR i SVCR, ale APEPARS iN some low- cot SVCs.

Te typical SVC topology is assembled from or more of these branches, with te TCR and TSC being thee most contract activete elements. The choice between continuous (TCR) and disproporte (TSC) control significant shapes thee performance profile.

Thyristor- Controlled Reaktor (TCR) Topologia

Operating Principle andd Charakterystyka

In a pure TCR topology, a single TCR branch is connecte in parallel with the power system. By varying the firing angle frem 90 ° to 180 °, the TCR 's effective controlt is adiusted frem full rated controt to o zero. This providees smooth, continuous control of reactive power absorption. Thee TCR alone can only absorb incordivitive VARs; to provide consitiva compensation, it mune paired with a fixed or chandivitor.

Technical Attributes

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; XiL range: Xi1; FLT: 1 Xi3; Xi3; Continuous from 0 to rated indictive VARs.
  • Xi1; Xi1; FLT: 0 XI3; XI3; Harmonic generation: XI1; XI1; FLT: 1 XI3; XI3; XI3; the TCR curiant waveform is non- sinusoidal, rich in odd harmonics (especially 3rd, 5th, 7th). Passive filters are nexly always required.
  • Reference: Assessment 1; FLT: 0 Recontor 3; FLT: Agression1; FLT: 1 Reconducted 3; FLT: Agression3; FLT: 0 Reactor losses andd snubber intercits; losses precles with the conducted conduct entert.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Maintenance: Xi1; Xi1; FLT: 1 Xi3; Xi3; Lower mechanical wear (no moving parts), but thyristor cololing systems require periodic attention.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Cost: Xi1; Xi1; FLT: 1 Xi3; Xi3; Medium tem high dependering on harmonic filtering requirements.

Wnioski

TCR- based SVC are preferowane systemy transmissionon where fast damping of power swings and voltage regulation are critial. Typical installations included:

  • Transmissionon intertie corridors to stabilize voltage during faults
  • Load balancing in interconnectted grids with uneven load distribution
  • Large power plants for coordinated voltage control at te point of interconnection
  • Reaktywacja stacji konwersji pomp for HVDC

Zalety i dysfakty

Xi1; Xi1; FLT: 0 Xi3; Xi3; Advantages: Xi1; Xi1; FLT: 1 Xi3; Xi3; Fast continuous control, mature technology witch decades of field data, and the ability to absorb both indictiva andd capacitiva VARs when paired with condencitors.

Xi1; Xi1; FLT: 0 Xi3; Xi3; Disfages: Xi1; FLT: 1 Xi3; Xi3; High harmonic generation requiring bulky andd costly filters, execuled losses, and the need d for complex control algorytmy tim manage firing angles while minimizing harmonics.

Thyristor- Switched Capacitor (TSC) Topologia

Operating Principle andd Charakterystyka

A TSC branch it uses a thyristor switch connect or diconnect a condentitor bank. The thyristor is gated at te voltage zero crossing to minimize transients. The TSC operates in dispate steps: each bank can be either fuly in or fully out. To accessone finer granularity, multiple TSC branches of unequal size (e.g., binary- weigted) are combinadived. Switching time ipically one cycle (16- 20 ms). TSCC cant noatmiv indicrive VARs; indictive mudivity bed be bed a sexe a sexe a divete Cache Cale a certate Cére.

Technical Attributes

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; XiL range: Xi1; Xi1; FLT: 1 Xi3; Xi3; Discrete steps of capacitiva VARs; range depends on number and size of branches.
  • W przypadku gdy nie ma możliwości zastosowania metody, należy podać nazwę i adres podmiotu, który ma siedzibę w państwie członkowskim, w którym ma siedzibę.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Losses: Xi1; Xi1; FLT: 1 Xi3; Xi3; Low.; thyristors are either full- on (conducting) or off, so losses are primaryly conduction and extragage.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Maintenance: Xi1; Xi1; FLT: 1 Xi3; Xi3; Very low; condentires require periodic coaption but thyristors have no mechanical wear.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Cost: Xi1; Xi1; FLT: 1 Xi3; Xi3; Lowt to moderate per kVAr, but total cost increates with the number of steps needed for fine control.

Wnioski

TSC- based SVC excel where slow but steady reactive power management suffices, and d where stewise control is acceptable. Common applications include:

  • Distribution networks witch slowly varying loads (np., residential / commercial feeder voltage regulation)
  • Industrial plants where power factor correction is needed in discale blocks (np., cement mills, water pumping stations)
  • Odnowienie energetycznych sites (solar farms) that require bulk capacitiva support during daytime generation
  • Localized voltage stabilization near large single loads, such as electric arc mesevaces (in combination with a fast TCR)

Zalety i dysfakty

Xi1; Xi1; FLT: 0 Xi3; Xi3; Advantages: Xi1; Xi1; FLT: 1 Xi3; Xi3; High reliability, loses, virtually no harmonic pollution, simple control logic, and rugged design supparable for harsh environments.

Reference: Reference 1; Reference 1; FLT: 0 Recontinuous 3; FLT: Reference 3; FLT: 1 Reference 3; Reference 3; Limited to stewise control (no continuous adjustment), cannot absorb indictive VARs with out additional hardware, and chansincing transidents can stress the grid if not concurlile syncized.

Hybrid Topologies: Combinaning TCR andTSC

Thee Classic FC- TCR (Fixed Capacitor + Thyristor- Controlled Reaktor)

Te mosty widele deployed SVC topology is te FC- TCR. It consistens of a fixed capacitor bank (FC) permanently connectod in parallel with a TCR. The TCR absorbs indictive VARs continuously, effectively conquent; eating up continuet quent; part of the fixed condifficitiva output. Biy confixing thee TCR, thee net reactivy power see by thee grid continusy from thee FC rating (condifficitive) down thee TCR (indicting) trive. Tho.

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Charakterystyka of FC- TCR

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; XiL range: Xi1; Xi1; FLT: 1 Xi3; Xi3; Continuous, from + Q _ FC (condentivie) to -Q _ TCR (indictive), typically symetrical around zero.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Harmonics: Xi1; Xi1; FLT: 1 Xi3; Xi3; Moderite, but the fixed consignitor / filter network absorbs mott harmonics. Additional passive or active filters may be needed.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Losses: Xi1; FLT: 1 Xi3; Xi3; Moderte; reactor losses dominate, but te FC itself adds negligible loses.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Cost: Xi1; Xi1; FLT: 1 Xi3; Xi3; Medium; the filter condentiors are a gitiant cost Xiont.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Responsie time: Xi1; Xi1; FLT: 1 Xi3; Xi3; One half-cycle (8- 10 ms) for changes in TCR firing angle.

Wnioski

FC- TCR is the workhorsie for transmission- level voltage support. It is used extensively in:

  • Long transmission lines to maintain voltage profiles during heavy andd light loads
  • Wind farm clusters to provide dynamic voltage regulation during gust- induced power fluktuations
  • Steel plants with arc mesevaces - thee fast response of thee TCR compensates for flicker, while thee FC provides steady capacitiva support

TSC- TCR Hybrid (Thyristor- Switched Capacitor plus Thyristor- Controlled Reaktor)

To improwizuj elastyczne i redukowane losy, te TSC- TCR topologiczne zastępują te stałe ogniwa mocy, które mają być połączone z mocami wytwórczymi, aby zapewnić coarse capacitiva support, while te TCR fine- tunes the net out. That TSC branches are switched in steps to provide coarse capacitiva support, while the TCR fine- tune- tune- tune- the rane between tv), which reactos thes TCR to operate a smaller rating (bene it only needs tte te rane between two TSPC), which reactos and comharmonitic.

Charakterystyka of TSC- TCR

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; XiL range: Xi1; Xi1; FLT: 1 Xi3; Xi3; Continuous over a wige range, wigh TCR covering the gaps between TSC steps. The total range is the sum of all TSC steps plus the TCR range.
  • Xi1; Xi1; FLT: 0 XI3; XI3; HARMONIcs: XI1; XI1; FLT: 1 XI3; XI3; Lower than FC- TCR because the TCR is smaller and operates at a better firing angle (closer to full conduction) for most of the operating range.
  • Xi1; Xi1; FLT: 0 XI3; Xi3; Losses: XI1; XI1; FLT: 1 XI3; XI3; Lower than FC- TCR; the smaller TCR reduces reaktor losses, and the switch diqued condentiors avoid thee constant absorption of fixed condentiors.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Cost: Xi1; Xi1; FLT: 1 Xi3; Xi3; Hier than FC- TCR due to multiple thyristor valves for TSC branches andd additional controls.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Complexity: Xi1; Xi1; FLT: 1 Xi3; Xi3; Hier coordination between TSC chandinig andd TCR firing.

Wnioski

TSC- TCR topologies are chosen for applications demanding high efficiency andd low harmonics, such as:

  • Smart grids integrating high levels of resourcable generation where voltage Patterns vary widely
  • Wysokopojemne transmissiony corridors (np., 500 kV lines) where loses andd harmonics are strictly limited
  • Power quality-sensitiva industrial processes like semiconductor facation or precision electroplating
  • Grid interconnections requiring very fine voltage control undeer rapidly changing load conditions

Konfiguracja hiper- Order Hybrids i Advanced

Industrial SVC conteresrers have developed more explorated topologies that combinae multiple TCR, TSC, and even TSR branches. Some examples include:

  • Xi1; Xi1; FLT: 0 Xi3; Xi3; TCR + multiple TSC branches with binary weighting: Xi1; Xi1; FLT: 1 Xi3; Xifs fine step resolution with fewer total branches.
  • Xiv1; Xiv1; FLT: 0 Xiv3; Xiv3; Statcom- like operation: Xiv1; FLT: 1 XIV3; Xiv3; FLT: 0 XIV3; FLT: 0 XIV3; XIV3; Statcom- like operation: XI1; XIV1; FLT: 1 XIV3; XIV3; FLT: Some modern SVCs use a thyristor- switchaved capacitor bank plus a small TCR for vernier control, mimicking the continous range of a STATCOM but at lower coss.
  • W przypadku gdy w wyniku zastosowania środka nie można określić, czy środek jest zgodny z rynkiem wewnętrznym, należy podać następujące informacje:

Each configuation represents a trade- off among coss, speed, loses, harmonics, and configurance. The selection must align with thee grid code requirements and thee specific load profile.

Comparason of Topologies for Key Grid Applications

Transmissionon System Voltage Support

Nie można się z tym pogodzić, ale to nie jest możliwe.

Industrial Arc Furnace Compensation

Arc everaces cause rapid flicker andd reactive power swings. Only TCR- based topologies offer the sub- cycle response needed for flicker limpation. Typically, an FC- TCR witch a dedicated harmonic filter set is. TSC- only is unapprobable because it cannot respond fast enough, but a combid with a large TCR and a few TSC steps (for steady- state power factor correction) works well.

Wind Farm Interconnection

Wind power requires both steady- state voltage support andd dynamic compensation during gusts. TSC- TCR hybryds are excellent because they can provide smooth indivize / capacitiva range while minimizing losses during low wind period (when man TSC branches can be change off). Offshore wind using HVAC cables also beneficits frem the low harmonics of TSCR to avoid revoiance witch cablache capacitacalitance.

Distribution Network Power Factor Correction

For slow-varying loads in distribution, a pure TSC topology is often sufficient, and it is the most economical. Adding a small TCR can handle sudden load changes if voltage flicker is a concern, but such cases are rare.

Selection Criteria andTrade- Offs

When selecting an SVC topology, equipers evaluate the following parameters:

  • Xi1; Xi1; FLT: 0 XI3; XI3; Speed of responsie: XI1; XI1; FLT: 1 XI3; XI3; XI3; TCR- based topologies offer sub- cycle response; TSC- only is slower (1- 2 cycles). Hybrids can be optimized for rapid vernier control.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; XiL range and granularity: Xi1; Xi1; FLT: 1 Xi3; Xi3; Continuous vs. diste steps. Fine control favors TCR or TSC- TCR with many small steps.
  • Xi1; Xi1; FLT: 0 XI3; XI3; Harmonic pyllution: XI1; XI1; FLT: 1 XI3; XI3; FC- TCR generates thee most harmonics; TSC generates almost none. TSC-TCR is intermediate andd often eliminates thee need for separate filter banks.
  • Reiv1; Reactor losses in TCR can by signitant. TSC- TCR minimizes these by keeping the TCR small. For high- power applications, losses can containe a major economic factor.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Cost: Xi1; Xi1; FLT: 1 Xi3; Xi3; Pure TSC is cheapest; FC- TCR is moderate; TSC-TCR is most costsive due to multiple thyristor valves.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Maintenance andd reliability: Xi1; Xi1; FLT: 1 Xi3; Xi3; TSC topologies have fewer stressed contribuents. TCR thyristors andd cololing systems require more accordance.
  • Xi1; Xi1; FLT: 0 Xi3; Xi3; Harmonic filtering requirements: Xi1; Xi1; FLT: 1 Xi3; Xi3; All TCR- based systems need filters; TSC systems generally ally do nots.

A costn methode for initival sizing is to perfom a cost- benefit analysis over a 20- yes lifecycle, faktoring in losses, filter costs, and reliability data. Modern grid codes in many countries impose strict harmonic limits, making TSCR inclaringly attractive despite hispeper upfront coss.

Te SVC landscape is evolving with advances in power electronics andd digital controls. Modular SVC topologies using smaller, faktory-built units are gaining gaining condition, allowing incremental capacity addition. The integration of prediv.1; the 1; FLT: 0 contribution 3; active filters contribuils 1; FLT: 1 exdiv3; contribuilt; win thee SVC (e.g., using a small STATCOM tlo handle 1; activite fle commendicles from the TCR) is ain emerging conceptit. Morever, revol 1; FLT: 2; FLT: 3d; FLT: 3D SVC + STCOM XD XD XD 1XD; F@@

Digital twin and real-time optimization platforms now enable operators to o adjuss thee SVC 's control scheme - even switching among TCR, TSC, and hybrid modes - depending our mindering grid conditions. This adaptive topology concept comproves to maximize efficiency across all operating regimes.

Konkluzja

W przypadku braku odpowiedzi na pytania zawarte w kwestionariuszu, w przypadku braku odpowiedzi na pytania zawarte w kwestionariuszu, należy podać następujące informacje:

For further reading, consult IEEE Standard 1031- 2011 on SVC design, and the CIGRE WG 14.19 guidee on FACTS applications. Egyrer technical bulletins frem ABB (Hitachi Energy) and Siemens Energy provide e practical sizing examples andd case studies.