Nini ni Static VAR Compensator (SVC)? Mzunguko na Mchakato katika Korreksi ya PF

Ni ni Static VAR Compensator (SVC)?

Static VAR Compensator (SVC), ambavyo pia inatafsiriwa kama Static Reactive Compensator, ni kifaa muhimu kwa kuongeza power factor katika mifumo ya umeme. Kama aina ya vifaa vya kununua reactive power vya kiwango cha chini, SVC huchakaza au kupata reactive power ili kukidhibiti kiwango cha vizuri la umeme, kutayari uongozi wa grid.

Sehemu muhimu ya Flexible AC Transmission System (FACTS), SVC unajumuisha banki ya capacitors na reactors zinazokidhibitiwa na power electronics kama thyristors au Insulated Gate Bipolar Transistors (IGBTs). Electronics hizi huwezesha kubadilisha haraka capacitors na reactors ili kuchakaza au kupata reactive power kulingana na hitaji. Mfumo wa kidhibiti wa SVC unapofuatilia muda wa umeme na current, ukibadilisha output ya reactive power ya kifaa hilo mara kwa mara ili kuzuia mabadiliko.

SVC zinahusisha kwa kutosha na mabadiliko ya reactive power yanayowekwa kwa maombi ya mizigo au utengenezaji wa muda (kwa mfano, umeme wa upepo au jua). Kwa kuchakaza au kupata reactive power kwa kasi, SVC huzitambua voltage na power factor kwenye point of connection, kutayari uongozi wa umeme wa imani na kuharibu tatizo kama voltage sags au swells.

Ujengo wa SVC

Static VAR Compensator (SVC) mara nyingi una sehemu muhimu ambazo zinajumuisha Thyristor-Controlled Reactor (TCR), Thyristor-Switched Capacitor (TSC), filters, mfumo wa kidhibiti, na vifaa vya msingi, kama ilivyotajwa chini:

Thyristor-Controlled Reactor (TCR)

TCR ni inductor unaoelekezwa kwa upande wa mstari wa kutumia umeme, unachokidhibitiwa na vifaa vya thyristor ili kudhibiti reactive power ya inductive. Inaweza kubadilisha kasi reactive power absorption kwa kubadilisha angle ya firing ya thyristor.

Thyristor-Switched Capacitor (TSC)

TSC ni banki ya capacitor pia imeelekezwa kwa upande wa grid, inachokidhibitiwa na thyristors ili kudhibiti reactive power ya capacitive. Inatoa reactive power injection kwa hatua, ni bora kwa kutambua maombi ya mizigo ya steady-state.

Filters na Reactors

Sehemu hizi huondokana na harmonics zinazotengenezwa na power electronics za SVC, kutayari utaalamu wa umeme. Harmonic filters mara nyingi hutafuta frequency components dominants (kwa mfano, 5th, 7th harmonics) ili kuzuia grid contamination.

Mfumo wa Kidhibiti

Mfumo wa kidhibiti wa SVC unafuatilia voltage na current wa grid kwa muda, ukibadilisha TCR na TSC operations ili kukidhibiti target voltage na power factor. Una controller wa microprocessor unayoprocess data ya sensor na kutuma signals za firing kwa thyristors, kuboresha reactive power compensation ya millisecond-level.

Vifaa vya Msingi

Inajumuisha transformers kwa ajili ya voltage matching, protective relays kwa ajili ya fault isolation, cooling systems kwa ajili ya power electronics, na monitoring instruments ili kutayari uongozi wa imani.

Sera ya Kufanya kazi ya Static VAR Compensator

SVC hukidhibiti voltage na reactive power katika mifumo ya umeme kwa kutumia power electronics, ikifuatilia kama dynamic reactive power source. Hii ndiyo jinsi inavyofanya kazi:

• Kudhibiti Reactive Power
  SVC hunajumuishia TCR (inductive) na TSC (capacitive) kwa upande wa grid. TCR inaweza kupata reactive power kwa kubadilisha angles ya firing ya thyristor, TSC inachakaza reactive power kwa hatua. Uunganisho huu unawezesha bidirectional reactive power control:

• Voltage Sag: Waktu voltage ya grid inapungua, SVC inachakaza capacitive reactive power kwa TSC ili kurusha voltage.

• Voltage Surge: Waktu voltage inapita setpoint, SVC inapata reactive power kwa TCR ili kupunguza voltage.

• Fuatilia Muda & Badilisha
  Sensors hupeleka data ya voltage na current kwa mfumo wa kidhibiti. Controller anahesabu reactive power yenye hitaji na kubadilisha angles ya firing ya thyristor ili kukidhibiti voltage stability kwenye ±2% ya nominal value.

• Harmonic Mitigation
  Action ya switching ya TCR hutengeneza harmonics, ambayo zinavunjika na passive LC filters (kwa mfano, 5th, 7th harmonic filters) ili kutayari grid compliance.

Faida za SVC

• Enhanced Power Transmission: Inongeza capacity ya line hadi 30% kwa reactive power compensation.

• Transient Stability: Damps voltage fluctuations wakati wa faults au mabadiliko ya mizigo, inaboresha resistance ya system.

• Voltage Control: Hunadhibiti steady-state na temporary overvoltages, ni bora kwa integration ya renewable energy.

• Reduced Losses: Inaboresha power factor (maranyundo >0.95), inapunguza resistive losses kwa 10–15%.

• Low Maintenance: Design ya solid-state bila sehemu zenye mzunguko, inapunguza gharama za kazi.

• Power Quality Improvement: Hutangaza voltage sags/swells na harmonic distortion.

Matumizi ya SVC

• High-Voltage Transmission Grids: Huweka voltage kwenye EHV/UHV lines (380 kV–1,000 kV) na kutambua long-line capacitive charging.

• Industrial Plants: Hutanasa power factor kwenye mizigo makubwa ya inductive (kwa mfano, steel mills, mining equipment) ili kupunguza gharama za utility.

• Renewable Energy Integration: Hutangaza voltage fluctuations kutoka wind farms au solar parks.

• Urban Distribution Networks: Huweka voltage stability kwenye eneo lenyenyekeni la watu wenye mizigo yanayobadilika.

• Railway Systems: Hutambua reactive power variations kwenye mifumo ya rail elektriki.