Main Transformer Backup Protection: Kyauke Funtakawa da Kungiyar Gajiya na Maimaita Aiki

Gaskiya na Aiki na Iya Da Nuna

Dalilin gaskiya na aiki na iya da nuna shine zama hankali cewa ba za a yi amfani da karamin sashen da ke faruwa saboda abubuwan gaba, ya kunshi aiki a matsayin gaskiya na aiki na mafi girma (busbars ko lines), da kuma a matsayin gaskiya na aiki na mafi girman transformer daga baya idan an samun abubuwan gaba. Gaskiya na aiki na iya da nuna ana amfani a matsayin tafara wajen kasa abubuwan gaba idan aikin mafi girma ko circuit breakers suka rarrabe.

Gaskiya na aiki na iya da nuna na zero-sequence ya shafi transformers a cikin sauran da na'urorin neutral suka duba. Ba yana da muhimmanci a cikin sauran da na'urorin neutral su ba su duba.

Gaskiyoyi na aiki na iya da nuna masu karfi ga transformers sun hada da overcurrent protection, low-voltage initiated overcurrent protection, composite-voltage initiated overcurrent protection, da negative-sequence overcurrent protection. Impedance protection ta shafi kowane lokaci a matsayin gaskiya na aiki na iya da nuna.

Bincike na Sababon Da Zai Haifar Gaskiya Na Aiki Na Iya Da Nuna Ga Transformer

• Directional Overcurrent Protection with Composite Voltage Blocking

• Yawan da ya zama na busbar: Idan ya haifar, wannan ya nuna cewa an samu short circuit a busbar ko feeder line inda aikin mafi girma ta rarrabe.

• Yawan da ya zama na transformer: Idan ya haifar, wannan ya nuna cewa an samu short circuit a downstream busbar ko feeder line inda aikin mafi girma ta rarrabe. Yawanci, ba za a iya haifar aikin mafi girman transformer ba.

• Non-Directional Overcurrent Protection with Composite Voltage Blocking

• Segment I: Idan ya haifar, wannan ya nuna cewa an samu busbar fault. Wannan ya kashe bus tie a lokacin da takwasar da tsawon da ya haifar, da kuma ya kashe local side a lokacin da takwasar da tsawon da ya haifar.

• Segment II: Ana kula da line protection; idan ya haifar, wannan ya nuna cewa line protection ta rarrabe.

• Segment III: Ya shafi Segment II; idan ya haifar, wannan ya kashe tsohon transformer.

• Ya shafi gaskiya na aiki na iya da nuna ga terminal substations.

• A cikin transformers da suka 330kV, composite voltage blocked overcurrent protection a high and medium-voltage side ya shafi large backup, ba da yawan da tsawon da ya haifar, saboda distance (impedance) protection ya shafi sensitive backup (misali, complete shutdown incident a Yongdeng Substation, Gansu, a 330kV).

• Idan yawan da ya zama na medium-voltage side ya shiga system, ya shafi gaskiya na aiki na iya da nuna, ya zama gaskiya na aiki na iya da nuna ga medium-voltage busbar:

• Idan gaskiya na aiki na iya da nuna ga transformer ya haifar da aikin mafi girma ba ta haifar, ya kamata a tabbatar da cewa an samu abubuwan gaba na busbar ko line da ya faɗa, wanda ya haifar gaskiya na aiki na iya da nuna ga transformer.

• Neutral Point Gap Protection: Idan ya haifar, wannan ya nuna cewa an samu system ground fault.

• Zero-Sequence Overcurrent Protection:

• Segment I: Ya shafi gaskiya na aiki na iya da nuna ga grounding faults a transformer da busbar.

• Segment II: Ya shafi gaskiya na aiki na iya da nuna ga grounding faults a outgoing lines.

• Amfani da operating current da time delay ya shafi ko da grounding backup stages ga adjacent components.

Bincike na Tsari na Abubuwan Gaba

• Ba a haifar gaskiya na aiki na iya da nuna ga transformer, adadin marubucin line fault da za a haifar ya fiye da busbar fault. Saboda haka, yanayin a lokacin da a haifar ya shafi cewa a duba cewa line protection ya haifar. A cikin lines da suka 220kV, ya kamata a duba cewa aikin device ta haifar.

• Idan ba a samu signals na protection operation a lines, akwai labaran abubuwa: either aikin mafi girma ta rarrabe a lokacin da an samu abubuwan gaba, ko an samu busbar fault.

• Idan a samu protection operation signals a feeder, kaɗe circuit breaker na corresponding line. Idan a tabbatar da ba a samu abubuwan gaba a busbar da transformer trip switches, yanayin a lokacin da a haifar ya shafi cewa a duba cewa line breaker ta rarrabe.

Kasa da Tattara Abubuwan Gaba

• Daga aikin mafi girma, signals, instrument indications, etc., ya tabbatar da tsari na abubuwan gaba da outage scope. Print fault recording report. Idan station service transformer ta lala, kaɗe zuwa backup station service transformer kuma kafo emergency lighting.

• Kaɗe all feeder switches a de-energized busbar. Idan a samu wanda ba ta kaɗe, kaɗe shi a kan gida. Idan a tabbatar da ba a samu abubuwan gaba a busbar da transformer switches, charge de-energized busbar:

• Idan high-voltage side switch ta haifar, amfani da bus tie switch don charge de-energized busbar (da charging protection engaged).

• Idan medium or low-voltage side switches ta haifar, amfani da main transformer switch don charge busbar (generally, the backup protection time delay should be reduced).

• A cikin substations da double-busbar configuration, idan an samu busbar fault, amfani da cold bus transfer method don move circuit breakers operating a faulty busbar zuwa healthy busbar don restore power.

• Idan kasa fault point ya haifar busbar PT ta lala, kaɗe PT zuwa gida, da kuma charge de-energized busbar. Idan charging ya barce, close PT secondary paralleling switch, da kuma restore power to the lines.

• Idan ba a samu signs of fault or abnormalities a de-energized busbar da lines, da all feeder switches kaɗe, follow dispatch instructions don close main transformer switch and bus tie switch don charge busbar. Idan charging ya barce, disable line auto-reclose and sequentially test-energize each line don identify breaker that failed to operate.

• Ba a haifar gap protection, idan ba a samu equipment abnormalities, await dispatch instructions for handling.

Bayanin Case

A 500kV substation, akwai autotransformers biyu wadanda suke yi aiki a matsayin parallel, kowane da dual protection systems. Idan an samu fault a section of 220kV busbar ko connected line, da kuma corresponding busbar or line circuit breaker (and its protection device) ta rarrabe, gaskiyoyi na aiki na iya da nuna ga transformers biyu—such as impedance protection, directional overcurrent protection with composite voltage blocking, and directional zero-sequence overcurrent protection—za su haifar a matsayin kungiyar don initiate tripping. Bus tie or sectionalizing switch za a kaɗe zuwa gida, ta haka a duba cewa non-faulted busbar sections suke yi aiki a cikin jiki, ta haka za a kasa tsari na outage da kuma a haifar impact of the power interruption.

Aikin mafi girma shine:

• Idan a samu fault a 220kV busbar ko line combined with a failure of the circuit breaker, gaskiya na aiki na iya da nuna ga transformer ya haifar a matsayin kungiyar.

• Gaskiya na aiki na iya da nuna ya kaɗe bus tie or sectionalizing switch zuwa gida don kasa zone na faulted da kuma a haifar fault from spreading to other normally operating parts of the system.

• Strategiya ta haka ta tabbatar da cewa, hakan da aikin mafi girma ta rarrabe, remainder of the system remains protected and unaffected, and the extent of the outage is minimized.

Case ya nuna muhimmancin gaskiya na aiki na iya da nuna a cikin aiki na power grid, particularly in effectively containing the impact of unexpected faults and maintaining the stability and reliability of the power system.