Rahotanni na ƙananan GIS Gas-Insulated Switchgear da aka samu a gaba 35 kV

GIS (Gas-Insulated Switchgear) ya bayar muhimmanci kamar hanyoyi mai kyau, ingantaccen gudanar, amfani da shiga mai kyau, tsari mai tsabta, amfani da shiga biliya, da kuma hanyoyin da ba a iya tabbatar da su. Kuma tana da muhimmanci masu yawan adalawa a cikin al'amuran hanyoyi, yanayin da ma'aikata, da kuma neman lamarin, kuma ana iya amfani da shi a kan masu asa, hakuraren sana'o'i, hakuraren kayayyakin, subways, wind power stations, da sauransu.

Wannan asalin 35 kV indoor substation ta aiki da air-insulated switchgear da ke 10 bays. Wannan ziyartar za a yi ƙara 4 bays. Amma, hanyoyin da aka aiki a zaman lafiya ba zai iya jagoranci na biyu. Ba tare da hakan, idan aka duba shekarun da amfani da abubuwan da suka fito da kuma kyauwar dalilin, an yi retrofit 35 kV substation da SF₆ gas-insulated metal-enclosed switchgear. Hanyoyin da ke aiki a lokacin da aka aiki zai iya jagoranci na biyu, da kuma kyauwar dalilin da amfani da abubuwan zai zama mafi kyau.

Littafin ya yi bincike, daga muhimman abubuwan da ke cikin switchgear, wannan testo suna da: insulation tests da busbar, vacuum circuit breaker tests, voltage transformer tests, current transformer tests, metal oxide surge arrester tests, da kuma power cable tests.

1. Test Item Classification and Sequence Arrangement
Buse Section III na 35 kV substation ana samun double-bus system da ke 14 ZX2-type SF₆ gas-insulated switchgear units. Duk abubuwan da ke magance a cikin cabinets suna da shiga gas-filled enclosures, wanda ya bar da amfani da shiga preventive testing. Saboda haka, testing ya kamata a yi daɗi a yi form test circuits da shiga adjacent switchgear units. Abubuwan da ke magance kamar voltage transformers da busbars suna amfani da plug-in connections. Don in tabbatar da kyauwar dalilin a duk joints, DC contact resistance measurements ya kamata a yi a duk joints. A lokacin da testing, temporary test plugs ya kamata a fi saki don in yi test access points, wanda ya zama karfin testing da kuma workload. Saboda haka, sequence na testing ya kamata a yi daidai don in haɓaka workload. Idan aka duba wasu abubuwa, electrical equipment testing na 35 kV Bus Section III ya kamata a yi da waɗanda suke a cikin cabinets da kuma waɗanda suke a fagen cabinets.

2. Characteristic Tests of Equipment Inside the Switchgear
A cikin cabinet tests suna da biyu. A round na biyu, low-voltage current injection test plugs suna da shiga cable installation sockets a cikin switchgear. A round na biyu, high-voltage test plugs suna da shiga cable installation sockets a cikin switchgear da kuma secured with screws don in introduce test voltage into the equipment under test.

2.1 First Round Tests
2.1.1 Vacuum Circuit Breaker Tests
A wannan round, mechanical characteristic tests da operating mechanism tests suna da shiga kowane circuit breaker dynamic characteristic tester. Waɗanda suke adjacent switchgear units suna da shiga biyu. Three-phase test leads suna da shiga karamin ɗaya, da kuma ɗaya suna da shiga ground. Mechanical characteristics da coil operating voltages na kowane series-connected circuit breakers suna da shiga kawai—i.e., idan aka duba mechanical characteristics na ɗaya circuit breaker, ɗaya circuit breaker suna da shiga closed to serve as the test path. The test method is identical to standard procedures. For the bus-tie breaker bay 9AH, which bridges the main and auxiliary buses of the double-bus system, it can be connected in series with the left-side breaker 10AH and the right-side breaker 8AH (three breakers total) to utilize the test paths of 10AH and 8AH.

2.1.2 DC Contact Resistance Test of Conductive Circuits and Bus Plug Joints
Don in measure the contact resistance of all vacuum circuit breakers, main/auxiliary bus disconnect switches, and main/auxiliary bus plug joints, adjacent switchgear units suna da shiga pairs, amma tested sequentially—i.e., 1AH–2AH, 2AH–3AH, ..., 13AH–14AH. For each pair, when the main (or auxiliary) bus disconnect switches of the two adjacent switchgear units are closed, the three-phase DC contact resistance of the corresponding main (or auxiliary) bus path is measured. A loop resistance tester is used with a test current of approximately 100 A. For example, for the bus-tie breaker 9AH, it can similarly be connected in series with the left-side 10AH and right-side 8AH to form two test paths: 10AH–main bus–9AH–auxiliary bus–8AH and 10AH–auxiliary bus–9AH–main bus–8AH. The test method is the same as for other switchgear units, with resistance values ranging from 200 to 300 μΩ.

2.1.3 Current Transformer Tests
The primary conductive parts of the gas-insulated dedicated current transformers installed inside the cabinet are sealed within the enclosure; therefore, their tests must be completed simultaneously during internal cabinet testing. In this round, ratio tests, polarity checks, and excitation characteristic curve tests are performed first. These tests are carried out using a multifunctional fully automatic comprehensive transformer tester.

For ratio tests and polarity checks: the test circuit configuration is consistent with that of the circuit breaker mechanical characteristic tests—i.e., two adjacent switchgear units are grouped, with their circuit breakers and same-side bus disconnect switches closed. High current is injected phase by phase, and secondary induced currents are drawn from the corresponding secondary current terminals to measure the ratio and polarity of all current transformers connected in series in the loop. The test method is identical to standard procedures.

For the excitation characteristic curve test: this test only requires the primary circuit to be open and can be performed at any time. Considering that it uses the same test equipment and shares the same secondary current terminals as the ratio test—i.e., test current is injected through the corresponding secondary current terminals—it can be performed simultaneously with the ratio test to improve work efficiency.

2.2 Azumi na Kafin Tattaunawa na Zaɓuɓɓuka
A cikin tattaunawa na biyu, an yi azumi na kafin tattaunawa na zaɓuɓɓukan da busbarre kadan-kadan, wato: azumi na kafin tattaunawa na ƙaramin mutanen daɗi zuwa ƙasa da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen, azumi na kafin tattaunawa na ƙaramin mutanen/ƙaramin mutanen mai yawan bayyana daɗi zuwa ƙasa da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen, azumi na kafin tattaunawa na primary to secondary da kuma zuwa ƙasa, da kuma azumi na kafin tattaunawa na duk ƙaramin mutanen/ƙaramin mutanen mai yawan bayyana da kuma abubuwa masu shirya zuwa ƙasa da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen.

An yi amfani da karamin mutanen daɗi tsawon lokaci biyu. A lokacin da farko, ana ƙara ƙaramin mutanen da ƙaramin mutanen mai yawan bayyana a kan fagen daɗi zuwa ƙasa tun daga wata zaɓuɓɓuka da aka zaba—wani haka, an samun zaɓuɓɓukan da ƙaramin mutanen da ƙaramin mutanen mai yawan bayyana. Sannan, an samun zaɓuɓɓukan da ƙaramin mutanen/ƙaramin mutanen mai yawan bayyana, kuma an yi ƙarfin daɗi tsawon lokaci a kan fagen daɗi zuwa ƙasa waɗanda suka fara da zaɓuɓɓukan, don haka ta ƙara ƙaramin mutanen da ƙaramin mutanen mai yawan bayyana a kan fagen.

A lokacin da zaɓuɓɓukan da ke amfani da ita, an yi amfani da ƙaramin mutanen mai yawan bayyana, wanda an yi girma a kan fagen daɗi tsawon lokaci don inganta ƙarfin daɗi tsawon lokaci.

A lokacin da farko da aka yi amfani da ƙarfin daɗi tsawon lokaci zuwa zaɓuɓɓukan, zaɓuɓɓukan ba ce, sannan an yi amfani da ƙaramin mutanen mai yawan bayyana a kan gida (ko kuma a kan gida da ƙasa), don haka ta yi azumi na kafin tattaunawa na primary-to-secondary da primary-to-ground, da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen.

A lokacin da biyu da aka yi amfani da ƙarfin daɗi tsawon lokaci, zaɓuɓɓukan ce, sannan an yi amfani da ƙaramin mutanen/ƙaramin mutanen mai yawan bayyana a kan gida, don haka ta yi azumi na kafin tattaunawa na duk zaɓuɓɓukan zuwa ƙasa da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen.

Don zaɓuɓɓukan mai yawan bayyana na 9AH, za a iya yanayi azumin daɗi tsawon lokaci a kan azumi na kafin tattaunawa na ƙaramin mutanen/ƙaramin mutanen mai yawan bayyana, wadannan za a iya samun lokaci uku. A lokacin da farko, zaɓuɓɓukan da ƙaramin mutanen mai yawan bayyana ce, sannan ƙaramin mutanen mai yawan bayyana ba ce. Ƙaramin mutanen mai yawan bayyana ta ƙara ƙasa tun daga wata zaɓuɓɓuka, kuma an yi amfani da ƙarfin daɗi tsawon lokaci zuwa ƙaramin mutanen a kan wata zaɓuɓɓuka. Sannan, za a iya yi azumi na kafin tattaunawa na ƙaramin mutanen, duk zaɓuɓɓukan zuwa ƙasa, da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen, kamar ya bayyana a Figur 1.

A lokacin da biyu, zaɓuɓɓukan da ƙaramin mutanen mai yawan bayyana ce, sannan ƙaramin mutanen mai yawan bayyana ba ce. Ƙaramin mutanen ta ƙara ƙasa tun daga wata zaɓuɓɓuka, kuma an yi amfani da ƙarfin daɗi tsawon lokaci zuwa ƙaramin mutanen mai yawan bayyana a kan wata zaɓuɓɓuka. Sannan, za a iya yi azumi na kafin tattaunawa na ƙaramin mutanen, duk zaɓuɓɓukan zuwa ƙasa, da kuma daga ƙaramin mutanen zuwa ƙaramin mutanen.

A lokacin da uku, za a iya yi azumi na kafin tattaunawa na ƙaramin mutanen zuwa ƙaramin mutanen. Sannan, ƙaramin mutanen mai yawan bayyana ce, zaɓuɓɓukan ba ce, sannan an yi amfani da ƙaramin mutanen mai yawan bayyana a kan gida. An yi amfani da ƙarfin daɗi tsawon lokaci zuwa ƙaramin mutanen mai yawan bayyana a kan wata zaɓuɓɓuka don yi azumi na kafin tattaunawa na ƙaramin mutanen zuwa ƙaramin mutanen.

3.Azumi na Kafin Tattaunawa na Zaɓuɓɓukan
Don abubuwa masu yawan bayyana, voltage transformers, da cables, duk azumin daɗi tsawon lokaci sun yi ne a baya idan yin amfani.

3.1 Azumi na Kafin Tattaunawa na Metal-Oxide Surge Arrester
Duk zaɓuɓɓukan a ƙaramin mutanen 35 kV Bus Section III (kawai bayan zaɓuɓɓukan mai yawan bayyana) suna da metal-oxide, gapless, shielded, plug-in surge arresters. Azumi na kafin tattaunawa suna yi ne a baya idan yin amfani. An yi amfani da insulation resistance both before and after the test. An yi amfani da DC high-voltage generator, kuma azumi na kafin tattaunawa suna yi ne a kan manufacturer specifications:

• DC reference voltage at 1 mA ≥ 73 kV

• Leakage current at 75% of U₁ₘₐ ≤ 50 μA

A lokacin da azumi na kafin tattaunawa, an buƙata ƙarfin daɗi tsawon lokaci a kan high-voltage terminal of the arrester; kuma, a cikin air, surface flashover zai faru saboda high voltage da small clearance, zai ƙara ƙarfin daɗi tsawon lokaci a kan arrester—don haka, azumi na kafin tattaunawa ba zai iya yi ne, kuma zai taka rawa da ƙarfin daɗi tsawon lokaci.

3.2 Azumi na Kafin Tattaunawa na Voltage Transformer (VT)
An yi amfani da 14 single-phase, plug-in, gas-insulated cabinet-specific voltage transformers a ƙaramin mutanen 35 kV Bus Section III. Bus VTs sun fi ƙarin da line VTs saboda suna da additional residual winding for zero-sequence voltage measurement.

• Ratio and Polarity Tests: An yi amfani da multifunctional CT/VT tester don measure the voltage ratio between the primary winding and each secondary winding (including the residual winding) and verify polarity relationships.

• Excitation Characteristic Curve: An yi amfani da multifunctional CT/VT tester, excitation voltage is applied to the secondary winding, and the excitation curve is recorded at 20%, 50%, 80%, 100%, and 120% of the secondary rated voltage (i.e., 20 V, 50 V, 80 V, 100 V, and 120 V).

A lokacin da azumi na kafin tattaunawa, an buƙata ƙarfin daɗi tsawon lokaci a kan primary high-voltage terminal; kuma, a cikin air, surface flashover zai faru, zai ƙara ƙarfin daɗi tsawon lokaci, kuma zai ba ƙarfin daɗi tsawon lokaci iya yi ne.

• DC Resistance of Windings: An yi amfani da DC resistance of both primary and secondary windings of each VT.

• Ikkar Dabam da Tsarin Kirkiya na AC: Saboda waɗannan VT suka haɗa ne kawai don gas-insulated switchgear, ba zai iya da damar tsari a kan kirkiyarsa a cikin gida. Saboda haka, ba a yi labari da dabam da tsarin kirkiya na AC a kan primary winding. Amma, ana amfani da labari da dabam da tsari mai saukarwa. Wannan labari mai saukarwa zai iya haɗa da labari da tsari mai saukarwa—wadanda ake magance shi a kan secondary side 120 V zuwa lokacin 1 minute.

• Magance 3 kV AC (power frequency) zuwa lokacin 1 minute bayan terminal N na primary winding da duka windings/ground masu yawan.

• Magance 2 kV AC (power frequency) zuwa lokacin 1 minute bayan har primary (ko residual) winding da duka windings/ground masu yawan.

• Labari da Ake Yi a Kan Component Mai Yawanci: Cikakken DC resistance na fuse na primary-side ta har VT da kuma tabbatar da insulation resistance na neutral-point spark gap protector.

4.Halayyar Labari

4.1 Tsari Mai Yawa Ta Hanyar Labari

• Gadiyar gas SF₆ ya zama a kan ƙananan green range.

• Enclosure na switchgear ya zama a kan ground, tare da grounding resistance ta da ma'ana.

• Tabbatar da cewa abubuwan da ake nuna a kan three-position disconnectors da circuit breakers suna daidai.

• Dukkan sockets da ba ake amfani da su a kan equipment under test suka fi sako da insulating plugs.

• A lokutan da ake yi labari da tsarin kirkiya, holes na cable termination, arrester mounting holes, da VT mounting holes a bays receiving voltage suka fi sako da dedicated insulating plugs; areas da ba suka samu energy ba suka buƙata.

• Tabbatar da cewa ends na busbar suka fi sako da insulating plugs da kuma end cabinets suka fi sako da ƙasa.

4.2 Kyakkyawan Labari Masu Kirkiya Masu Yawa
Saboda ba damar tsari na external insulation na VTs a kan gida ba sufi, labari da dabam da tsari mai saukarwa a kan primary winding ya zama a kan labari da tsari mai saukarwa ta yawa, wadanda ba su iya duba tsari mai tsari na standard. Kuma, measurements na DC contact resistance sun nuna total resistance na entire series path—including circuit breakers, disconnectors, bus plug joints, and CT primaries—wanda ke ɗaya da ƙarfin tabbatar da wani component na musamman ya kasance a nan idan total value ta kasance a nan.

4.3 Kyakkyawan Tsarin Labari Masu Kirkiya Masu Yawa
Saboda ba zai iya yi labari da equipment sealed a kan gas-filled enclosures, test circuits suka haɗa da adjacent switchgear units da kuma busbars. Saboda haka, comprehensive testing na entire 35 kV Bus Section III zai iya a yi kawai a lokutan da bus system ta de-energy. Amma, wasu labari suka iya a yi a kan individual de-energized bays:

• Dukkan CT tests (except ratio tests)

• Withstand tests on circuit breaker contact gaps and line-side sections

• Mechanical characteristic tests of circuit breakers (except the bus-tie breaker)

• Dukkan tests on removable components such as cables, surge arresters, and VTs

4.4 Halayyar Ma'aikata na Labari
A lokutan da ake yi internal AC withstand tests, saboda circuit breakers, disconnectors, CTs, and busbars suka haɗa a kan labari, test voltage ya zama a kan lowest withstand rating among them—76 kV (the CT standard)—wanda ke ɗaya da ƙarfin ƙarɓar stress levels for other components. Ba ɗaya ga ake yi labari, original wiring ya zama a kan ƙara ƙara don ba su ka ɗauke ko open circuits.

5.Kammala
High-voltage testing na compact gas-insulated switchgear na kyakkyawan challenges da ƙarfin operational requirements. Saboda haka, fahimta mai yawa a kan characteristics na equipment ita ce muhimmanci. Zabi appropriate test equipment and methodologies tailored to these features, and summarizing effective testing procedures and standards, provides valuable reference and technical basis for resolving similar engineering challenges.