Tahaddarin da Gargajiya na Kofin Kofin Kofin na SF6 na Faduwar Sule da Sabon Inganci Daga Yawancin Aiki a Cikin Kofin Inganci
Maimaito - voltage SF₆ circuit breakers su ke tsari mai yawa da kashi na gida. Su amfani da sabon yanayi da shi da kyau da kuma alamar spring operating mechanisms. Waɗannan circuit breakers suna da muhimmanci, karin zafi, da kuma ingantaccen amincewa. Saboda haka, su fi sani a cikin kontrol da kuma gidaje na maimaito da kashi, ko kuma za su iya zama tie - type circuit breakers.
Sistem 110kV na wata substation ta amfani da wannan nau'o'i na circuit breaker. Amma, idan shekaru mai girma suka ɗauki, ma'anafiyar tushen don duka suka samu nasara. Yana da kyau, abubuwan da take da shi da kyau da kuma tushen energy - storage suka samu nasara sosai. Wannan littafi ya nuna tushen da ya faru a lokacin da waɗannan circuit breakers suke yi rayuwa, kuma ya bayyana masu saƙo da kuma tushen da za su iya yi aiki.
1 Tushen
110kV SF₆ circuit breaker a 220kV substation ta amfani da spring operating mechanism a matsayin energy - storage device. Idan circuit breaker ya ɗauki da kuma tushen closing electrical circuit ya nuna cewa shi ne na zafi, masu aiki suka bayar signal na closing operation. Amma, circuit breaker ba ya ɗauki ba, kuma closing coil ta ya ɗauki. Me kuma yana iya faru wannan tushen da ake da shi da kyau? Don in hana amsa a cikin tushen da za su iya faru, yawanci ya faru ainihi da kuma tushen.
2 Tushen Analysis
A cikin tushen closing control circuit na wannan nau'o'i na circuit breaker, YF shine "local/remote" transfer switch (kamar da Figure 1). Idan an bukata closing da kasa, positive pole na operating power supply ta taka C7→YF contacts 3 - 4→normally closed contacts 31 - 32 of the anti - tripping auxiliary relay 52Y→normally closed contacts 21 - 22 of the spring energy - storage relay 99CN→normally closed contacts 31 - 32 of the relay 49MX→normally closed contacts 31 - 32 of the closing spring status monitoring relay 33HBX→normally closed auxiliary contacts 1 - 2 and 5 - 6 of the circuit breaker→closing coil 52C→normally closed contacts 31 - 32 of the SF₆ gas low - voltage locking relay 63GLX→negative pole na operating control power supply. Idan an kafa power supply voltage a cikin closing coil 52C, electromagnet ta yi aiki don ɗauki circuit breaker.
Daga cikin bayanin tushen, don in closing coil 52C ya ƙunshi, ya kamata da shi da kyau:
Coils of 52Y, 49MX, and 33HBX ba su ƙunshi, kuma normally closed contacts 31 - 32 suka ɗauki a cikin closing control circuit;
Coil of 99CN ba ya ƙunshi, kuma normally closed contacts 21 - 22 suka ɗauki a cikin closing control circuit;
52B ta ɗauki, kuma normally closed auxiliary contacts 1 - 2 and 5 - 6 suka ɗauki a cikin closing control circuit;
Normally closed contacts 31 - 32 of the SF₆ gas relay 63GLX suka ɗauki, kuma suka ɗauki closing control circuit.
Daga cikin bayanin tushen, ita ce idan duka shi da kyau, control voltage za iya ƙunshi a cikin coil, kuma closing coil za iya ɗauki. Idan a duba chassis na farko, ana iya samun cewa SF₆ gas pressure gauge ta nuna zafi, amma mechanical indication of the closing spring ba ta nuna energy storage. Me kuma closing circuit zai iya ɗauki idan ba a gina energy storage? Saboda haka, ya kamata ainihin closing spring energy - storage circuit.
Daga cikin motor energy - storage circuit a Figure 1, idan closing spring na circuit breaker ba ya ƙunshi, normally closed contact C - NC of the energy - storage limit switch 33HB installed on the back of the circuit breaker mechanism ya kontrola 99CN and 33HBX relays simultaneously, kuma suka ɗauki positive pole na DC control power supply:
Spring energy - storage relay 99CN ya ƙunshi kuma ya yi aiki, kuma power supply ta ɗauki motor circuit, kuma closing spring ya ƙunshi don energy storage; a kan haka, normally closed contacts 21 - 22 of 99CN suka rasa a cikin closing control circuit, kuma suka haɓaka circuit breaker ya ɗauki na gaba a lokacin da spring energy -storage process.
Idan coil of the closing spring status monitoring auxiliary relay 33HBX ya ƙunshi, normally closed contacts 31 - 32 of 33HBX connected in the closing control circuit suka rasa. Wannan ya haɓaka cewa a lokacin da spring energy -storage process, secondary closing circuit of the circuit breaker ya ɗauki, kuma akwai dual - locking function da normally closed contacts 21 - 22 of 99CN.
Idan spring energy storage ya ɗauki, mechanical components of the energy -storage mechanism suka rasa normally closed contact C - NC of the energy -storage limit switch 33HB. Coils of 99CN and 33HBX suka ƙare, kuma energy storage ya ƙare. Normally closed contacts 21 - 22 of 99CN and normally closed contacts 31 - 32 of 33HBX suka ɗauki closing control circuit. Daga cikin bayanin tushen, only when 99CN and 33HBX relays su ƙunshi and activated, closing circuit zai iya ƙare. Saboda haka, daga cikin bayanin tushen, ita ce failure of the normally closed contact C - NC of the energy -storage limit switch 33HB shine sababbin motor's inability to store energy.
Maintenance personnel suka buɗe rear cover plate of the circuit breaker mechanism on - site and removed the energy -storage limit switch. Ba a duba da kuma takarda, ana samun cewa internal contacts of the energy -storage limit switch 33HB suka ɗauki a lokacin da energy -storage process, kuma power supply ba za iya ƙare through its normally closed contact C - NC. Saboda haka, coils of 99CN and 33HBX ba su ƙunshi. 99CN contactor ba ya yi aiki, kuma power supply ba za iya ɗauki a cikin energy -storage motor. A kan haka, normally closed contacts 21 - 22 of 99CN and normally closed contacts 31 - 32 of 33HBX suka ɗauki closing circuit for a long time. Saboda spring mechanism of the circuit breaker ba ya ƙunshi and secondary closing circuit ya ɗauki, not only could the circuit breaker not close normally, but the closing coil would also be burned out.
3 Treatment and Modification
Kawai in kawo energy -storage limit switch ba za iya ƙare wannan tushen da ake bayar a cikin wannan littafi. Saboda design da ba daidai da interlocking mechanism da ba daidai, idan energy -storage limit switch ya ɗauki, za iya ƙare tushen a cikin closing circuit. Saboda haka, ake yi amfani a cikin energy -storage and closing control circuits:
(1) Energy -storage limit switch 33HB shine pairs of normally closed contacts and a pair of normally open contacts, with the two pairs of contacts mechanically interlocked. Daga cikin bayanin travel switch, ake yi amfani: Connect the normally closed contact C - NC of 33HB to the coil of 99CN, kamar da Figure 2. Wannan amfani ya ƙare function of the circuit breaker's closing circuit being disconnected and unable to close during the energy -storage process. Connect the normally open contact O - NO of 33HB to the coil of 33HBX. After the spring energy storage is in place, normally open contact O - NO of 33HB closes to connect the coil of 33HBX. At the same time, remove the normally closed contacts 31 - 32 of the relay 33HBX connected in the closing control circuit and replace them with the normally open contacts 43 - 44 of 33HBX. The above modification changes from one pair of contacts controlling two relays to each pair of contacts controlling one relay. This ensures that the closing control circuit cannot be conducted during the non - energy -storage and energy -storage processes. Only after the spring energy storage is in place, when the coil of 33HBX is energized and the normally open contacts 43 - 44 close, can the closing control circuit be connected. At the same time, it also reduces the long - term load on the energy -storage limit switch and extends its service life.
(2) Add a time relay T. Connect the normally closed contacts 31 - 32 of the relay 33HBX in series with the coil of the time relay, and set the operating time limit of the time relay to 15s, which is slightly longer than the spring energy -storage time of the circuit breaker. Adding the time relay can achieve the following: During the 15s when the spring is not energized and during the energy -storage process, the coil of 33HBX is not energized, the normally closed contacts 31 - 32 are closed, and the time relay sends a signal indicating no energy storage. After the spring energy storage is in place, 33HBX is energized and operates, the normally closed contacts 31 - 32 are disconnected, and the time relay stops sending the no - energy -storage signal, indicating that the energy storage is successful.
4 Conclusion
Wannan littafi ta nuna amfani a cikin defects in the control circuit of a 110kV SF₆ circuit breaker. Normally open contact of the energy -storage limit switch is connected in series to the motor control circuit of 99CN, and the normally closed contact of the 33HBX relay connected in series in the closing control circuit is replaced with a normally open contact. This ensures that only when the mechanical components press the energy -storage limit switch 33HB, that is, after the spring energy storage is in place and the 33HBX relay operates, can the closing control circuit be connected.
A kan haka, addition of a time relay provides an alarm function for the energy -storage signal. The modified closing control circuit of the circuit breaker not only has a simple and reliable wiring but also helps operating personnel quickly determine whether energy storage has occurred, effectively preventing the failure of the coil burnout caused by lack of energy storage. After the modification and commissioning, all indicators of the secondary circuit of this type of circuit breaker operate normally, parameter tests are correct, and no abnormal faults occur during opening and closing operations.
